Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Abstract

We present herein the synthesis of novel pseudo‐metalla‐carbaporphyrinoid species (1M: M=Pd and Pt) achieved through the inner coordination of palladium(II) and platinum(II) with an acyclic N‐confused tetrapyrrin analogue. Despite their tetrapyrrole frameworks being small, akin to well‐known porphyrins, these species exhibit an unusually narrow HOMO–LUMO gap, resulting in an unprecedentedly low‐energy absorption in the second near‐infrared (NIR‐II) region. Density functional theory (DFT) calculations revealed unique d_π‐p_π‐conjugated electronic structures involving the metal d_π‐ligand p_π hybridized molecular orbitals of 1M. Magnetic circular dichroism (MCD) spectroscopy confirmed distinct electronic structures. Remarkably, the complexes feature an open‐metal coordination site in the peripheral NN dipyrrin site, forming hetero‐metal complexes (1Pd‐BF₂ and 1Pt‐BF₂) through boron difluoride complexation. The resulting hetero metalla‐carbaporphyrinoid species displayed further redshifted NIR‐II absorption, highly efficient photothermal conversion efficiencies (η; 62–65 %), and exceptional photostability. Despite the challenges associated with the theoretical and experimental assessment of d_π‐p_π‐conjugated metalla‐aromaticity in relatively larger (more than 18π electrons) polycyclic ring systems, these organometallic planar tetrapyrrole systems could serve as potential molecular platforms for aromaticity‐relevant NIR‐II dyes.

DOI： 10.1002/anie.202405059

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jinorgbio.2023.112435

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Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

Abstract

The reaction of 2-nitro-3,3′-bi(1-benzothiophene) bearing ester groups at 7- and 7′-positions under the Cadogan cyclization conditions (PPh3, o-C6H4Cl2, refl.) afforded the targeted 10H-di(1-benzothiopheno)[2,3-b:3′,2′-d]pyrrole-1,8-dicarboxylate derivative in a low yield accompanied with a byproduct. On the other hand, the Cadogan reaction of 2-nitro-3,3′-bi(1-benzothiophene) without ester groups did not provide the corresponding pyrrole but gave a mixture of thiophene-ring-opening products, from which dibenzothiophenothiopyrans were isolated. The structures of these ring-opening products were fully characterized by spectroscopic and X-ray analyses and the generation mechanism giving the byproducts was deduced. Pristine 10H-di(1-benzothiopheno)[2,3-b:3′,2′-d]pyrrole could be prepared via another route, namely nitrosation followed by cyclization and reduction.

DOI： 10.1093/bulcsj/uoae010

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Other Link： https://academic.oup.com/bcsj/article-pdf/97/3/uoae010/56957275/uoae010.pdf

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsaom.3c00400

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Publishing type：Research paper (scientific journal)  

Stable neutral metal radicaloid complexes have been synthesized from a modified tetrapyrrolic pigment, bilatriene, with iridium(I) and rhodium(I) cyclooctadiene (COD) synthons. The bilatriene skeleton contains α-linked conjugated pyrrole units, whereas an N-confused analogue used in this work possesses β-linked pyrrole moieties at the terminal, demonstrating a unique metal binding capability. Unprecedentedly, the metal-COD cations are accommodated at the outer nitrogen sites, which induced the formation of open-shell metal-radicaloid species. The resulting compounds are highly stable under ambient conditions and demonstrated facile redox conversion to afford the corresponding cation and anion species. Furthermore, the radicaloid complexes showed a distinct second near-infrared absorption (NIR-II) capability extending up to 1500 nm along with high photostability. These features emphasized that the complexes can be potential NIR-II light-responsible photothermal and photoacoustic imaging contrast agents based on the metal-radicaloid dye platform.

DOI： 10.1002/anie.202418751

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

Pyrones and their aromatic ring-fused derivatives have gained significant attention due to their diverse biological activities and potential as foundational frameworks for advanced materials. In this paper, we describe a proficient approach for the preparation of azuleno[1,2-c]pyran-1-ones, which are difficult to produce by using conventional methods. The synthesis was achieved through Bro̷nsted acid-mediated cyclization of 2-azulenylalkynes. The structural and optical properties of azuleno[1,2-c]pyran-1-ones were characterized by single-crystal X-ray analysis, NMR, UV/vis, and fluorescence spectroscopies. Under acidic conditions, these compounds displayed notable spectral alterations and emission, distinct from their spectra in neutral medium. These results suggest that azuleno[1,2-c]pyran-1-ones hold great potential for applications in organic electronic materials and fluorescent pH sensors.

DOI： 10.1021/acs.joc.3c01742

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Publishing type：Research paper (scientific journal)  

The synthesis and biological studies of a series of Pd(II)dipyrrinato complexes are reported. The thiogalactosyl and/or oligoethyleneglycol moieties were linked with themeso-aryl rings of the Pd(II)dipyrrinato complexes. The Pd(II)dipyrrinato complexes were characterized by MASS, IR, UV-Vis, and NMR spectroscopic techniques. Single crystal X-ray structure of the homoleptic Pd(II)dipyrrinato complex (Pd1) revealed typical square planar geometry around the metal center. The anti-bacterial studies of Pd(II) dipyrrinato complexes were performed on theM. Tuberculosis H37Rv and M. Bovis BCG strains and complex Pd4 showed excellent anti-TB activity with MIC values of 25 μM and 12.5 μM, respectively. The ease of synthesis and good MIC values of Pd(II)dipyrrinato complexes make them promising candidates for anti-TB activity.

DOI： 10.1142/S108842462350089X

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Brønsted acid-mediated intramolecular cyclization of 2-amidoazulene derivatives, prepared by the reaction of 1-cyano-2-aminoazulene derivatives with perfluoroalkyl acid anhydrides, resulted in the formation of 2-perfluoroalkylazuleno[2,1-d]pyrimidin-4(3H)-ones. Heating of these products in phosphoryl chloride led to 4-chloro-2-perfluoroalkylazuleno[2,1-d]pyrimidines. We also evaluated the reactivity of these pyrimidin-4(3H)-ones and pyrimidine derivatives toward the electrophilic and nucleophilic substitution reactions, revealing that a variety of functional groups can be incorporated into these derivatives. The NMR studies, NICS calculations, and single-crystal X-ray structure analyses revealed structural features including the bond-length alternation of the azuleno[2,1-d]pyrimidin-4(3H)-ones and pyrimidine derivatives.

DOI： 10.1002/adsc.202300371

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

DOI： 10.1039/D2SC07037E

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.joc.3c00196

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Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Ltd  

Two blueish materials were obtained in the acid-catalyzed condensation of 5-pentafluorophenyldipyrromethane-1,9-bis{(petafluorophenyl)-methanol} with 4,8-dihydro-4,8-ethanopyrrol[3,4-f]isoindole followed by oxidation, although the yields were low. Their structures were unambiguously determined by the X-ray analysis. One was ethylene-connected bisdipyrromethene and another was bicyclo[2.2.2]octene-crosslinked dihydrohexaphyrin, which was gradually transformed to benzene-crosslinked hexaphyrin under air in solution via bicyclo[2.2.2]octadiene-crosslinked hexaphyrin. The benzene-crosslinked hexaphyrin was directly obtained in the similar acid-catalyzed condensation procedure of the dipyrromethane with 4,8-dihydropyrrol[3,4-f]isoindole, although the yield was also low.

DOI： 10.1142/s1088424623500980

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.orglett.3c00876

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.orglett.3c00848

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Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Ltd  

Cyclo[8]pyrrole–phosphonate complexes were synthesized via the anion exchange method from cyclo[8]pyrrole sulfate. The molecular structures were determined by X-ray diffraction studies.

DOI： 10.1142/s1088424623500438

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Ltd  

Bicyclo[2.2.2]octadiene(BCOD)-fused 5,15-diazaporphyrins were synthesized via a metal-template aza-annulation of dipyrrin-metal complexes as a soluble precursor of tetrabenzodiazaporphyrin. 10-Azacorrole copper complex with a meso-imine bridge was serendipitously obtained via the same reaction using dimethylBCOD-fused dipyrrin-copper complex.

DOI： 10.1142/s1088424623500074

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Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Ltd  

A ring-opening of nickel 10,20-dimesityl-5,15-dioxaporphyrin (NiDOP) proceeded in a reaction with aryl Grignard reagents to afford 1,9-diaryldipyrrins instead of demetallation reaction to form a free base form. A reagent scope for the ring-opening reaction revealed that reactions with less-sterically hindered aryl Grignard reagents, such as phenyl and para-substituted phenylmagnesium bromides, provided the dipyrrin products. In contrast, no reaction occurred, and unreacted NiDOP was recovered when alkyl, ethynyl, and 2-thienylmagnesium bromides and sterically hindered mesitylmagnesium bromide were used for the reactions. Herein, the unique ring-opening reactivity of NiDOP and characterization of the 1,9-diaryldipyrrin products are reported.

DOI： 10.1142/s1088424623500293

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Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Ltd  

Novel cobalt(III) complexes of N-confused porphyrin (5,10,15,20-tetrakis(penta-fluorophenyl)-2-aza-21-carbaporphyrin) and its 3,3[Formula: see text]-linked dimer, Co1 and Co2, were synthesized and their structures were elucidated by X-ray crystallographic analysis and NMR spectroscopy. The redox properties of the complexes were examined by electrochemical approaches, and the corresponding oxidized/reduced species were analyzed by spectroelectrochemistry and DFT calculations. Notably, due to the facile redox feature of the N-confused porphyrins, ligand-centered oxidative/reductive processes were assumed for Co1 and Co2 presumably as inferred from the spectral analyses. These results indicate the unique multi-electron reservoir capability of the metal complexes of the N-confused porphyrin dimer.

DOI： 10.1142/s1088424623500281

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Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Ltd  

DOI： 10.1142/s1088424623500232

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/ange.202212726

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Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Ltd  

DOI： 10.1142/s1088424622500869

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Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Ltd  

DOI： 10.1142/s1088424622500900

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Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Ltd  

Novel site-selective hetero-copper(II)/zinc(II) complexes of a cisoid-configured doubly N-confused dioxohexaphyrin analog (c-ZnCu-2 and c-CuZn-2) were synthesized and characterized. The resulting heterometal complexes exhibited a unique near-infrared (NIR) absorption feature, and the facile redox-active properties originated from the large 26[Formula: see text]-conjugated structure. The distinct difference between the site-dependent c-ZnCu-2 and c-CuZn-2appeared in the specific structural parameters of the d⁹ copper centers in the electron paramagnetic resonance spectra and the Lewis acidity of the zinc centers upon the base-titrations. These complexes have potential for the hetero-metal-containing [Formula: see text]-material applications that respond to the NIR light.

DOI： 10.1142/s1088424622500456

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/anie.202212726

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

A σ-bonded platinum(II) diketopyrrolopyrrole (Pt-DPP) complex was synthesized from a reaction of p-pinacolatoborylphenyl-substituted DPP with dichloro(1,5-cyclooctadiene)platinum(II), followed by a ligand exchange reaction with triphenylphosphine. The Pt-DPP complex is highly fluorescent not only in solution but also in the solid state. From the comparison of the emission properties with those of N-benzyl-DPPs bearing phenyl and p-bromophenyl substituents, the intense emission of the Pt-DPP complex is ascribed to the DPP-centered fluorescence. In the solid state, aggregation-caused quenching is mitigated by the well-segregated molecular packing due to the bulky triphenylphosphine ligands. The facile synthesis and unique fluorescence properties of the Pt-DPP complex are beneficial for creating DPP-based functional chromophores.

DOI： 10.1002/ejic.202200081

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ejic.202200081

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

The synthesis of 8-aryl-2H-cyclohepta[b]furan-2-ones was accomplished by the Suzuki-Miyaura coupling of arylboronic acids with the triflates prepared from an 8-hydroxy-2H-cyclohepta[b]furan-2-one derivative. The 8-aryl-2H-cyclohepta[b]furan-2-ones were converted to 4-arylazulenes via an [8 + 2] cycloaddition reaction with the enamine prepared from acetaldehyde and diethylamine. The optical properties of 4-arylazulenes were characterized by UV/Vis and fluorescence spectra.

DOI： 10.1246/cl.220076

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Publishing type：Research paper (scientific journal)  

A series of luminescent Ir(iii) dipyrrinato complexes were synthesized having various aromatic chromophores at the C-5 position of dipyrrin ligands. The presence of different chromophores on the Ir(iii) dipyrrinato complexes altered their optical properties and produced strong emission in the red to NIR region (680-900 nm) with huge Stokes shifts (5910-7045 cm−1). TD-DFT studies indicated significant charge distribution between dipyrrin ligands and Ir-cyclometalated units in all the molecules. X-ray crystal structures revealed an octahedral geometry of the Ir(iii) center in the complex. The in vitro studies of the glycosylated Ir(iii) complexes revealed strong photoluminescence with maximum Stokes shifts, and they showed significant photocytotoxicity in skin keratinocyte (HaCaT) and lung adenocarcinoma (A549) cells. The singlet oxygen generation quantum yields of glycosylated Ir(iii) complexes were in the range of 70-78% in water. The estimated IC50 values were between 17 and 25 μM after light exposure, and confocal microscopy revealed significant localization of the glycosylated Ir(iii) complexes in the endoplasmic reticulum (ER) of cancer cells. The neutral Ir(iii) dipyrrinato complexes are promising tracking agents for cellular imaging in the biological window and for photodynamic therapy (PDT) applications.

DOI： 10.1039/d1dt04218a

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Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

Tropo(thio)ne-embedded homoHPHACs and their dications were synthesised by an electrophilic annulation of secoHPHAC and successive oxidation. 13C NMR spectra of the dications represented global 22π homoaromaticity via homoconjugation, while alkylation...

DOI： 10.1039/d1cc07152a

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Publishing type：Research paper (scientific journal)  

1,4-Phenylene-linked cyclotrimer (3T) and cyclotetramer (4T) have been synthesized via Lewis acid-catalyzed self-condensation of appropriate precursors. Structural and Density Functional Theory (DFT) studies reveal the disruption of annulenic conjugation in both 3T and 4T by linking phenylene rings prevented them from global antiaromaticity. The single crystal X-ray structure of 4T reveals all the nitrogens are pointing toward the macrocyclic core with near-planar and square-shaped geometry, thus in sharp contrast to the ring-strained conformation of 3T.

DOI： 10.1021/acs.orglett.1c03903

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

A rigid wing-shaped bicyclo[2.2.2]octadiene-fused bis-hexapyrrolohexaazacoronene (HPHAC) is synthesized, and subsequent chemical oxidation affords a stable biradical dication and an aromatic tetracation. The physicochemical properties and single-crystal structures in various oxidation states are characterized. The face-to-face π-stacked dimeric structures are observed in the neutral and dicationic states. The HPHAC flakes can act as aromatic walls in a tetracation state, producing enlarged induced magnetic shielding space through the superimposition effect.

DOI： 10.1021/acs.orglett.1c03669

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

A “3+3” condensation reaction of 1,3-di(2-pyrrolyl)azulene with aryl aldehyde followed by an oxidative aromatization afforded diazuliamethyrin, [24]diazulihexaphyrin(0.1.0.0.1.0). X-ray diffraction analysis revealed a relatively planar structure of diprotonated diazuliamethyrin with a mean plane deviation of 0.37 Å. A 24π non- or antiaromatic character was confirmed by 1H NMR, absorption, MCD spectra, and TD-DFT calculations that included the NICS values and ACID plots.

DOI： 10.1021/acs.orglett.1c03882

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Publishing type：Research paper (scientific journal)   Publisher：The Chemical Society of Japan  

DOI： 10.1246/cl.210381

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/chem.202101755

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/chem.202101755

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

DOI： 10.1021/acs.organomet.1c00314

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Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Lt  

An ether cleavage reaction of A₂B-type subporphyrin bearing an ortho-anisyl substituent afforded a phenolate-bridged dimer. A head-to-tail structure of the dimer was unambiguously elucidated by single crystal X-ray diffraction analysis. UV-vis absorption and magnetic circular dichroism spectra indicated a minor interaction between the subporphyrin chromophores. Density functional theory calculations provided a detailed insight into the electronic structures of the subporphyrin dimer.

DOI： 10.1142/s1088424621500796

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Publishing type：Research paper (scientific journal)  

In this study, we report the emissive properties of a heteroleptic cyclometalated Ir(iii) complex, [Ir(bzq)2(PBO)] (bzqH = benzo[h]quinoline; PBOH = 2-(2-hydroxyphenyl)benzoxazole). The complex, [Ir(C^N)2(N^O)], was synthesised and optically resolved using a chiral column. Two geometrical isomers,trans-(N,N) andcis-(N,N) isomers, were obtained as the major and minor products in an enantiopure form, respectively. Their molecular structures were determined using single crystal X-ray analysis. In the crystalline states, the intermolecular C-H⋯π interaction between PBO−and an H atom in bzq−was the main factor influencing molecular packing. When the complexes were dissolved in CH2Cl2and excited at 430 nm under N2atmosphere, yellow (λmax= 550 nm) and orange emissions (λmax= 570 nm) were observed for thetrans-(N,N) andcis-(N,N) isomers, respectively, with the quantum yield higher for the former than the latter.

DOI： 10.1039/d1dt00783a

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N-fused porphyrin (NFP) is a unique class of photostable near-infrared dyes with an 18π aromatic tetrapyrrole macrocyclic skeleton containing a tri-fused pentacyclic moiety. Here, the synthesis of an iridium complex of N-fused bilatrienone is reported as the degradation product of Ir-cyclooctadiene (cod)-induced oxidative cleavage of NFP under aerobic conditions. Similar to the native bilin chromophores, the ring-opened complex featured a broken π-conjugation circuit and exhibited a broad visible absorption band. In contrast, metalation of NFP using an iridium(I)(cod) complex under an inert atmosphere resulted in the formation of a cod-isomerized (κ1,η3-C8H12)-Ir complex.

DOI： 10.1002/chem.202100789

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Monomeric α-Keggin-type polyoxotungstate-coordinated mono- and di-palladium(II) complexes, i. e., Cs5[α-PW11O39{PdII(Me2ppz)}] ⋅ 5H2O (Cs-1) (Me2ppz=N,N’-dimethylpiperazine), [(CH3)4N]4H[α-PW11O39{PdII(Me2ppz)}] ⋅ 8H2O (TMA-1), and Cs2.5H0.5[α-PW11O39{PdII(en)}2] ⋅ 7H2O (en=ethylenediamine) (Cs-2), were synthesized by 1 : 1 or 1 : 2 stoichiometric reactions of mono-lacunary α-Keggin polyoxotungstate [α-PW11O39]7− with PdCl2(Me2ppz) and PdCl2(en) in aqueous solution. Subsequent purification from water afforded these compounds as analytically pure homogeneous yellow precipitates. Single-crystal X-ray structural analysis of Cs-1 revealed that a palladium(II) moiety, i. e., [Pd(Me2ppz)]2+, was coordinated to two oxygen atoms in the mono-vacant site of [PW11O39]7− with an asymmetric configuration, resulting in an overall C1 symmetry. With regard to the crystal structure of Cs-2, two palladium species of the [Pd(en)]2+ type were coordinated to two oxygen atoms in the mono-vacant site with symmetric configuration, resulting in an overall Cs symmetry. A unique structural transformation of the mono-lacunary α-Keggin structure of Cs-1 to the di-lacunary γ-Keggin polyoxotungstate Cs7[γ-PW10O36] was observed upon the addition of cesium chloride.

DOI： 10.1002/ejic.202100075

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Cyclo[9]pyrrole, a ring-expanded porphyrin without meso-bridges and having an odd number of pyrroles, was synthesized via the oxidative coupling of 2,2′:5′,2″-terpyrrole. X-ray crystallography showed a C2-like symmetry with a large root-mean-square deviation. The optical properties and electronic structures were analyzed using magnetic circular dichroism spectroscopy and time-dependent density functional theory calculations.

DOI： 10.1021/acs.orglett.1c00899

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Inner-and peripheral-metal complexation behaviors of 5,10,15-tris(pentafluorophenyl)-20-pyrrolyl N-confused porphyrin (5) and its meso-pyrrolyl-bridged dimers (6-Ni and 7-Ni) were studied in this work. The resulting inner-Ag and peripheral-BF2 complex (5-AgBF2) exhibited the bathochromically shifted absorption feature (72 nm), which was attributed to the BF2 complexation. Furthermore, the bis-Ag/Ni complexes of dimer (6-Ag2Ni and 7-Ag2Ni) revealed remarkably lower energy bands in the deeper near-infrared (i.e. NIR-II) region (λmax = 1226 and 1042 nm, respectively) through strong interchromophore interactions.

DOI： 10.1142/S1088424621500255

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A facile synthetic strategy towards conformationally stable chiral chromophores based on dimeric porphyrinoids has been established. A peculiar class of face-to-face intramolecularly interlocked corrole dimers were formed by the oxidative C−C coupling linked at the inner carbon sites upon simple treatment of copper(II) ions. Their intrinsic electronic structures were modulated by the peripheral corrole ring annulations, which lead to distinct optical properties and redox profiles. The stereogenic carbon centers implemented in the confused corrole skeleton provided a rationale for designing novel chiral materials.

DOI： 10.1002/asia.202100083

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A bright near-infrared (NIR) fluorescent molecule was developed based on the donor–acceptor–donor (D–A–D) approach using an aza-BODIPY analog called pyrrolopyrrole aza-BODIPY (PPAB) as an electron-accepting chromophore. Directly introducing electron-donating triphenylamine (TPA) to develop a D–A–D structure caused redshifts of absorption and emission of PPAB into the NIR region with an enhanced fluorescence brightness of up to 5.2×104 m−1 cm−1, whereas inserting a phenylene linker between the TPA donor and the PPAB acceptor induced solvatochromic behavior in emission. Transient absorption spectra and theoretical calculations revealed the presence of a highly emissive hybridized locally excited and charge-transfer state in the former case and the contribution of the dark charge-separated state to the excited state in the latter case. The bright D–A–D PPAB as a novel emitter resulted in a NIR electroluminescence with a high external quantum efficiency of 3.7 % and a low amplified spontaneous emission threshold of ca. 80 μJ cm−2, indicating the high potential for NIR optoelectronic applications.

DOI： 10.1002/chem.202005360

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Radially π-extended hexapyrrolohexaazacoronene (HPHAC 2) was synthesized in two steps with 2,5-di-tert-butyl-acenaphtho[1,2-c]pyrrole and hexafluorobenzene. Like its parent HPHAC 1a, 2 exhibited reversible oxidation behavior. Crystal structures of not only the neutral and dicationic compounds but also the radical cation were all revealed. While analyzing its peculiar structure, the formation of a 1:1 complex with C60 was observed in solution by NMR and absorption analyses. The spectroscopic analyses of 2 and 1a were performed based on magnetic circular dichroism and theoretical calculations.

DOI： 10.1021/acs.joc.0c02825

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Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

<p>Ring rotation of ruthenium(<sc>iv</sc>) N-confused porphyrin μ-oxo-dimer was controlled by protonation at the peripheral nitrogen moieties.</p>

DOI： 10.1039/d1ra05063j

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Symmetrical octaphenyltetrabenzoporphyrins 3 were synthesized via cyclotetramerization from bicyclo[2.2.2]octadiene (BCOD)-fused pyrrole, followed by a thermal conversion based on retro DielsAlder reaction. X-ray diffraction analysis revealed that the zinc complex 3b had C4h symmetry.

DOI： 10.1246/CL.210045

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Bicyclo[2.2.2]octadiene(BCOD)-fused dithiaamethyrin 4 was synthesized via a "3+3"condensation method. Thermal conversion of the BCOD moieties afforded tetrabenzodithiaamethyrin 5. The highly planar structures of 4 and 5 were confirmed by X-ray diffraction studies. The 1H NMR, absorption and MCD spectra, together with TD-DFT calculations revealed that both BCOD-fused and -extended dithiaamethyrins have a 24 antiaromatic character.

DOI： 10.1142/S1088424621500966

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© 2020 American Chemical Society. All rights reserved. Performing bottom-up synthesis by using molecules adsorbed on a surface is an effective method to yield functional polycyclic aromatic hydrocarbons (PAHs) and nanocarbon materials. The intramolecular cyclodehydrogenation of hydrocarbons is a critical process in this synthesis; however, thus far, its elementary steps have not been elucidated thoroughly. In this study, we utilize the metal tip of a low-temperature noncontact atomic force microscope as a manipulable metal surface to locally activate dehydrogenation for PAH-forming cyclodehydrogenation. This method leads to the dissociation of a H atom of an intermediate to yield the cyclodehydrogenated product in a target-selective and reproducible manner. We demonstrate the metal-tip-catalyzed dehydrogenation for both benzenoid and nonbenzonoid PAHs, suggesting its universal applicability as a catalyst for nanographene synthesis.

DOI： 10.1021/acs.nanolett.0c03510

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© 2020 Wiley-VCH GmbH Quinoidal dimeric porphyrin dye synthesis exhibiting second near-infrared (NIR-II) absorbability is described herein. A precisely designed meso-pyrrolyl-substituted N-confused porphyrin possesses a distinct metal coordination site at the periphery. Nickel metalation of this compound led to the oxidative C−H coupling between adjacent α-pyrrole rings, affording two dimeric complexes, which exhibited intense NIR-II absorptions ranging from 1000 to 1400 nm. As was evidenced by decreased aromaticity, the quinoidal resonant structures contributed to the emergence of photoacoustic spectral capabilities in the NIR-II window. Thus, the potential of these compounds as prototypical contrast agents in various bioimaging applications has been demonstrated.

DOI： 10.1002/chem.202002406

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© 2020 American Chemical Society. Nuclear magnetic resonance (NMR) spectroscopy cannot be used to discriminate enantiomers, and NMR resonances of enantiomeric mixtures are generally not affected by enantiomeric excess (ee). Here, we report that a coordination complex (L 2Zn 3C), where L is a salen-like prochiral ligand and C is an exchangeable acetate coligand, exhibits symmetrical splitting of one of the 1H NMR resonances of L with the degree of splitting linearly proportional to ee of the chiral guest coligand C, 2-phenoxypropionic acid. Despite the well-defined chirality in the crystal structure of L 2Zn 3C, concurrent fast chiral inversion and coligand exchange in solution renders L 2Zn 3C the primary example of prochiral solvating agent (pro-CSA) based on a coordination complex. Notably, the NMR resonances remain split even in dilute solution due to the lack of chiral guest dissociation in the coligand exchange system. This work provides new insights into chiral transfer events in metal-ligand complexes.

DOI： 10.1021/acs.jpclett.0c02284

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© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The synthesis of organometallic complexes of modified 26π-conjugated hexaphyrins with absorption and emission capabilities in the third near-infrared region (NIR-III) is described. Symmetry alteration of the frontier molecular orbitals (MOs) of bis-PdII and bis-PtII complexes of hexaphyrin via N-confusion modification led to substantial metal dπ–pπ interactions. This MO mixing, in turn, resulted in a significantly narrower HOMO–LUMO energy gap. A remarkable long-wavelength shift of the lowest S0→S1 absorption beyond 1700 nm was achieved with the bis-PtII complex, t-Pt2-3. The emergence of photoacoustic (PA) signals maximized at 1700 nm makes t-Pt2-3 potentially useful as a NIR-III PA contrast agent. The rigid bis-PdII complexes, t-Pd2-3 and c-Pd2-3, are rare examples of NIR emitters beyond 1500 nm. The current study provides new insight into the design of stable, expanded porphyrinic dyes possessing NIR-III-emissive and photoacoustic-response capabilities.

DOI： 10.1002/anie.202006026

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© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim A copper complex of a heterocorrole analogue with an N–N linkage, 1,19-diaza-21,24-dicarbadibenzocorrole (Cu-5), was successfully synthesized via oxidative metalation–cyclization of a tetrapyrrolic precursor. The N–N linkage in the skeleton of Cu-5, which serves as a mediator of π-electron delocalization, features an 18π aromatic system. The electronic structure of Cu-5 is best described as a ground-state singlet species stabilized by the distinct NNCC coordination core. This finding shows how the ligand's design can be used to modulate the Cu (Formula presented.) orbital energy, thereby making such compounds invaluable for copper-based catalytic applications.

DOI： 10.1002/anie.202005167

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/ange.202005167

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/ange.202006026

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.jpca.0c04779

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© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Beta-pyrrole-substituted porphyrin dyads connected by ethynyl linkage to N-butylcarbazole or triphenylamine donors are reported. Donor-π-acceptor type beta-substituted porphyrin dyads and their Zn(II) and Pd(II) complexes were characterized by MALDI-MS, NMR, UV-vis absorption, fluorescence and cyclic voltammetry techniques. The S1 emission dynamics were analyzed by time-resolved spectroscopy (TCSPC); dyads exhibited efficient energy transfer up to 93% from beta-donors (N-butylcarbazole or triphenylamine group) to the porphyrin core. The efficiency of energy transfer for the beta-substituted porphyrin dyads were much higher than those of the corresponding meso-substituted porphyrin dyads, reflecting enhanced communications between the beta-donors and the porphyrin core. The Pd(II) dyads, showed characteristic phosphorescence in the near IR region and very efficient singlet oxygen quantum yields (53–60%); these dyads are promising candidates for photocatalytic oxidations of organic compounds. The donor-acceptor interaction between the porphyrin core and the beta-donors was supported by the DFT studies in the porphyrin dyads.

DOI： 10.1002/asia.202000463

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Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Hexapyrrolohexaazacoronene (HPHAC) is one of the N-containing polycyclic aromatic hydrocarbons in which six pyrroles are fused circularly around a benzene. Despite the recent development of HPHAC analogues, there is no report on direct introduction of functional groups into the HPHAC skeleton. This work reports the first example of nitration reaction of decaethylHPHAC. The structures of nitrodecaethylHPHAC including neutral and two oxidized species (radical cation and dication), intramolecular charge transfer (ICT) character, and global aromaticity of the dication are discussed.

DOI： 10.3390/molecules25112486

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A bicyclo[2.2.2]octadiene(BCOD)-fused bis(dipyrromethane) derivative was reacted with methylal in the presence of trifluoroacetic acid followed by oxidation with chloranil to give a doubly N-confused phlorin derivative, which did not undergo the retro-Diels–Alder reaction extruding an ethylene molecule on heating. In contrast, a 7-tert-butoxybicyclo[2.2.1]heptadiene(7-BuOBCHD)-fused bis(dipyrromethane) yielded benzene-ring-fused doubly N-confused porphyrins by following similar reaction sequences.

DOI： 10.1002/chem.202000339

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/chem.202000339

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© 2020 Elsevier Ltd This work is focused on the design and synthesis of donor-acceptor pairs comprising of aza-BODIPY and tetraphenylethene (TPE) fluorogens with large pseudo Stokes shifts (386–424 nm). Femtosecond transient absorption spectroscopy, single crystal X-ray technique and TD-DFT studies were used to get more insight about their spectral behavior. As compared to the tetra-phenylaza-BODIPY, the four aza-BODIPYs exhibited 50–90 nm red shifted absoprtion and emission spectra. When the donor-acceptor architectures were excited at 300 nm, the aza-BODIPY unit emitted strong fluorescence in red region. This suggested an intramolecular energy transfer between donor (TPE) and the aza-BODIPY acceptor; with 81–90% energy transfer efficiencies. Femtosecond transient absorption studies also supported energy transfer process in the molecules, with 3.7 ps time constant associated with it. Aggregation studies in THF/n-heptane solution showed hypsochromic shifts in the aggregated form; X-ray packing structures indicated H-type aggregates (slip angle > 54.7°) in the solid state. Scanning electron microscopy (SEM) measurement revealed 200–700 nm size sphere shaped structures in the aggregated forms.

DOI： 10.1016/j.dyepig.2020.108249

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.tetlet.2020.151724

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© 2020 Shimada et al. A series of α- and β-ethynyl-substituted BODIPY derivatives (3a, 4a, 5a, 5b, 6a, 6b) were synthesized by gold(I)-catalyzed direct C–H alkynylation reactions of dipyrromethane and BODIPY, respectively, with ethynylbenziodoxolone (EBX) in a regioselective manner. Depending on the position of the ethynyl substituent in the BODIPY skeleton, the photophysical properties of the resulting α- and β-substituted BODIPYs are notably altered. The lowest S0–S1 transition absorbance and fluorescence bands are both bathochromically shifted as the number of substituents increases, while the emission quantum yields of the β-ethynylated derivatives are significantly lower than those of α-ethynylated ones. The current method should be useful for fine-tuning of the photophysical properties of BODIPY dyes as well as for constructing BODIPY-based building cores for functional π-materials.

DOI： 10.3762/bjoc.16.53

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© 2020 American Chemical Society. An expanded metalloporphyrin-based "black dye" Au-Pd oxohexaphyrin (AuPd-1) with absorption capabilities across the visible-to-near-infrared (NIR) range was synthesized. This black dye, AuPd-1, possessed efficient light-harvesting and photostable capabilities, which were indicative of superior photothermal (PT) conversion abilities. Encapsulation of AuPd-1 with a micellar nanocapsule resulted in a compound that demonstrated intense photoacoustic (PA) properties in the NIR region in water. This finding indicated how metal (d)-ligand (π) molecular orbital interactions in metalloporphyrins could aid in the design of visible-to-NIR light-harvesting black dyes for PT and PA applications.

DOI： 10.1021/jacs.0c01824

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© 2020 American Chemical Society. We investigated the detailed photophysical properties of a series of bis-metal (Zn and Cu) dioxohexaphyrin complexes as potential second near-infrared (NIR-II)-light responsive dyes. A cisoid-configured 28π-electron-conjugated dioxohexaphyrin analogue (c-3a) containing two peculiar "confused pyrrole" moieties in the framework is identified as a reduced isomer derivative of a transoid 26π-dioxohexaphyrin (t-2a). The symmetry-altered structure of c-3a affords a heteroleptic inner environment within the NNNN/NNOO donor core, which imparts its highly flexible electronic features and nonplanar geometry. The macrocycle c-3a can be transformed into the corresponding 26π-electron congener (c-2a) having a coplanar rectangular structure by unique solvent-mediated redox reactivity. Furthermore, upon metal complexation, saddle-distorted bis-metal complexes (c-M2-2a) were formed as the 26π-conjugated structural isomer of the trans-dioxohexaphyrin species (i.e., t-M2-2a). These isoelectronic dioxohexaphyrins demonstrate precise geometry-dependent photophysical properties. Broad tailing NIR-II absorption, weak emissive character, and rapid-decay of the S1 state are observed for c-Zn2-2a. In contrast, the coplanar t-M2-2a exhibits efficient photoacoustic response upon laser excitation with NIR-II light (λ > 1000 nm). To the best of our knowledge, this is the first example of an expanded porphyrin-based photoacoustic contrast agent responsive to NIR-II light.

DOI： 10.1021/jacs.9b13475

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© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Incorporating tungsten into the N3 core of a N-fused porphyrin (NFP; 1) affords high-valent tungsten(VI)-NFP complexes, WClO2-1 and 21-chlorinated WClO2-3. The X-ray structure of WClO2-1 reveals a distorted octahedral geometry with sitting atop metal coordination. The absorption spectrum of WClO2-1 displays bathochromically shifted Q-like bands beyond 1000 nm, indicating an inherently narrow HOMO-LUMO energy gap. DFT calculations show that the degeneracy of the LUMO and LUMO+1 pair of 1 is significantly resolved by the tungsten(VI) coordination. Conclusively, magnetic circular dichroism (MCD) spectroscopy and cyclic voltammetry provide a rationale for the narrow HOMO-LUMO energy gap in the “16-electron” d0 tungsten(VI)-NFP complexes.

DOI： 10.1002/asia.202000014

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Pyrrolopyrrole aza-BODIPY analogues (PPABs) are a new class of UV/vis and near-infrared chromophores. Varying the substituents results in red-shifts of both the absorption and emission spectra. Extension of the lengths of the oligothiophene substituents from thiophene to quaterthiophene caused red-shifts of the absorption and emission from 699 and 712 nm to 809 and 853 nm, respectively. The piperidylthiophene-substituted PPAB exhibited similar red-shifts of the absorption and emission to 810 and 831 nm, respectively, although only a single thienyl component is present, because of the strong electron-donating nature of the piperidine substituent.

DOI： 10.1002/cplu.201900226

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Copyright © 2019 American Chemical Society. An antiaromatic cation of the expanded hexapyrrolohexaazacoronene (HPHAC) 1+ was synthesized by a Vilsmeier-type reaction of the partially unfused HPHAC 2. X-ray diffraction analysis revealed the formation of a seven-membered ring with a methyne linkage between the pyrrole moieties. Although 1+ is a monocation, upfield shifts of the peripheral ethyl protons were clearly observed in the 1H NMR spectra, indicating 24πantiaromaticity. Global antiaromaticity was also supported by nucleus-independent chemical shift and anisotropy of the induced current density calculations. Cation 1+ displayed two reversible oxidations and one irreversible reduction in the cyclic voltammetry measurements. Treatment of 1+ with NOSbF6 gave aromatic trication 13+ with 22π-electron conjugation.

DOI： 10.1021/jacs.9b09260

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

© 2019 Elsevier Inc. The facile synthesis of water-soluble mitochondria targeting thioglycosylated BODIPYs is reported. Thioglycosylated BODIPYs were synthesized in 25–26% yields via thioglycosylated dipyrromethanes in four steps. The dipyrromethanes and thioglycosylated BODIPYs were characterized by various techniques including HRMS, NMR spectroscopy and X-ray crystallography. In-vitro cellular investigations in skin keratinocyte (HaCaT) and cervical (HeLa) cancer cells revealed significant cytotoxicities with IC50 values between 23.83 to 48.61 μM. The flow cytometry experiments revealed significant cellular uptake of thioglycosylated BODIPYs into HaCaT cells and thioglucosyl substituted BODIPY (9) showed higher cellular uptake and ROS generation than the rest of the molecules. The highlight of this study is the mitochondrial targeting by the neutral BODIPYs, as judged by the colocalization experiments using confocal microscopy.

DOI： 10.1016/j.bioorg.2019.103139

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© the Partner Organisations. The reaction of several azulenylalkynes having an aryl substituent with elemental sulfur afforded the corresponding azuleno[2,1-b]thiophenes in moderate to good yields. Decarboxylation of an azuleno[2,1-b]thiophene derivative with an ester function was also achieved by treatment with 100% H3PO4. The structural features of the azuleno[2,1-b]thiophene derivatives were revealed by X-ray single-crystal analysis. The optical and electrochemical properties of the azuleno[2,1-b]thiophene derivatives were investigated by UV/Vis spectroscopy, voltammetry experiments and theoretical calculations.

DOI： 10.1039/c9qo00593e

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Bis(1,3-dithiol-2-ylidene)-substituted subtriazachlorin was formed because of an unusual reaction of a 1,3-dithiole-2-one-fused subphthalocyanine in a triethylphosphite-mediated tetrathiafulvalene synthesis. In this novel molecule, the bis(1,3-dithiol-2-ylidene)ethane moiety and subtriazachlorin structure are fused, resulting in an electron-donating ability and broad absorption in the near-infrared region.

DOI： 10.1002/anie.201905331

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/ange.201905331

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© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim A series of free-base and phosphorus(V) complexes of tetrabenzoporphyrin (TBP) and some phosphorus(V) porphyrins containing four or eight phenyl groups on the periphery have been synthesized and characterized by X-ray crystallography, electronic absorption, and magnetic circular dichroism (MCD) spectroscopy, together with quantum chemical calculations. All phosphorus TBP and meso-tetraphenyl porphyrin complexes adapted ruffled conformations due to the small P(V) ion, although the Zn(II)TBPs containing eight phenyl (Φ) groups at the so-called β and α positions showed planar and saddled structures in the solid state, due to, respectively, marginal or severe steric hindrance between the neighboring Φ groups. All P(V)TBPs showed the Soret and Q bands beyond 450 and 700 nm, respectively, which are some of the longest wavelengths exhibited by metallated TBPs reported to date. Of the eight Φ group-substituted P(V)TBPs, those substituted at α positions always showed absorption bands at longer wavelengths than those at β positions, which was reproduced by calculated absorption spectra. The Soret band positions of meso-tetraphenylated P(V) species without fused benzo-groups (ca. 430–440 nm) were also some of the longest among metalloporphyrins of this type.

DOI： 10.1002/ejoc.201900528

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© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Three types of ruthenium(II) N-confused porphyrin (NCP) complexes bearing an axial 2-thiopyridine, 2-pyridone, and 2-iminopyridine moiety at the inner carbon atom, respectively, were synthesized. The unique reactivity of the 2-substituted pyridine derivatives (2-X-pyridine; X=SH, OH, NH2) toward the inner carbon atom of the NCP allows the formation of two types of coordinated products (i. e., pyridine donor versus 2-heteroatom donors), as inferred from single-crystal X-ray structures. The selective reactivity was investigated by using density functional theory (DFT) calculations. Finally, the catalytic activity of these ruthenium complexes was demonstrated through the styrene oxidation reactions. As a result, the ruthenium(II) NCP complex bearing a 2-thiopyridine moiety, together with aqueous H2O2 as an oxidant showed the highest selectivity for benzaldehyde (benzaldehyde/styrene oxide=20 : 1).

DOI： 10.1002/cplu.201800630

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Bis(bicyclic) molecules dimethanochrysene and diethanochrysene were prepared by Diels-Alder reaction of the naphthodiyne equivalent with cyclopentadiene and 1,3-cyclohexadiene, respectively. Reaction of dimethanochrysene and 7,9-diphenyl-8H-cyclopent[a]acenaphthylen-8-one resulted in the generation of a fluorescent hydrocarbon in unexpected multistep pericyclic reactions. Syn-oriented diethanochrysene-connected bisporphyrin tweezers was prepared from the reaction of chrysene-bridged syn-dipyrrole with tripyrranedicarbaldehyde. The structure of the receptor and its 1 : 1 complex with C60 or C70 was determined by X-ray diffraction analysis. The dihedral angles of the bicyclo[2.2.2]octadiene moieties were narrowed by complexation of the receptor with the fullerenes. The binding affinities of the tweezers with C60 and C70 were calculated to be 2.7(4)×104 and 8.01(7)×104 M−1, respectively by UV-vis and fluorescence spectroscopy.

DOI： 10.1002/cplu.201900046

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© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Triplet photosensitizers that generate singlet oxygen efficiently are attractive for applications such as photodynamic therapy (PDT). Extending the absorption band to a near-infrared (NIR) region (700 nm≈) with reasonable photostability is one of the major demands in the rational design of such sensitizers. We herein prepared a series of mono- and bis-palladium complexes (1-Pd-H 2 , 2-Pd-H 2 , 1-Pd-Pd, and 2-Pd-Pd) based on modified calix[6]phyrins as photosensitizers for singlet oxygen generation. These palladium complexes showed intense absorption profiles in the visible-to-NIR region (500–750 nm) depending on the number of central metals. Upon photoirradiation in the presence of 1,5-dihydroxynaphthalene (DHN) as a substrate for reactive oxygen species, the bis-palladium complexes generated singlet oxygen with high efficiency and excellent photostability. Singlet oxygen generation was confirmed from the characteristic spectral feature of the spin trapped complex in the EPR spectrum and the intact 1 O 2 emission at 1270 nm.

DOI： 10.1002/asia.201801671

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim A novel N-confused porphyrin (NCP) analogue bearing an external aza-dipyrrin-like coordination site was synthesized by a Schiff-base forming reaction of N-confused oxoporphyrin and 2-aminopyridine derivatives. The chimera molecule enhances the intrinsic NH tautomerism of NCP to enable four possible tautomeric structures, three of which were identified by metal coordination.

DOI： 10.1002/asia.201801750

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

© 2019 American Chemical Society. Subphthalocyanine (SubPc) and its benzo ring-removed analogue, subporphyrazine (SubPz), bearing 1,3-dithiole-2-one (S 2 CO) groups as a new class of substituents were synthesized. In addition to the perturbed optical properties due to the presence of electron-withdrawing S 2 CO units, the deep bowl-shaped structure of the SubPz derivative allowed concave-convex interaction to form a unique co-crystal structure with C 60 . Finally, using the reactivity of the peripheral S 2 CO units, S 2 CO-fused SubPc was successfully converted into tetrathiafulvalene (TTF)-annulated SubPc in a yield higher than that of the direct synthesis from a TTF-fused phthalonitrile.

DOI： 10.1021/acs.orglett.9b00752

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

© 2019 American Chemical Society. Synthesis of an azacoronene, in which both pyrrole and azulene moieties are circularly fused, was achieved just in three steps. This new azacoronene exhibited multistep reversible oxidations under electrochemical and chemical conditions. Formation of an aromatic 22π-electron conjugation and a tropylium cation (6π-electron conjugation) in the dicationic state was revealed by the single-crystal X-ray crystallographic analysis as well as the nucleus-independent chemical shift (NICS) and anisotropy of the induced current density (ACID) calculations.

DOI： 10.1021/acs.orglett.9b00515

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

© 2018 Elsevier Inc. The cationic Ga(III) and Zn(II) phthalocyanines carrying N-methyl-pyridinium groups at eight peripheral β-positionshave been synthesized. These complexes are highly soluble in dimethyl sulfoxide (DMSO) and moderately soluble in water and phosphate buffered saline (PBS); both Ga(III)Cl and Zn(II) complexes have shown no aggregation in water up to 1.2 × 10−4 and 1.5 × 10−5 M, respectively. A higher water-solubility of Ga(III)Cl complex as compared to Zn(II) complex is ascribed to the presence of an axially coordinated chloride. The spectroscopic properties, photogeneration of singlet oxygen (1O2), and cytotoxicity of these complexes have been investigated. The absolute quantum yields (ΦΔabsolute) for the photogeneration of singlet oxygen using Ga(III)Cl and Zn(II) complexes have been determined to be 4.4 and 5.3%, respectively, in DMSO solution. The cytotoxicity and intracellular sites of localization of Ga(III)Cl and Zn(II) complexes have been evaluated in human HEp2 cells. Both complexes, localized intracellularly in multiple organelles, have shown no cytotoxicity in the dark. Upon exposure to a low light dose (1.5 J/cm2), however, Zn(II) complex has exhibited a high photocytotoxicity. The result suggests that Zn(II) complex can be considered as a potential photosensitizer for Photodynamic therapy (PDT).

DOI： 10.1016/j.jinorgbio.2018.11.013

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© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The Lewis acid catalyzed self-condensation of hybrid diheterole (furan-pyrrole and thiophene-pyrrole) precursors has afforded novel Hückel antiaromatic 24π hexaphyrin(1.0.1.0.1.0) and 32π octaphyrin(1.0.1.0.1.0.1.0) structures without β-annulated bridges. Single-crystal X-ray diffraction analysis of the hybrid porphyrinoids (S 3 N 3 -ox and O 4 N 4 -ox) revealed a nearly planar conformation and the 1 H NMR spectra suggest the presence of paratropic ring currents. These antiaromatic macrocycles show characteristic optical features and underwent reversible two-electron reduction to Hückel aromatic 26π- and 34π-electron species, respectively, as is evident from the results of spectroscopic and theoretical studies (nucleus-independent chemical shift (NICS) and anisotropy of the current-induced density (ACID) calculations). The incorporation of hybrid diheteroles alternately into expanded porphyrin skeletons provides a novel approach to the fine-tuning of the electronic structures of planar antiaromatic macrocycles.

DOI： 10.1002/chem.201805861

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DOI： 10.1246/bcsj.20190074

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© 2019 World Scientific Publishing Company. Upon oxidation of 20π-electron antiaromatic 5,15-dioxaporphyrin (DOP) using nitrosonium ions as oxidants, a tetrakis-β-nitrated compound was formed instead of the expected 18π-electron aromatic dication species via an oxidative nitration reaction mechanism. Compared with the original DOP, this tetranitro DOP product exhibited a blue shift of absorption and downfield shifts of the β-pyrrolic proton signals. The unique antiaromatic electronic structure of the tetranitro DOP was disclosed experimentally by electrochemistry and theoretically by DFT and NICS calculations.

DOI： 10.1142/S108842461950113X

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© 2019 The Chemical Society of Japan. 1,3-Dihydrothieno[3,4-a]- and 1,3,8,10-tetrahydrodithieno-[3,4-a;3¤4¤-m]-HPHACs were prepared by the successive SNAr reactions of hexafluorobenzene with 1,3-dihydrothieno[3,4-c]-pyrrole and 3,4-dihexylpyrrole followed by Scholl oxidation. Oxidation of 1,3-dihydrothieno-fused HPHACs with excess amounts of iodine at room temperature quantitatively gave the corresponding dication bis(triiodide)s. Further dehydrogenative oxidation of the dicationic species with iodine giving a thieno-[3,4-a]HPHAC dication was achieved at a higher temperature by removing hydrogen iodide generated during the reaction. Neutral species of thieno[3,4-a]HPHAC could not be isolated.

DOI： 10.1246/bcsj.20190022

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© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim In this paper, we describe an efficient and atom-economical synthesis of highly functionalized pyrroles, pentafulvenes, and pyrrolopyridines by [2+2] cycloaddition–retroelectrocyclization of N-substituted propargylamines with tetracyanoethylene, followed by the treatment of the resulting tetracyanobutadiene derivatives with silica gel. In this reaction, silica gel plays an important role to promote the intramolecular cyclization to afford the heterocyclic products from the tetracyanobutadiene intermediates. The products were obtained selectively depending on the substituent on the nitrogen atom of the starting propargylamines.

DOI： 10.1002/chem.201904926

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© 2019 The Japan Institute of Heterocyclic Chemistry. We have successfully synthesized 2,3-di(3-thienyl)benzo[b]porphyrin based on retro Diels-Alder reaction of bicyclo[2.2.2]octadiene(BCOD)-fused porphyrin and investigated its photoisomerization reaction.

DOI： 10.3987/COM-18-S(F)102

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© 2019 The Chemical Society of Japan. A helicene compound called AIBTh, wherein two azulene units are fused with isobenzothiophene, has been prepared and characterized by spectroscopic and crystallographic methods. The enantiomers of AIBTh were resolved by HPLC, exhibiting stable optical activity. AIBTh showed two reversible oxidation and one irreversible reduction waves with a HOMO-LUMO gap of 2.07 eV. Upon one-electron oxidation of AIBTh, its air-stable cation radical was isolated and analyzed by EPR as well as X-ray crystallography. Based on the EPR spectrum, the crystal structure, and DFT calculation, it is suggested that favorable resonance structures including aromatic tropylium cation forms and wide delocalization of electronic spin are dominating in the electronic structure of the cation radical.

DOI： 10.1246/bcsj.20190219

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© 2019 World Scientific Publishing Company. A ring-contracted carbaporphyrin, azulitriphyrin(2.1.1), was synthesized via intramolecular McMurry coupling reaction. Absorption, NMR spectra and NICS calculations of protonated azulitriphyrin(2.1.1) revealed its Hückel aromatic character as a 14 porphyrinoid.

DOI： 10.1142/S108842461950130X

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© 2019 The Chemical Society of Japan Di(acenaphtho)-fused BODIPYs with four electron-withdrawing N,N-dimethylcarbamoyl groups were obtained by complexation of the corresponding dipyrrins, which were also proven to be a stable deep-red dye.

DOI： 10.1246/bcsj.20190021

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© 2019 The Royal Society of Chemistry. An approach of molecular tectonics was applied to synthesize a tetranuclear Pd(ii) complex with axial chirality, [{(Lt)Pd(ii)(taet)Pd(ii)}2(tpret)] (LtH = benzoylacetone (bzacH) or 2-naphthoylacetone (npacH), taetH2 = 1,1,2,2-tetraacetylethane and tpretH2 = 1,1,2,2-tetrapropanoylethane). As a first step, a two-handed tecton, [{taetH}Pd(ii)]2(tpret)], was synthesized. Next monomeric Pd(ii) units were connected to both ends of the tecton to form a reactive tetranuclear intermediate, [{(hfac)Pd(ii)(taet)Pd(ii)}2(tpret)] (hfacH = hexafluoroacetylacetone). Finally terminal hfac groups were replaced with the β-diketonato ligands having one or two bulky groups such as dibenzoylmethane (dbmH), bzacH and npacH. In the case of the symmetrically substituted ligand (dbm), the formed complex was achiral and its structure was determined by single crystal X-ray analysis. In the case of unsymmetrical ligands (bzac and npac), the complexes were axially chiral due to the vertical twisting of the terminal ligands. The complexes were optically resolved chromatographically on a chiral column. Their chiro-optical properties were investigated by means of electronic (ECD) and vibrational circular dichroism (VCD) spectroscopy. Notably the twisting relation between the two terminal ligands of the tetranuclear complexes influenced significantly chiral electronic properties, although they were separated by a distance longer than 3 nm.

DOI： 10.1039/c9dt01913h

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© The Royal Society of Chemistry. A series of rhenium(i) dipyrrinato complexes (Re1-Re8) have been prepared and characterized; their crystal structures, phosphorescence and singlet oxygen generation studies are reported. The aromatic substituents, such as thienyl, p-bromophenyl, p-fluorophenyl, m-fluorophenyl, pentaflurophenyl, N-butylcarbazole, N-phenylcarbazole, and N-butylphenothiazine, are linked to the C5 position of Re-dipyrrinates. Varying the electronic nature of the substituents from electron donating (e.g., carbazole) to electron withdrawing (e.g., pentaflurophenyl) allowed the change in the structural, electrochemical, and spectroscopic properties of these complexes. In particular, the rhenium dipyrrinates showed phosphorescence in the near IR region with sufficiently longer triplet state lifetimes (τ T = 9-29 μs). Also, a large Stokes shift (Δν = 5682-6957 cm —1 ) was witnessed for all the rhenium dipyrrinates. Triplet emission was reflected in the efficient singlet oxygen generation yields (Φ Δ ∼ 0.75-0.98) along with the distinct photo-stability. Density functional theory (DFT) calculations revealed that the electron density is spread over the dipyrrin unit in most complexes. Rhenium dipyrrinate having a phenothiazine substituent exhibited the smallest HOMO-LUMO band gap (2.820 eV) among all Re-complexes.

DOI： 10.1039/c8dt04540b

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© 2018 Elsevier Ltd New types of macrocyclic compounds, deltaarenes, are prepared. The compounds were readily synthesized in three steps from an arenedithiol and benzoquinone, and the yields of the macrocyclization reaction reached up to 40% under high dilution conditions. X-ray crystallographic analysis revealed that the macrocycle has a relatively rigid trimeric structure with a unique triangular hole, the size of which was approximately 11 Å along each side. NMR data suggests that the ring has a C3-symmetric structure. The X-ray analysis showed that the hole is large enough to capture one molecule of chlorobenzene. Use of a variety of dithiols allowed the synthesis of different types of deltaarene derivatives. MO calculations showed that the hole size depends on the dithiol unit. Deprotection of the twelve methoxyl groups was easily achieved by treatment with BBr3 and yielded the free-OH deltaarene derivative.

DOI： 10.1016/j.tet.2018.04.070

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© 2018 American Chemical Society. Derivatives of a new bis-fused donor composed of TTF and extended TTF with an anthraquinoid spacer (TTFAQ) (2) were successfully synthesized. X-ray structure analysis of the tetrakis(methylthio) derivative 2Aa and its I3- salt revealed that the TTFAQ moieties of both 2Aa and 2Aa+ adopt the so-called saddle conformation similar to most neutral TTFAQs. The results obtained from the X-ray structure analysis and cyclic voltammetry suggest that a positive charge in 2Aa+ is unevenly distributed on the TTF moiety, while both positive charges of 22+ are mainly located on the TTFAQ moiety. In the first two-electron redox processes, an extra cathodic wave attributed to the coexistence of a different reduction process from the oxidation process was observed for most of the derivatives.

DOI： 10.1021/acs.orglett.8b01985

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Copyright © 2018 American Chemical Society. A core-expanded, pyrrole-fused azacoronene analogue containing two unusual N-doped heptagons was obtained from commercially available octafluoronaphthalene and 3,4-diethylpyrrole in two steps as a heteroatom-doped nonplanar nanographene. Full fusion with the formation of the tetraazadipleiadiene framework and the longitudinally twisted structure was unambiguously confirmed by single-crystal X-ray diffraction analysis. The edge-to-edge dihedral angle along the acene moiety was 63°. This electron-rich π-system showed four reversible oxidation peaks. Despite the nonplanar structure, the Hückel aromaticity owing to a peripheral π-conjugation in the dicationic state was concluded from the bond-length alternation and nucleus-independent chemical shift (NICS) and anisotropy of the induced current density (ACID) calculations.

DOI： 10.1021/jacs.8b06079

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© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 5,15-Dioxaporphyrin was synthesized for the first time by a nucleophilic aromatic substitution reaction of a nickel bis(α,α′-dibromodipyrrin) complex with benzaldoxime, followed by an intramolecular annulation of the α-hydroxy-substituted intermediate. This unprecedented molecule is a 20π-electron antiaromatic system, in terms of Hückel's rule of aromaticity, because lone pair electrons of oxygen atoms are incorporated into the 18π-electron conjugated system of the porphyrin. A theoretical analysis based on the gauge-including magnetically induced current method confirmed its antiaromaticity and a dominant inner ring pathway for the ring current. The unique reactivity of 5,15-dioxaporphyrin forming a β,β-linked dimer upon oxidation was also revealed.

DOI： 10.1002/anie.201804648

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© 2018 American Chemical Society. Stable square planar organocopper(III) complexes (CuNCC2, CuNCC4, and CuBN) supported by carbacorrole-based tetradentate macrocyclic ligands with NNNC coordination cores were synthesized, and their structures were elucidated by spectroscopic means including X-ray crystallographic analysis. On the basis of their distinct planar structures, X-ray absorption/photoelectron spectroscopic features, and temperature-independent diamagnetic nature, these organocopper complexes can be preferably considered as novel organocopper(III) species. The remarkable stability of the high-valent Cu(III) states of the complexes stems from the closed-shell electronic structure derived from the peculiar NNNC coordination of the corrole-modified frameworks, which contrasts with the redox-noninnocent radical nature of regular corrole copper(II) complexes with an NNNN core. The proposed structure was supported by DFT (B3LYP) calculations. Furthermore, a π-laminated dimer architecture linked through the inner carbons was obtained from the one-electron oxidation of CuNCC4. We envisage that the precise manipulation of the molecular orbital energies and redox profiles of these organometallic corrole complexes could eventually lead to the isolation of yet unexplored high-valent metal species and the development of their organometallic reactions.

DOI： 10.1021/jacs.8b01876

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© 2018 American Chemical Society. The use of chiral auxiliaries, which derivatize enantiomers to diastereomers, is an established technique for NMR spectroscopic analysis of chirality and enantiomeric excess (ee). Here we report that some small prochiral molecules exhibit ee-dependent splitting of 1H NMR signals at room temperature based on acid/base interactions with chiral analytes, especially when either a chiral or prochiral acid contains a phenoxy group at the α-position of the carboxylic acid. As a representative case, the benzylamine (BA)/2-phenoxylpropionic acid (PPA) complex was comprehensively investigated by using various methods. Notably, X-ray crystallographic analysis shows that there are multipoint interactions in the BA/PPA complex, implying that "fixing" of molecular conformation is critical for efficient intermolecular transfer of magnetic anisotropy. Our results suggest that a wide range of prochiral molecules are available for NMR determination of ee when intermolecular interactions between prochiral molecules and chiral analytes are adequately designed.

DOI： 10.1021/acs.jpcb.8b03684

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© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Complexation of a RuCp* cation with N-confused tetraarylporphyrins (NCPs) forms directly bound ruthenium(II) pentamethylcyclopentadienyl (Cp*) π-complex on a specific meso-aryl group (e.g., phenyl) neighboring peripheral imino nitrogen of NCPs in high yields. In contrast, in the case of NCPs bearing bulky meso-substituents (e.g., 3,5-di-tert-butylphenyl), new ruthenocenophane-like complex embedded on an N-confused calix[4]phyrin was formed through multiple C−H bond activation of methyl groups of Cp* ligand. The mechanistic insight into the formation of the ruthenocenophane was derived from DFT calculations.

DOI： 10.1002/chem.201801237

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© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim A novel helically twisted π-extended corrorin derivative having two boron dipyrrin (BODIPY) moieties at the periphery, a BODIPY DYEmer (6-BF2) cross-bridged with π-conjugated dipyrrinylidene unit, was synthesized and characterized. The neutral 6-BF2 is nonfluorescent due to the internal photoinduced charge transfer (CT) character in the excited state as inferred from the femtosecond transient absorption spectroscopy. However, upon protonation, the CT process is suppressed and the species H6-BF2+ becomes near infrared (IR) emissive. With the aid of rigid helical conformations in 6-BF2, the helical isomers (P- and M-forms) were resolved and their chiroptical property was investigated. The distinct circular dichroism (CD) spectral changes of the enantiomers were observed in the presence of acids, which demonstrates that 6-BF2 can be utilized for potential acid-responsive chiroptical materials.

DOI： 10.1002/chem.201705516

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© 2018 American Chemical Society. The adsorption configurations of heptahelicene ([7]H) molecules on Cu(001) are investigated with noncontact atomic force microscopy (ncAFM) and scanning tunneling microscopy (STM). Because of the suppression of thermal diffusion at 5 K, racemic [7]H molecules exist as monomers, dimers, trimers, and tetramers on the surface. The terminal naphthaleno part of the molecule is attached horizontally to the substrate so that the two benzene ring centers are located at the hollow sites, whereas the other terminal is protruded toward a vacuum. A procedure for picking a [7]H molecule up from the surface (vertical manipulation) enables us to functionalize the tip apex to enhance the spatial resolution of ncAFM. The ncAFM images with the helicene tip clarify that whereas the tetramers are homochiral, the dimers and trimers are heterochiral. In contrast, homochiral dimers and trimers are unobservable probably because of the rapid formation of the stable homochiral tetramers. Thus, ncAFM imaging can identify the geometries and chiralities of the individual component molecules in a nondestructive manner, which would be an indispensable method to characterize complicated chiral aggregates at the single-molecule level.

DOI： 10.1021/acs.jpcc.8b00487

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© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2-Formylazulene derivatives have been obtained in good yields by the reactions of 2-methylazulenes with N,N-dimethylformamide dimethyl acetal, followed by oxidative cleavage of the intermediately formed enamines with NaIO4. Vilsmeier formylation of 1-phenyl-3-methylazulenes also afforded the corresponding 2-formylazulenes in moderate yields. The treatment of a 2-methylazulene derivative bearing a formyl group at the 1-position with sodium methoxide led, through a self-condensation reaction, to a trans-1-(azulen-1-yl)-2-(azulen-2-yl)ethylene derivative, the structure of which was verified by single-crystal X-ray diffraction analysis. The 2-formylazulenes obtained were transformed into 2-ethynylazulenes in good yields by a modified Seyferth–Gilbert reaction. The reactivity of a 1-iodoazulene bearing a 2-formyl function in palladium-catalyzed cross-coupling reactions has also been examined.

DOI： 10.1002/ejoc.201701746

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© 2018 American Chemical Society. A practical synthesis of a variety of λ5-phosphinines, which show distinct fluorescence both in solution and solid state, is described. Both C4-selective electrophilic substitutions and the following conversions realized an easy preparation of a wide range of derivatives having several substituents for electronic modification, which provides the potential for fine-tuning of the photophysical properties.

DOI： 10.1021/jacs.7b13018

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© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Bioinspired pentadentate ligand N-confused porphyrin (NCP) bearing a 2-mercaptopyridine group and its RuII and CoIII complexes were synthesized. Their structures were revealed by single-crystal X-ray crystallographic analysis. Installation of an axial thiopyridine ligand shifts the redox potentials negatively and enhances the catalytic activity largely, which was demonstrated in the cyclopropanation reaction using the Co complex.

DOI： 10.1002/ejic.201701494

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© 2017 Elsevier Inc. Pyrrocorphin is an air-sensitive porphyrinoid with a highly reduced hexahydroporphyrin core. In contrast, pyrrolidine-fused pyrrocorphin (Pyr) obtained by successive 1,3-dipolar cycloaddition reactions of azomethine ylide to 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin is less air-sensitive. In order to reveal the effect of highly reduced porphyrin rings on the physicochemical properties of their metal complexes, we have prepared diamagnetic (S = 0) Ni(II) complex Ni(II)(Pyr). The addition of excess pyridine (Py) to the toluene solution of Ni(II)(Pyr) yielded five-coordinate Ni(II)(Pyr)(Py), which was then completely converted to six-coordinate paramagnetic (S = 1) Ni(II)(Pyr)(Py)2. The latter was characterized by UV–Vis, 1H NMR, CV, SQUID, and X-ray crystallography as well as DFT calculations. As compared with analogous complexes of porphyrin (Por), chlorin (Chl), and isobacteriochlorin (Iso) reported by Herges and co-workers (R. Herges et al., Inorg. Chem. 2015), Ni(II)(Pyr)(Py)2 has longer equatorial Ni–N and shorter axial Ni–N bonds. The CV study has shown a large decrease in HOMO–LUMO gap as the reduction of porphyrin ring proceeds, which has further been confirmed by UV–Vis and DFT calculation. Titration studies using 1H NMR and UV–Vis have shown that the first binding constant of pyridine toward Ni(II)(Pyr) is ca. 4 times as large as that of Ni(II)(Iso) and ca 230 times as large as that of Ni(II)(Por). Thus, we have concluded that the binding constant of pyridine to Ni(II) porphyrinoid increases by the following order: Por < Chl < Iso < Pyr. The high affinity of pyridine binding in Ni(II)(Pyr) was discussed both from the structural and thermodynamic point of view.

DOI： 10.1016/j.jinorgbio.2017.10.012

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© 2018 The Japan Institute of Heterocyclic Chemistry. A series of sapphyrins fused with bicyclo[2.2.2]octadiene were successfully synthesized via [3+1+1] porphyrinoid synthesis. The retro Diels-Alder thermal conversion afforded the corresponding di-, tri-, tetra-, and pentabenzosapphyrins.

DOI： 10.3987/COM-18-13910

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© 2018 The Pharmaceutical Society of Japan. Three 2-fluoroacetonylbenzoxazole ligands 1a–c and their new Zn(II) complexes 2a–c have been synthesized. In addition, syntheses of new metal [Mg(II), Ni(II), Cu(II), Pd(II), and Ag(I)] complexes from 1a have been also described. The molecular and crystal structures of six metal complexes 2b and 2d–h were determined by single-crystal X-ray diffraction analyses. Their antibacterial activities against six Gram-positive and six Gram-negative bacteria were evaluated by minimum inhibitory concentrations (MIC), which were compared with those of appropriate antibiotics and silver nitrate. The results indicate that some metal compounds have more antibacterial effects in comparison with free ligands and have preferred antibacterial activities that may have potential pharmaceutical applications. Noticeably, the Ag(I) complex 2h exhibited low MIC value of 0.7µM against Pseudomonas aeruginosa, which was even superior to the reference drug, Norfloxacin with that of 1.5µM. Against P. aeruginosa, 2h is bacteriostatic, exerts the cell surface damage observed by scanning electron microscopy (SEM) and is less likely to develop resistance. The new 2h has been found to display effective antimicrobial activity against a series of bacteria.

DOI： 10.1248/cpb.c18-00158

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© 2018 American Chemical Society. Derivatives of a new bis-fused donor composed of TTF and extended TTF with an anthraquinoid spacer (TTFAQ) (2) were successfully synthesized. X-ray structure analysis of the tetrakis(methylthio) derivative 2Aa and its I3- salt revealed that the TTFAQ moieties of both 2Aa and 2Aa•+ adopt the so-called saddle conformation similar to most neutral TTFAQs. The results obtained from the X-ray structure analysis and cyclic voltammetry suggest that a positive charge in 2Aa•+ is unevenly distributed on the TTF moiety, while both positive charges of 22+ are mainly located on the TTFAQ moiety. In the first two-electron redox processes, an extra cathodic wave attributed to the coexistence of a different reduction process from the oxidation process was observed for most of the derivatives.

DOI： 10.1021/acs.orglett.8b01985

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© 2018 The Royal Society of Chemistry. The preparation of azulene-substituted benzofurans and isocoumarins was established by two types of intramolecular cyclization reaction of 1-ethynylazulenes. 2-(1-Azulenyl)- and 2,3-bis(1-azulenyl)benzofurans were prepared by the palladium-catalyzed cross-coupling reaction of 1-iodoazulenes with 2-ethynylphenol and that of 1-ethynylazulenes with 2-iodophenol under Sonogashira-Hagihara reaction conditions following the intramolecular nucleophilic addition of the oxygen nucleophile to the presumed 1-arylethynylazulenes. In contrast, 1-(phenylethynyl)azulenes bearing an o-methoxycarbonyl function on the substituted phenyl moiety exhibited intramolecular cyclization either in the presence of trifluoroacetic acid or N-iodosuccinimide (NIS) to afford azulene-substituted isocoumarins and 4-iodoisocoumarins, and the structures were clarified by single-crystal X-ray analysis. The optical properties of these compounds were also investigated by UV/vis spectroscopy and theoretical calculations.

DOI： 10.1039/c7ob02861j

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© 2018 The Japan Institute of Heterocyclic Chemistry – 3-Substituted 2-amino-1-cyanoazulene derivatives were prepared by the reaction of 2H-cyclohepta[b]furan-2-ones with malononitrile in the presence of triethylamine as a base. The great influence of the substituent at their 3-position on the reactivity to form the 2-aminoazulene derivatives was revealed. The intramolecular charge transfer (ICT) characters of 2-amino-1-cyano-3-vinylazulenes were investigated by UV/Vis spectroscopy and theoretical calculations. The structure of compounds 13b and 14b was clarified by single crystal X-ray analysis.

DOI： 10.3987/COM-18-S(T)89

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© The Royal Society of Chemistry and the Chinese Chemical Society 2018 Dimerization of the so-called pyrrolopyrrole aza-BODIPY, which is a new class of aza-BODIPY analogues exhibiting intense absorption and emission in the visible (Vis) and near infrared (NIR) region, via a bithienyl linkage led to the creation of a novel black dye with dual emission and panchromatic absorption properties in the Vis/NIR region. The role of the linkage in the dye was unambiguously elucidated by comparison of the optical properties with those of its biphenyl-linked counterpart.

DOI： 10.1039/c7qm00438a

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© 2018 The Royal Society of Chemistry. Benzene-fused bis(acenaphthoBODIPY)s prepared by retro-Diels-Alder reaction of bicyclo[2.2.2]octadiene-fused precursors showed strong absorption bands in the near-infrared region and very weak absorptions in the visible region.

DOI： 10.1039/c8ra01694a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

In this study, a benzene-fused bis(thiaporphyrin) was synthesized by the retro-Diels-Alder reaction of a bicyclo[2.2.2]octadiene (BCOD)-fused bis(thiaporphyrin) precursor. This precursor was prepared by the double [3+ 1] porphyrin synthesis of the BCOD-fused dipyrrole with thiatripyrrane. The ultraviolet-visible (UV-vis) spectrum of benzene-fused bis( thiaporphyrin) in dichloromethane was extremely different from that of the corresponding benzene-fused bis(porphyrin). In contrast, extremely similar spectra were obtained in the presence of trifluoroacetic acid. The similar electronic structures in the protonated states were supported by X-ray analysis and time-dependent density-functional theory (TD-DFT) calculations.

DOI： 10.1246/bcsj.20170257

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© 2017 American Chemical Society. The ligand exchange reactions of the ruthenium(II) complex of N-fused tetraphenylporphyrin, Ru(NFp)(CO)2Cl (2), with various anions were investigated. The chloride ligand of the isomers 2a-c was stereoretentively exchanged with bromide (Br-), iodide (I-), and acetate (AcO-) anions in toluene at 100 °C, structures of which were confirmed by 1H NMR as well as single crystal X-ray diffraction analysis. The silver (AgOAc, AgOTf) and boron (NaBPh4) reagents also afforded the corresponding stereoretentive products. On the other hand, the reaction with NaBH4 afforded the hydride complex Ru(NFp)(CO)2H (7) with low stereospecificity, showing a higher reactivity of 2c than other isomers. The ligand dissociation mechanism was proposed with the help of theoretical calculations on the plausible five-coordinated intermediates.

DOI： 10.1021/acs.inorgchem.7b01972

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© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim A novel [36]octaphyrin analogue embedding two N-confused pyrrole units demonstrated unique prototropy-coupled isomerization between the Figure-of-eight and dumbbell conformers. Upon bis-metal coordination, fixation of fully π-conjugated Figure-of-eight structures was achieved as referred from the X-ray crystal structure. Chirogenesis of the helical enantiomers was proved by intense circular dichroism (CD) response in the near infrared (NIR) region.

DOI： 10.1002/anie.201708253

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DOI： 10.1002/ange.201708253

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© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim A contracted doubly N-confused dioxohexaphyrin(1.1.1.1.1.0) complex consisting of two paramagnetic copper metals and open-shell π-radical ligand was synthesized as a new multi-heterospin motif. X-ray spectroscopy supported the divalent character of the inner copper centers, and electron paramagnetic resonance and magnetometric studies suggested the presence of unpaired d electrons strongly antiferromagnetically coupled with π-radicals delocalized on the macrocycle. The 25 π non-innocent dioxohexaphyrin ligand allowed the facile interconversion between antiaromatic 24 π and aromatic 26 π species, respectively, upon redox reactions.

DOI： 10.1002/chem.201704321

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© 2017, Springer Science+Business Media, LLC. Carbazole and p-anisyl substituted BODIPY dyes with a cyanoacetic acid anchoring group have been prepared and their spectral, electrochemical properties and photosensitizing potential in DSSC have been evaluated. X-ray structure of N-phenylcarbazole substituted BODIPY revealed lower torsion angle between BODIPY plane and carbazole plane, suggesting increased communication between the two units. DFT studies indicated effective electronic interactions between the BODIPY unit and carbazole substituents. The N-butylcarbazole and N-phenylcarbazole substituted BODIPYs showed anodic shifts in their reduction potentials, indicating facile reduction process. The predicted HOMO–LUMO gaps are in agreement with the electrochemical result and the lower band gap was observed for the carbazole substituted BODIPYs.

DOI： 10.1007/s10895-017-2152-9

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© 2017 American Chemical Society. Organoplatinum(II) complexes of calix[4]phyrin analogues, singly N-confused calix[4]phyrin (Pt-2), and doubly N-confused calix[4]phyrin (Pt-3), were synthesized and characterized. The explicit structures of these organoplatinum(II) complexes were elucidated by single-crystal X-ray diffraction and spectroscopic studies. The introduction of N-confused pyrrole rings to the parent calix[4]phyrin scaffold was found to have profound effects on the photophysical properties, such as the bathochromic shifts of both the absorption and phosphorescence maxima. The triplet excited state properties of these platinum complexes were analyzed by DFT calculations at the B3LYP level. The organoplatinum(II) complexes derived from the deformed scaffolds can serve as potent triplet sensitizers for singlet oxygen generation under aerobic conditions.

DOI： 10.1021/acs.inorgchem.7b02047

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© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Complexation of group 11 metal cations with an α-bis(phenylthio)-substituted trans-doubly N-confused porphyrin (trans-N2CPSPh: 4) afforded a series of square-planar trivalent organometallic complexes (i.e., Cu-H4, Ag-H4, and Au-H4). The X-ray crystal structures of the complexes revealed highly planar core geometries along with the presence of peripheral amine and imine nitrogen sites of the pyrrolic moieties. NMR, UV/Vis absorption, and magnetic circular dichroism (MCD) spectroscopies suggested the 18 π-electron aromaticity of the complexes. The aromaticity was also fully analyzed by various theoretical methodologies such as nucleus-independent chemical shift (NICS) and anisotropic induced current density (ACID) calculations. The central metal affects the amphiprotic character of the complexes possessing both pyrrolic amino nitrogen and imino nitrogen atoms at the periphery, which was examined by the photometric titration with trifluoroacetic acid (TFA) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), respectively. The inherent acidity of the complexes was followed in the order; Cu-H4>Au-H4>Ag-H4 and that of basicity was Au-H4>Ag-H4>Cu-H4. The complexes could be considered as an “expanded imidazole” structural motif.

DOI： 10.1002/chem.201701958

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© 2017 American Chemical Society. Pyridylethenyl-substituted N-confused porphyrins (NCPs) were synthesized, and their cis-trans isomerization was studied. Among four possible isomers, trans-3H and cis-2H types of structures, of which aromaticity and absorption/emission properties differ largely, were isolated. The cis-isomer was largely stabilized by the intramolecular hydrogen bonding between the pyrrolic-NH and the pyridinic-N in the vicinity. The thermal cis-trans isomerization proceeded even at 30 °C, which was significantly accelerated by the pyridine added to the system. The kinetic studies revealed that the isomerization reaction was second-order and the activation energy of the thermal isomerization from cis to trans isomer was ΔG0‡cis→trans = 35.7 kcal/mol at 298 K, which is significantly smaller than that of Ni complex (42.3 kcal/mol). An intermolecular proton transfer induced cis-trans isomerization mechanism was proposed.

DOI： 10.1021/acs.joc.7b01770

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Controlling the structural deformation of organic molecules can drive unique reactions that cannot be induced only by thermal, optical or electrochemical procedures. However, in conventional organic synthesis, including mechanochemical procedures, it is difficult to control skeletal rearrangement in polycyclic aromatic hydrocarbons (PAHs). Here, we demonstrate a reaction scheme for the skeletal rearrangement of PAHs on a metal surface using high-resolution noncontact atomic force microscopy. By a combination of organic synthesis and on-surface cyclodehydrogenation, we produce a well-designed PAH - diazuleno[1,2,3-cd:1′,2′,3′-fg]pyrene - adsorbed flatly onto Cu(001), in which two azuleno moieties are highly strained by their mutual proximity. This local strain drives the rearrangement of one of the azuleno moieties into a fulvaleno moiety, which has never been reported so far. Our proposed thermally driven, strain-induced synthesis on surfaces will pave the way for the production of a new class of nanocarbon materials that conventional synthetic techniques cannot attain.

DOI： 10.1038/ncomms16089

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：INT UNION CRYSTALLOGRAPHY  

Pyrroloquinoline quinone (PQQ) is a water-soluble quinone compound first identified as a cofactor of alcohol- and glucose-dehydrogenases (ADH and GDH) in bacteria. For example, in the process of ADH reaction, alcohol is oxidized to the corresponding aldehyde, and inversely PQQ is reduced to pyrroloquinoline quinol (PQQH(2)). PQQ and PQQH(2) molecules play an important role as a cofactor in ADH and GDH reactions. However, crystal structure analysis has not been performed for PQQ and PQQH(2). In the present study, the synthesis of PQQH(2) powder crystals was performed under air, by utilizing vitamin C as a reducing agent. By reacting a trihydrate of disodium salt of PQQ (PQQNa(2)center dot 3H(2)O) with excess vitamin C in H2O at 293 and 343 K, yellowish brown and black powder crystals of PQQH(2) having different properties were obtained in high yield, respectively. The former was PQQH(2) trihydrate (PQQH(2)center dot 3H(2)O) and the latter was PQQH(2) anhydrate (PQQH(2)). Furthermore, sodium-free red PQQ powder crystal (a monohydrate of PQQ, PQQ center dot H2O) was prepared by the reaction of PQQNa(2)center dot 3H(2)O with HCl in H2O. Single crystals of PQQH(2) and PQQ were prepared from Me2SO/CH3CN mixed solvent, and we have succeeded in the crystal structure analyses of PQQH(2) and PQQ for the first time.

DOI： 10.1107/S2052520617002281

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The SNAr reaction of 2-chloroazulene derivative 1 with ethoxycarbonyl groups at the 1,3-positions of the azulene ring with several amines afforded the corresponding 2-aminoazulenes 3-9 in excellent yields. 2-Chloroazulene (2) without the electron-withdrawing groups reacted with highly nucleophilic cyclic amines (i.e., morpholine, piperidine and pyrrolidine) under the high-temperature conditions in a sealed tube to produce the corresponding 2-aminoazulenes 10-12 in good yields. 2-Aminoazulenes 10-14 without the electron-withdrawing groups were also obtained in good yields by the treatment of compounds 3-7 with 100% H3PO4, but in the cases of the reaction of 8 and 9 with a secondary amine function, the decomposition of the products resulted. The synthesis of 2-arylazoazulenes 15-18 was also established via the SNAr reaction of 1 with arylhydrazines. The optical and electrochemical properties of the 2-arylazoazulene derivatives were examined by UV/Vis spectroscopy, theoretical calculations and voltammetric experiments.

DOI： 10.1039/c7ob00691h

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Synthesis of 2-aminofuran derivatives with an azulene or N,N-dimethylanilino substituent was established by the formal [2+2] cycloaddition-retroelectrocyclization of 3-(1-azulenyl or N,N-dimethylanilino)-2-propyn-1-ols with tetracyanoethylene, followed by intramolecular nucleophilic addition to the initially formed tetracyanobutadiene moiety of the internal hydroxyl group that come from 2-propyn-1-ol. The reaction proceeds under mild conditions with short reaction period. The products of the reaction are readily available through a simple purification procedure. 2-Aminofuran derivatives obtained by this reaction could be converted into 6-aminofulvene derivatives upon reaction with various amines. The structures of 2-aminofuran and 6-aminopentafulvene with a N,N-dimethylanilino substituent were confirmed by single-crystal X-ray structural analysis.

DOI： 10.1002/chem.201700121

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© The Partner Organisations. A series of donor-acceptor type trans-A2B2 porphyrins and their Zn(ii) and Pd(ii) complexes 5-13 have been synthesized and characterized by various spectroscopic techniques. The effect of the donor moieties (e.g., N-butylcarbazole, N-butylphenothiazine, and triphenylamine) on the spectroscopic properties of the porphyrins has been studied. The structural changes indeed affected the optical and electrochemical properties of these porphyrins. Higher energy shifts of the Soret bands were observed for porphyrins upon varying the donor moieties. The electrochemical studies of all the derivatives indicated increased interactions between the donor groups and the porphyrin core, which in turn are reflected in the anodic shifts in their reduction potentials. Both steady-state and time-resolved fluorescence studies revealed effective energy transfer (EET; up to 87%) from donor groups to the porphyrin core in the porphyrins, 5-10. The palladium(ii) porphyrin complexes, 11-13, showed characteristic phosphorescence in the near IR region. Density functional theory (DFT) studies support the presence of donor-acceptor interaction between the porphyrin core and the meso-substituents in the dyads. Density functional theory (DFT) and time dependent-density functional theory (TD-DFT) studies showed that in 5, 8 and 11, the transitions are of π → π∗ type; whereas in the other molecules viz.6, 7, 9, 10, 12 and 13 intramolecular charge transfer (ICT) is involved in all the respective highest intensity absorption transitions.

DOI： 10.1039/c6qi00558f

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

A cyclophane composed of diethanoanthracene (DEA)-fused dipyrrole and tetrafluorobenzene was synthesized by one-pot aromatic nucleophilic substitution (SNAr). Reflecting the fixed angle of DEA-fused dipyrrole, X-ray single-crystal structure analysis of the cyclophane revealed its rice-ball-shaped structure.

DOI： 10.1246/cl.161026

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The protonation behavior of bicyclo[2.2.2]octadiene (BCOD)-fused thiaporphyrin and thiabenzoporphyrin was examined by titration with trifluoroacetic acid. Neutral, monorotonated, and diprotonated species of thiaporphyrins were easily detected by UV-vis spectral measurement. The first (K-1) and second (K-2) equilibrium constants were found to be K-1 = 520 and K-2 approximate to 7.1 for BCOD-fused thiaporphyrin and K-1 = 1.4 x 10(4) and K-2 approximate to 1.4 for thiabenzoporphyrin. The difference between K-1 and K-2 values of thiaporphyrins is larger than that observed for porphyrins (N-4-porphyrins). The main contributing conjugation pathways for thiaporphyrins in both protonated species were investigated by NICS and AICD quantum calculations using their atomic geometries obtained by X-ray structural analysis. The 18 pi-conjugation pathways of the neutral, monoprotonated, and diprotonated species thiaporphyrins were found to contain 18, 19, and 20 atoms, respectively. Results of H-1 NMR studies also support the major contributing pathways. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2016.12.067

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Parikh-Doering oxidation of diethyl 9-hydroxy-2,6-dimethy1-4,8-dihydro-4,8-methanopyrrol[3,4-f]isoindole-1,7-dicarboxylate produced diethyl 9-oxo-2,6-dimethy1-4,8-dihydro-4,8-methanopyrrol[3,44] isoindole-1,7-dicarboxylate. This carbonyl derivative spontaneously underwent cheletropic extrusion of carbon monoxide, producing diethyl 2,6-dimethylpyrrol[3,4-f]isoindole-1,7-dicarboxylate, which showed 14 pi-electronic aromaticity on the whole five-six-five ring system. (C) 2017 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2017.01.015

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© 2016 Informa UK Limited, trading as Taylor & Francis Group. Synthesis and properties of a novel meso-oxo carbaphlorin analogue embedded with an N-free pyrazole moiety are described. The N-benzyl precursor was prepared by a [3 + 1]-MacDonald condensation of N-benzyl pyrazole dialdehyde and β-alkyl-substituted tripyrrane dicarboxylic acid and subsequent oxidation by ferric chloride. Upon deprotection of the benzyl group, the resulting N-free oxophlorin analogue formed a unique supramolecular dimer through mutual hydrogen bonding interactions between the pyrazole NH and meso-carbonyl group. The assembled behaviour was characterised by various spectroscopies, X-ray crystallographic analysis and vapour pressure osmometry. Under the similar reaction conditions, the condensation of meso-phenyl-substituted tripyrrane derivative afforded an unprecedented tetrapyrrolic macrocycle fused with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone unit at their α-pyrrolic positions. The X-ray crystallographic analysis of the macrocycle revealed a twisted core structure, and nonaromatic nature was elucidated.

DOI： 10.1080/10610278.2016.1158408

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

In contrast to the general tendency that six coordinate iron( III) porphyrin complexes with neutral oxygen ligands adopt a high-spin state in a wide range of temperature, some complexes with substituted pyridine N-oxides have exhibited spin-crossover from high-spin to low-spin states with decreasing temperature both in solution and in the solid state.

DOI： 10.1039/c6dt03859j

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© The Royal Society of Chemistry. Vibrational circular dichroism (VCD) spectra are measured for dichloromethane solutions of the resolved enantiomers of [Ir(bzq)2(phen)]+ (bzqH = benzo[h]quinoline; phen = 1,10-phenanthroline). The absolute configuration of each enantiomer is determined by comparing the experimental and theoretical spectra. The result is in accord with the results of the X-ray single crystallographic analysis on the enantiomeric crystal. Moreover, the importance of the CH-π interaction is derived between phen and a hydrogen atom in bzq in the molecular packing of both the enantiomeric and racemic crystals. A helical column is formed in the enantiomeric crystal in the tetragonal space group P43, whereas a tight racemic pair is formed in the racemic crystal in the monoclinic space group P21/n.

DOI： 10.1039/c7dt00606c

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© 2017 Elsevier B.V. New synthetic strategy to synthesize α-methyl BODIPY derivatives from dipyrromethanes is reported. The method involves regioselective formylation of dipyrromethane followed by modified Wolff-Kishner reduction. The photophysical, electrochemical and computational studies of α-methyl BODIPY derivatives have been investigated in detail. The α-methyl BODIPY derivative was utilized further to prepare biologically important functionalized styryl-BODIPY library in high yield using microwave assisted Knoevenagel condensation. These synthesized dye derivatives were screened to find a potential candidate to track real-time in vitro tau protein fibrillization. Quinoxaline functionalized styryl-BODIPY derivative (5i) exhibited significant fluorescence enhancement upon binding to tau fibrils. Furthermore, tau-5i conjugate was systematically characterized by emission, aggregation kinetics, fluorescence microscopy and Atomic Force Microscopy techniques. Cell culture studies proved that compound 5i was cell permeable and non-toxic to live cells. In addition, a mechanism by which 5i interacts with tau fibrils has been elucidated which can be potentially exploited to further develop reporting dyes and inhibitors for tau aggregates.

DOI： 10.1016/j.snb.2016.12.104

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© 2017 The Japan Society for Analytical Chemistry. The title complex of a six-coordinated [5,10,15,20-tetrakis(2,4,6-trimethylphenyl)-porphyrinato-k4N]iron(III) complex with two 3,5-dimethylpyridine N-oxides, [Fe(TMP)(3,5-Me2PyNO)2]ClO4 (ClO4: perchlorate), was prepared, and characterized by a single-crystal X-ray diffraction method at 100(2)K. The title complex crystallizes in the triclinic space group P-1 with a = 15.2889(4)Å, b = 15.8587(4)Å, c = 16.2403(5)Å, α= 84.596(2)°, β= 63.769(3)°, γ= 84.162(2)°, V = 3508.49(19)Å3, Dx = 1.345 g/cm3, and Z = 2. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.0628 and 0.1517, respectively, for all 16923 independent reflections. The average Fe-N and Fe-O distances are 2.041(3)Å and 2.033(3)Å. The porphyrin ring is a completely planar structure. We will determine the magnetic behaviors by SQUID and ESR measurements.

DOI： 10.2116/xraystruct.33.49

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© 2017 The Japan Institute of Heterocyclic Chemistry. 4-Trifluoroacetyl-3-phenylsydnone was first synthesized by trifluoromethylation of 4-formyl-3-phenylsydnone followed by oxidation of the corresponding trifluoromethyl alcohol. The structure of the product was determined by single-crystal X-ray analysis.

DOI： 10.3987/COM-17-13802

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The title complex, [2,3,9,10,16,17,23,24-octakis(3-carboxyphenoxy)phthalocyaninato-k N-4](pyridine-k/N)zinc(II)pyridine octasolvate abbreviated as [ZnPc(3-CO2H)(8)(Py)].8(Py) (2), has been obtained by recrystallization of [ZnPc(3-CO2H)(8)] (1) from pyridine. Molecular structure of 2 determined by X-ray crystallography exhibits the anticipated Ns square pyramidal coordination around zinc(II) ion, where the average Zn-N(Pc) and Zn-N(Py) bond lengths are 2.027(4) angstrom and 2.121(4) angstrom, respectively. The deviation of the zinc(II) ion from phthalocyanine N-4 plane is 0.417 angstrom. Eight pyridine molecules are involved in hydrogen bonding with the carboxylic acid moieties of phenoxy rings in a 1:1 Two discrete phthalocyanine molecules in a unit cell are stacked in a back-to-back fashion with an interplanar distance of 3.376 angstrom. Pyridine solutions of 1 exhibit well-resolved H-1 NMR, UV-Vis, and fluorescent spectra, suggesting that 1 exists pyridine ligated monomeric species.

DOI： 10.3987/COM-16-13608

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Bis- and tris-fused pi-electron donors composed of extended tetrathiafulvalene with anthraquinoid spacers (4 and 5) were successfully synthesized. X-ray structure analysis of tetrakis(methylthio)-5 (5a) revealed that the molecule adopted a transoid-cisoid conformation. The cyclic voltammogram of 4a is composed of two pairs of two-electron redox waves, while the cyclic voltammogram of tetrakis(hexylthio) derivative 5b consists of one pair of four-electron redox waves and one pair of two electron redox waves, respectively. Spectroelectrochemistry of 4a and H-1 NMR spectrum of a 4b salt revealed that two positive charges in 4(2+) are distributed mainly on one TTFAQ (9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene) moiety.

DOI： 10.1021/acs.orglett.6b02944

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In this study, hexagonal shape-persistent cyclophane with D-2h symmetry and rigid dihedral angles was obtained through the key SNAr reaction of perfluorobenzene moieties and dipyrroles. The X-ray analysis of the compound thus obtained revealed a hexagonal macrocyclic structure with D-2h symmetry due to the dihedral angles of 120 degrees and double 120 degrees for bicyclo[2.2.2]octadiene:fused dipyrrole and syn-diethanotetrahydroanthracene-fused dipyrrole, respectively. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2016.07.086

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WORLD SCI PUBL CO INC  

A novel isoindole-containing polyaromatic hydrocarbon was unexpectedly formed during the synthesis of meso-2,6-dichlorophenyl-substituted tribenzosubporphyrin from a reaction of phthalimide and 2,6-dichlorophenylacetic acid in the presence of boric acid. Due to the highly annulated structure, this molecule exhibited blue color in solution, which was theoretically well reproduced by the HOMO-LUMO transitions based on the time-dependent DFT calculation. In this manuscript, the synthesis and properties of this polyaromatic hydrocarbon and meso-2,6-dichlorophenyl-substituted tribenzosubporphyrin are reported.

DOI： 10.1142/S1088424616500541

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A complex of Cyclo[8]pyrrole with polyoxometalate, POM-to-Rings, was synthesized by anion exchange from cyclo[8]pyrrole sulfate. X-ray crystallographic study revealed the double-decker structure. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2016.06.021

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An acenaphthylene-fused cyclo[10]pyrrole 1b was selectively synthesized via an oxidative coupling reaction of the corresponding 2,2'-bipyrrole with the appropriate dianion template, croconate anion. The structure of 1b as the isolated largest cyclo[n]pyrrole was elucidated by X-ray crystallographic analysis. The absorption spectrum exhibited a markedly red-shifted, intensified L band at 1982 nm, which was interpreted by application of Michl's perimeter and Gouterman's 4-orbital models, supported by magnetic circular dichroism (MCD) data and theoretical calculations.

DOI： 10.1021/jacs.6b04941

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Two ferrocene substituted aza-BODIPYs and their corresponding aza-dipyrrins were synthesized and studied. All the compounds were characterized by HRMS, NMR, IR, absorption spectroscopy and cyclic voltammetry techniques. Absorption spectra indicated intramolecular electron transfer from the ferrocene to the aza-BODIPY core. The X-ray crystal structure of 1,7-bisferrocenyl-aza-BODIPY suggested moderate interactions between the ferrocene moieties and aza-BODIPYs core. Ferrocenyl-aza-BODIPYs were non-emissive due to electron transfer from ferrocene moieties to boron aza-dipyrrin core. However the emission of these compounds was dramatically enhanced by oxidizing the ferrocene moieties to ferrocenium ions, which prevents electron transfer between these moieties. Cyclic voltammetry studies suggested that aza-BODIPYs were easier to be reduced as compared to their corresponding aza-dipyrrins.

DOI： 10.1142/S1088424616500693

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Novel near-infrared phosphorescent iridium(III) complexes based on benzo-annulated N-linked corrole analogue (termed as benzonorrole) were synthesized. The structures of the complexes revealed octahedral coordination geometries involving an organometallic iridium-carbon bond with two external axial ligands. Interestingly, the iridium(III) complex exhibits near-infrared phosphorescence at room temperature at wavelengths beyond 900 nm. The significant redshift of the emission, as compared to the corrole congener, is originated from the ligand-centered triplet character. The fine-tuning of the photophysical properties of the complexes was achieved by introducing electron-donating and electron-withdrawing substituents on the axial pyridine ligands.

DOI： 10.1021/acs.inorgchem.6b00853

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

The aromaticity reversal in the lowest triplet state (T-1) of a comparable set of Huckel/Mobius aromatic metalated expanded porphyrins was explored by optical spectroscopy and quantum calculations. In the absorption spectra, the T-1 states of the Mobius aromatic species showed broad, weak, and ill-defined spectral features with small extinction coefficients, which is in line with typical antiaromatic expanded porphyrins. In combination with quantum calculations, these results indicate that the Mobius aromatic nature of the S-0 state is reversed to Mobius antiaromaticity in the T-1 state. This is the first experimental observation of aromaticity reversal in the T-1 state of Mobius aromatic molecules.

DOI： 10.1002/anie.201602083

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Six donor-acceptor-type near-infrared (NIR) azaboron-dipyrromethene (BODIPY) dyes and their corresponding aza-dipyrrins were designed and synthesized. The donor moieties at the 1,7-positions of the aza-BODIPY core were varied from naphthyl to N-phenylcarbazole to N-butylcarbazole. The 3,5-positions were also substituted with phenyl or thienyl groups in the aza-BODIPYs. Photophysical, electrochemical, and computational studies were carried out. The absorption and emission spectra of aza-BODIPYs were significantly redshifted (approximate to 100 nm) relative to the parent tetra-phenylaza-BODIPY. Fluorescence studies suggested effective energy transfer (up to 93%) from donor groups to the aza-BODIPY core in all of the compounds under study. Time-dependent (TD)-DFT studies indicated effective electronic interactions between energy donor groups and aza-dipyrrin unit in all the aza-BODIPYs studied. The HOMO-LUMO gap (DE) calculated from cyclic voltammetry data was found to be lower for six aza-BODIPYs relative to their corresponding aza-dipyrrins.

DOI： 10.1002/asia.201600167

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The first synthesis of meso-fused carbaporphyrin via a premodification method was accomplished by substituting two pyrrole moieties and one meso-carbon with 2-(naphthalen-1-yl)thiophene. The obtained global pi-conjugation pathway of the macrocycle noticeably disturbs the 10 pi local aromaticity of naphthalene, and its aromatic nature was supported NMR spectroscopy together with nucleus-independent chemical shift, anisotropy of the induced current density, and harmonic oscillator stabilization energy calculations. In addition, the meso-fused carbaporphyrin also allowed the formation of a square planar Pd-II complex.

DOI： 10.1021/jacs.6b01063

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BODIPY-clickates, F1 and F2, for the detection of Hg2+ have been designed, synthesized and characterized. Both F1 and F2 showed hyperchromic shifts in the UV-visible spectra in response to increasing Hg2+ concentrations. Hg2+ ion binding caused perturbation of the emission quenching process and chelation induced enhanced bathochromic emission of F1 and F2 to 620 nm and 660 nm, respectively. Job's plot clearly indicated that the binding ratio of F1 and F2 with Hg2+ was 1 : 1. The NMR titration of BODIPY-clickates with Hg2+ confirmed that aromatic amines and triazoles were involved in the binding event. Furthermore, HRMS data of F1-Hg2+ and F2-Hg2+ supported the formation of mercury complexes of BODIPY-clickates. The dissociation constant for the interaction between fluorescent probes F1 and F2 with Hg2+ was found to be 24.4 +/- 5.1 mu M and 22.0 +/- 3.9 mu M, respectively. The Hg2+ ion induced fluorescence enhancement was almost stable in a pH range of 5 to 8. Having less toxicity to live cells, both the probes were successfully used to map the Hg2+ ions in live A549 cells.

DOI： 10.1039/c5dt04042f

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Language：Japanese   Publisher：The Surface Science Society of Japan  

DOI： 10.14886/sssj2008.36.0_289

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Trialkyl phosphites were evaluated as phosphorus nucleophiles for addition to mesoionic 4-trifluoroacetyl-1,3-oxazolium-5-olates (1), thereby producing tetravalent phosphorus zwitterions (2) in good yields. The structure of 2 was determined to be a tetravalent phosphonium enolate via single crystal X-ray analysis.

DOI： 10.1039/c6cc01627h

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(mu-1,2-Peroxo) diiron(III) complexes (2-R) with dinucleating ligands (R-L) generated from the reaction of bis(mu-hydroxo) diiron(II) complexes [Fe-2(R-L)(OH)(2)](2+) (1-R) with dioxygen in acetone at -20 degrees C provide a diiron-centred electrophilic oxidant, presumably diiron(IV)-oxo species, which is involved in aromatic ligand hydroxylation.

DOI： 10.1039/c5dt04088d

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

A series of symmetric and asymmetric benzo[c,d]indole-containing aza boron dipyrromethene (aza-BODIPY) compounds was synthesized by a titanium tetrachloride-mediated Schiff-base formation reaction of commercially available benzo[c,d]indole-2(1H)-one and heteroaromatic amines. These aza-BODIPY analogues show different electronic structures from those of regular aza-BODIPYs, with hypsochromic shifts of the main absorption compared to their BODIPY counterparts. In addition to the intense fluorescence in solution, asymmetric compounds exhibited solid-state fluorescence due to significant contribution of the vibronic bands to both absorption and fluorescence as well as reduced fluorescence quenching in the aggregates. Finally, aggregation-induced emission enhancement, which is rare in BODIPY chromophores, was achieved by introducing a nonconjugated moiety into the core structure.

DOI： 10.1002/chem.201501464

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/ange.201502285

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

A contracted doubly N-confused dioxohexaphyrin derivative served as a dinucleating metal ligand for unsymmetrical coordination. The complexation of two palladium(II) cations led to the formation of pi-radical species that were persistent in atmospheric air in the presence of moisture. Effective delocalization of an unpaired electron over the hexaphyrin backbone could contribute to the distinct chemical stability.

DOI： 10.1002/anie.201502285

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Molecular binding of fullerenes, C-60 and C-70, with the Zn-II complex of a monomeric ring-fused porphyrin derivative (2-py) as a host molecule, which has a concave pi-conjugated surface, has been confirmed spectroscopically. The structures of associated complexes composed of fullerenes and 2-py were explicitly established by X-ray diffraction analysis. The fullerenes in the 2:1 complexes, which consist of two 2-py molecules and one fullerene molecule, are fully covered by the concave surfaces of the two 2-py molecules in the crystal structure. In contrast, in the crystal structure of the 1:1 complex consisting of one 2-py molecule and one C-60 molecule, the C-60 molecule formed a pi-pi stacked pair with a C-60 molecule in the neighboring complex using a partial surface, which was uncovered by the 2-py molecule. Additionally, the molecular size of fullerene adopted significantly affects the H-1 NMR spectral changes and the redox properties of 2-py upon the molecular binding.

DOI： 10.1002/chem.201500389

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Ficifolidione (1), a moderately active insecticidal compound from two species of Myrtaceae, and its derivatives were synthesized to evaluate their insecticidal activity. X-ray crystallographic analyses and specific rotation values of ficifolidione and its C-4 (2) demonstrated that the structure of ficifolidione differs from the reported absolute structure; that is, the C-4 configuration of ficifolidione should have an S configuration. The reported insecticidal activity of ficifolidione (1) and its C-4 epimer (2) against adult houseflies (Musca domestica), mosquito larvae (Culex pipiens), and cutworms (Spodoptera litura) was not observed. The cytotoxicities of ficifolidione and its derivatives (14) against four cell lines, Sf9, Colon26, HL60, and Vero, were also measured because ficifolidione has a phloroglucinol-derived moiety, a motif that is often present in the structure of cytotoxic chemicals. Compound 1 exhibited IC50 values of ca. 32, 9, 3, and 12 mu M for Sf9, Colon26, HL60, and Vero cells, respectively, indicating that ficifolidione possesses selective cytotoxicity against the four cell lines. In HL60 cells treated with 1, DNA fragmentation and the activation of procaspase 3 were observed, suggesting that the cytotoxicity is induced by apoptosis.

DOI： 10.1021/np5006746

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WORLD SCI PUBL CO INC  

Novel tin(IV) halo complexes of an N-confused tetraphenylporphyrin with different axial ligands have been synthesized and characterized by various spectroscopic methods including X-ray crystallographic analysis. The molecular structures of the dichloro and dibromo derivatives possess perfect octahedral geometries, which are nearly comparable to the corresponding regular porphyrin complexes. In contrast, the iodide/triiodide complex obtained by a same reaction manner, demonstrated that the tin(IV) cation is slightly displaced towards axially coordinated iodide anion, giving rise to the different electronic structure due to the tautomeric form of N-confused porphyrin ligand. These structural differences reflected to the distinct photophysical and electrochemical properties. The Sn(IV) complexes are near IR luminescent, however the unsymmetrical axial coordination of iodide and triiodide anions in the tin(IV) N-confused porphyrin complex allows, in particular, the longer emission lifetimes and a smaller singlet-triplet energy gap, which were investigated by steady-state and time-resolved spectroscopies as well as theoretical calculations.

DOI： 10.1142/S1088424615500212

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

4,8-Dihydropyrrol[3,4-f]isoindole was prepared from 4,7-dihydroisoindole based on the modified Barton-Zard reaction. Addition of phenylsulfenyl chloride followed by oxidation and dehydrochlorination gave phenylsulfonyldihydroisoindole, which underwent the smooth reaction with an isocyanoacetate under basic conditions to give 4,8-dihydropyrrol[3,4-f]isoindole-1,5- and 1,7-dicarboxylates in good yields. The pyrrolisoindole was successfully converted to the benzene-fused bisBODIPY, absorption maximum of which was 758 nm.

DOI： 10.3987/COM-14-S(K)91

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Herein we demonstrate that the addition of tert-butyl cobalt phthalocyanine (tb-CoPc) into the electrolyte improved the charging performance in a coin-type Li-air battery. The improvement is attributed to the ability of the added tb-CoPc to serve as a diffusive catalyst for the aprotic oxygen evolution reaction. (C) 2014 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2014.12.036

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A series of bis-BODIPYs 1-6 bridged via thiophene, furan, N-alkylcarbazole, triphenyl-amine, para-and meta-phenylene groups have been synthesized and characterized by various spectroscopic techniques. The change in the spectroscopic properties of bis-BODIPYs upon varying the size of spacers was studied. X-ray crystal structures of three bis-BODIPYs containing triphenylamine, para- and meta-phenylene bridges were solved. Intermolecular C(H)center dot center dot center dot pi and pi center dot center dot center dot pi stacking interactions were observed in solid state structures of three bis-BODIPYs. The dihedral angles between the spacer unit and two boron-dipyrrin units were lower in all three compounds as compared to their corresponding monomers. This suggests increased interactions between the two boron-dipyrrin units in molecules which are in turn reflected in the anodic shifts in their reduction potentials. DFT studies indicated effective electronic interactions between spacers and two boron dipyrrin units in all the bis-BODIPYs. The calculated HOMO-LUMO gap was found to be lower for bis-BODIPY having bulky carbazole spacers and higher for bis-BODIPY having smaller furan spacers. Changing the spacer size clearly affected the spectroscopic properties of the bis-BODIPYs and red shifted absorption and emission maxima were observed for bis-BODIPYs with furan and thiophene spacers as compared to bis-BODIPYs with phenylene or bulky aromatic spacers.

DOI： 10.1039/c5dt01925g

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Since the oxygen evolution reaction (OER) in aprotic Li ion electrolytes is a crucial reaction in the charging process of nonaqueous aprotic Liair batteries, there is a strong demand for decreasing the overpotential by developing more efficient OER catalysts. Herein, we investigated the effect of addition of transition metal complexes with macrocyclic ligands, such as porphyrins and phthalocyanines, for OER in aprotic Li ion electrolytes. Electrochemical experiments using a three-electrode system revealed that such complexes functioned as efficient OER catalysts, in which the center metal in the complex played an essential role in the catalytic process. Among the metal complexes studied, cobalt tert-butylphthalocyanine was found to be the best catalyst: the charging potential was lowered from 4.1 V to about 3.4 V at 1 mu A/cm(2) by addition of 1 mM catalyst

DOI： 10.1021/jp5088465

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Electrophilic phenylsulfenylation of syn-7-tert-butoxy-2-phenylsulfonyl- bicyclo[2.2.1] hepta-2,5-diene with phenylsulfenyl chloride yielded a mixture of three simple adducts, two of which were derived by the endo face attack of the phenylsulfenyl cation. In the analogous reaction with the anti derivative, only one adduct with the exo phenylsulfanyl group at the nearer carbon was obtained. This product was derived by the attack of the phenylsulfenyl cation from the exo face followed by the endo attack of a chloride anion at the carbon opposite to the phenylsulfonyl group. The similar reaction of 7-tert-butoxybicyclo[2.2.1]hepta-2,5-diene itself underwent no Wager-Meerwein-type rearrangement or transannular reaction, and simple adducts were formed in good combined yield. The combined yield of the products reacted at the syn double bond was ca. 80%.

DOI： 10.1002/hc.21172

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WORLD SCI PUBL CO INC  

A series of O-chelated BODIPYs fused with aromatic rings such as benzene and acenaphthylene at beta,beta-positions was synthesized as a near-infrared dye. The photophysical properties were examined by UV-vis-NIR absorption and fluorescence measurement. Acenaphthylene-fused O-BODIPYs showed a intense absorption at 750-840 nm with the epsilon of 10(5) M-1.cm(-1). and a fluorescene emission at 770-850 nm with the high Phi value of 0.06-0.43.

DOI： 10.1142/S1088424614500503

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

The simple molecular salt NMQ[Ni(dmit)(2)] (NMQ = N-methylquinolinium, dmit = 1,3-dithiol-2-thione-4,5-dithiolate) functions as a diamagnetic insulator with an activation energy E-a(dark) of 0.20 eV. However, at 300 K, it exhibits ca. 40 times higher conductivity (sigma(UV)) under UV irradiation [(375 +/- 5) nm, 15.7 mW cm(-2)] than it does under dark conditions (sigma(dark)). The ratio sigma(UV)/sigma(dark) rapidly increases with decreasing temperature and reaches ca. 880 at 200 K. From the temperature dependence of sigma(UV), the activation energy under irradiation E-a(UV) is 0.12 eV. These observations cannot be explained as the result of sample heating during UV irradiation. Rather, the X-ray photoelectron spectra of the sulfur and nickel atoms, the calculated band structure, and the UV/Vis spectra of the salt can all be explained consistently as follows: charge transfer between the Ni(dmit)(2) moieties upon exposure to 375 nm UV light induces melting of the charge-ordered state and produces the unusually large photoconductivity of NMQ[Ni(dmit)(2)].

DOI： 10.1002/ejic.201402035

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

beta-DiCC[Ni(dmit)(2)] (dmit: 1,3-dithiole-2-thione-4,5-dithiolato and DiCC: 3,3'-dihexyloxacarbocyanine) is a charge-transfer salt with redox activity. When voltages are applied, it brings about a reversible, hysteretic, solid-state-electrolytic reaction exhibiting a capacitor-like electric response. Based on the electron spin resonance spectra, the resistivity behavior, and the tight-binding band calculation, it is indicated that one can finely and reversibly control the redox equilibrium between DiCC(+) and [Ni(dmit)(2)](-) molecules by applying voltages.

DOI： 10.1246/cl.140309

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

1,3-Bisarylated-2,2'-biazulene 1 and 1,1'-bisarylated-2,2'-biazulene 1' were obtained by the Suzuki-Miyaura crosscoupling reaction of 1,1',3,3'-tetrahalo-2,2'-biazulene 2 with 4-tert-butylphenylboronic acid (3b). The other two halogen atoms were reductively removed by hydrogenation under the same reaction conditions. The major regioisomer 1 was obtained with a selectivity of up to 94% (15:1) and a combined yield of 1 and 1' of up to 77%.

DOI： 10.1246/cl.131142

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Free-bases and a nickel(11) complex of phenothiazine-bridged cyclic porphyrin dimers bearing self-ssembling 4-pyridyl groups (M(2)PtzCPD(Py)(OCn); M = H-2 or Ni, OCn = OC6 or OC3) at opposite mesopositions have been prepared as host molecules for fullerenes. The freebase dimer (H(4)Ptz-CPDPy(OC6)) includes fullerenes with remarkably high association constants such as 3.9 +/- 0.7 x 10(6) M-1 for C-60 and 7.4 +/- 0.8 x 10(7) M-1 for C-70 in toluene. This C-60 affinity is the highest value ever among reported receptors composed of freebase porphyrins. The nickel dimer (Ni-2-Ptz-CPDPy(OC6)) also shows high affinities for C-60 (1.3 +/- 0.2 x 10(6) M-1) and C-70 (over 10(7) M-1). In the crystal structure of the inclusion complex of C-60 within H(4)PtzCPD(Py)(OC3()), the C-60 molecule is located just above the centers of the porphyrins. The two porphyrin planes are almost parallel to each other and the center-to-center distance (12.454 angstrom) is close to the optimal separation (similar to 12.5 angstrom) for C-60 inclusion. The cyclic porphyrin dimer forms a nanotube through its self-assembly induced by C-H center dot center dot center dot N hydrogen bonds between porphyrin beta-CH groups and pyridyl nitrogens as well as pi-pi interactions of the pyridyl groups. The C-60 molecules are linearly arranged in the inner channel of this nanotube.

DOI： 10.1021/jo500034f

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Protonation of meso-aryl [28]hexaphyrins(1.1.1.1.1.1) triggered conformational changes. Whereas protonation with trifluoroacetic acid led to the formation of monoprotonated Mobius aromatic species, protonation with methanesulfonic acid led to the formation of diprotonated triangular antiaromatic species. A peripherally hexaphenylated [28]hexaphyrin was rationally designed and prepared to undergo diprotonation to favorably afford a triangular-shaped antiaromatic species.

DOI： 10.1002/anie.201400301

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The Hinsberg thiophene synthesis using 4,5,6,7-tetrahydro-4,7-ethanothiophene-5,6-dione and diethyl thiodiglycolate afforded a mixture of diethyl 4,8-dihydro-4,8-ethanobenzo[1,2-c;4,5-c']dithiophene-1,3-dicarboxylate and its dihydrate, although the yields were low. The latter dihydrate was converted to the former dithiophene in a good yield by the treatment with Ac2O and DMAP.

DOI： 10.3987/COM-13-S(S)53

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Cyclo[8]pyrrole with eight 9,10-dihydroanthracene wings was synthesized by oxidative coupling of the corresponding 2,2'-bipyrrole in good yield. The molecular structure was determined by single crystal X-ray analysis. The three-dimensionally structured cyclo[8]pyrrole possessed a cavity created by a pair of slip-stacked cyclo[8]pyrroles.

DOI： 10.3987/COM-13-S(S)42

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：World Scientific Publishing Co. Pte Ltd  

A series of O-chelated BODIPYs fused with aromatic rings such as benzene and acenaphthylene at β,β-positions was synthesized as a near-infrared dye. The photophysical properties were examined by UV-vis-NIR absorption and fuorescence measurement. Acenaphthylene-fused O-BODIPYs showed a intense absorption at 750-840 nm with the ε of 105 M-1.cm-1. and a fuorescene emission at 770-850 nm with the high Φ value of 0.06-0.43.

DOI： 10.1142/S1088424614500503

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society for Analytical Chemistry  

The title complex of a six-coordinated (2,3,7,8,12,13,17,18-octaethylporphyrinato)iron(III) complex with two 4-methylpyridine N-oxides, [Fe(OEP)(4-MePyNO)2]BF4 (BF4: Tetrafluoroborate), was isolated, and the crystal structure was determined by the single-crystal X-ray diffraction method at 100(2)K. It crystallizes in the triclinic space group P-1 with a = 7.9064(2)Å, b = 13.7091(4)Â, c = 20.7535(6)Å, A = 90.870(2)°, ß = 92.579(2)°, γ = 93.419(2)°V = 2242.83(11)Å3, Dx = 1.323 g/cm3, and Z = 2. The R1 [I &gt
2σ(I)] and wR2 (all data) values are 0.0517 and 0.1167, respectively, for all 10829 independent reflections. The average Fe-N and Fe-O distances are 2.045(2)Â and 2.093(1)Å. The porphyrin ring is a perfectly planar structure. We will determine the magnetic behaviors by SQUID and ESR measurements.

DOI： 10.2116/xraystruct.33.25

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A novel doubly N-confused isophlorin (2) was prepared by the nucleophilic ring-opening reaction of N-confused, N-fused porphyrin (1) with benzenethiol. The structure, redox property and copper coordination ability of isophlorin 2 were investigated by various spectroscopic methods and theoretical calculations.

DOI： 10.1039/c4cc06259k

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Bicyclo[2.2.2]octadiene-fused (BCOD-fused) bis(benzoborondipyrromethene)s (bisbenzoBODIPYs) bearing electron-withdrawing groups such as fluorine and cyano groups were prepared either by incorporating tetrafluoroisoindole moieties into BODIPY chromophores or by introducing cyano or ethoxycarbonyl groups at the 3,5-positions. The BCOD-fused bisbenzoBODIPYs were quantitatively converted to the corresponding benzene-fused bisbenzoBODIPYs by a retro-Diels-Alder reaction. The pi-fused bisbenzoBODIPYs were found to have intense absorption in the near-infrared region and not to have any strong absorption bands in the visible region. Moreover, the bisbenzoBODIPYs were stable under atmospheric conditions.

DOI： 10.1039/c3ob41996g

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A novel doubly N-confused isophlorin (2) was prepared by the nucleophilic ring-opening reaction of N-confused, N-fused porphyrin (1) with benzenethiol. The structure, redox property and copper coordination ability of isophlorin 2 were investigated by various spectroscopic methods and theoretical calculations.

DOI： 10.1039/c4cc06259k

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Boron complexes of [14]triphyrins(2.1.1) were prepared from free-base [14]triphyrins(2.1.1) with phenylboron dichloride. The absorption spectrum of the meso-free β-alkyl-triphyrin boron complex in CH2Cl 2 showed a broad weak band at around 640 nm assigned to transition from B-phenyl to the triphyrin, while that of the meso-aryl benzotriphyrin boron complex showed only Soret and Q bands. © 2013 The Royal Society of Chemistry.

DOI： 10.1039/c3cc44788j

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

An acenaphthylene-fused cyclo[8]pyrrole was synthesized by using an oxidative coupling reaction of the corresponding 2,2-bipyrrole. Two conformational isomers 1a and 1b were isolated, and their molecular structures were elucidated by X-ray crystallographic studies. The less-polar and lower-symmetry 1b isomer can be converted into the 1a isomer through a thermal ring flip. Application of the perimeter model developed by Michl to magnetic circular dichroism spectroscopic data and theoretical calculations demonstrate that there is a marked redshift of the near-IR absorption maxima relative to cyclo[8]isoindole because there is a significant stabilization of the LUMO due to the differing effects of a fused ring expansion with acenaphthylene and benzene moieties on the frontier molecular orbitals.

DOI： 10.1002/chem.201301294

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/ange.201302955

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Metalation of 6,13,20,21-tetrakis(4-methyl-phenyl)-22H-tribenzo[14]triphyrin(2.1.1) with PtCl2 gave a platinum(II) complex having a square-planar coordination structure with two pyrrolic nitrogen atoms and two chloride ions, with a saddle-shaped macrocycle. This platinum(II) complex was easily oxidized by air to an octahedral platinum(IV) complex coordinated by three pyrrolic nitrogen atoms as a tridentate monoanionic cyclic ligand and three chloride ions. When platinum(II) triphyrin was crystallized in air, an oxygen atom was incorporated between two alpha-carbon atoms of the pyrroles as an oxygen bridge to intercept the 14 pi aromatic system.

DOI： 10.1021/ic302624h

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Elusive in its free-base form, the core-modified contracted porphyrin thiatriphyrin(2.1.1) was prepared with p-tolyl substituents by intramolecular McMurry coupling and then converted into various alkoxy-substituted analogues (see scheme; DBU=1,8-diazabicyclo[5.4.0]undec-7-ene). In the presence of trifluoroacetic acid (TFA), each of these compounds was transformed into the protonated thiatriphyrin(2.1.1), which exhibited moderate aromaticity. © 2013 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

DOI： 10.1002/anie.201209678

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

A pyrrolic rearrangement reaction of singly N-confused [26]hexaphyrin mediated by PdCl2 afforded doubly N-confused [26]hexaphyrin bis(PdII) complex. The bis(PdII) complex is a rare example of an aromatic compound with definite non-degenerate HOMOs and LUMOs. Copyright © 2013 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

DOI： 10.1002/anie.201302955

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Ethyl 12-oxo-4,11-dihydro-4,11-ethanonaphth[2,3-f]isoindole-1-carboxylate (2) was prepared from 7-tert-butoxynorbornadiene and quantitatively converted to ethyl naphth[2,3-f]isoindole-1-carboxylate (3) by the thermal or photochemical cheletropic reaction. Ethyl naphth[2,3-f] isoindole-1-carboxylate (3) existed in a 2H-form both in solution and as a solid, and gradually dimerized to give a dianthradiazafulvalene derivative under aerobic conditions.

DOI： 10.1039/c2ra22870j

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Peripherally pi-extended N-confused porphyrin rhenium complexes were synthesized by the rhenium-mediated reactions of N-confused porphyrins with 2-methyl azaarene and the structures were elucidated by X-ray crystallographic analyses. Extension of the pi-conjugation in the complexes was supported by the absorption spectra, electrochemical measurements and theoretical calculations.

DOI： 10.1039/c2sc20708g

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The ring-opening reaction of N-fused tetraphenylporphyrin (NFTPP-H, 2) to C3-substituted N-confused tetraphenylporphyrin (NCTPP-S-Ar, 4) proceeded efficiently in 85-95% yields. Furthermore, removal of the C3-arylthio-substituents in 4 was achieved by the two types of desulfurization reactions. The Ni2B-mediated desulfurization afforded C3-free N-confused tetraphenylporphyrin (NCTPP-H, 1) whereas the radical-mediated desulfurization with (n-Bu)(3)Sn-H and AIBN promoted the ring-fusion to afford 2. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2012.08.131

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UV irradiation reversibly switches a new insulating and nonmagnetic molecular crystal, BPY[Ni(dmit)(2)](2) (BPY = N,N'-ethylene-2,2'-bipyridinium; Ni(dmit)(2) = bis(1,3-dithiole-2-thione-4,5-dithiolato)nickelate(III)), into a magnetic conductor. This is possible because the bipyridyl derivative cations (BPY2+) trigger a photochemical redox reaction in the crystal to produce a change of similar to 10% in the filling of the Ni(dmit)(2) valence band, leaving localized spins on the BPY themselves. In the dark, almost all of the BPY molecules are closed shell cations, and most of the Ni(dmit)(2). radical anions form spin singlet pairs; thus, this material is a diamagnetic semiconductor. Under UV irradiation, a photocurrent is observed, which enhances the conductivity by 1 order of magnitude Electron-spin resonance. measurements indicate that the 'UV:. irradiation reversibly generates. carriers and localized spins on the Ni(dmit)(2). and the BPY, respectively: This high photoconductivity can be explained by charge transfer (CT) transitions between Ni(dmit)(2) and BPY in the UV region. In other words, the photoconduction and "photomagnetism" can be described as reversible optical control of the electronic states between an ionic salt (BPY2+/[Ni(dmit)(2)](-), nonmagnetic insulator) and a CT complex (BPY2(1-delta)+/[Ni(dmit)(2)]((1-delta)-) (delta approximate to 0.1), magnetic conductor) in the solid state.

DOI： 10.1021/ja306260b

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6,13-Diiododibenzo[a,h]anthracene and 5,8-diiodopicene were synthesized by AuCl-catalyzed double cyclization. The highly selective reaction yielded a new class of pen-halogenated fused aromatics. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2012.01.071

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

5,14-alpha-Diketopentacene, a structural isomer of 6,13-alpha-diketopentacene, was prepared from pentacene in three steps. In addition to the typical n-pi* absorption of the diketone moiety at around 468 nm and the anthracene-like absorption at 333, 349, and 367 nm, a broad absorption was observed at around 386 nm, which could be assigned to an intramolecular charge-transfer absorption from anthracene to the diketone moiety. 5,14-alpha-Diketopentacene could be converted into pentacene quantitatively by photoirradiation at 405 and 468 nm in toluene with quantum yields of 2.3 and 2.4%, respectively, and these values are higher than the quantum yield of 1.4% obtained for 6,13-alpha-diketopentacene irradiated at 468 nm. The quantum yields in acetonitrile were lowered to 0.33 and 0.28% with irradiation at 405 and 468 nm. The crystal structure of 5,14-alpha-diketopentacene showed a CH-pi interaction and pi-pi stacking between neighbouring anthracene and benzene moieties. The lower solubility of 5,14-alpha-diketopentacene compared with the 6,13-isomer could be explained by this crystal structure.

DOI： 10.1002/ejoc.201101736

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Singly N-confused [26] and [28]hexaphyrins (4, 5) with planar and twisted structures, respectively, were prepared via the acid catalyzed [3 + 3] condensation of N-confused and regular tripyrrane precursors. Huckel aromaticity is observed for [26]hexaphyrin, while the [28]hexaphyrin and its mono-Pd(II) complex exhibit "nonaromaticity" in spite of their Mobius-type structures, judging from the spectroscopic features and theoretical calculations.

DOI： 10.1039/c2dt30306j

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Benzene-fused bis-(borondipyrromethene)s (bis-BODIPYs) were synthesized by retro-Diels-Alder reaction of the corresponding bicyclo[2.2.2]octadiene-fused (BCOD-fused) bis-BODIPYs, which were, in turn, prepared from 4,8-ethano-4,8-dihydropyrrolo[3,4-f]isoindole derivatives. The pi-fused bis-BODIPY chromophores were designed to show intensive absorption and strong fluorescence in the near-infrared region and not to have any strong absorption in the visible region. A 6,10-dibora-5a,6a,9a,10a-tetraaza-s-indaceno[2,3-b:6,5-b']difluorene derivative (syn-bis-benzoBODIPY) obtained by a thermal retro-Diels-Alder reaction of the corresponding BCOD-fused BODIPY dimer has strong absorption and emission bands at 775 and 781 nm, respectively. The absolute quantum yield is 0.36. The absorption is more than 5.0 times stronger than other absorptions observed in the visible region. In the case of 6,15-dibora-5a,6a,14a,15a-tetraaza-s-indaceno[2,3-b:6,7-b']difluorene derivatives (anti-bis-benzoBODIPY), the absorption and emission maxima exceed 840 nm.

DOI： 10.1039/c2ob25930c

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WORLD SCI PUBL CO INC  

A series of benzoporphycenes and naphthoporphycenes and their zinc complexes were prepared from bicyclo[2.2.2]octadiene fused porphycenes by a retro-Diels-Alder reaction and their photophysical properties were studied. Free-base tetranaphthoporphycene was not soluble in common organic solvents, but zinc tetranaphthoporphycene was slightly soluble in pyridine and showed B- and Q-bands at 507 and 690 nm, respectively. Dinaphthoporphycene showed broad B- and Q-bands due to its lower symmetry. Tetrabenzo-, dibenzo-, and dinaphthoporphycenes showed fluorescence at 673, 654, and 670 nm with quantum yields of 0.32, 0.42, and 0.31, respectively, although their precursors were non-fluorescent. Zinc complexes of tetrabenzo-, dibenzo-, tetranaphtho-, dinaphthoporphycenes and their bicyclo[2.2.2]octadiene-fused precursors revealed moderate fluorescence with quantum yields of 0.15-0.37. The crystal structures of tetrabenzo-and dibenzoporphycenes showed herringbone structures, while the zinc tetrabenzoporphycene showed a hexagonal box-structure with six pyridine ligands inside.

DOI： 10.1142/S1088424611003823

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WORLD SCI PUBL CO INC  

Facing zinc bisporphyrins connected with diethanoanthracene and diethanonaphthacene (syn-1 and syn-2) are prepared by double [3+1] porphyrin synthesis of tripyrranedicarbaldehyde with syn-5,11-dimethoxy-4,6,10,12-tetrahydro-4,12;6,10-diethanoanthracene[2,3-c;7,8-c']dipyrrole and syn-4,7,11,14-tetrahydro-4,14;7,11-diethanonaphthacene[2,3-c;8,9-c']dipyrrole. These bisporphyrins contain large clefts with different sizes capable for complexation with fullerenes such as C-60 and C-70. These designed syn-oriented bisporphyrins serve as effective and selective molecular tweezers for C-70. Binding affinity of the zinc bisporphyrins, namely, syn-1 and syn-2, towards C-60 and C-70 in solution is determined by employing UV-vis spectrophotometric technique. Values of binding constants (K) in toluene for the non-covalent complexes of syn-1 with C-60 and C-70 are estimated to be 3.1(4) x 10(4) and 5.0(2) x 10(5) M-1, respectively, and those of syn-2 with C-60 and C-70 are enumerated to be 2.1(4) x 10(4) and 1.70(13) x 10(5) M-1, respectively. Binding of C-60 and C-70 in the clefts of syn-1 and syn-2 is clearly demonstrated by the crystal structures of C-60/syn-1, C-70/syn-1, C-60/syn-2, and C-70/syn-2 complexes. In the crystal structures with C-70, the directions of the long axis of C-70 are found to be quite different: in the case of C-70/syn-1 complex the axis lies perpendicularly to the line connecting two zinc atoms; however, for the C-70/syn-2 complex, the axis occupies in-plane to the same line. Both the clefts of syn-1 and syn-2 are induced to fit the included fullerenes by domed out-of-plane distortion of porphyrin rings. Moreover, the bicyclo[2.2.2]octadiene moieties of syn-1 are widened by complexation with the fullerenes, while the same moieties of syn-2 are narrowed by the complexation. Therefore, syn-1 catches the fullerenes at the shallow part of the cleft. On the other hand, syn-2 catches the fullerenes at the bottom part of the cleft. NMR experiments of the complexes in THF-d(8) also support these orientations even in solution.

DOI： 10.1142/S1088424611003872

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

A pi-expanded BODIPY dye with an intramolecular boronate skeleton was synthesized by retro Diets-Alder reaction of the bicyclo[2.2.2]octadiene (BCOD)-fused BODIPY and the subsequent O-chelation. The photophysical and electrochemical properties were examined by UV-vis, fluorescence, CV measurements, and DFT calculation. This BODIPY exhibited the absorption and emission over a visible-NIR region at 600-850 nm. O-chelated BODIPY showed a bathocromic shift compared to F-BODIPYs. This dye showed a bright fluorescence emission at 733 nm with the high phi value of 0.58. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2011.03.016

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

The synthesis of dodecasubstituted porphycenes has not been reported, to date. Herein, the preparation of tetramethyloctaethylporphycene by a McMurry-type coupling of 3,3', 4,4'-tetraethyl-5,5'-diformyl-2,2'-bipyrrole was attempted at first, but dodecasubstituted porphycene was not successfully obtained and only pyrrolocyclophene was obtained. The structure of the pyrrolocyclophene was determined by H-1 NMR spectroscopy, FAB MS, and X-ray crystal-structure analysis. The pyrrolocyclophene was not successfully oxidized to porphycene. Then, the McMurry-type coupling of bicyclo[2.2.2]octadiene (BCOD)-fused 5,5'diacyl-2,2'-bipyrroles was performed and tetra-meso-octa-beta-substituted (dodecasubstituted) porphycenes were successfully obtained for the first time. The structures were determined by H-1 NMR spectroscopy and X-ray crystal-structure analysis. The crystal structures and NMR spectra were compared carefully with octasubstituted porphycenes, and there was a good correlation between the position of the substituents, the N1-N2 and N1-N4 distances of the porphycene inner nitrogen atoms, and NMR chemical shifts of the inner NH protons, which expressed the strength of N-H center dot center dot center dot N hydrogen bonding between N1 and N2. These results suggested that the BCOD structure was relatively compact compared with common alkyl groups and that was why the dodecasubstituted porphycenes were available this time. UV/Vis absorption and fluorescence properties are also discussed.

DOI： 10.1002/chem.201002788

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

5,12-Dicyanonaphthacene and 6,13-dicyanopentacene have been synthesized for the first time. The LUMO and HOMO levels are deepened as predicted and fabricated organic field-effect transistors (OFETs) showed ambipolar responses with carrier mobilities of 10(-3) cm(2)/V.s.

DOI： 10.1021/ol200145r

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The effects of artificial porphyrins on the electron-transport chains of living microbes were investigated. The participation of porphyrins in the microbial electron-transport chains was demonstrated by spectroscopic and current-generation measurements. Large enhancement of the microbial current generation was accomplished by adding a cationic water-soluble manganese porphyrin as an electron mediator.

DOI： 10.1021/ic100342k

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Retro: Cyclo[8]isoindole, which has a saddle-shaped geometry (see picture, 2), was synthesized by oxidative coupling of a bicyclo[2.2.2]octadiene(BCOD)- fused 2,2′-bipyrrole followed by a retro-Diels-Alder reaction of BCOD-fused cyclo[8]pyrrole (1). Key trends in the optical spectra of ring-annelated cyclo[8]pyrroles are identified based on magnetic circular dichroism spectra and theorectical calculations. Copyright © 2011 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

DOI： 10.1002/anie.201007510

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Novel bisimide-fused acenes were synthesized via bismuth triflate mediated double-cyclization reaction of acid chlorides and isocyanates. Their optical and electrical properties revealed significantly smaller HOMO-LUMO gaps compared with those of their parent acenes. Fabricated OFET based on tetracene bisimide showed n-type OFET outputs.

DOI： 10.1039/c1cc13980k

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

The metal-free and meso-free [14]triphyrin(2.1.1) compound was successfully prepared based on the intramolecular McMurry coupling reaction of diformyl-tripyrrane in 16% yield, and was converted to the bowl-shaped Mn(I)(TriP)(CO)(3) and Re(I)(TriP)(CO)(3).

DOI： 10.1039/c0cc04286b

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

(Chemical Equation Presented) Mix and match: The title porphyrinoid has been synthesized and shows unique coordination chemistry by incorporating two different metals with different oxidation states (see figure). X-ray crystallography was used to confirm that a rectangular conformation in both mono- and binuclear complexes was retained. © 2011 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

DOI： 10.1002/anie.201006784

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Pore genius: A nanoporous composite of graphite felt and polyaniline was developed and used as the anode of a microbial fuel cell, resulting in an order of magnitude increase in power output. The hierarchical conductive anode is a promising strategy for constructing highly efficient microbial fuel cells (see figure). (Figure Presented) © 2010 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

DOI： 10.1002/chem.200903486

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A mild, efficient and LiCl-free synthetic method for indole derivatives based on the heteroannulation of alkynes with 2-iodoanilines was achieved using palladium on carbon (Pd/C) and NaOAc in heated NMP. The N-tosyl protection of 2-iodoaniline expedited the reaction progress, while other protecting groups, such as tert-butoxycarbonyl, acetyl, and benzyloxycarbonyl groups, underwent deprotection under the present conditions. A variety of di- and monosubstituted alkynes could effectively react with N-tosyl-2-iodoaniline to give the corresponding indoles in good to high yields.

DOI： 10.1039/c004939e

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SOC MICROBIOLOGY  

Although members of the genus Shewanella have common features (e. g., the presence of decaheme c-type cytochromes [c-cyts]), they are widely variable in genetic and physiological features. The present study compared the current-generating ability of S. loihica PV-4 in microbial fuel cells (MFCs) with that of well-characterized S. oneidensis MR-1 and examined the roles of c-cyts in extracellular electron transfer. We found that strains PV-4 and MR-1 exhibited notable differences in current-generating mechanisms. While the MR-1 MFCs maintained a constant current density over time, the PV-4 MFCs continued to increase in current density and finally surpassed the MR-1 MFCs. Coulombic efficiencies reached 26% in the PV-4 MFC but 16% in the MR-1 MFCs. Although both organisms produced quinone-like compounds, anode exchange experiments showed that anode-attached cells of PV-4 produced sevenfold more current than planktonic cells in the same chamber, while planktonic cells of MR-1 produced twice the current of the anode-attached cells. Examination of the genome sequence indicated that PV-4 has more c-cyt genes in the metal reductase-containing locus than MR-1. Mutational analysis revealed that PV-4 relied predominantly on a homologue of the decaheme c-cyt MtrC in MR-1 for current generation, even though it also possesses two homologues of the decaheme c-cyt OmcA in MR-1. These results suggest that current generation in a PV-4 MFC is in large part accomplished by anode-attached cells, in which the MtrC homologue constitutes the main path of electrons toward the anode.

DOI： 10.1128/AEM.01142-09

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/ange.200900596

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

At room temperature, meso-hexaaryl-substituted [28]hexaphyrins(1.1.1.1.1.1) in solution exist largely as an equilibrium between planar antiaromatic and distorted Mobius aromatic conformers. As the temperature decreases, the molecular structure changes into the distorted Mobius topology that commonly occurs in [28]hexaphyrins, which gives rise to longer excited singlet and triplet state lifetimes than planar antiaromatic [28]hexaphyrins. Temperature-dependent two-photon absorption measurements of [28]hexaphyrin indicate that the degree of aromaticity of Mobius [28]hexaphyrin is large, comparable to that of Huckel aromatic planar [26]hexaphyrin. Through our spectroscopic investigations, we have demonstrated that a subtle balance between the strains induced by the size of the [28]hexaphyrin macrocyclic ring and the energy stabilization contributed by pi-electron delocalization in the formation of distorted Mobius [28]hexaphyrin leads to the molecular structure change into the Mobius topology as the temperature decreases.

DOI： 10.1021/jp8111205

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

The electronic excited states of two forms of meso-hexakis(pentafluorophenyl)-substituted gold(III) hexaphyrin(1.1.1.1.1.1) have been investigated by density functional calculations and magnetic circular dichroism (MCD) spectroscopy, in order to assign their low-energy excited singlet states. We found that the perimeter model can be successfully applied to the interpretation of the electronic states. In the case of the neutral forms (Au(2)-N, Au-N), the absorption bands observed in the NIR and visible region can be assigned to pi-pi* transitions referred to as the L and B bands, respectively, analogous to the Q and Soret bands of regular porphyrins. In marked contrast with the neutral forms, the absorption bands of the reduced forms (Au(2)-R and Au-R) are attributed to pi-pi* transitions involving six frontier molecular pi orbitals. By applying the 4N-electron perimeter model, the six orbitals are labeled as h(-), h(+), s(-), s(+), l(-), and l(+), while the observed absorption bands can be assigned to the S, N(1), N(2), P(1), and P(2) transitions, in order of increasing energy.

DOI： 10.1002/chem.200801742

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Getting in shape: Meso-pentafluorophenyl triply N-confused hexaphyrins have been synthesized in the free-base and oxidized forms and shown to have a triangular shape and efficient emission in the NIR region (see picture). The triangular shape is achieved by the presence of alternating confused and normal pyrrole rings. DFT calculations show that the triangular shape is more stable than a rectangular form. © 2009 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

DOI： 10.1002/anie.200900596

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

meso-Aryl-substituted [28]hexaphyrins(1.1.1.1.1.1) have been examined by (1)H, (13)C, and (19)F NMR spectroscopies, UV-vis absorption spectroscopy, magnetic circular dichroism spectroscopy, and single-crystal X-ray diffraction analysis. All of these data consistently indicate that [28]hexaphyrins(1.1.1.1.1.1) in solution at 25 degrees C exist largely as an equilibrium among several rapidly interconverting twisted Mobius conformations with distinct aromaticities, with a small contribution from a planar rectangular conformation with antiaromatic character at slightly higher energy. In the solid state, [28]hexaphyrins(1.1.1.1.1.1) take either planar or Mobius-twisted conformations, depending upon the meso-aryl substituents and crystallization conditions, indicating a small energy difference between the two conformers. Importantly, when the temperature is decreased to -100 degrees C in THF, these rapid interconversions among Mobius conformations are frozen, allowing the detection of a single [28]hexaphyrin(1.1.1.1.1.1) species having a Mobius conformation. Detailed analyses of the solid-state Mobius structures of compounds 2b, 2c, and 2f showed that singly twisted structures are achieved without serious strain and that cyclic pi-conjugation is well-preserved, as needed for exhibiting strong diatropic ring currents. Actually, the harmonic-oscillator model for aromaticity (HOMA) values of these structures are significantly large (0.85, 0.69, and 0.71, respectively), confirming the first demonstration of stable Mobius aromatic systems consisting of free-base expanded porphyrins without the assistance of metal coordination.

DOI： 10.1021/ja801983d

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

(AuCuIII)-Cu-III and (AuRhI)-Rh-III heterobismetal complexes of meso-aryl-substituted [26]hexaphyrin were rationally prepared from a monometal Au-III complex. The (AuCuIII)-Cu-III complex is an aromatic molecule with a rectangular shape, while (AuRhI)-Rh-III complexes are out-of-plane macrocycles, being either aromatic or antiaromatic depending upon the number of conjugated pi electrons. The 26,7 (AuRhI)-Rh-III complex was converted into an aromatic and planar 26 pi (AuRhIII)-Rh-III complex via double C-H bond activation upon refluxing in pyridine.

DOI： 10.1021/ic8004147

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

N-fused pentaphyrins (NFP(5)), stable forms of meso-aryl pentaphyrins, are interesting platforms to realize Huckel aromaticity, nonaromaticity and Mobius aromaticity depending upon the number of pi-electrons, meso-substituent, and metalation. Remarkably, Rh(1) complex of pentakis(pentafluorophenyl) substituted [24]NFPS has been characterized as a Mobius aromatic macrocycle by the crystal structure, (1)H NMR spectrum, NICS calculation, and two-photon absorption (TPA) cross section. This system is, to the best of our knowledge, the smallest Mobius aromatic molecule with a distinct diatropic ring current characterized so far. This work demonstrates the great potential of our synthetic strategy toward Mobius aromatic molecules as well as the possible use of TPA value as a quantitative measure of aromaticity.

DOI： 10.1021/ja7100483S0002-7863(71)00048-9

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

(Chemical Equation Presented) Round the twist: Metalation of [36]octaphyrin 1 provided the Möbius aromatic Pd2 complex 3 as well as the Hückel antiaromatic Pd2 complex 2. This method can be applied to other expanded porphyrins and Group 10 metal ions. The aromatic/antiaromatic character was supported by NMR spectrscopy, NICS calculation, and two-photon absorption measurements. © 2008 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

DOI： 10.1002/anie.200704407

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Peripheral modifications of bis-gold(III) [26]hexaphyrin(1.1.1.1.1.1) have been explored via perbromination and subsequent Pd-catalyzed cross-coupling reactions. beta-Phenylethynylated [26]hexaphyrin complex shows the large two-photon absorption (TPA) value due to its extended pi-conjugation. Aromatic-to-antiaromatic switches through two-electron reduction from [26]hexaphyrins to [28] hexaphyrins cause a sharp drop in TPA value, which has emerged as a new quantitative measure of aromaticity versus antiaromaticity.

DOI： 10.1021/ja0744908

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Language：English   Publishing type：Research paper (scientific journal)  

Metalation of meso-hexakis(pentafluorophenyl)-substituted [26]-hexaphyrin(1.1.1.1.1.1) (1) has been explored with group 12 metal ions Zn(II), Cd(II), and Hg(II). Zn(II) and Cd(II) ions afforded dinuclear gable-shaped complexes 2 and 3 in good yields, while Hg(II) ion provided bis-Hg(II) and mono-Hg(II) planar complexes (4 and 5) via C-H bond cleavage. © 2007 American Chemical Society.

DOI： 10.1021/ic7004216

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

(Chemical Equation Presented) Going round the outside: The palladium-catalyzed coupling of meso-bromoporphyrins with a variety of internal alkynes efficiently provides peripherally cyclopentadiene-fused porphyrins. This modification has a significant impact on the electronic system of the porphyrin rings (see scheme), which results in non-porphyrin-like absorption spectra and narrower HOMO-LUMO gaps. Oxidation of the outer C=C bond is facilitated by the induced strain. © 2006 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

DOI： 10.1002/anie.200603580

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Nickel(II), palladium(II), and platinum(II) complexes of meso-aryl-substituted [26]hexaphyrin have been prepared and structurally characterized. In mono-metalated complexes, the metal ion is commonly bound with three pyrrolic nitrogen atoms and one pyrrolic beta-carbon, whereas a bis-Pd(II) complex exhibits a unique structure involving a Pd-C-alpha. bond. These results reveal novel coordination abilities of the hexaphyrin that lead to a metal-carbon bond at either pyrrolic C-beta or C-alpha position.

DOI： 10.1021/ic050447e

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Au(III) metalation of hexakis(pentafluorophenyl) [26]hexaphyrin led to formation of aromatic mono-Au(III) hexaphyrin and bis-Au(III) hexaphyrin, in which the inner pyrrolic β-protons are activated to form gold-carbon bonds, hence accommodating Au(III) ion with a NNCC core in a square planar manner. Two-electron reductions of these complexes with NaBH4 provided the corresponding [28]hexaphyrin complexes which exhibit distinct paratropic ring currents. Copyright © 2005 American Chemical Society.

DOI： 10.1021/ja051662x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

meso-Aryl substituted pentaphyrins were isolated in the modified Rothemund-Lindsey porphyrin synthesis as a 22-pi-electron N-fused pentaphyrin ([22]NFP(5)) and a 24-pi-electron N-fused pentaphyrin ([24]NFP(5),), which were reversibly interconvertible by means of two-electron reduction wit NaBH(4) or two-electron oxidation with dichlorodicyanobenzoquinone (DDQ). Judging from (1)H-NMR data, [22]NFP(5), is aromatic and possesses a diatropic ring current, while [24]NFP(5) exhibits partial anti-aromatic character. Metalation of [22]NFP(5), 1 with a rhodium(I) salt led to isolation of rhodium complexes 9 and 10, whose structures were unambiguously characterized by X-ray diffraction analyses and were assigned as conjugated 24-pi and 22-pi electronic systems, respectively. In the rhodium(I) metalation of 1, the complex 9 was a major product at 20 degrees C, but the complex 10 became preferential at 55 degrees C. Upon treatment with DDQ, compound 9 was converted to 10 with an unprecedented rearrangement of the rhodium atom.

DOI： 10.1002/chem.200401042

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Total pages：245  

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