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

DOI： 10.1142/s1088424622500900

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Language：English   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  

DOI： 10.1142/s1088424623500980

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Ltd  

DOI： 10.1142/s1088424622500869

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Authorship：Lead author,　Corresponding author   Language：English   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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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.orglett.1c03882

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Authorship：Corresponding author   Language：English   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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Language：English   Publishing type：Research paper (scientific journal)  

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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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Introduction of functional groups on a -conjugated system is one of the most promissing methods to modulate their chemical and physical properties. Here, dinitrohexapyrrolohexaazacoronene (dinitroHPHAC) was synthesized, in which two nitro groups are introduced at the same pyrrole ring. The dinitroHPHAC possesses a large dipole moment (μ = 11.7 D at B3LYP/6-31G(d,p)) and showed solvatochromism with decreased HOMO-LUMO energy gap. Interestingly, the colour of the solid is black to the naked eye. The global aromaticity of the dication state is decreased compared with those of pristine HPHAC and mononitroHPHAC.

DOI： 10.1142/S108842462150098X

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

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

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

A hexapyrrolohexaazacoronene (HPHAC) with 12 less-bulky peripheral ethyl groups than its aryl-containing HPHAC counterpart was synthesized to investigate the innate character of HPHAC. X-ray diffraction analysis revealed that HPHAC had a planar structure and close packing because of CH-πinteractions between the alkyl groups and the HPHAC core. Compared to the previously reported HPHAC decorated with 12 peripheral aryl groups, this electron-rich π-system exhibited reversible multistep oxidations at low potentials and easily formed mono- and dicationic salts and charge-transfer (CT) complexes with 7,7,8,8-tetracyano-p-quinodimethane. These oxidized species exhibited clear changes in the bond-length alternation of the pyrrole units in the crystal state, indicating charge and spin delocalization. The distinct upfield shift of the central carbon signal of the dication in the 13C NMR spectrum affirms the global aromaticity from the viewpoint of a magnetic criterion. In the UV-vis/NIR spectra, broad absorption in the NIR region was observed only for HPHAC2+ and not the structurally similar cyclo[6]pyrrole. Magnetic circular dichroism measurements and time-dependent density functional theory calculations revealed that the broad absorption was assigned to the CT transition from the central benzene ring to the outer pyrrole rings.

DOI： 10.1021/acs.joc.0c03042

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

Collected in the Virtual Issue “Molecular Nanocarbons: Organic Chemistry with Atomic Precision”
https://pubs.acs.org/page/vi/ol-joc-molecular-nanocarbons?ref=vi_journalhome

DOI： 10.1021/acs.joc.0c02825

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Other Link： https://pubs.acs.org/page/vi/ol-joc-molecular-nanocarbons?ref=vi_journalhome

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

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

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

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[Formula: see text] porphyrinoid.

DOI： 10.1142/s108842461950130x

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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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© 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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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)  

Collected in the Virtual Issue “Organic Chemistry in Japan: A Strong Foundation and Honorable Tradition”
https://pubs.acs.org/page/orlef7/vi/organic-chemistry-japan?ref=vi_collection

DOI： 10.1021/acs.orglett.9b00515

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

Stable conjugated oligomer dications 1(2+) and 2(2+) composed of 2,5-di(2-thienyl)-N-methylpyrrole (DTP) units at the both ends of the pi-systems with methoxy substituents at the 3-position of thienyl units and methylthio end-capping group and benzo[2,1-b:3,4-b ']dithiophene (BDT) unit(s) at the central part with sterically demanding phenyl substituents were synthesized. From DFT calculations and ESR experiments, it was concluded that the diradical character in 1(2+) and 2(2+) was reduced in comparison with the radical character of their reference compound 3(center dot+) composed of one DTP and one BDT units. In addition, the shorter 1(2+) was considered to have a further lower diradical character than that of 2(2+). Nevertheless, judging from the results of VT-UV-vis-NIR measurements, both 1(2+) and 2(2+) showed a comparable pi-dimerization ability at the DTP moiety in dichloromethane solution with 3(center dot+).

DOI： 10.1002/hc.21452

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Chinese Chemical Society Taiwan  

Precise, efficient one-pot synthesis of star shaped (tri-, tetra-arm) π-conjugated systems has been achieved by olefin metathesis of 5-substituted-2-propenyl-thiophene or N-vinyl carbazole (arm segment) using a molybdenum-alkylidene reagent and subsequent Wittig-type cleavage with core segments containing aldehydes [tri(4-formylphenyl)amine, 2,4,6-tri(4-formyl-biphenyl)benzene, 1,4-dimethoxy-2,3,5,6-tetra(4-formylphenyl)-benzene, etc.]
effects of the core and the arm have been clearly demonstrated.

DOI： 10.1002/jccs.201700058

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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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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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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  

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

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：PERGAMON-ELSEVIER SCIENCE LTD  

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

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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Language：English   Publishing type：Part of collection (book)   Publisher：Wiley Blackwell  

This chapter summarizes oligopyrroles and related compounds of linear and circular shapes from the viewpoints of redox-active functional materials. In the light of recent comprehensive reviews of porphyrin and related compounds including linear ones such as bile, only oligopyrroles possessing directly connected 2-2' bonds are highlighted. The investigation of oligomers with different chain lengths gives useful information for the molecular design that shows the desired optical and electronic properties and morphologies. Among them, linear oligomers are naturally the first choice for synthetic reasons. Based on the rich chemistry of oligopyrroles, the author and his coworkers reported the synthesis and physical properties of pyrrole-fused azacoronenes, namely, hexapyrrolohexaazacoronene (HPHAC). Pyrrole can stabilize its oxidation states by the nitrogen atom with strong electronegativity and also by releasing hydride. This feature of pyrrole with diversity in redox condition would be beneficial in designing novel π-electron materials.

DOI： 10.1002/9781118858981.ch15

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

A series of novel toroidal cyclo-2,9-tris-1,10-phenanthroline macrocycles with an unusual hexaaza cavity are reported. Nickel-mediated Yamamoto aryl-aryl coupling was found to be a versatile tool for the cyclotrimerization of functionalized 1,10-phenathroline precursors. Due to the now improved processability, both liquid-crystalline behavior in the bulk phase and two-dimensional self-assembly at the molecular level could be studied, for the first time, for a torand system. The macrocycles exhibited a strong affinity for the complexation of different metal cations, as evidenced by MALDI-TOF analysis and spectroscopic methods. Experimental results were correlated to an extensive computational study of the cyclo-2,9-tris-1,10-phenanthroline cavity and its binding mode for metal cations. Due to the combination of several interesting features, toroidal macrocycles may find future applications in the field of ion and charge transport through molecular channels, as well as for chemical sensing and molecular writing in surface-confined monolayers under STM conditions.

DOI： 10.1002/chem.201406602

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

Two isomers of a multifunctional pi-expanded macrocyclic oligothiophene 8-mer, E,E-1 and Z,Z-1, were synthesized using a McMurry coupling of a dialdehyde composed of four 2,5-thienylene and three ethynylene units under high dilution conditions. On the other hand, cydo [8]-(2,5-thienylene-ethynylene) 2 was synthesized by intramolecular Sonogashira cydization of ethynyl bromide 5. From STM measurements, both E,E-1 and Z,Z-1 formed self-assembled monolayers at the solid liquid interface to produce porous networks, and from X-ray analyses of E,E-1 and 2, both compounds had a round shape with a honeycomb stacked structure. E,E-1 formed various fibrous polymorphs due to nanophase separation of the macrorings. E,E-1 and Z,Z-1 in solution exhibited photochromism upon irradiation and UV light, respectively, and this photoisomerization was confirmed by using STM. Furthermore, amorphous films of Z,Z-1 and E,E-1 showed photoisomerization, although single crystals, fibers, and square tubes of E,E-1 remained unchanged under similar conditions. E,E-1 with a 12.5-14.7 angstrom inner cavity incorporated fullerene C-60 in the cavity in solution and the solid state to produce a Saturn-like complex, whose structure was determined by X-ray analysis. 2 also formed a Saturn-like complex with C-60 in the solid state. These Saturn-like complexes are stabilized by van der Waals interactions between the sulfur atoms of 8-mer and C-60. The complexes exhibited charge-transfer interactions in the solid state. Like E,E-1, Saturn-like complex E,E-1 superset of C-60 formed small cube and fiber structures depending on the solvent used, whereas those of Saturn-like complex 2 superset of C-60 were limited due to the rigidity of the macroring of 2.

DOI： 10.1021/jacs.5b00291

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

Gold-nanoparticles (AuNPs) protected by thiolates of methylthio end-capped terthiophene la and quaterthiophene 2a partially annelated with bicyclo[2.2.2]octene (BCO) unit(s) were designed and synthesized. AuNP covered with nonannelated terthiophene 3a was also synthesized for comparison. The formation of the AuNPs was confirmed by absorption spectra and transmission electron microscopy (TEM) measurements. The electric conductivities of AuNP-1a(-) and AuNP-3a(-) films were moderate (similar to 10(-3) S cm(-1)) due to conduction through core-to-core tunneling, whereas the conductivity of AuNP-2a(-) films was very low (<10(-6) S cm(-1)). The low conductivity of AuNP-2a(-) films would be due to a larger separation distance between the particles by two sterically demanding BCO units as suggested by the TEM analysis and DFT calculations. Importantly, after doping with iodine vapor, the enhancements in the conductivities of AuNP-1a(-) and AuNP-3a(-) were only 4- and 10-fold, respectively. In sharp contrast, the conductivity of AuNP-2a(-) after I-2-doping was increased by more than 10(4)-fold. The latter conductivity was comparable to the previously reported conductivities of AuNPs directly linked by oligothiophenes, and these results are consistent with the hypothesis that the electric conduction through g-dimers of oxidized oligothiophenes is as effective as through covalently linked oligothiophenes.

DOI： 10.1021/cm501438j

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

We designed and synthesized a new quadrivial anchoring unit 4-TEB, to construct a stable single-molecule junction with gold electrodes, which should have equivalent conducting electron pathways between two electrodes. The conductances of single-molecule junctions comprising 4-TEB and its bidirectional counterpart 2-TEB were determined to be 2.7 x 10(-4)G(0) (2e(2)/h) and 5.0 X 10(-5)G(0), respectively, by using scanning tunneling microscope break junction (STM-BJ) techniques. The single 4-TEB molecule junction had higher stability and conductivity compared to those of the single 2-TEB molecule junction. Although the number of electron pathways from/to the electrode to/from the molecule was additive using the equivalent multianchoring the conductance of the single-molecule junction was not additive. From first-principles electronic transport calculations, the mechanism for the new quadrivial 4-TEB single-molecule junction involved an overlap resonance effect to the HOMO conducting orbital, giving rise to tunneling. Using fixed nanogap electrodes, we constructed stable molecular junctions of 4-TEB and observed symmetric peaks in the derivative of the conductance-voltage (G-V) curves, which were assigned to electron transport through the HOMO on the basis of theoretical calculations.

DOI： 10.1021/jp4100262

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

Benzo- and naphtho-annelated thiophene-pyrrole mixed octamers Bz8TP-C-m and Np8TP-C-m, comprising benzo- or naphthodithiophene and two dithienylpyrrole units, were synthesised. Density functional theory (DFT) calculations based on B3LYP/6-31G(d) with the broken symmetry method predicted that dications Bz8TP-C-1(2+) and Np8TP-C-1(2+) have stronger diradical character than previously investigated non-annelated thiophene-pyrrole mixed octamer 8TP-C-1(2+) (R-1 = R-2 = H). Compounds Bz8TP-C-8 and Np8TP-C-8 showed a one-step, two-electron oxidation process based on cyclic voltammetry analysis. Reaction with SbCl5 involved a two-electron oxidation. Bz8TP-C-8(2+) and Np8TP-C-8(2+) displayed similar absorption spectra to that of nonamer 9TP-C-12(2+) (R-1 = R-2 = H), rather than that of octamer 8TP-C-12(2+), indicating the stronger diradical characters of octamers Bz8TP-C-8(2+) and Np8TP-C-8(2+), as enhanced by benzo- and naphtho-annelation, and were comparable with that of 9TP-C-12(2+). Time-dependent-DFT calculations supported the conclusion obtained from the experimental results.

DOI： 10.1071/CH13522

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

A series of 2,5-di(2-thienyl)-N-methylpyrrole derivatives 1a-1d with methylthio end-capping groups and electrondonating substituents at the 3-position of the thiophene rings was synthesized, and the effects of the substituents on the structure, stability, and ir-dimerization ability of the radical cation investigated using UV vis NIR electron spin resonance spectra and density functional theory (DFT) calculations. Among the electron-donating methyl, methoxy, and methylthio substituents, the methoxy derivative lc gave the most stable radical cation, which persisted in dichloromethane at room temperature under nitrogen for several hours without any apparent decomposition. In addition, 1c(+) had the largest g-dimerization enthalpy among 1a(+) 1d(+). DFT calculations with the M06-2X method revealed that methyl and methylthio derivatives 1b(+) and 1d(+) as well as 1c(+) adopt a cis-cis conformation, in contrast to the trans-trans conformer of unsubstituted 1a(+), while the ir-dimers of all of these compounds were shown to have a cis cis conformation. On the basis of further detailed analyses, the preformed cis cis conformation and the weaker intramolecular and intermolecular steric repulsions were considered to explain why 1c(+) has the largest Ir-dimerization enthalpy.

DOI： 10.1021/jo401453s

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

The design and synthesis of a new planar cyclooctatetraene (COT) with protons directly connected to the COT ring was attained by monoannelation with dithieno[3,4-b:3′,4′-d]thiophene. The planar structure of the COT core was unambiguously confirmed by X-ray crystallography. The magnetic antiaromaticity of the COT core was found to be higher than that of the previously synthesized planar COTs with olefinic protons, according to the results of 1H NMR and absorption spectra as well as NICS calculations. © 2013 American Chemical Society.

DOI： 10.1021/ol401125f

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

We have investigated the photophysical properties of star-shaped oligothiophenes with three terthiophene arms (meta to each other, S3) or six terthiophene arms (ortho-, meta-, and para-arranged, S6) connected to an ethynylbenzene core to elucidate the relationship between their molecular structure and electronic properties by using a combination of ensemble and single-molecule spectroscopic techniques. We postulate two different conformations for molecules S3 and S6 on the basis of the X-ray structure of hexakis(5-hexyl-2-thienlyethynyl)benzene and suggest the coexistence of these conformers by using spectroscopic methods. From the steady-state spectroscopic data of compound S6, we show that the exciton is delocalized over the core structure, but that the meta-linkage in compound S3 prevents the electronic communication between the arms. However, in single-molecule spectroscopic measurements, we observed that some molecules of compound S3 showed long fluorescence lifetimes (about 1.4 ns) in the fluorescence-intensity trajectories, which indicated that π electrons were delocalized along the meta linker. Based on these observations, we suggest that the delocalized exciton is intensely sensitive towards the dihedral angle between the core and the adjacent thiophene ring, as well as to the substituted position of the terthiophene arms. Our results highlight that the fluorescence lifetimes of compounds S3 and S6 are strongly correlated with the spatial location of their excitons, which is mainly affected by their conformation, that is, whether the innermost thiophene rings are facing each other or not. More interestingly, we observed that the difference between the degrees of ring-torsional flexibility of compounds S3 and S6 results in their sharply contrasting fluorescence properties, such as a change in fluorescence intensity as a function of temperature. Written in the stars: The electronic nature of star-shaped oligothiophenes can be controlled by increasing the number of branched arms (see figure), because these structural modifications lead to differences in the ring-torsional flexibility, which determines the degree of exciton delocalization throughout the core structure. Copyright © 2013 WILEY-VCH Verlag GmbH &amp
Co. KGaA, Weinheim.

DOI： 10.1002/chem.201300313

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

The expeditious synthesis of donor-acceptor segregated paracyclophanes has been achieved by a selective SNAr reaction of hexafluorobenzene with o-dipyrrolylbenzenes and subsequent cyclodehydrogenation. An orthogonally arranged D-A segregated structure was confirmed by X-ray crystallography. The combined results of DFT calculations and absorption spectra revealed the charge transfer (CT) nature from the naphthobipyrrole (donor) to the stacked fluoroarene moiety (acceptor).

DOI： 10.1021/ol400882q

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A novel pyrrole-fused azacoronene family was synthesized via oxidative cyclodehydrogenation of the corresponding hexaarylbenzenes as the key step, and the crystal structures of tetraazacoronene 3b and triazacoronene 4a were elucidated. The photophysical properties for neutral compounds 1-4 were investigated using steady-state UV-vis absorption/emission spectroscopy and time resolved spectroscopy (emission spectra and lifetime measurements) at both room temperature and 77 K. The observation of both fluorescence and phosphorescence allowed us to estimate the small S-1-T-1 energy gap (Delta ES-T) to be 0.35 eV (la), 0.26 eV (2a), and 0.36 eV (4a). Similar to the case of previously reported hexapyrrolohexaazacoronene 1 (HPHAC), electrochemical oxidation revealed up to four reversible oxidation processes for all of the new compounds. The charge and spin delocalization properties of the series of azacoronene pi-systems were examined using UV-vis-NIR absorption, ESR, and NMR spectroscopies for the chemically generated radical cations and dications. Combined with the theoretical calculations, the experimental results clearly demonstrated that the replacement of pyrrole rings with dialkoxybenzene plays a critical role in the electronic communication, where resonance structures significantly contribute to the thermodynamic stability of the cationic charges/spins and determine the spin multiplicities For HPHAC 1 and pentaazacoronene 2, the overall aromaticity predicted for dosed shell dications 1(2+) and 2(2+) was primarily based on the theoretical calculations, and the open shell singlet biradical or triplet character was anticipated for tetraazacoronene 3(2+) and triazacoronene 4(2+) with the aid of theoretical calculations These polycyclic aromatic hydrocarbons (PAHs) represent the first series of nitrogen containing PAHs that can be multiply oxidized.

DOI： 10.1021/ja402371f

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

A Two series of oligothiophenes 2(nT) (n=4,5), annelated with bicyclo[2.2.2]octene (BCO) units at both ends, and quaterthiophenes 3ac, annelated with various numbers of BCO units at different positions, were newly synthesized to investigate the driving forces of -dimerization and the structureproperty relationships of the -dimers of oligothiophene radical cations. Their radical-cation salts were prepared through chemical one-electron oxidation by using nitrosonium hexafluoroantimonate. From variable-temperature electron spin resonance and electronic absorption measurements, the -dimerization capability was found to vary among the members of the 2(nT)+.SbF6 series and 3+.SbF6 series of compounds. To examine these results, density functional theory (DFT) calculations at the M06-2X/6-31G(d) level were conducted for the -dimers. This level of theory was found to successfully reproduce the previously reported X-ray structure of (2(3T))22+ having a bent -dimer structure with ciscis conformations. The absorption bands obtained by time-dependent DFT calculations for the -dimers were in reasonable agreement with the experimental spectra. The attractive and repulsive forces for the -dimerization were divided into four factors: 1)SOMOSOMO interactions, 2)van der Waals forces, 3)solvation, and 4)Coulomb repulsion, and the effects of each factor on the structural differences and chain-length dependence are discussed in detail.

DOI： 10.1002/chem.201204332

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

Tetra[2,3-thienylene] planarised by sulphur bridges and radially pi-extended with (triisopropylsilyl)ethynyl groups had a narrow HOMO-LUMO gap due to the antiaromatic cyclooctatetraene core, and its single crystal FET device exhibited ambipolar characteristics with hole and electron mobilities of up to 0.40 and 0.18 cm(2) V-1 s(-1), respectively.

DOI： 10.1039/c3cc41764f

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

We report the synthesis and photophysical characterization of a series of hexa-peri-hexabenzocoronene (HBC)/perylenetetracarboxy diimide (PDI) dyads that are covalently linked with a rigid bridge. Both the ratio of the vs. two components and the conjugation of the bridging element are systematically modified to study the influence on self-assembly and energy and electron transfer between electron donor HBC and acceptor PDI. STM and 2D-WAXS experiments reveal that both in solution and in bulk solid state the dyads assemble into well-ordered two-dimensional supramolecular structures with controllable mutual orientations and distances between donor and acceptor at a nanoscopic scale. Depending on the symmetry of the dyads, either columns with nanosegregated stacks of HBC and PDI or interdigitating networks with alternating HBC and PDI moieties are observed. UV-vis, photoluminescence, transient photoluminescence, and transient absorption spectroscopy confirm that after photoexcitation of the donor HBC a photoinduced electron transfer between HBC and PDI can only compete with the dominant Forster resonance energy transfer, if facilitated by an intimate stacking of HBC and PDI with sufficient orbital overlap. However, while the alternating stacks allow efficient electron transfer, only the nanosegregated stacks provide charge transport channels in bulk state that are a prerequisite for application as active components in thin film electronic devices. These results have important implications for the further design of functional donor acceptor dyads, being promising materials for organic bulk heterojunction solar cells and field-effect transistors.

DOI： 10.1021/ja211504a

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

Sterically congested pyrrole-fused tetrathiafulvalene (TTF) decamer 4 was designed and synthesized via the SNAr reaction of decafluorobiphenyl with the corresponding pyrrolyl sodium salt, which formed amorphous spin-coated films showing good conductivity of up to 4.4 S cm(-1) after iodine doping as the result of multi-dimensional pi-pi stacking between the TTF units.

DOI： 10.1039/c2ra00035k

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

Conjugated benzenoid aromatics with large inner cavities and alkyl side chains self-associate to produce dimers in solution and fibrous materials in the solid state. The self-association is enthalpically and entropically driven. The compound forms a 1:3 charge-transfer (CT) complex with 2,4,7-trinitrofluorenone (TNF) with a microball structure, where a nano-sized branched structure forms first at the growth points, followed by production of the microball with a dendritic interior. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/asia.201100336

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Language：English   Publishing type：Part of collection (book)   Publisher：John Wiley and Sons  

DOI： 10.1002/9781118011263.ch12

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

A series of star-shaped pyrrole-fused tetrathiafulvalene (TTF) oligomers 1-3 was synthesized via an S(N)Ar reaction of fluorinated benzenes with the pyrrolyl sodium salts. Electrochemical and chemical oxidations of 1-3 revealed that a radical cation moiety on each TTF unit was successfully accumulated in all oligomers. Self-assembled structures of neutral and oxidized species were characterized by SEM and XRD, and their conductive properties of the Iodine-doped 1-3 as well as an intermolecular mixed-valence ion radical salt were investigated.

DOI： 10.1021/ol2014279

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

A series of 3,4-propylenedioxythiophene (ProDOT) oligomers (nP(Hex)) with dihexyl side chains and methylthio end-capping units was synthesized as a model of poly(3,4-alkylenedioxythiophene)s. The slope of the linear relationship between the energy of the absorption maxima of nP(Hex) in the neutral states and the reciprocal of the number of monomer units (1/n) was found to be comparable to that of 3,4-ethylenedioxythiophene (EDOT) oligomers, suggesting that both the ProDOT and the EDOT oligomers have a similar effective conjugation. In cyclic voltammetry measurements, both the first and second oxidation waves and the third and fourth waves were shown to merge into one peak with increasing chain length. The stepwise chemical oxidations of nP(Hex) with SbCl5 in CH2Cl2 at room temperature gave their stable cationic species in various oxidation states, and it was found that only the radical cations (polarons) have an obvious absorption band in the visible region. Interestingly, when the absorption spectra of tetramer radical cation 4P(Hex)(+center dot). were measured at low temperatures, reversible disproportionation into dication 4P(Hex)(2+) and neutral species 4P(Hex) was observed in addition to pi-dimer formation. Furthermore, the radical cations of the longer oligomers showed only the disproportionation reaction. From the comparisons of the results of experiments and the theoretical calculations of the dications, 6P(Hex)(2+) was found to have a closed-shell nature, and only a weak singlet biradical character appeared even in longer oligomers 10P(Hex)(2+) and 12P(Hex)(2+). Overall, the electron-donating dioxy substituents are considered to stabilize high p-doping levels with closed-shell dication (bipolaron) structures in poly(3,4-alkylenedioxythiophene)s, which enables the transparency properties of the polymers.

DOI： 10.1021/ja2035442

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

The reaction of diformyldithienylacetylene 4 with a McMurry reagent prepared from TiCl(4), Zn, and pyridine in THF afforded 24 pi-dimer 1b (15%), 36 pi-trimer 2b (13%), and 48 pi-tetramer 3b (6%). From X-ray analysis, 1b adopts a twisted conformation, although the (1)H NMR spectrum of 1b shows a symmetrical structure owing to a rapid conformational change in solution. Absorption and emission spectra, redox properties, and electric conductivities of 1b-3b were measured in order to study the structure-property relationship of these macrocyclic systems.

DOI： 10.3987/COM-10-S(E)96

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

alpha-Linked thiophene-pyrrole mixed hexamers 3a-5a end-capped with two phenyl, two pentafluorophenyl and both phenyl and pentafluorophenyl units were newly synthesized, and their structural, electronic, optical and FET properties were investigated. Structural analyses by means of X-ray crystallography and theoretical calculations showed that the pi-system of the oligomer chains is twisted due to the steric repulsion between the hexyl group of the pyrrole unit and the adjacent thiophene moiety. From comparison of the absorption maxima and redox potentials, end-capping with phenyl and pentafluorophenyl units did not affect the HOMO-LUMO gap for the thiophene-pyrrole hexamer, and the multiple fluorine substituents slightly decreased both HOMO and LUMO levels by the inductive effects of the electronegative fluorine atoms. Although the diphenyl derivative 3a with a herringbone-type packing structure did not serve as an active layer for FET devices, a unique crystal-to-crystal phase transition with a color change from yellow to red was observed upon heating. In contrast to the herringbone-type packing structure of 3a, the unsymmetrical phenyl-pentafluorophenyl derivative 5a showed a partially pi-stacked structure, most likely due to dipole-dipole interactions. The pi-stacked structure of 5a caused a good hole mobility of 4.1 x 10(-2) cm(2) V-1 s(-1) in a single crystal FET device.

DOI： 10.1039/c1jm12966j

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

Combined DFT calculations and UV-vis-NIR, ESR, and SQUID measurements revealed that the ground-state electronic structure of a linear pi-conjugated oligomer dication composed of two pyrrole and six or seven thiophene rings and methylthio end-capping units is dominated by a singlet biradical character.

DOI： 10.1021/ol101997w

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Language：English   Publishing type：Part of collection (book)   Publisher：Wiley-VCH  

DOI： 10.1002/9783527632664.ch6

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

The FeCl3-mediated homo-coupling of 4,5-bis(alkylthio)-4'-tetrathiafulvalenylmagnesium bromide 5 produced the corresponding bitetrathiafulvalene derivatives 2a-d in moderate yields (25-51%). Bitetrathiafulvalenes 2c and 2d having long alkylthio chains formed nanostructures and showed bulk electric conductivities (sigma(rt) = 2.6 - 8.0 x 10(-5) S cm(-1)) in the neutral state owing to the fastener effect. Interestingly, the nanofiber of tetrakis(dodecylthio)bitetrathiafulvalene 2d exhibited a p-type semiconductivity as detected by AFM. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2009.11.106

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

Shining star: Star-shaped hexakis(oligothienylethynyl)benzene with C 6 symmetry shows solvatochromic fluorescence with a marked redshift in emission. Furthermore, the star-shaped molecule shows a fairly large two-photon absorption property. Interestingly, the molecule forms fluorescent fibrous materials from hexane, DMF, and isopropyl alcohol owing to its disc-like structure (see graphic). © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/chem.201001413

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

A novel synthetic method toward nitrogen containing positively charged dibenzo[jk,mn]naptho[2,1,8-fgh]thebenidinium (DBNT, 1) salts was developed. In this method, the undehydrogenated precursor of DBNT, 14-phenyl-14-dibenzo[aj]acridinium salt (6), was produced directly from the reaction between 14-phenyl-14-dibenzo[aj]xanthenylium (2) and annine/aniline in reasonable yield. Various DBNT salts with different alkyl and alkylphenyl chains were synthesized in this two-step method. The self-assembly behavior of two alkylated DBNT salts, 1c and If, Was Studied in this work. Due to the different substituents and counterions, Compound 1c formed nanoscale wirelike fibers, and helical aggregates were obtained from 1f, in their methanolic solutions. (C) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2008.08.063

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

Two novel triangle-shaped discotic graphenes with swallow-like alkyl tails are synthesized; these discotic graphenes allow facile purification, control over thermotropic properties, and solution fabrication into efficient photovoltaic devices. The unique molecular design results in an extremely broad liquid-crystalline range and the ability to self-heal at low processing temperatures, which improves the performance of photovoltaic cells.

DOI： 10.1002/adma.200800642

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

A study was conducted to analyze the synthesis, helical organization, and fibrous formation of C 3 symmetric Methoxy-substituted discotic hexa-peri-hexabenzocoronene (HBC). HBCs were synthesized using the oxidative cyclodehydrogenations of proper hexaphenyl-benzene precursors. NMR spectroscopy was used to analyze the property of HBCs toward self-assembly in solution. The self-assembly led to fibrous nanostructures with several hundred micrometers in length upon drop-casting. Differential scanning calorimetry (DSC) was used to observe thermotropic properties of HBCs. The UV-vis and photoluminescence spectra was used to analyzed internal structure of HBCs for observing fibrous structures. Results show that HBC with three alternative dodecyl1 and methoxy substitutions was synthesized using the Scholl reaction.

DOI： 10.1021/cm800515s

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

Everysecond counts: Enhanced control over the self-organization of discotic compounds has been obtained by introducing alternating arrays of apolar (alkyl) and polar (ester) substitutents on to C 3 -symmetric hexa-peri-hexabenzocoronenes. The local dipole moments and the nanophase separation between the polar and apolar sites significantly influence the self-assembly in solution and in the solid state (see schematic representation). (Figure Presented). © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.

DOI： 10.1002/anie.200703967

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

(Figure Presented) The heteroatom-stabilized annularly fused hexapyrrolohexaazacoronene shown (N blue, F green) was synthesized and isolated as a representation of a new class of nitrogen-containing molecules with extended π systems. The reversible redox behavior, a consequence of the interior N atoms, hints at potential applications in organic electronics. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.

DOI： 10.1002/anie.200701452

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

Molecular recognition materials bearing halogen bonding-based binding sites were synthesized by a non-covalent imprinting technique using a 2,3,5,6-tetrafluoro-4-iodostyrene (TFIS) as the functional monomer. The binding sites were generated by co-polymerizing TFIS, styrene and divinylbenzene in the presence of the template molecule (4-dimethylaminopyridine-DMAP). The imprinted polymer preferentially adsorbed aminopyridine derivatives, suggesting that halogen bonding may play a role in the selective recognition of analytes by the synthesized synthetic receptor. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2005.10.098

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATL ACAD SCIENCES  

Establishing a reliable genotyping protocol is a critical matter in postsequence genetics. In this article, we describe a highly sensitive electrochemical detection of complementary DNAs (up to 43-mer) based on hole transport with molecular-scale, "wire-like" DNA probes. The presence of a single-base mismatch in the DNA duplexes caused a dramatic decrease in the electrochemical response. We applied this method to detect all of the possible transition and transversion SNPs and achieved "on-off"-type discrimination of fully complementary DNAs from their SNPs. Furthermore, naturally occurring polymorphisms, "hot spots" from the p53 gene, could clearly be distinguished from wild type by using our methodology.

DOI： 10.1073/pnas.0502078102

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

A triple hydrogen-bonding module based on 6-alkynyl-2-amino-3H-pyrimidin-4-one was developed such as for self-dimerization and for nucleobase recognition processes. The strength of the module for the self -dimerization was determined by NMR and fluorimetric analyses in chloroform (Delta G(298) = -22 to -23 kJ/mol). DFT calculations and X-ray structure analysis showed that the self -dimerization consists of the three-point hydrogen-bonding including two kinds of tautomers of the module in an ADD-DAA mode. Selective recognition of the module for a cytidine derivative was also observed, and the free energy change for the complexation (Delta G(298) = -31 kJ/mol) is one of the highest values among triple hydrogen-bonded complexes so far reported. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

DOI： 10.1002/ejoc.200500010

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

An extended hexagonal molecule that has high symmetry and rigidity was designed and synthesized by a cobalt-catalyzed cyclotrimerization reaction. The ligand possesses six benzoic acids at its periphery, which were connected to a central hexakis(2,5-dodesyloxyphenyl)hexaphenylbenzene core with a maximum intramolecular carboxyl group distance of approximately 3.5 nm. (C) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2005.01.014

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

Atrazine imprinted synthetic polymers were prepared using a combination of methacrylic acid and 2-sulfoethyl methacrylate that bound and converted atrazine and other 6-chlorotriazine herbicides to less toxic compounds. A chloride at the 6-position of the triazines was converted to a methoxy group by the polymer in a methanol-containing solvent, where the imprinting effects enhanced the catalytic activity. Competitive inhibition of the atrazine methanolysis was observed in the presence of a structurally related binder, ametryn, suggesting that the catalytic reaction proceeded in the binding sites generated by the molecular imprinting process.

DOI： 10.1039/b407002j

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

Femtosecond fluorescence anisotropy measurements for a variety of cyclic porphyrin arrays such as Zn(II)porphyrin m-trimer and hexamer are reported along with o-dimer and monomer as reference molecules. In the porphyrin arrays, a pair of porphyrin moieties are joined together via triphenyl linkage to ensure cyclic and rigid structures. Anisotropy decay times of the porphyrin arrays can be well described by the Forster incoherent excitation hopping process between the porphyrin units. Exciton coupling strengths of 74 and 264 cm(-1) for the m-trimer and hexamer estimated from the observed excitation energy hopping rates are close to those of B800 and B850, respectively, in the LH2 bacterial light-harvesting antenna. Thus, these cyclic porphyrin array systems have proven to be useful in understanding energy migration processes in a relatively weak interaction regime in light of the similarity in overall structures and constituent chromophores to natural light-harvesting arrays.

DOI： 10.1021/ja021476g

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

[GRAPHICS]
The reaction of 3,5-di-O-benzyl-2-deoxy-D-ribofuranose with various alkynyllithium reagents afforded diastereomeric mixtures of the corresponding ring-opened alkynyldiols. The resulting diastereomeric mixtures were successively treated with CO2(CO)(8), a catalytic amount of TfOH, Et3N, and iodine in one pot to give alkynyl C-3,5-di-O-benzyl-2-deoxy-beta-D-ribofuranosides with high beta-selectivities. The cobalt-mediated cyclization (intramolecular Nicholas reaction) is reversible; thus, thermodynamically more stable beta-anomers were obtained preferentially. The alkynyl C-deoxyribofuranosides were converted to a variety of C-deoxyribofuranoside derivatives.

DOI： 10.1021/ol027210w

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

Synthesis and binding affinity of rationally designed artificial ditopic nucleobase receptors are reported. The ditopic receptors were designed to recognize thymine-thymine dinucleotides by their two hydrogen-bonding moieties, which are connected to conformationally well-defined linkages such as ferrocene and biphenylene. The ditopic receptors exhibited a remarkably strong binding affinity for lipophilic TpT analogue in CDCl3/DMSO-d(6) (85:15, v/v). The binding affinity of the ditopic receptors for the dinucleotide was so high that even native TpT was extracted by them into CDCl3. Detailed comparisons for the recognition abilities of the ditopic receptors were also conducted.

DOI： 10.1021/jo0264473

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

Palladium- and cobalt-catalyzed trimerization of diphenylethynyl-bridged diporphyrin gave benzene-centered cyclic porphyrin hexamers. (C) 2002 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4039(02)00970-X

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

A ferrocene-linked bis(spiropyridopyran) was designed and synthesized, that recognized guanine-guanine dinucleoside derivatives via complementary hydrogen bonds in CH2Cl2, resulting in the isomerization of the colorless spiropyridopyran as self-indicating receptors.

DOI： 10.1039/b107306k

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

The multipoint hydrogen-bonded complex 1 (R = alkanoyl) is readily formed between a ferrocene-modified artificial receptor and a dinucleotide. This principle can be used effectively in highly selective, large-scale separations of dinucleotides from mixtures of mono- and oligonucleotides. The process is economically viable and environmentally friendly.

DOI： 10.1002/1521-3773(20010504)40:9<1746::AID-ANIE17460>3.0.CO;2-U

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：GORDON BREACH SCI PUBL LTD  

A novel ferrocene-modified bis(spirobenzopyran) was designed and synthesized. The spirobenzopyran possesses two photochromic moieties, which were tethered to two cyclopenta-dienyl rings of ferrocene via ethynediyl spacers. Photochromic properties of the spirobenzopyran were investigated in the absence and presence of various metal cations.

DOI： 10.1080/10587250008023855

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Responsible for pages：103-118  

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Responsible for pages：141-153  

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Language：English   Publisher：ROYAL SOC CHEMISTRY  

DOI： 10.1039/b407002j

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Language：English   Publisher：ROYAL SOC CHEMISTRY  

Web of Science

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Event date： 2023.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：枚方市総合文化芸術センター   Country：Japan  

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Event date： 2023.9

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Bali   Country：Indonesia  

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Event date： 2023.9

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：広島国際会議場   Country：Japan  

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Event date： 2023.6

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：National Yang Ming Chiao Tung University (NYCU)   Country：Taiwan, Province of China  

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Event date： 2022.12

Presentation type：Oral presentation (general)  

Venue：富山大学 黒田講堂   Country：Japan  

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Event date： 2022.9

Presentation type：Oral presentation (general)  

Venue：京都パルスプラザ  

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Event date： 2022.7

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Warsaw   Country：Poland  

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Event date： 2022.1

Language：English   Presentation type：Symposium, workshop panel (nominated)  

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Event date： 2021.3

Presentation type：Oral presentation (general)  

Venue：オンライン  

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Venue：東京都立大学南大沢キャンパス   Country：Japan  

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Venue：Oxford, UK  

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Venue：松山  

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Venue：小樽  

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Venue：松山  

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Venue：Oxford, UK  

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Venue：Seattle, USA  

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Venue：オンライン  

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Venue：岡山  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Sapporo  

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