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

Pentakis-fused TTF derivatives extended with two cyclohexene-1,4-diylidenes (2a and 2b) have been successfully synthesized. Cyclic voltammetry of the tetrakis(2-ethylhexylthio) derivative (2b) has revealed that it exhibits five stages of the redox process to form 2b(10+). A coin-type cell composed of a positive electrode incorporating the tetrakis(methylthio) derivative (2a) exhibits a discharge capacity of 196 mA h g(-1), which corresponds to participation of a ten electron redox. It shows a high performance of energy density of 700 mW h g(-1) and an output power density of 69 W g(-1) with a relatively stable cycle-life performance (72% of the initial discharge capacity after 30 cycles).

DOI： 10.1039/c3ta14920j

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

Novel bis- and tris-fused tetrathiafulvalene (TTF) analogs possessing [5]radialene with quintuple 1,3-dithioI-2-ylidene moieties (2-4) were successfully synthesized. Cyclic voltammetry and differential pulse voltammetry revealed that they exhibited a simultaneous four- or eight-electron transfer process. It is suggested that four positive charges are distributed mainly over each of one or two DT[5]radialene units in 2(4+), 3(4+), and 4(8+).

DOI： 10.1021/ol401350c

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

Rechargeable batteries using bis- or tris-fused tetrathiafulvalenes as an active electrode material exhibit good cycle performance by controlling the number of electrons participating in the redox reaction. The TTPY cell using a four-electron redox process shows a discharge capacity of 168 mAhg-1 and good cycle-life stability of 84% of the initial capacity after 100 cycles (see charge-discharge curves). © 2012 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim.

DOI： 10.1002/cplu.201200197

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

Novel 1,3-dithiole[4]dendralene derivatives 3 with two thiophene spacers were synthesized. Cyclic voltammetry and spectroelectrochemistry suggested the dications of most derivatives of 3 have dimeric thiophene quinoid radical cation structures, while tetramethyltetrakis(methoxycarbonyl) derivative 3Bd adopts a vinylogous TTF dication structure.

DOI： 10.1246/cl.2011.467

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

A new charge transfer complex (CPDT-STF)(TCNQ) has been prepared. An X-ray crystal structure analysis revealed that this complex is composed of the donor and acceptor sheets orthogonally arranged to each other, which is similar to (ET)(TCNQ) and (ET)(TCNQF(1)). The band calculations indicate that the CPDT-STF layer has a significantly two-dimensional interaction, while the TCNQ one has a one-dimensional Fermi surface. The electrical resistivity of the present complex showed metallic temperature dependence down to 0.6 K. The thermoelectric power was negative and changed from the positive to the negative gradient at 60 K. The static magnetic susceptibility and transport properties indicate coexistence of local and itinerant electrons in the present complex. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0038-1098(99)00247-1

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

DOI： 10.1002/adma.19970090906

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

DOI： 10.1002/adma.19970090808

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VCH PUBLISHERS INC  

Below 4 K the [Au(CN) 2 ] salt of the radical cation of 1 shows superconductivity. The X‐ray structure analysis reveals that this salt has a two‐dimensional array of donors. The relatively large interactions between the stacks result in a closed Fermi surface. (Figure Presented.) Copyright © 1995 by VCH Verlagsgesellschaft mbH, Germany

DOI： 10.1002/anie.199512221

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DOI： 10.1246/cl.1993.1337

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

Synthesis of the title compound (1), and its molecular structure determined by X-ray crystallographic analysis, and electrochemical property investigated by cyclic voltammetry are described. Several cation radical salts of 1 have been prepared by electrochemical oxidation method, and their electrical properties are also presented.

DOI： 10.1246/cl.1992.2321

DOI： 10.1002/chin.199342168

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1,3-Dithiole-[3]- and [4] -dendralenes (2 and 3) have successfully been synthesized by using Vilsmeyer reactions on 2,2′-(ethanediylidene)bis(1,3-dithiole) (5) and 2 and the following Wittig reaction. Their electrochemical properties are discussed in comparison with those of 5 and 1,3-dithiole[4]radialene (4). Furthermore, conversion of 2 and 3 to 1,3-dithiole-[3] radialene and 4, respectively, was attempted by using zero-valent nickel complexes. © 1989.

DOI： 10.1016/S0040-4039(01)93767-0

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

DOI： 10.1021/ja00210a069

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

DOI： 10.1021/ja00247a042

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DOI： 10.3390/chemistry6060091

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Publishing type：Research paper (scientific journal)   Publisher：Georg Thieme Verlag KG  

Abstract

We synthesized diarylated 10-(1,3-dithiol-2-ylidene)anthracene-9-(10H)-one derivatives, which serve as important precursors of unsymmetrical arylated TTFAQs, via the palladium-catalyzed direct C–H arylation. Unsymmetrical diarylated TTFAQs were synthesized by the Horner–Wadsworth–Emmons reaction using diarylated 10-(1,3-dithiol-2-ylidene)anthracene-9-(10H)-one as the starting materials. Additionally, we have successfully synthesized unsymmetrical tetraarylated TTFAQs by a second palladium-catalyzed C–H arylation of diarylated TTFAQs.

DOI： 10.1055/a-2416-2206

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DOI： 10.1021/acsapm.4c00973

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Abstract

Derivatives of a 1,3-dithiole[6]dendralene analog with two thiophene spacers inserted (2) have been successfully synthesized. Cyclic voltammetry and spectroelectrochemistry revealed that their redox behavior, based on the distribution of the positive charges, differed depending on the position and the electronic effect of substituents on the 1,3-dithiole rings.

DOI： 10.1093/chemle/upae104

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Other Link： https://academic.oup.com/chemlett/article-pdf/53/6/upae104/58334564/upae104.pdf

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Abstract

Derivatives of vinyl‐extended tetrathiafulvalene (TTF) functionalized with two 2,6‐dicyano‐λ⁵‐phosphinine units (3 a–c) have been successfully synthesized. Cyclic voltammograms of all the derivatives are composed of three pairs of redox waves. The first and second redox waves correspond to one‐electron transfer processes, in which the extended TTF moiety participated predominantly. The third redox wave corresponded to a two‐electron transfer process, in which the two 2,6‐dicyano‐λ⁵‐phosphinine units were involved. The redox potentials at which the tetracations of 3 a–c were generated were considerably more negative than expected, probably due to the formation of stable closed‐shell structures by conjugation between 2,6‐dicyano‐λ⁵‐phosphinine units. X‐ray structural analyses of 3 b, 3 c, and (3b²⁺)(Sb₂Cl₈²⁻)(C₆H₅OCH₃) revealed that the vinyl‐extended TTF moiety in all the compounds adopts an almost planar structure, while the phosphinine units are significantly rotated relative to the extended TTF plane. The fluorescence spectroscopy revealed that the emission intensity of 3 b was very small in both the neutral and oxidized states.

DOI： 10.1002/ejoc.202400088

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We fabricated MISM and MISIM devices using DA-type single-component molecules as the S layer and examined their photocurrent and polarization hysteresis.

DOI： 10.1039/d3fd00125c

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Publishing type：Research paper (scientific journal)   Publisher：Walter de Gruyter GmbH  

Abstract

Lithium-ion batteries are attractive for their use in portable electronics and electric vehicles owing to their high energy and power density. Organic materials as active materials for the positive electrode have attracted attention as an alternative to inorganic materials in sustainable batteries. However, there is a serious drawback that elution into the electrolyte solution. This article describes our attempts in the development of tetrathiafulvalene (TTF) analogs for active materials. We have developed four types of fused TTF systems; multifused TTF systems, TTF analogs extended with cyclohexene moieties, TTF analogs extended with an anthraquinoid spacer, and fused TTF and benzoquinone systems. These molecules were designed based on the idea that increasing the size and planarity of the molecules and intermolecular interactions. They were successfully synthesized and their cell performances were clarified. We also describe that a TTF analog bearing triphenylamines was applied to long-cycle-life electrodes as a recent effort. This molecule was successfully synthesized using palladium-catalyzed C-H arylation and the cycle life of the cells comprising this molecule was markedly improved by in-cell electropolymerization.

DOI： 10.1515/pac-2023-0302

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Other Link： https://www.degruyter.com/document/doi/10.1515/pac-2023-0302/pdf

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

Molecular and charge arrangements in the solid state were controlled by a new building block: a triad molecule.

DOI： 10.1039/d3cc03198e

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We have found that benzene-fused TTFs bearing polymerization sites could prolong the cycle life of LIBs via “in-cell polymerization”.

DOI： 10.1039/d3nj00289f

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

DOI： 10.1246/bcsj.20220281

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Other Link： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-20H05621/

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

DOI： 10.1246/bcsj.20220191

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DOI： 10.1021/acsami.2c09302

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DOI： 10.1021/acs.inorgchem.1c04004

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DOI： 10.1246/cl.220064

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<jats:title>Abstract</jats:title><jats:p>4,8‐Dialkylbenzo[1,2‐<jats:italic>d</jats:italic>:4,5‐<jats:italic>d’</jats:italic>]bis[1,2,3]triselenoles [alkyl=Et, Bu, and Oc (C<jats:sub>8</jats:sub>H<jats:sub>17</jats:sub>)] were first prepared and treated with concentrated sulfuric acid‐<jats:italic>d</jats:italic><jats:sub>2</jats:sub> to generate benzobistriselenole dications, which were determined by NMR spectroscopy. The oxidation of dioctylbenzobistriselenole with three equivalents of single‐electron oxidizing reagent (NOSbF<jats:sub>6</jats:sub>) produced the corresponding dication<jats:sup>.</jats:sup>2SbF<jats:sub>6</jats:sub><jats:sup>−</jats:sup>, and the salt was isolated into a stable form. The ESR spectra of the dications measured in concentrated sulfuric acid in the range of room temperature and −196 °C were observed as split peaks similar to that of solid state dication<jats:sup>.</jats:sup>2SbF<jats:sub>6</jats:sub><jats:sup>−</jats:sup>. Magnetic susceptibility of the dication<jats:sup>.</jats:sup>2SbF<jats:sub>6</jats:sub><jats:sup>−</jats:sup> was determined by a superconducting quantum interference device (SQUID) magnetometer, which showed the salt is diamagnetic. The optimized structures and the total energy of the singlet‐ and triplet‐state benzobistriselenole dications were calculated using the density functional theory (DFT) method at the B3LYP6‐311G**(d,p) level. The results revealed that the structures of the singlet‐ and triplet‐state dications calculated have a completely planar forms and the triplet‐state dication is slightly more stable than the singlet‐state one in acetonitrile using a polarizable continuum model (PCM).</jats:p>

DOI： 10.1002/slct.202102375

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

DOI： 10.1021/acs.joc.1c00856

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

DOI： 10.1246/cl.210218

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DOI： 10.1246/bcsj.20210115

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DOI： 10.1002/tcr.202100107

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

DOI： 10.1246/bcsj.20200399

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DOI： 10.1246/bcsj.20200406

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DOI： 10.1002/ejoc.202100039

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Publisher：Wiley  

DOI： 10.1002/ejoc.202100320

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DOI： 10.1246/bcsj.20200357

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DOI： 10.1246/cl.210070

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：GEORG THIEME VERLAG KG  

Peripherally arylated tetrathiafulvalenes with an anthraquinoid spacer (TTFAQs) have been synthesized by using palladium-catalyzed direct C-H arylation of the 1,3-dithiole rings. Electrochemical analysis by cyclic voltammetry has revealed that the new tetraarylated TTFAQs show one pair of simultaneous two-electron transfer waves as the parent TTFAQ does. The hydrolysis of the tetra( p -ethoxycarbonylphenyl)-substituted derivative affords the corresponding tetracarboxylic acid, which forms a new double-helical metal-organic framework upon complexation with cobalt(III) nitrate.

DOI： 10.1055/s-0040-1707177

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Heterocyclic Chemistry  

DOI： 10.3987/com-21-14428

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I031465348

Publishing type：Research paper (scientific journal)   Publisher：Georg Thieme Verlag {KG}  

DOI： 10.1055/s-0040-1707256

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

Novel multistage redox tetrathiafulvalenes (TTFs) bearing 6-aryl-1,4-dithiafulvene moieties were synthesized by palladium-catalyzed direct C-H arylation. In the presence of a catalytic amount of Pd(OAc)2, P(t-Bu3)·HBF4, and an excess of Cs2CO3, the C-H arylation of TTF with several aryl bromides bearing 1,3-dithiol-2-ylidenes took place efficiently to produce the corresponding π-conjugated molecules. We also succeeded in the estimation of the oxidation potentials and number of electrons involved in each oxidation step of the obtained compounds by digital simulations.

DOI： 10.3762/bjoc.16.86

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

DOI： 10.1016/j.tetlet.2020.151724

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

Organic molecules carrying both electron-donating and accepting sites have received considerable attention as functional electronic materials. Donor-acceptor triads composed of tetrathiafulvalene (TTF) and benzoquinone (BQ) fused by a benzene-spacer were synthesized. The fused diad and triads could be utilized as positive electrode active materials for used in the Li-ion battery. Among the prepared cells, the compound 3/Li cell exhibited high energy density (703 mWh/g) during the first discharge. The insertion of the fused benzene ring between the TTF and BQ units was useful to improve the cycle-life performance. In contrast, the direct fusion of TTF and BQ was effective in increasing the discharge voltage involving the BQ site, leading to an increase in the discharge capacity.

DOI： 10.1246/BCSJ.20200202

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

Derivatives of a tris-fused donor composed of two tetrathiafulvalenes (TTFs) and one extended TTF with an anthraquinoid spacer (TTFAQ) (3) were successfully synthesized. Cyclic voltammetry of the tetrakis(n-hexylthio) derivative (3Dd) indicated the coexistence of two different reduction processes from 3Dd(2+) to 3Dd. A coin-type cell composed of the positive electrode incorporating the tetramethyl-3 (3Bb) showed relatively stable cycle-life performance (75% of the initial discharge capacity after 50 cycles).

DOI： 10.1246/cl.190703

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DOI： 10.1246/cl.190383

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DOI： 10.1002/ejoc.201801877

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

DOI： 10.1002/ejoc.201900457

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Tris-fused π-electron donors composed of two tetrathiafulvalenes (TTFs) and one extended TTF with anthraquinoid spacer (3) were successfully synthesized. The cyclic voltammograms of the tetrakis(n-hexylthio)- and bis(ethylenedioxy) derivatives 3c and 3d consisted of three-pairs of two-electron redox waves. Spectroelectrochemitry of 3c indicated that two positive charges in 3c 2+ are located mainly on the central extended TTF moiety. Coin-type cells composed of the positive electrodes incorporating the unsubstituted-3 (3a) and 3d showed the discharge capacities of 192 and 160 mAh g –1 , respectively, in which six electrons per molecule are involved.

DOI： 10.1002/ejoc.201801877

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DOI： 10.1002/chem.201901030

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[5]Radialene with quintuple 4,5-benzo-1,3-dithiol-2-ylidenes (DTs) easily forms a stable polycationic salt (1) 4+ (BF 4− ) 4 owing to its aromatic character in the central cyclopentadienide ring. In this work, it was found that the polycationic salt (1) 4+ underwent a hydration reaction in moist polar solvent to give several unexpected products, namely, an oxygen adduct dicationic salt (2) 2+ , a tetrathiafulvalene (TTF) vinylogue (3) with 1,4-dithiine-2(3H)-one moieties, and an oxygen adduct of π-extended TTF with a cyclopentenone core (4). Their molecular structures were fully determined by X-ray crystal-structure analysis. In this reaction, irreversible hydration to the polycationic salt might either initiate the ring expansion and lead to the successive hydration at the specific cationic DT ring (for 3), or promote the transannular reactions to the next DT ring followed by elimination of the DT ring (for 4). Cyclic voltammetry and differential pulse voltammetry measurements for compound 3 indicated the occurrence of multi redox process resulting from electronic delocalization on the vinylogous TTF moiety. The electronic structures of the cationic species of 3 were also investigated by electronic spectra.

DOI： 10.1002/chem.201805994

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

DOI： 10.1002/chem.201805994

DOI： 10.5059/yukigoseikyokaishi.77.1234_references_DOI_HqFPKQxD3WDWeKqowzRgash5MGP

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Publisher：Jenny Stanford Publishing  

DOI： 10.1201/9780429468131-4

DOI： 10.5059/yukigoseikyokaishi.77.1234_references_DOI_OWFKcVCDP2VOR4fhMnfCbzXfHmL

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A bis-fused donor composed of dimethyl-tetrathiafulvalene and tetraselenafulvalene (DM-ST-STP) was successfully synthe-sized. X-ray structure analysis of the salts with PF6- and AsF6-anions revealed that the molecular packing could be classified as β-type. A tight-binding band calculation suggested these salts had a quasi-one-dimensional Fermi surface. They exhibited high conductivity of σrt = 390-540Scm-1 and metallic behavior down to low temperature.

DOI： 10.1246/cl.190383

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

<p>Gold(<sc>iii</sc>) atoms reversibly deviate from the molecular plane on receiving thermal and photon energy.</p>

DOI： 10.1039/c9dt02377a

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The Au(iii)-complex anions in a newly synthesised compound BPY[Au(dmit)2]2 (BPY = N,N-ethylene-2,2-bipyridinium, dmit = 1,3-dithiole-2-thione-4,5-dithiolate) reversibly exhibit a molecular distortion in the solid state under UV-radiation. The photoexcited state is maintained for a week at 298 K, during which time molecules relax to their original structures and energy is gradually released as heat without decomposition or light emission. Most Au atoms adopt square planar (SP) coordination geometries, but some anions have unusual non-planar (NP) coordination geometries that produce disorder at the Au sites. The total (Gibbs) energy of the system depends on the proportion of Au atoms of NP geometry, which is directly determined from the occupancy (Occ (%)) by X-ray diffractometry. Due to phase transition, Occ substantially changes at a critical temperature (TC) of ∼280 K without other structural changes; however it remains almost constant in each phase. In addition, due to UV-promoted charge-transfer transitions between BPY and Au(dmit)2, Occ can be controlled by UV irradiation (∼250-450 nm). The UV-excited states have unprecedentedly long relaxation times (t1/2 > 36 h at 298 K), which is attributed to the close connection between the degrees of freedom on charge, spin, and molecular structures.

DOI： 10.1039/c9dt02377a

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DOI： 10.1246/bcsj.20180157

DOI： 10.1021/acs.inorgchem.1c04004_references_DOI_GUmzMLxBYs0dmryHMSMBdEzIDB6

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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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DOI： 10.1246/cl.180496

DOI： 10.1246/cl.190703_references_DOI_Vhn8Ell7DkeZOCBOVWCKpFeYQ2s

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

DOI： 10.1246/cl.180371

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X-ray structure analysis of (DM-TTP)2X (X= PF6, AsF6 and SbF)6 was successfully performed. The arrangement of DM-TTP molecules was classified as β 20-Type. A tightbinding band calculation suggested these salts had a quasione-dimensional Fermi surface. (DM-TTP)2SbF6 exhibited metallic conductivity down to 10K with = 1.4 S cm1 at room-Temperature.

DOI： 10.1246/bcsj.20180157

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2,5-Diphenylthiophene-based macrocycles were synthesized by Ni-mediated coupling of the corresponding building units. X-ray analysis revealed that the cyclic trimer had a saddle-shaped structure due to the steric demands of the biphenyl and thiophene-phenylene units, whereas DFT calculation showed that the cyclic dimer had a rigid and almost coplanar structure regardless of the steric hindrance between the benzene rings of the biphenyl units. Moreover, the packing diagram of the cyclic trimer showed alternating stacked layers of macrocycles and solvent molecules.

DOI： 10.1246/cl.180187

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

2,5-Diphenylthiophene-based macrocycles were synthesized by Ni-mediated coupling of the corresponding building units. X-ray analysis revealed that the cyclic trimer had a saddle-shaped structure due to the steric demands of the biphenyl and thiophene-phenylene units, whereas DFT calculation showed that the cyclic dimer had a rigid and almost coplanar structure regardless of the steric hindrance between the benzene rings of the biphenyl units. Moreover, the packing diagram of the cyclic trimer showed alternating stacked layers of macrocycles and solvent molecules.

DOI： 10.1246/cl.180187

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An ethylenedioxy derivative of a bis-fused donor composed of tetrathiafulvalene and tetraselenafulvalene (EO-ST-STP) was successfully synthesized. X-ray structure analysis revealed that (EO-ST-STP)2X (X = PF6 and ClO4) adopted the so-called β-type molecular packing. A tight-binding band calculation suggested these salts had a closed Fermi surface. Both salts exhibited high conductivity of σrt = 990-1200 S cm11 and metallic temperature dependence down to TMI = 50-70 K.

DOI： 10.1246/cl.180371

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[3]Dendralenes possessing both strongly electron donating 1,3-dithiol-2-ylidenes and electron accepting dicyanomethyli-dene (24) have been successfully synthesized. The results of cyclic voltammetry suggest that they exhibit oxidation processes accompanied by a conformational change. The rechargeable batteries using the tetrathiafulvalene-fused derivatives (3d, 4) as a positive electrode material showed the initial full charge-discharge capacities of 150 and 189 mAh g11.

DOI： 10.1246/cl.180496

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X-ray structure analysis of the [5]radialene with quintuple 1,3-benzodithiol-2-ylidenes (4) and its tetracation salt, 4 a⋅CS2 and (4 a)4+(ReO4–)4(CH3CN), was successfully carried out. The neutral [5]radialene molecule in 4⋅CS2 adopted a non-planar structure with an envelope conformation of the central five-membered ring. In contrast, the central five-membered ring of 4 a4+ in (4 a)4+(ReO4−)4(CH3CN) adopted a planar structure with significant contribution of an aromatic cyclopentadienide structure. An anion-π interaction was observed between the ReO4– anion and the central five-membered ring in (4 a)4+(ReO4–)4(CH3CN). The electronic structures of 4 a and its oxidative species (4 a2+ and 4 a4+) were estimated by density functional theory (DFT) calculations. The optimized structure of 42+ suggested the delocalization of a positive charges over two 1,3-benzodithiol-2-ylidene units through the central five-membered ring.

DOI： 10.1002/slct.201700288

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

Fused donor-donor-acceptor triads composed of tetrathiafulvalenes (TTFs) and benzoquinone (BQ) or naphthoquinone (NQ) were synthesized. The bis(methylsulfanyl)-TTFs-BQ and TTFs-NQ serve as a positive electrode active material for the rechargeable lithium battery with an energy density of over 800 mWh g(-1) . The bis(methylsulfanyl)-TTFs-NQ also functions as an active material for the rechargeable sodium battery.

DOI： 10.1246/cl.161077

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Other Link： https://kaken.nii.ac.jp/grant/KAKENHI-PUBLICLY-15H00948/

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Fused donordonoracceptor triads composed of tetrathiafulvalenes (TTFs) and benzoquinone (BQ) or naphthoquinone (NQ) were synthesized. The bis(methylsulfanyl)-TTFs-BQ and TTFs-NQ serve as a positive electrode active material for the rechargeable lithium battery with an energy density of over 800mWh g-1. The bis(methylsulfanyl)-TTFs-NQ also functions as an active material for the rechargeable sodium battery.

DOI： 10.1246/cl.161077

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

Molecular and crystal structures of dicationic tetrakis-(1,3-benzodithiol-2-ylidene)cyclopentanone (1b), (1b(2+))(2)-(ReO4-)(4)(CH3CN)(3)(H2O)0.7, were successfully determined by X-ray single-crystal diffraction. It was suggested that two 1,3-dithiol-2-ylidenes adjacent to the carbonyl group were effectively conjugated with each other. The remaining two 1,3-dithiol-2-ylidenes, where two positive charges were mainly distributed, were considerably twisted from the central five-membered ring.

DOI： 10.1246/bcsj.20160271

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Bis- and tris-fused π-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 1H NMR spectrum of a 4b salt revealed that two positive charges in 42+ 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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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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The structural, transport, and magnetic properties of the new organic conductors (DMEDO-TTF)2X (X = ClO4 and BF4), where DMEDO-TTF is dimethyl(ethylenedioxy)tetrathiafulvalene, have been investigated. These compounds have a complete uniform stack structure, indicating that a quasi-one-dimensional 3=4-filled band without a dimerization gap is realized. The ClO4 and BF4 salts show a first-order metal-insulator (MI) transition at approximately 190 and 210 K, respectively, in the cooling process. The ground state is a nonmagnetic insulator on the basis of magnetic susceptibility measurements. Low-temperature X-ray diffraction measurements show that the MI transition originates in the anion ordering transition with a superstructure wave vector of q = (0, 1/2, 0) corresponding to the stacking direction; the uniform donor stacking structure changes to the tetramerized structure with a large shift of the donors. The shift of the anion toward the central two donors in a tetramer indicates that the insulating phase is a charge-density-wave state.

DOI： 10.7566/JPSJ.85.094701

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

The structural, transport, and magnetic properties of the new organic conductors (DMEDO-TTF)(2)X (X = ClO4 and BF4), where DMEDO-TTF is dimethyl(ethylenedioxy)tetrathiafulvalene, have been investigated. These compounds have a complete uniform stack structure, indicating that a quasi-one-dimensional 3/4-filled band without a dimerization gap is realized. The ClO4 and BF4 salts show a first-order metal-insulator (MI) transition at approximately 190 and 210 K, respectively, in the cooling process. The ground state is a nonmagnetic insulator on the basis of magnetic susceptibility measurements. Low-temperature X-ray diffraction measurements show that the MI transition originates in the anion ordering transition with a superstructure wave vector of q = (0, 1/2, 0) corresponding to the stacking direction; the uniform donor stacking structure changes to the tetramerized structure with a large shift of the donors. The shift of the anion toward the central two donors in a tetramer indicates that the insulating phase is a charge-density-wave state.

DOI： 10.7566/JPSJ.85.094701

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Understanding the details of the electronic structure in face-to-face arranged tetrathiafulvalenes (TTFs) is very important for the design of supramolecular functional materials and superior conductive organic materials. This article is a comprehensive study of the interactions among columnar stacked TTFs using trimeric (trimer) and tetrameric (tetramer) TTFs linked by alkylenedithio groups (-S(CH2)nS-, n=1–4) as models of triple- and quadruple-decker TTF arrays. Single-crystal X-ray analyses of neutral trimeric TTFs revealed that the three TTF moieties are oriented in a zigzag arrangement. Cyclic voltammetry measurements (CV) reveal that the trimer and tetramer exhibited diverse reversible redox processes with multi-electron transfers, depending on the length of the -S(CH2)nS- units and substituents. The electronic spectra of the radical cations, prepared by electrochemical oxidation, showed charge resonance (CR) bands in the NIR/IR region (1630–1850 nm), attributed to a mixed valence (MV) state of the triple- and quadruple-decker TTF arrays. In the trimeric systems, the dicationic state (+2; 0.66 cation per TTF unit) was found to be a stable state, whereas the monocationic state (+1) was not observed in the electronic spectra. In the tetrameric system, substituent-dependent redox processes were observed. Moreover, π-trimers and π-tetramers, which show a significant Davydov blueshift in the spectra, are formed in the tricationic (trimer) and tetracationic (tetramer) state. In addition, these attractive interactions are strongly dependent on the length of the linkage unit.

DOI： 10.1002/chem.201601785

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

Versatile π-electron systems with interesting electronic properties have been synthesized as potential candidates. This chapter focuses on a series of cross-conjugated compounds such as radialenes, dendralenes, tetraethynylethane (TEE), and radiaannulene containing tetrathiafulvalene (TTF) or 1,3-dithiole (DT) moieties. It presents recent syntheses, redox properties, and electronic structures of the multi-redox system of TTF or DT rings in cross-conjugation. Dendralenes, acyclic cross-conjugated polyenes having a nonplanar structure, containing DT rings have received considerable attention as novel multistage redox systems. [n]Radialenes are cyclic dendralenes. They are formally composed of the n-membered ring and n-exocyclic double bonds. [n]Radialenes substituted with DT rings are regarded as multistep redox systems, and on-site Coulomb repulsion in their dicationic states is considerably reduced by delocalization of two positive charges over the whole multi-DTunits. TTF dimer and higher oligomers connected by a cross-conjugated system are expected to provide a stable high-spin system.

DOI： 10.1002/9783527671182.ch8

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Publishing type：Part of collection (book)  

Versatile π-electron systems with interesting electronic properties have been synthesized as potential candidates. This chapter focuses on a series of cross-conjugated compounds such as radialenes, dendralenes, tetraethynylethane (TEE), and radiaannulene containing tetrathiafulvalene (TTF) or 1,3-dithiole (DT) moieties. It presents recent syntheses, redox properties, and electronic structures of the multi-redox system of TTF or DT rings in cross-conjugation. Dendralenes, acyclic cross-conjugated polyenes having a nonplanar structure, containing DT rings have received considerable attention as novel multistage redox systems. [n]Radialenes are cyclic dendralenes. They are formally composed of the n-membered ring and n-exocyclic double bonds. [n]Radialenes substituted with DT rings are regarded as multistep redox systems, and on-site Coulomb repulsion in their dicationic states is considerably reduced by delocalization of two positive charges over the whole multi-DTunits. TTF dimer and higher oligomers connected by a cross-conjugated system are expected to provide a stable high-spin system.

DOI： 10.1002/9783527671182.ch8

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The Vilsmeier-Haack type formylations on various 6-aryl-1,4-dithiafulvenes were examined. The furyl derivatives on treatment with an excess of POCl3 in DMF at room temperature mainly afforded dialdehydes substituted at the 6-position and the furan ring, while the thienyl derivatives and the phenyl derivatives mainly gave monoformylated derivatives substituted at the 6-position. The obtained mono- and dialdehydes were converted into monoaryl-substituted 2,2′-ethanediylidene-bis(1,3-dithiole) derivatives and heteroaromatic ring-inserted [3]dendralene derivatives with triple 1,3-dithiol-2-ylidenes and their TTF-fused analogues. Electrochemical properties of the new π-electron donors were also investigated by cyclic voltammetry.

DOI： 10.1055/s-0035-1560400

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：化学工業社  

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Molecular and crystal structures of dicationic tetrakis-(1,3-benzodithiol-2-ylidene)cyclopentanone (1b), (1b2+)2-(ReO4 )4(CH3CN)3(H2O)0.7, were successfully determined by X-ray single-crystal diffraction. It was suggested that two 1,3-dithiol-2-ylidenes adjacent to the carbonyl group were effectively conjugated with each other. The remaining two 1,3-dithiol-2-ylidenes, where two positive charges were mainly distributed, were considerably twisted from the central five-membered ring.

DOI： 10.1246/bcsj.20160271

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

In this study, we synthesized 2-(4-chloro-5-methyl-1,3-dithio1-2-ylidene)-5-(4,5-dimethy1-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (ClMe3-TTP). Results show that the cation radical salts of ClMe3-TTP with PF6- and AsF6- anions show high conductivities (10(1) S cm(-1)) at room temperature and semiconducting behavior with low activation energy (24-27 meV). A crystal structure analysis of the PF6- and AsF6- salts reveals a 3:1 donor-anion ratio of these salts. The CIMe3-TTP molecules form one-dimensional columns along the a axis, and tape-structures, connected by the side-by-side S center dot center dot center dot S interactions, also form along the a axis. The calculated intracolumn and intratape overlap integrals are relatively large; however, the overlap integrals between the one-dimensional columns and the tapes are approximately 1/2-1/5 the value of the intracolumn and intratape overlap integrals. The band calculations suggest that they have one-dimensional electronic structures, indicating that they would comprise a Mott insulator.

DOI： 10.1246/bcsj.20140413

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Derivatives of tris-fused TTF extended with two ethanediylidenes (5), tris- and pentakis-fused TTFs extended with two thiophene- 2,5-diylidenes (6-9) were successfully synthesized. Cyclic voltammograms of the tetrakis(n-hexylthio) derivative of 5 and 7 (5d, 7d) consisted of two pairs of two-electron redox waves and two pairs of one-electron redox waves. On the other hand, four pairs of two-electron redox waves and two pairs of one-electron redox waves were observed for the tetrakis(n-hexylthio) derivative of 9 (9d). Coin-type cells using the bis(ethylenedithio) derivatives of 5 (5b), 6 (6b) and the tetrakis(methylthio) derivatives of 5 (5c) and 8 (8c) as positive electrode materials showed initial discharge capacities of 157-190 mAh g^-1 and initial energy densities of 535-680 mAh g^-1 . The discharge capacities after 40 cycles were 64-86% of the initial discharge capacities.

DOI： 10.3762/bjoc.11.128

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

Bis- and tris-fused pi-electron donors containing one or two vinylogous 1,3-dithiole[5]radialene unit (7-10) were successfully synthesized. Cyclic voltammetry revealed that the first redox waves of 7-10 correspond to simultaneous four-electron or eight-electron redox processes because of significant contribution of the moieties of vinylogous 1,3-dithiole[5]radialene exhibiting a simultaneous four-electron redox. The UV-vis-NIR spectra of the oxidative species of 7-10 generated by constant voltages exhibited absorption bands attributed to (7-9)(2+) and 10(4+) with structures of dicationic 1,3-dithiole[5]radialene vinylogs.

DOI： 10.1246/bcsj.20150047

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

Extensively conjugated tetrathiafulvalene (TTF) derivatives substituted with a TTF-fused 1,4-dithiafulven-6-yl group 4 have been synthesized. Theoretical calculation and X-ray crystal structure analysis of 4a demonstrated that the conformation A, in which the two TTF units are linearly oriented, is slightly more stable than the conformation B, which adopted orthogonal arrangement of two TTF units in the neutral state. Cyclic voltammetry revealed the presence of the intramolecular 1,5-S center dot center dot center dot S interaction that brings about the stabilization of the conformation B in the tricationic state.

DOI： 10.1246/cl.141182

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In this study, we synthesized 2-(4-chloro-5-methyl-1,3-dithiol-2-ylidene)-5-(4,5-dimethyl-1,3-dithiol-2-ylidene)- 1,3,4,6-tetrathiapentalene (ClMe3-TTP). Results show that the cation radical salts of ClMe3-TTP with PF6- and AsF6- anions show high conductivities (101 Scm-1) at room temperature and semiconducting behavior with low activation energy (2427 meV). A crystal structure analysis of the PF6- and AsF6- salts reveals a 3:1 donor-anion ratio of these salts. The ClMe3-TTP molecules form one-dimensional columns along the a axis, and tape-structures, connected by the side-by-side S⋯S interactions, also form along the a axis. The calculated intracolumn and intratape overlap integrals are relatively large; however, the overlap integrals between the one-dimensional columns and the tapes are approximately 1/2-1/5 the value of the intracolumn and intratape overlap integrals. The band calculations suggest that they have one-dimensional electronic structures, indicating that they would comprise a Mott insulator.

DOI： 10.1246/bcsj.20140413

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Bis- and tris-fused π-electron donors containing one or two vinylogous 1,3-dithiole[5]radialene unit (7-10) were successfully synthesized. Cyclic voltammetry revealed that the first redox waves of 7-10 correspond to simultaneous four-electron or eight-electron redox processes because of significant contribution of the moieties of vinylogous 1,3-dithiole[5]radialene exhibiting a simultaneous four-electron redox. The UVvisNIR spectra of the oxidative species of 7-10 generated by constant voltages exhibited absorption bands attributed to (7-9)2+ and 104+ with structures of dicationic 1,3-dithiole[5]radialene vinylogs.

DOI： 10.1246/bcsj.20150047

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© 2015 Iwamoto et al.Derivatives of tris-fused TTF extended with two ethanediylidenes (5), tris- and pentakis-fused TTFs extended with two thiophene- 2,5-diylidenes (6-9) were successfully synthesized. Cyclic voltammograms of the tetrakis(n-hexylthio) derivative of 5 and 7 (5d, 7d) consisted of two pairs of two-electron redox waves and two pairs of one-electron redox waves. On the other hand, four pairs of two-electron redox waves and two pairs of one-electron redox waves were observed for the tetrakis(n-hexylthio) derivative of 9 (9d). Coin-type cells using the bis(ethylenedithio) derivatives of 5 (5b), 6 (6b) and the tetrakis(methylthio) derivatives of 5 (5c) and 8 (8c) as positive electrode materials showed initial discharge capacities of 157-190 mAh g&lt;sup&gt;-1&lt;/sup&gt; and initial energy densities of 535-680 mAh g&lt;sup&gt;-1&lt;/sup&gt; . The discharge capacities after 40 cycles were 64-86% of the initial discharge capacities.

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

The electron donor 2-isopropylidene-1,3-dithiolo[4,5-d]-4,5-ethylenediselenotetrathiafulvalene (3) provides two new molecular conductors, (3)(2)[M(CN)(2)] (M = Ag and Au). These salts crystallize in the triclinic P (1) over bar space group. The donor sheet structure of these salts is the so-called beta-type molecular array, in which the donor molecules form a head-to-tail dimer. The formation of considerable dimerization and the 2:1 donor-anion ratio result in an effectively half-filled electronic nature. These salts show metallic conducting behavior from room temperature. The metallic conducting behavior of (3) (2)[Ag(CN)(2)] was retained down to 8 K; however, the resistivity of (3)(2)[Au(CN)(2)] increased at around 50 K. The magnetic susceptibility of (3)(2)[Au(CN)(2)] suggests that the strength of the electron correlation for this salt is enhanced below 50 K.

DOI： 10.1002/ejic.201402006

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

Dendritic tetrathiafulvalene (TTF) derivatives linked by methylenedithio groups 3 were synthesized. Cyclic voltamrnetry and spectroelectrochemistry analyses revealed the presence of considerable mutual interaction among multiple TTF units in the oxidation states.

DOI： 10.1246/cl.140092

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

A new cyclic tetrathiafulvalene (TTF) tetramer 1 was synthesized. The cyclic voltammogram of 1 consists of four pairs of two-electron redox waves. UV-vis-NIR spectra of the oxidative species of 1 suggest that 1(2+), 1(4+), and 1(6+) possibly adopt two pairs of dimeric TTF structures that interact with each other through the so-called side-by-side interaction.

DOI： 10.1246/cl.131231

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

Ammonium tetrathiapentalene carboxylate [(TTPCOO)(2)NH4] was prepared via protonic defect-induction doping without electrochemical oxidation. The high electric conductivity of 13 S cm(-1) and Pauli paramagnetic-like behavior of magnetic susceptibility in a wide temperature range exhibit a melting of the charge degrees of freedom induced by a mobile dopant in a salt bridge. Solid-state H-1 NMR strongly indicates a stable metallic state of this compound down to 4 K.

DOI： 10.1039/c4cc00678j

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Spectroelectrochemistry of [5]radialenes with five 1,3-dithiol-2-ylidenes (DTs) (1) was carried out. The UV-vis-NER spectra of 1(2+) suggest delocalization of two positive charges over three DT units. X-ray structure analysis of an oxygen adduct (2)(2+)(AsF6-)(2)(PhCl)(1.5) reveals that 2(2+) has a cyclopentadienide structure in the central five-membered ring.

DOI： 10.1246/cl.130142

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

Novel [5]radialenes with four 1,3-dithiol-2-ylidene (DT) units (2) and ethylene analogs of [5]dendralene derivatives with five DT units (3) were synthesized. Cyclic voltammetry revealed that 2 exhibited two pairs of two-electron redox processes, whereas the bis(methylthio) derivative of 3 (3a) showed a simultaneous four-electron-transfer process.

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DOI： 10.5517/ccznjz3

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Other Link： http://orcid.org/0000-0002-7119-2017

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DOI： 10.1246/cl.130822

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DOI： 10.1246/cl.130841

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Language：Japanese   Publisher：The Society of Synthetic Organic Chemistry, Japan  

DOI： 10.5059/yukigoseikyokaishi.71.1319

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Synthetic Organic Chemistry, Japan  

Dendralenes, acyclic cross-conjugated polyenes having a nonplanar structure, containing 1,3-dithiole (DT) rings are of considerable interest as novel multi-stage redox systems for potential application to electrical conducting, magnetic, electrochromic, and nonlinear optical materials. In the present review, we focus on the electronic structures of DT[n] dendralenes and their nextended compounds in which phenylene, thienylene, furylene, or tetrathiapenthalene (TTP) moieties are inserted. DT[n] dendralenes (n = 3 and 4) employ a non-planar structure due to the steric effect, and cyclic voltammetry (CV) suggested multi-redox behavior of extended vinylogues. Their electronic structure and conjugation pathway in cationic states are strongly affected by the aromaticity of the inserted aryl groups. As for dication of DT[4] dendralenes with two thiophene spacers, the electronic structures depend on their substituents. In the cationic states of DT[5] dendralenes with two thiophene spacers, the positive charges are mainly located on the outer TTF moieties. On the other hand, cationic species of DT[3] dendralene having two TTP moieties, the positive charges are distributed mainly in the outer branching vinylogues.

DOI： 10.5059/yukigoseikyokaishi.71.1268

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

Bis-fused donors composed of (thio) pyran-4-ylidene-1,3-dithiole and tetraselenafulvalene (1a, 2a) and their bis(methylthio) derivatives (1b, 2b) were synthesized. Cyclic voltamograms of all the donors consisted of four pairs of one-electron redox waves, and it was suggested that a positive charge of 1(+center dot) and 2(+center dot) distributed mainly on the (thio) pyran-4-ylidene-1,3-dithiole moiety. X-ray structure analysis revealed that (1b)PF6(C6H5Cl)(0.5) and (2b)PF6(C6H5Cl) formed one-dimensional conducting stacks in which the donors were dimerized or tetramerized. In those salts, intramolecular charge disproportionation of the donors was suggested by X-ray structure analysis and density functional theory (DFT) calculation with UB3LYP/6-31G(d) basis function. A tight-binding band calculation suggested that these materials were band insulators. All the donors gave highly conducting TCNQ (7,7,8,8-tetracyanoquinodimethane) complexes and I-3(-) salts (sigma(rt) = 0.3-19 S cm(-1) on a compressed pellet) with very low activation energies of 0.017-0.040 eV, while single crystals of (1b)PF6(C6H5Cl)(0.5) and (2b) PF6(C6H5Cl) exhibited semiconductive behavior with large activation energies (E-a = 0.16-0.22 eV).

DOI： 10.3390/cryst2031092

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

A series of quasi-one-dimensional molecular conductors (DMEDO-TTF)(2)XF6 (X = P, As, and Sb), where DMEDO-TTF is dimethyl(ethylenedioxy)tetrathiafulvalene, undergo characteristic structural transitions in the range of 130-195 K for the PF6 salt and 222-242 K for the AsF6 salt. The dramatic structural transition is induced by the order of the ethylenedioxy moiety, and the resulting anion rotation leads to the reconstruction of the H center dot center dot center dot F interaction between the methyl groups and the anions. The unique hydrogen bonds play a crucial role in the transition. As a result, the molecular packing is rearranged entirely; the high-temperature molecular stacks with an ordinary quasi-triangular molecular network transforms to a quasi-square-like network, which has never been observed among organic conductors. Nonetheless, the low-temperature phase exhibits a good metallic conductivity as well, so the transition is a metal-metal (MM) transition. The resistivity measured along the perpendicular direction to the conducting ac-plane (rho(perpendicular to)) and the calculation of the Fermi surface demonstrate that the high-temperature metal phase is a one-dimensional metal, whereas the low-temperature metal phase has considerable interchain interaction. In the SbF6 salt, a similar structural transition takes place around 370 K, so that the quasi-square-like lattice is realized even at room temperature. Despite the largely different MM transition temperatures, all these salts undergo metal-insulator (MI) transitions approximately at the same temperature of 50 K. The low-temperature insulator phase is nonmagnetic, and the reflectance spectra suggest the presence of charge disproportionation with small charge difference (0.14).

DOI： 10.1021/ja303435n

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New tris-fused tetrathiafulvalene analogues, in which the outer two TTF units were replaced by [3]dendralenes with triple 1,3-dithiole rings, were synthesized. A theoretical calculation of the unsubstituted derivative based on density functional theory (DFT) using B3LYP/6-31G(d) method suggested that branching 1,3-dithiole rings were almost perpendicular to the central TTF moiety. Cyclic voltammogram of the octakis(methylthio) derivative exhibited five pairs of redox waves at -0.03, 0.06, 0.37, 0.48, and 1.14 V (V vs. Fc/Fc(+), in benzonitrile). The first, the second, and the fifth redox processes corresponded to simultaneous two-electron-transfer processes, while the others corresponded to one-electron transfer. The redox behavior and UV-vis-NIR spectra of the octamethyl derivative suggested that the positive charges in the dication and tetracation states distributed mainly on the outer branching vinylogous TTF moieties. A compressed pellet of the charge-transfer complexes of the octamethyl and octakis(methylthio) derivatives with TCNQF(4) exhibited moderate conductivity of sigma(rt) = 10(-3)S cm(-1) and semiconductive behavior with activation energies of 0.10-0.13 eV.

DOI： 10.1246/bcsj.20120063

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

Tetrathiafulvalene derivatives condensed with 2-alkylidene-1,3-dithiole moiety, MeDTES (2-isopropylidene-1,3-dithiolo[4,5-d]-4,5-ethylenediselenotetrathiafulvalene), EtDTES (2-(pentan-3-ylidene)-1,3-dithiolo[4,5-d]-4,5-ethylenediselenotetrathiafulvalene), and CPDTES (2-cyclopentanylidene-1,3-dithiolo[4,5-d]-4,5-ethylenediselenotetrathiafulvalene) have been synthesized. Crystal structure analysis of MeDTES salts with Au(CN)(4)(-), ReO4-, and I-3 and a CPDTES salt with I-3 reveals that the donor-anion ratios of all salts are 1:1. Band calculation of (MeDTES)[Au(CN)(4)] suggests a quasi-one-dimensional Fermi surface that could be the result of the uniform stack of donor molecules. In spite of this stacking, the salt is a Mott insulator because of a large on-site Coulomb interaction U. (MeDTES)(ReO4)(H2O)(0.5) possesses Fermi points and exhibits semiconducting behavior with small activation energy (E-a = 0.058 eV). I-3(-) ions form disordered infinite chain in (MeDTES)(I-3)(DCE)(0.25), but those in (CPDTES)(I-3) exist as discrete ions. They show low conductivity (10(-4)-10(-2) S cm(-1)) at room temperature and the band calculation suggests that they are band insulator.

DOI： 10.3390/cryst2020393

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

Bis-fused tetrathiafulvalenes with mono- and dicarboxylic acids, 2-{5-(1,3-dithiol-2-ylidene)-[1,3]dithiolo[4,5-d][1,3]dithiol-2-ylidene}-1,3-dithiole-4-carboxylic acid (1) and 2{5-(1,3-dithiol-2-ylidene)-[1,3]dithiolo[4,5-d][1,3]dithiol-2-ylidene}-1,3-dithiole-4,5-dicarboxylic acid (2) have been synthesized. The electronic structure of 1 and 2 was examined from their optical absorption spectra and using density-functional calculations. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2012.04.064

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

A new 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (BDT-TTP) type donor, 2-(4,5-dimethoxy-1,3-dithiol-2-ylidene)-5-(4,5-ethylenedithio-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (MOET-TTP) was synthesized and its magnetic and non-magnetic anion salts (MOET-TTP)2MCl4 (M=Fe and Ga), were prepared. These salts are isostructural and belong to the space group of P1. They show metal-like behavior down to 200K for the FeCl4 salt and 20K for the GaCl4 salt. The band structures of these salts are two-dimensional. The MCl4 anions are located between the donor columns and close to the ethylenedithio and methoxy groups of the donor molecules. The magnetic susceptibilities of the FeCl4 salts follow the CurieWeiss law with Curie constant of 4.3emuKmol-1 and Weiss temperature of =-1.8K, revealing a weak antiferromagnetic interaction of 3d spins of the FeCl4 anions. The Fe center dot Fe (6.508(3) angstrom) and Cl center dot Cl (3.784.69 angstrom) distances in the crystal structure of the salt are significantly long. Therefore, the direct magnetic interaction between the 3d spins of the nearest neighboring Fe3+ ions does not seem readily accessible.

DOI： 10.1002/pssb.201100674

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

The temperature and polarization dependence of the optical reflectivity spectra of a quasi-one-dimensional 1/4-filled band system,. DMEDO-EBDT/2PF6, have been investigated. We observed clear anisotropy in the electronic structures corresponding to the anisotropic transport properties. The appearance of a charge gap (E-g &gt; 0.1 eV) and transfer of the spectral weight accompanied by the metal-insulator phase transition were clearly observed. In addition, a split of the intramolecular vibrational modes was observed, which strongly suggested the existence of charge disproportionation in the low temperature phase. We also observed a photoinduced reflectivity change, which implied the occurrence of a photoinduced phase transition from the low temperature insulating phase to the high temperature metallic phase.

DOI： 10.1088/0953-8984/24/19/195501

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：WILEY-V C H VERLAG GMBH  

The title salt, where BSM-TTP is 2-[4,5-bis(methylseleno)-1,3-dithiol-2-ylidene]-5-(1,3-dithiol-2ylidene)-1,3,4,6-tetrathiapentalene, was prepared. The X-ray structure analysis reveals that the donors form teramerized columns, each of which is connected through an edge-to-edge chalcogen interaction. A tight-binding band calculation suggests that this salt is a semi-metal with small Fermi surfaces. Indeed, this salt exhibited high conductivity of sigma(rt) = 25 S cm(-1) at room temperature, and showed metallic conducting behaviour down to T-MI = 170 K. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

DOI： 10.1002/pssc.201100690

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

Several derivatives of a new donor-acceptor diad 1 composed of DT-TTF and dicyanomethylidene group were synthesized. The IR spectra of 1 demonstrated considerable contribution of a polarized structure. Electronic spectra and molecular orbital calculation suggested that the absorption maximum of 1 was due to NHOMO-LUMO transition. Cyclic voltammetry revealed that the compound 1 exhibited three-stage of oxidation and one-stage of reduction processes. The bis(methylthio)-substitudted derivative 1a exhibited conductivity of 10(-6) S cm(-1) in spite of a single-component material.

DOI： 10.3987/COM-11-12277

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

Trimeric and tetrameric TTFs 1 and 2 linked alternately by methylenedithio groups were synthesized. Cyclic voltammetry and spectroelectrochemistry indicated that the dicationic state of tetrameric TTF 2 exhibited the mixed-valence state constructed not by the tetrameric TTF units but by two dimeric mutually independent TTF units.

DOI： 10.1246/cl.2011.883

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

New dimeric and trimeric TTF derivatives with methylenedithio spacers (1ab, 2a, and 2b) have been synthesized. X-ray structure analysis revealed that TTF units of the dimer 1b adopted distorted face-to-face overlapping arrangement both in intra- and intermolecular stacking. Cyclic voltammetric study indicated that trimeric 2a was in favor of taking di- and tetracationic states, while the dimeric la was in favor of taking a monocation. The absorption spectroscopic study suggested an existence of the strong face-to-face interaction particularly in di-, tri-, and tetracationic state of the trimeric TTF derivatives.

DOI： 10.1021/ol201025g

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

Several molecular conductors based on CP-TTP, where CP-TTP is 2-(4,5-cyclopenteno-1,3-dithiol-2-ylidene)-5-(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene, have been prepared. X-ray structure analyses revealed that all the CP-TTP conductors obtained so far have beta-type array of the donors regardless of the counter anions. Among them, the ReO4- and Au(CN)(2)(-) salts exhibited metallic conducting behavior down to 10K.

DOI： 10.1246/cl.2011.452

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

(BTM-TS-TTP)(4)PF6, where BTM-TS-TTP is 2-[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-5-(1,3-diselenol-2-ylidene)-1,3,4,6-tetrathiapentalene, has been prepared. An X-ray structure analysis reveals that it has a lambda-type array of the donors. It exhibited metallic conducting behavior down to 5 K.

DOI： 10.1246/bcsj.20100235

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

A new tetrathiapentalene (TTP) donor 2-(4,5-dimethoxy-1,3-dithiol-2-ylidene)-5-(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (DMO-TTP) has been synthesized, and the PF6 and AsF6 salts have also been prepared by electrochemical crystallization. X-ray structure analyses have revealed that intermolecular and intramolecular CH center dot center dot center dot O hydrogen bondings are constructed in the neutral crystal and the cation radical salts, respectively. The PF6 and AsF6 salts have a so-called A-type arrangement of the donors and show metallic behavior down to around 10 K.

DOI： 10.1246/cl.2011.81

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

A new donor (ST-STP), in which tetrathiafulvalene and tetraselenafulvalene are fused, has been synthesized. This donor shows unexpectedly large on-site Coulomb repulsion compared with other bis-fused TTF systems In (ST-STP)ReO4, intramolecular charge disproportionation is suggested by the crystal structure and transport properties.

DOI： 10.1246/cl.2010.1093

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

Novel 1,3-dithiole[5]dendralene derivatives with two thiophene spacers 3a and 3b were synthesized. Cyclic voltammetry and spectroelectrochemistry revealed that the positive charges of 3 in the dication and tetracation states mainly distribute on the outer two extended TTF moieties.

DOI： 10.1246/cl.2010.989

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

We synthesized vinylogous 4 5-ethylenedioxy-tetrathiafulvalenes (EDO-TTFs) 4 5-ethylenedioxy-2 2&apos;-ethanediylidenebis(1 3-dithiole) (EDO-EBDT) 4 5-dimethyl-4&apos; 5&apos;-ethylenedioxy-2 2&apos;-ethanediylidenebis(1 3-dithiole) (DMEDO-EBDT) 4 5-bis(thiomethyl)-4&apos; 5&apos;-ethylenedioxy-2 2&apos;-ethanediylidenebis (1 3-dithiole) (BTMEDO-EBDT). and 4 5-bis(methoxycarbonyl)-4&apos; 5&apos;-ethylenedioxy-2 2&apos;-ethanediylidenebis(1,3-dithiole) (BMCEDO-EBDT) The cyclic voltammograms of the vinylogous EDO-TTFs show two pairs of single-electron redox waves The first oxidation potentials (E(1)) of vinylogous EDO-TTFs are lower than those of the related TTFs, indicating that the electron donating abilities of new donors are stronger than those of the corresponding TTFs The smaller E(2)-E(1) values of new donors compared with those of the related TTFs suggest a decrease in the on-site Coulombic repulsion in the dication state X-ray crystal structure analysis of BMCEDO-EBDT reveals that the inter-molecular C-H O type hydrogen bond is constructed between the hydrogen atom and the oxygen atom of the ethylenedioxy group Single crystalline TCNQ complexes of DMEDO-EBDT and BTMEDO-EBDT have been prepared and their conducting properties and crystal structure have been investigated The TCNQ complexes of DMEDO-EBDT and BTMEDO-EBDT show low electrical conductivities (art sigma(pi) &lt; 10(-6)S cm for (DMEDO-EBDT)(TCNQ)(chlorobenzene) and sigma(pi)=2 2 X 10(-3)S cm(-1) for (BTMEDO-EBDT)(TCNQ)) clue to DDAA-type alternate stacking (C) 2009 Elsevier B V All rights reserved

DOI： 10.1016/j.physb.2009.12.024

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

An organic conductor theta-(BTM-TTP)(2)SbF(6) where BTM-TTP denotes 2-[4 5-bis(methylthio)-1 3-dithiol-2-ylidene]-5-(1 3-dithiol-2-ylidene)-1 3 4 6-tetrathiapentalene is semiconducting and shows Curie-Weiss-like magnetism whereas the X-ray structure shows that all BTM-TFP molecules are crystallographically equivalent and the tight-binding band calculation affords the closed Fermi surface We have studied the electrical properties and Raman spectra of theta-(BTM-TTP)(2)SbF(6) in order to clarify the origin of the carrier localization From the electrical resistivity measurement the maximum of activation energy appeared at ca 240 K Raman spectroscopy reveals the charge disproportionation in theta-(BTM-TTP)(2)SbF(6) from room temperature and the degree of charge disproportionation is estimated to be +0 0(3)similar to 0 1(3) +0 9(3) at 6 K (C) 2010 Elsevier B V All rights reserved

DOI： 10.1016/j.physb.2010.01.127

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Language：English   Publisher：NATL INST MATERIALS SCIENCE  

The synthesis, structure and properties of tetrathiapentalene-based (TTP) organic conductors are reviewed. Among various TTP-type donors, bis-fused tetrathiafulvalene, 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (BDT-TTP) and its derivatives afford many metallic radical cation salts stable down to low temperatures, regardless of the size and shape of the counter anions. Most BDT-TTP conductors have a beta-type donor arrangement with almost uniform stacks. Introduction of appropriate substituents results in molecular packing that differs from the beta-type. A vinylogous TTP, 2-(1,3-dithiol-2-ylidene)-5-(2-ethanediylidene-1,3-dithiole)-1,3,4,6-tetrathiapentalene (DTEDT) has yielded an organic superconductor (DTEDT)(3)Au(CN)(2) as well as metallic radical cation salts, regardless of the counter anions. (Thio) pyran analogs of TTP, namely (T)PDT-TTP and its derivatives produce molecular conductors with novel molecular arrangements. A TTP analog with reduced pi-electron system 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP) has afforded several organic superconductors. Highly conducting molecular metals with unusual oxidation states (+1, +5/3 and neutral) have been developed on the basis of 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (BDT-TTP) derivatives and analogous metal derivatives M(dt)(2) (M = Ni, Au).

DOI： 10.1088/1468-6996/10/2/024301

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

Novel dendralene type cross-conjugate molecules based on 1,3-dithiol-2-ylidene units with thiophene have been prepared. The conjugation in the oxidized stage is mainly through the thiophene core, while the cross-conjugated nature is observed in the neutral state. The CT complex of 2a with TCNQF(4) shows moderated electrical conductivity of 10(-4) S cm(-1).

DOI： 10.1246/cl.2008.474

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Two kinds of (BTM-TTP)(2)SbF6 salts, where BTM-TTP is 2-[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-5-(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene, have been prepared. X-ray structure analyses have revealed that needle-like and plate-like crystals have the so-called beta- and theta-type arrays of the donors, respectively. The beta-type salt exhibits metallic conducting behavior down to 5 K, while the theta-type salt is a semiconductor even at room temperature.

DOI： 10.1246/cl.2008.396

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

A series of 2D metals, beta-(BDT-TTP)(6)[Re(6)S(5)Cl(8)].(CHCl(2)-CHCl(2))(2), 2; beta-(ST-TTP)(6)[Re(6)S(6)Cl(8)]center dot(CH(2)Cl-CHCl(2))(2), 3; beta-(BDT-TTP)(7)[Re(6)S(6)Cl(8)](0.5)[Re(6)S(7)Cl(7)](0.5)center dot(CH(2)Cl(2)), 4; beta-(BDT-TTP)(7)[Re(6)Se(6)Cl(8)](0.5)[Re(6)S(7)Cl(7)](0.5)center dot(CH(2)Cl(2)), 5; beta-(BDT-TTP)(8)[Re(6)S(7)Cl(7)]center dot(CH(2)Cl(2))(4), 6 (BDT-TTP and ST-TTP are 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene and 2-(1,3-diselenol-2-ylidene)-5(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene, respectively) is reported to have one single beta-slab layered topology despite successive increases of the cluster anion negative charge. The charge density within the templating composite inorganic-neutral molecule slab is shown to remain above a threshold of ca. one negative charge per square nanometer, that is, for cluster anions with two negative charges and higher. Conversely, discrete stacks are shown to be stabilized instead in the semiconducting salts (BDT-TTP)(2)[Re(6)S(5)Cl(9)], 1 where the cluster anion bears one negative charge only. The electronic structure of salts 2-6 is shown to be very stable and kept almost intact across the series. The templating strategy is shown to fulfill its anticipated potential for deliberate installment of incommensurate band fillings in molecular metals. The deliberate admixture of the 6:1 and 8:1 structures yields novel phases with a 7:1 stoichiometry with the anticipated crystal and electronic structures. The action at the organic-inorganic interface triggered by changing the anion charge yet keeping its shape and volume identical, which ultimately governs the shape of the unit cell, is of paramount importance in defining the Fermi surface of these metallic salts. The present BDT-TTP salts thus provide a series of materials with strongly related but subtly different Fermi surfaces worthy of many physical studies. Shubnikov-de Haas measurements are expected to be particularly interesting since they are especially sensitive to, the details of the Fermi surface.

DOI： 10.1021/ja074774s

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

For the development of magnetic molecular conductors, we succeeded in the synthesis of new pi-electron donors containing TTF (tetrathiafulvalene) or TTP (tetrathiapentalene) framework and a stable 2,2,5,5-tetramethylpyrrolin-1-yloxyl radical within a molecule and clarified the crystal structure and physical properties of these donors. We also discuss the conducting and magnetic properties of a TCNQF(4) complex of the synthesized TTF type donor.

DOI： 10.1246/cl.2008.84

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

A bis-fused donor composed of TTF vinylogues, 2,5-bis(2-ethanediylidene- 1,3-dithiole)-1,3,4,6-tetrathiapentalene (BisEDT, 1a) and its derivatives have been synthesized. Cyclic voltammograms of 1 consist of four-pairs of one-electron redox waves. X-ray structure analysis of tetrakis(methylthio)-1 (1b) reveals the donor adopts almost planar structure. The TCNQF(4) complexes of I showed moderate conductivity of sigma(rt) = 10(-2) S cm(-1) on a compressed pellet.

DOI： 10.1246/cl.2008.82

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Institute of Physics Publishing  

DOI： 10.1088/1742-6596/132/1/011001

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

Oligocarboxamide molecular strands based on carboxamide between 1,8-naphthyridine and pyridine, pyridine and pyridine, 1,8-naphthyridine and benzene, and pyridine and benzene have been prepared. They have afforded various inclusion complexes with organic solvents. Structural features of the inclusion complexes determined by X-Ray crystal structure analyses are described.

DOI： 10.3987/com-06-10833

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

A series of multi-fused extended tetrathiafulvalene (TTF), in which thiophene ring is inserted between two 1,3-dithiole rings in TTF (ThTTF-n, n = 3-5,7), have been synthesized. In the electronic spectra, no significant red shift bas been observed as the number of fused extended TTFs increases. Cyclic voltammograms of the ThTTF-n are composed of n-2 pairs of two-electron transfer waves and two pair of one-electron-transfer ones, while four pairs of single-electron-transfer waves have been observed for ThTTF2. Molecular orbital calculation suggests the highest occupied molecular orbitals (HOMOs) of ThTTF-n spread over the molecule, while the lowest unoccupied molecular orbitals (LUMOs) are localized on the central thiophene moieties. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cap.2005.01.043

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Several bis(alkyldithio) derivatives of BDT-TTP (BTCn-TTP), where BDT-TTP is 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene, have been synthesized. Cyclic voltammograms of new donors consist of four pairs of single-electron transfer waves, and the first redox potentials (E-1) are higher by 0.04-0.05 V than that of unsubstituted BDT-TTP. The TaF6- salt of bis(methylthio) derivative (BTM-TTP) have the so-called beta-type array of the donors. A tight-binding band calculation of (BTM-TTP)(2)TaF6 suggests that this salt. has a quasi one-dimensional Fermi surface. The BTM-TTP salts with the PF6- and TaF6- anions exhibit metallic temperature dependence down to 90 K, while the SbF6- salt is a semiconductor with the activation energy of 0.13 eV. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cap.2005.01.052

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The ab initio molecular orbital analysis of tetrathiafulvalene (TTF) and TTF thiolate derivative adsorbed on the Au(111) surface was performed by means of the natural bond orbital (NBO) scheme to comprehend the interaction in Au-S bonds. The sulfur atoms of thiolate group have the direct connections with the Au surface, whereas those of TTF ring have the planar connections. In addition, not the 5d atomic orbitals of Au but 6s orbitals principally contribute to the interaction. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cap.2005.01.051

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

Dimeric and trimeric tetrathiafulvalene (TTF) derivatives possessing carbonyl groups in the spacer (1, 2) and dimeric TTF derivatives and tetrathiapentalene (TTP) derivatives possessing ester groups in the spacer (3, 4) have been synthesized. Cyclic voltammogram of 1-3 exhibits two pairs of redox waves. No significant shift of redox potentials was observed as increase of the TTF units. Cyclic voltammogram of 4 shows four pairs of two-electron redox waves. The E-1/2(2)-E-1/2(1) value of 4 is larger than that of the corresponding monomer and the first redox wave is slightly broad, suggesting small intramolecular interaction between two TTP units in the oxidation states.

DOI： 10.1016/j.synthmet.2005.07.323

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

Selenium-substituted TTM-TTP (2,5-bis[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene) derivatives (1a-1d), in which several 1,3-dithiole rings of the bis-fused TTF framework are replaced by 1,3-diselenole rings, have been prepared. In particular, we have accomplished the first selenium substitution of the inner TTP part (1a). The 1:1 composition iodine salt, (1a)I-3, is an insulator constructed of the donor trimers. The 1:1 GaCl4 salt, (1a)GaCl4, has a uniform column isostructural to the sulfur analog, (TTM-TTP)FeBr1.8Cl2.2; it exhibits metallic conduction down to about 60 K, the lowest metal-insulator (M-I) transition temperature in 1:1 salts. The donors le and Id give the iodine salts isostructural to the sulfur analog, (TTM-TTP)(I-3)(5/3). By the selenium substitution, the M-I transition of (1d)(I-3)(5/3) is entirely suppressed.

DOI： 10.1246/bcsj.77.1449

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The conducting materials based on 2-(1,3-dithiol-2-ylidene)-5-(pyran-4-ylidene)-1,3,4,6-tetrathiapentalene (PDT-TTP) and its thiopyran and/or selenium analogues have been developed. The ethylenedithio derivative (ET-PDT) affords 4:1 salt with PF6- anion (ET-PDT)(4)PF6(cn) (cn = 1-chloronaphthalene). It has the so-called lambda-type array of the donors with quasi one-dimensional electronic structure due to strongly tetramerized stack. On the other hand, (TM-TPDS)(2)AsF6 adopt the "windmill type" array of the donors. In this salt, relatively large side-to-edge interactions stabilize their electronic structure, while effective side-by-side interaction is inhibited by methythio groups projected along the molecular short axis. In contrast, edge-to-edge interactions are dominant in (SM-PDT)PF6(PhCl)(x) through selenium-selenium contacts along the molecular long axis. (ET-PDT)(4)PF6(cn) shows metallic conductivity down to 1.5 K, while (TM-TPDS)(2)AsF6 is in organic metal exhibiting M1 transition at 100 K. On the other hand, (SM-PDT)PF6(PhCl)(x) is a semiconductor with relatively high conduuctivity of sigma = 4.8 S cm(-1) in spite of 1: 1 composition.

DOI： 10.1051/jp4:2004114102

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

Charge localization generates a non-uniform charge distribution in some organic conductors. Phase transitions accompanying such a localization of charge are studied by using infrared and Raman spectroscopy. We first introduce theta-(BEDT-TTF)(2)MM'(SCN)(4) (M=Rb, Cs, Tl; M'=Zn, Co) as typical examples of a charge-ordering system, where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene. We apply the same spectroscopic technique to alpha'-(BEDT-TTF)(21)Br-2, theta-(BDT-TTF)(2)Cu(NCS)(2), and (TTM-TTP)I-3, which show the phase transitions from low-resistivity to high-resistivity state, where TTM-TTP is 2,5-bis[4,5-bis(methylsulfonyl)-1,3-dithiol-2-ylidene]- 1,3,4,6-tetrathiapentalene.

DOI： 10.1002/masy.200450815

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Tris-fused tetrathiafulvalene (TTF) derivatives, TTCn-TTPY, 2,2'-bis[4,5-alkylthio-(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalenytidene] with four alkylthio chains [CnH2n+1S-: n = 3-5] are prepared and the structural and conducting properties are investigated. Crystals of the neutral molecules show very low electrical resistivity (400 Omega cm) as single-component pure organic materials. Irrespective of the alkylthio chain length, the crystal structures are so-called beta"-type consisting of uniform stacks of the tris-fused TTF parts. Iodine-doped TTC3-TTPY exhibits metallic conductivity down to liquid helium temperature. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/S0379-6779(03)00416-8

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

Four kinds of 1:1 and 1:3 salts of 3-[4-(trimethylammonio)phenyl]-1,5-diphenyl-6-oxoverdazyI radical cation ([1](+)) and its mono- and dimethyl derivatives ([2](+) and [3](+)) with Ni(dmit)(2) anions (d(mit) = 1,3-dithiol-2-thione-4,5-dithiolate) ([1](+)[Ni(dmit)(2)](-) (4), [2](+)[Ni(dmit)(2)](-) (5), [3](+)[Ni(dmit)(2)](-) (6), and [1](+)[Ni(dmit)(2)](3)(-) (7)) have been prepared, and the magnetic susceptibilities (chi(M)) have been measured between 1.8 and 300 K. The chi(M) values of salts 5 and 7 can be well reproduced by the sum of the contributions from (i) a Curie-Weiss system with a Curie constant of 0.376 (K emu)/mol and negative Weiss constants (Theta) of -0.4 and -1.7 K and (ii) a dimer system with strong negative exchange interactions of 2J/k(B) = -354 and -258 K, respectively. The dimer formations in Ni(dmit)(2) anions have been ascertained by the crystal structure analyses of salts 4-6. In salts 4 and 6, Ni(dmit)(2) dimer molecules are sandwiched between two verdazyl cations, indicating the formation of a linear tetramer in 4 and 6. The magnetic susceptibility data for salts 4 and 6 have been fitted to a linear tetramer model using an end exchange interaction of 2J(1)/k(B) = -600 K and a central interaction of 2J(2)/k(B) = -280 K for 4 and 2J(1)/k(B) = -30 K and 2J(2)/k(B) = -580 K for 6, respectively. The results of the temperature dependence of the 9(T) value in salts 4-6 obtained by ESR measurement also support the above analyses. The 1:1 salts 4-6 are insulators. On the other hand, the conductivity of the 1:3 salt 7 at 20 degreesC was sigma = 0.10 S cm(-1) with an activation energy E-A = 0.099 eV, showing the semiconductor property. Salt 7 is a new molecular paramagnetic semiconductor.

DOI： 10.1021/ic030068q

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Tris-fused tetrathiafulvalenes, TTCn-TTPY (n = 2-5) have been prepared, and the structural and conducting properties have been investigated. The neutral crystals of TTCn-TTPY exhibit low electrical resistivity as a neutral organics
the lowest is 80 Ωcm in TTC2-TTPY. When TTCn-TTPY is exposed to iodine vapor, the sample becomes highly conducting in a few minutes, but again becomes insulating on account of overdoping. When taken out from the iodine atmosphere, the high conducting state is recovered, and the high conducting sample shows metallic conductivity and thermoelectric power down to helium temperatures. © EDP Sciences.

DOI： 10.1097/00005176-200411000-00019

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Language：Japanese   Publisher：応用物理学会  

It is almost probable that the contribution of chemists is indispensable to the development of molecular nanotechnology. In this article, we describe the present status of the design and synthesis of molecular nanowires as well as single-molecule spin devices based on organic molecules, and of the understanding of electrode contacts utilizing a gold-thiol bond at the molecular engineering level.

DOI： 10.11470/oubutsu.72.12_1493

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TMET-TTP derivatives in which one or both of the outer 1,3-dithiole rings are replaced by 1,3-diselenole rings (1a-1d) have been prepared (TMET-TTP: 2-[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-5-(4,5-ethylenedithio-1,3-dithio-1-2-ylidene)-1,3,4,6-tetrathiapentalene). The neutral crystal of 1c has beta-type uniform stacks, whereas 1a shows a theta-type molecular arrangement in the neutral crystal. The AsF6 salts of 1a and 1d have a theta-type structure similarly to other TMET-TTP salts. In spite of the relatively small dihedral angle (117), the conductivity is weakly semiconductive from room temperature. Selenium substitution causes unbalance of the diagonal intermolecular interactions, which may be the origin of a deviation from the universal phase diagram of the theta-phase.

DOI： 10.1246/bcsj.76.2091

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

The platelike crystals of a series of novel molecular conductors, which are based on the pi-donor molecules BDT-TTP (2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) with a tetrathiapentalene skeleton and lanthanide nitrate complex anions [Ln(NO3)(x)](3-x) (Ln = La, Ce, (Pr), Tb, Dy, Ho, Er, Tm, Yb, Lu) with localized 4f magnetic moments, were synthesized. Except for the Ce complex, the salts were composed of (BDT-TTP)(5)[Ln(NO3)(5)] and were isostructural. Even though the Ce crystal had a different composition, (BDT-TTP)(6)[Ce(NO3)(6)](C2H5OH)(x) (x approximate to 3), the crystals all had the space group P (1) over bar. Although the X-ray examination of the Pr salts was insufficient, the existence of two modifications was suggested in these systems by preliminary X-ray examination. Previously, we reported the crystal structures and unique magnetic properties of (BDT-TTP)(5)[Ln(NO3)(5)] (Ln = Sm, Eu, Nd, Gd). Thus, by combining the results of this work with previous one, we for the first time succeeded in obtaining a complete set of organic conductors composed of the identical pi-donors (BDT-TTP in this case) and all the lanthanide nitrate complex anions (except the complex with Pm3+). The crystals were all metallic down to 2 K. Electronic band structure calculations resulted in two-dimensional Fermi surfaces, which was consistent with their stable,metallic states. Except for the Lu complex, which lacked paramagnetic moments, the magnetic susceptibilities were measured on the six heavy lanthanide ion complex salts by a SQUID magnetometer (Ln = Tb, Dy, Ho, Er, Tm, Yb). The large paramagnetic susceptibilities, which were caused by the paramagnetic moments of the rare-earth ions, were obtained. The Curie-Weiss law fairly accurately reproduced the temperature dependence of the magnetic susceptibilities of (BDT-TTP)(5)[Ho(NO3)(5)] in the experimental temperature range (2-300 K) and-a comparatively large Weiss temperature (\Theta\) was obtained (Theta(Ho) = -15 K). A Weiss temperature (Theta(Tm) = -8 K) was also obtained for Tm. The \Theta\ values of other (BDT-TTP)(5)[Ln(NO3)(5)] salts and (BDT-TTP)(6)[Ce(NO3)(6)](C2H5OH)(x)(x approximate to 3) were as follows: \Theta\/K = 4 (Er), less than or equal to2 (Ce, Tb, Dy, Yb). The comparatively strong intermolecular magnetic interaction between Ho3+ ions, which was suggested by the \Theta\ value, is inconsistent with the traditional image of strongly localized 4f orbitals shielded by the electrons in the outer 5s and 5p orbitals. The dipole interactions between Ln(3+) ions causing the Curie-Weiss behavior and the comparatively large Theta value of (BDT-TTP)(5)[Ho(NO3)(5)] is inconsistent with the data, since the complexes exhibit isostructural properties and there is not a clear relationship between the magnitudes of Theta values and those of magnetic moments. Therefore, it is possible that the 4f orbitals of Ho atom are sensitive to the ligand field, which will have an effect on the orbital moment of the Ho3+ ion and/or produce a small amount of mixing between 4f and ligand orbitals to give rise to "real" intermolecular antiferromagnetic interaction through intermolecular overlapping between pi (BDT-TTP) and ligand orbitals of lanthanide nitrate complex anions.

DOI： 10.1021/ic034459g

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Selenium substitution of the outer 1,3-dithiole rings of TTM-TTP and TMET-TTP has been performed. The selenium analogues of TTM-TTP give the phases isostractural to (TTM-TTP)(I-3)(5/3). The selenium substitution of the single outer ring does not suppress the 25 K transition, whereas the substitution of both outer rings affords a practically metallic phase.

DOI： 10.1016/S0379-6779(02)00814-7

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The metal-insulator phase transition accompanying charge disproportionation was studied for two charge-transfer salts, theta-(BDT-TTP)(2)Cu(NCS)(2) and (TTM-TTP)l(3). In the former compound the localized generates a charge disproportionation such as (+0.1, +0.9). On the other hand, the charge disproportionation was not found in (TTM-TTP)l(3). Alternatively, the intra-molecular charge distribution becomes asymmetric below the phase transition temperature. Both phenomena are derived from the localization of charge with asymmetry breaking.

DOI： 10.1016/S0379-6779(02)00741-5

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New organic molecular conductors based on BDT-TTP [2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene] molecules and LnCl(x)(H2O)y [Ln = Ce, Eu and Ho, X = 4-5, Y = 4-5] anions were synthesized. The crystal structures of (BDT-TTP)(3) [LnCl(4)(H2O)(4)]Cl (Ln = Ce and Ho) were determined. The salts with EuClx(H2O(X = 4-5, Y = 4-5)and (BDT-TTP)(3)[HoCl4(H2O)(4)]Cl salts showed metallic behaviors down to about 120K. The magnetic susceptibilities of (BDT-TTP)(3) [LnCl(4)(H2O)(4)]Cl (Ln = Ce and Ho) measured on SQUID magnetometer showed the Curie-Weiss behaviors.

DOI： 10.1016/S0379-6779(02)00757-9

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Several radical cation salts based on SMEO-ST-TTP and SMEO-TTP have been prepared. X-Ray structure analyses reveal that (SMEO-ST-TTP)(2)PF6 has the so-called beta-type donor packing, in which the donors are strongly dimerized in a stack. On the other hand, (SMEO-ST-TTP)Au(CN)(2) and (SMEO-TTP)Au(CN)(2) have strongly dimerized one-dimensional stacking structure. The PF6- and AsF6- salts based on SMEO-ST-TTP show metallic conductivity down to 22 and 90 K, respectively, below which resisitivity increases a little.

DOI： 10.1016/S0379-6779(02)00771-3

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Several derivatives of new TTP type donor composed of 2,2'-ethanediylidenebis(1,3-dithiole) and 2-(pyran-4-ylidene)-1,3-dithiole (1) and its thiopyrane analog (2) have been synthesized. Cyclic voltammograms of 1 and 2 consist of four pairs of single-electron redox waves. They afford highly conducting TCNQ complexes and I-3(-) salts (sigma(rt) = 10(-2) - 10(0) S cm(-1) on a compressed pellet), which exhibit semiconducting temperature dependence with relatively low activation energy of 0.030 - 0.081 eV.

DOI： 10.1016/S0379-6779(02)00773-7

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Derivatives of dimeric BDT-TTP (2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene), in which two BDT-TTP units are linked by 1,3-propylenedithio (1) or 1,4-butylenedithio (2) group, have been synthesized. Cyclic voltammograms of 1 and 2 exhibit four pairs of two-electron redox waves, although the redox wave at the lowest voltage region is slightly broad. This result indicates there is small intradimer interaction in the oxidation states.

DOI： 10.1016/S0379-6779(02)01191-8

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We expect pi-extended donors that fused crown ether forming a stable complex with alkali metal functions as a molecular photonic switch. We synthesized new pi-extended donors incorporating a 2,5-bis(1,3-dithiol-2-yliden)-1,3,4,6-tetrathiapentalene (TTP) unit as a conductive site and crown ether units as metal binding sites. syntheses of new donors and results of their electrochemical and spectral properties will de discussed.

DOI： 10.1016/S0379-6779(02)01133-5

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θ-(BDT-TTP)2Cu(NCS)2 (BDT-TTP = 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathia-pentalene) is a highly correlated organic conductor with a quasi-two-dimensional electronic structure. This compound undergoes a second-order phase transition at 250 K, which accompanies a disproportionation of charge. The optical spectrum and magnetic susceptibility suggest that the separated charge forms a vertical stripe along the b-axis. The ESR experiment shows that the ground state is a non-magnetic state, which suggests the doubling of b-axis below 5 K. The properties which characterize the CO and magnetic phase transition were compared with those of θ-(BEDT-TTF)2RbZn(SCN)4. © 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0379-6779(02)00312-0

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EPR measurements of a new two-component organic conductor, (CHTM-TTP)(2)TCNQ, were performed. This salt shows two drastic successive phase transitions at low temperatures. The electronic phases of the title salt are discussed by microscopic point of view. The contributions of the two-spin species of the magnetic properties are separated. Possibility of cooperative phenomena in the two-spin system with itinerant and localised moments is discussed. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0379-6779(02)00274-6

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Investigation of the extended Hubbard model considering the second nearest V in the atomic limit demonstrates the appearance of many patterns of charge-ordered states, even including Devil's staircase at finite temperatures. This explains not only the observed modulations in theta-(BEDT-TTF)(2)RbZn(SCN)(4) above T-M1, but also the first-order transition and the nearly temperature-independent resistivity. The same logic may be extended to many other organic conductors showing flat resistivity. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0379-6779(02)00310-7

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With the aim of developing organic conductors with new types of molecular arrangements, some organic conductors composed of elongated pi donors BDT-TTP (2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) and simple I--anions were prepared by electrocystallization. The crystal of (BDT-TTP)(3)I has a very unique three-dimensional donor arrangement, where six BDT-TTP molecules are crystallographically independent. Despite the three-dimensional intermolecular short S...S network, the examination of C=C bond lengths of six BDT-TTP molecules indicates an inhomogeneous charge distribution, which is unfavorable for the formation of metallic bands. The resistivity measurements showed the system to be. a semiconductor with a very small activation energy. On the other hand, the needle-shaped crystal has beta-type donor arrangement and 2:1 stoichiometry. The crystal of beta-(BDT-TTP)(2)I retains its metallic state down to 2 K. Though an open Fermi surface was obtained by tight-binding band calculation, the fairly strong two-dimensionality of the electronic structure was suggested.

DOI： 10.1246/bcsj.76.97

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Two kinds of iodide salts of 3-(4-and3-methylpyridinium)-1,5-diphenylverdazyl radical cations ([p-MePyDV]I-+(-) (1) and [m-MePyDV]I-+(-) (2)) and four kinds of 1 : 1 and 1 : 2 salts of the same verdazyl radical cations with tetracyanoquinodimethanide (TCNQ) anion ([p-MePyDV](+)[TCNQ](-) (3), [m-MePyDV](+)[TCNQ](-) (4), [p-MePyDV](+)[TCNQ](2)(-) (5), and [m-MePyDV](+)[TCNQ](2)(-) (6)) have been prepared, and the magnetic susceptibilities (chi(M)'s) have been measured between 1.8 and 300 K. Salts (1) and (2) behave as one-dimensional (1D) alternating and nonalternating Heisenberg antiferromagnets with exchange interactions of 2J(I-II)/k(B) = -171 +/- 4 K (alternation parameters alpha = J(I-III)/J(I-II) = 0.5) and 2J/k(B) = -15.4 +/- 0.9 K (alpha = 1), respectively. The chi(M) of (3) follows the Curie-Weiss law with a Curie constant of 0.365 K emu mol(-1) and a positive Weiss constant of +2.1 +/- 0.2 K, indicating disappearance of a net magnetic moment due to the formation of strong spin pairs in TCNQ anion molecules. The chi(M) of (4) shows a broad maximum at T-max = 24 +/- 1 K. The chi(M) can be well reproduced by the sum of the contributions from i) a 1D Heisenberg antiferromagnetic alternating-chain system with 2J(1)/k(B) = -47 +/- 2 K (alpha = J(2)/J(1) = 0.9) and ii) a dimer system with 2J/k(B) = -636 +/- 30 K. The susceptibilities of (5) and (6) showed anomalous magnetic behavior that cannot be explained by a simple model. The separate contributions of the verdazyl cation and TCNQ anion subsystems to the total magnetic susceptibility of the salts were evaluated from measurements of the temperature dependence of the g-value. The 1 : 1 salts (3) and (4) are insulators. On the other hand, the pressed pellet conductivity (sigma) of the 1 : 2 salts (5) and (6) at 20 degreesC was sigma = 8.1 x 10(-3) and 2.9 x 10(-2) S cm(-1) with activation energy of E-A = 0.092 +/- 0.005 and 0.091 +/- 0.005 eV, respectively. The two 1 : 2 salts (5) and (6) are new genuine organic magnetic semiconductors.

DOI： 10.1039/b300029j

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Low-temperature crystal structure and optical properties of the quasi-one-dimensional organic conductor (ChTM-TTP)2GaCl4 (ChTM-TTP: 2-[4,5-(1,2-cyclohexylenedithio)-1,3-dithiol-2-ylidene]-5-[4,5-bis(methylthio) -1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene) have been investigated. As the temperature lowers, the disordered anion transforms to an ordered state with a superstructure wave vector of q = (1/2,0,1/2). The peak intensities of the superlattice gradually increase in the metallic region, and are saturated below 150 K
this indicates that the charge localization below 150 K is independent of the evolution of the superlattice. The reflectance spectra of (ChTM-TTP)2X suggest the existence of moderate interchain interactions. The transverse interactions are more pronounced in the GaCl 4 salt (t⊥/t∥ ≈ 1/7) than the AuBr2 and Au(CN)2 salts. The low-temperature optical reflectance of the GaCl4 salt shows no significant change, indicating that (ChTM-TTP)2GaCl4 goes to an insulating state with a small charge gap, which is consistent with the transport property. The low-frequency peak in the chain-axis optical conductivity is attributed to a correlation gap, though the expected on-site Coulomb repulsion U is relatively small.

DOI： 10.1143/JPSJ.71.3059

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Crystal structure analysis, transport properties, and ESR study of the new organic conductor (DTEDT)(3)Ag(CN)(2), where DTEDT is 2-(1,3-dithiol-2-ylidene)-5-(2-ethanediylidene-1,3-dithiole)1,3,4,6-tetrathiapentalene, have been carried out. The crystal structure and the energy band structure of the present compound are the same as (DTEDT)(3)Au(CN)(2), which shows superconductivity around 4 K at ambient pressure, whereas the electrical resistivity of the Ag(CN)(2) salt shows a metal-semiconductor transition at T-c = 40 K. The increase of the resistivity has been suppressed under a pressure of 10.3 kbar. The ESR spin susceptibility of this salt goes to zero below T-c without divergence of the linewidth. The ground state of (DTEDT)(3)Ag(CN)(2) is a nonmagnetic semiconductor.

DOI： 10.1143/JPSJ.71.2975

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Polarized reflectance spectra were measured on the conductive (010) plane of metallic (EO-TTP)2AsF6 single crystal. At room temperature, well-defined plasma edges appeared in both directions parallel (E∥a) and perpendicular (E⊥a) to the molecular stack. The intra- and inter-stack transfer integrals were estimated from the plasma frequencies in the framework of tight-binding model. Based on these transfer integrals, we suggested that the Fermi surface was open in the kc direction. Using a generalized Drude model, we obtained the frequency dependence of relaxation rate, which conformed to γ(ω) = γ0 + bω2 in the frequency range 1800-5500 cm-1. © 2002 Elsevier Science (USA).

DOI： 10.1006/jssc.2002.9734

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Novel molecular metal salts comprising an organic donor 2,5-bis(1, 3-dithiol-2-ylidene)-1,3,4,6- tetrathiapentalene (BDT-TTP) and lanthanide nitrato complex anions [M(NO3)y] (-(y-3)) were synthesized as the composition (BDT-TTP),[M(NO3)(y)]. Attempts on X-ray crystal structure analyses gave rise to a detection of two polymorphs. One of the polymorph, which had a composition of (BDT-TTP)(5)[M(NO3)(5)] for M = Nd, Sm, Eu and Gd, was analyzed in detail. Five crystallographically independent BDT-TTP molecules were stacked face-to-face to form a pentad, which was jointed one after another by crystallographic inversion centers into a one-dimensional column. The calculated overlap integrals of the highest occupied molecular orbitals revealed that not only intracolumnar orbital overlaps but also transverse intermolecular interactions were important in the electronic band formation. Consequently, the system has two-dimensional Fermi surfaces that explain the stable metallic states. Magnetic measurements on the four salts, with M = Nd, Sm, Eu and Gd, showed Curie paramagnetic moments on rare-earth ions which were superimposed on the Pauli paramagnetism of metallic pi electrons. Especially, the magnetic susceptibility of the isolated Eu3+ ion was written using Curie term and extremely large Van Vleck term. (C) 2002 Elsevier Scieme (USA).

DOI： 10.1006/jssc.2002.9727

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Several radical cation salts based on TMEO-ST-TTP (2-[4,5-bis(methylthio)-1,3-diselenol-2-ylidenel-5-(4,5-ethylendioxy-1,3- dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) have been prepared. X-ray structure analyses of (TMEO-ST-TTP)(2)X (X = PF6, AsF6, TaF6) reveal that they have the so-called beta-type array of donors with dimerized stacks. A tight-binding band calculation suggests that the present salts have a quasi-one-dimensional Fermi surface. On the other hand (TMEOST-TTP)Au(CN)(2) has strongly dimerized one-dimensional electronic structure. (TMEO-ST-TTP)(2)X (X=PF6, AsF6 TaF6) exhibit a high conductivity of sigma(rt)=10(0)-10(1) S cm(-1) and retain metallic conductivity down to 4.2K, while the tetrahedral (ReO4-) and linear (I-3(-) and Au(CN)(2)(-)) anions give semiconductors. Thermoelectric power of (TMEO-STTTP)(2)PF6 shows T-linear temperature dependence characteristic of a metal. (C) 2002 Elsevier Science (USA).

DOI： 10.1006/jssc.2002.9758

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New families of extended tris-fused TTFs, in which aromatic rings are inserted, have been synthesized. Cyclic voltammetry and theoretical calculation of them indicate electronic structure of the furan and thiophene derivatives may be regarded as tris-fused TTFs, whereas the benzene derivative as a dimeric (2-methylidene- l,3-dithiolo[4,5-d])-TTF.

DOI： 10.1246/cl.2002.1002

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Five kinds of (1:1), (1:3), and (2:1) salts of 3-[4-(diethylmethylammonio)phenyl]-1,5-diphenyl-6-oxoverdazyl radical cation [V](+) with M(dmit)(2) anions (M = Ni, Zn, Pd, and Pt, dmit = 1,3-dithiol-2-thione-4,5-dithiolate) ([V](+)[Ni(dmit)(2)](-) (1), [V](+)[Ni(dmit)(2)](3)(-) (2), [V](2)(+)[Zn(dmit)(2)](2-) (3), [V](2)(+) [Pd(dmit)(2)](2-) (4), and [V](2)(+)[Pt(dmit)(2)](2-) (5)) and an iodide salt of [V](+) ([V](+)[I](-) (6)) have been prepared, and the magnetic susceptibilities (Zm values) have been measured between 1.8 and 300 K. The chi(M) of the (1:1) Ni salt (1) can be well reproduced by the sum of the contributions from (i) a Curie-Weiss system with a Curie constant (C) of 0.376 K emu/mol and a negative Weiss constant (theta) of -1.5 K and (ii) the one-dimensional Heisenberg antiferromagnetic alternating chain system with 2J(A-B)/k(B) = -274 K (alternation parameter alpha = J(A-C)/J(A-B) = 0.2). The chi(M) of the (1:3) Ni salt (2) can be well explained by the two-term contributions from (i) the Curie-Weiss system with C = 0.376 K emu/mol and theta = -5.0 K and (ii) the dimer system with 2J/k(B) = -258 K. The magnetic properties of 1 and 2 were discussed based on the results obtained by crystal structure analysis and ESR measurements of 1 and 2. The chi(M) values of the (2:1) Zn, Pd, Pt salts 3, 4, and 5 and [V](+)[I](-) salt 6 follow the Curie-Weiss law with C = 0.723, 0.713, 0.712, and 0.342 K emu/mol and theta = -2.8, -3.1, -2.6, and +0.02 K, respectively, indicating that only the spins of the verdazyl radical cation contribute to the magnetic property of these salts. The salts 1, 3, and 5 are insulators. On the other hand, the conductivity (sigma) of the Ni salt 2 and Pd salt 4 at 20 degreesC was sigma = 8.9 x 10(-2) and 1.3 x 10(-4) S cm(-1) with an activation energy E-A = 0.11 and 0.40 eV, respectively. The salts 2 and 4 are new molecular magnetic semiconductors.

DOI： 10.1021/ic020212s

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Low-temperature electronic phases in a new two-component organic conductor, a segregated-stack charge-transfer salt called (CHTM-TTP)(2)TCNQ, are investigated. The ESR g tensor analyses indicate that there exist itinerant CHTM-TTP spins and localized TCNQ spins at R.T. The temperature dependence of the physical parameters reveals that this salt undergoes two drastic, successive phase transitions at low temperatures. The effective moment of the localized TCNQ spins decreases at the 245 K transition and completely disappears at the transition around 195 K. These curious physical properties are explained by the drastic changes in the electronic states of the two different types of spins. The spin susceptibility was decomposed into the contribution of each of the two spin species by using ESR, H-1-NMR, and static susceptibility analyses. We present a microscopic investigation of the two-spin system with itinerant and localized moments.

DOI： 10.1143/JPSJ.71.2208

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

Synthesis and X-ray structure of novel ligands containing tetrathiafulvalene (TTF) are reported. These compounds have been prepared by condensation between diazafluorene coordination site and TTF moiety as conductivity site.

DOI： 10.1246/cl.2002.592

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

Crystal structure analyses, measurements of transport and magnetic properties, and low-temperature X-ray studies of new organic conductors: (ChTM-TTP)(2)AuBr2, (ChTM-TTP)(2)GaCl4, and (ChTM-TTP)ReO4, where ChTM-TTP is 2[4,5-(1,2-cyclohexylenedithio)-1,3-dithiol-2-ylidene]-5-[4,5-bis (methylthio)-1,3-dithiol-2-ylidenel-1,3,4,6-tetrathiapentalene, have been carried out, In these compounds, the donors form quasi-one-dimensional columns with dimerization induced by the steric hindrance of the 1,2-cyclohexylene unit. The crystal structures and the energy band structures of both AuBr2- and GaCl4- salts are similar to those of the Bechgaard salts. The electrical resistivity and the thermoelectric power show metallic behavior above 100 K for the AuBr2- salt and above 150 K for the GaCl4- salt. The results of the ESR spin susceptibility, the static magnetic susceptibility, and the low-temperature X-ray studies indicate that the ground states of both salts are antiferromagnetic insulators. The Neel temperatures are about 38 K for the AuBr2- salt and about 32 K for the GaCl4- salt. These salts are the first materials showing an antiferromagnetic state among the TTP series conductors. In (ChTM-TTP)(2)X (X = Au(CN)(2), AuBr2, and GaCl4), the strength of the dimerization is related to the charge localization temperature. For the ReO4- salt, the donor to anion ratio is 1: 1 in spite of the tetrahedral anion being similar to the GaCl4- anion. Although the interstack interactions are not small, the degree of charge transfer of the donor molecule is + 1; thus this salt has an energy gap at the Fermi level, in agreement with the semiconducting transport behavior.

DOI： 10.1246/bcsj.75.435

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Single-wall carbon nanotubes (SWNTs) encapsulating fullerenes, so-called fullerene peapods, were synthesized in high yield by using diameter-selected nanotubes as pods. Transmission electron microscopy revealed high-density fullerene chains inside the nanotubes. X-ray-diffraction measurements indicate 85% filling for C60 and 72% filling for C70 molecules as a total yield. Interestingly, C60 peas do not show any thermal expansion while C70 peas show normal behavior. Room-temperature Raman spectra show one-dimensional photopolymerization of C60 inside nanotubes by blue-laser irradiation, suggesting molecular rotation inside them. In C70 peapods, no photopolymerization was observed but the relative Raman intensity of each peak is different from the C70 3D crystal. This is probably caused by mixing of two different crystal structures in C70 peas. Furthermore, we synthesized Zn-diphenylporphyrin peapods. Optical absorption and Raman spectra suggest that the encapsulated molecules are deformed by interaction with the SWNT.

DOI： 10.1007/s003390201276

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Several TM-PDT analogous donors, where TM-PDT is 2-[4,5-bis(thiomethyl)-1,3-dithiol-2-ylidene]-5-(pyran-4-ylidene)-1,3,4,6-tetrathiapentalene, have been prepared. Cyclic voltammetry demonstrated that chalcogen atom exchange at chalcogenopyran moiety in donors strongly influenced their redox potentials. Electrical conductivity of all their salts showed a semiconducting behavior with relatively small activation energy. Crystal structure of (SM-PDT)(TCNQ), where TM-PDT is 2-[4,5-bis(selenomethyl)-1,3-dithiol-2-ylidene]-5-(pyran-4-ylidene)-1,3,4,6-tetrathiapentalene, has been revealed to compose of the D-A type mixed stacks.

DOI： 10.1080/10587250210766

DOI： 10.1088/1468-6996/10/2/024301_references_DOI_4fGsSJpZVPIdsNLkptckjfpeqeW

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Several copper and platinum complexes with TTP (2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) dithiolato ligands, Cu(ttpdt) 2 ( 1 ) and Pt(ttpdt)(bpy) ( 2 ), have been prepared. The tetrakis(ethylthio) and tetrakis(hexylthio) derivatives of neutral Cu(ttpdt) 2 showed relatively high conductivity of † rt =10 m 2 S cm m 1 on compressed pellets. On the other hand, radical cation salts of 1 and 2 exhibited moderate conductivity of † rt =10 m 2 m 10 m 4 S cm m 1 . dithiolene complex tetrathiapentalene cyclic voltammetry electrical conductivity

DOI： 10.1080/713738644

DOI： 10.1088/1468-6996/10/2/024301_references_DOI_qGpD7arZBsleSPlkYYUNurSuJA

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DOI： 10.1080/713738695

DOI： 10.1088/1468-6996/10/2/024301_references_DOI_FFo6WWuFGA310UkTsAynFgc4PYh

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

TTM-TTP-based 1:1-composition organic conductors with counteranions containing alloyed metals, (TTM-TTP)MxM1-x'Cl-4 [TTM-TTP = 2,5-bis[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene; M, M' = Fe, Ga, Co, and Mn], have been prepared. The degrees of oxidization of TTM-TTP molecules change with the ratio of monovalent (FeCl4- and GaCl4-) and divalent anions (CoCl42- and MnCl42-). Accordingly, the band filling of the donor HOMO is chemically changed. These salts have the same crystal structure, consisting of one-dimensional uniform donor stacks, and are highly conductive. The conductivity is essentially flat down to 100-200 K, but the room-temperature resistivity and the thermoelectric power systematically increase as the band filling decreases from half filling to empty.

DOI： 10.1021/cm010808y

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DOI： 10.1080/713738725

DOI： 10.1143/jpsj.71.2975_references_DOI_aTOGSZCMOp78n7ZlPI3RoG1dkgX

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DOI： 10.1080/713738710

DOI： 10.1088/1468-6996/10/2/024301_references_DOI_AzZ8ZSyTQqUupKC7wQMkCp4a2o1

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ESR investigation was carried out for the organic conductor with itinerant and local spins, (CHTM-TTP)(2)TCNQ. This salt shows two drastic successive phase transitions at low temperatures. The contributions of the two spin species of the magnetic properties are separated using with the g-tensor analyses. The electronic phases of the title salt are discussed by microscopic point of view.

DOI： 10.1016/B978-044450973-4/50035-4

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A bis-fused TTF donor, 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (TTP) and its derivatives affords many metallic salts stable down to low temperatures, X-Ray structure analysis reveals that most TTP salts have beta-type conducting sheets regardless of counter anions, On the other hand, CH-TTP and TMET-TTP have a tendency to form kappa-type and theta-type salts, respectively. A vinylogous TTP DTEDT has afforded an organic superconductor (DTED-T)(3)Au(CN)(2), and a TTP analog containing thiopyran ring TM-TPDS has yielded the AsF6 salt with three-dimensional molecular array.

DOI： 10.1080/10587250290101388

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Several copper and platinum complexes with TTP (2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) dithlolato ligands, Cu(ttpdt)(2) (1) and Pt(ttpdt)(bpy) (2), have been prepared. The tetrakis(ethylthio) and tetrakis(hexylthio) derivatives of neutral Cu(ttpdt)2 showed relatively high conductivity of sigma(rt) = 10(-2) S cm(-1) on compressed pellets. On the other hand, radical cation salts of 1 and 2 exhibited moderate conductivity of sigma(rt) = 10(-2) -10(-4) S cm(-1).

DOI： 10.1080/10587250290090282

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A new tetrathiapentalene (TTP) type donor, 2-(2-cyclohexenediylidene-1,3-dithiole)-5-(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (CHDTDT), has been prepared. Cyclic voltammogram of CHDTDT showed three pairs of redox waves at 0.00 (2e), +0.42 (1e) and +0.66 (1e) V (vs, Ag/Ag+, in PhCN). CHDTDT has yielded several metallic radical cation salts. Among them, the AsF6 salt exhibited metallic conductivity down to 4.2 K.

DOI： 10.1080/10587250290101504

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An organic donor TTM-TTP (TTM-TTP (radical anion) 2,5-bis[4,5-bis (methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene) forms 1:1 composition salts with metal halides. The salts of pure anions, (TTM-TTP)MX4(PhCl)(0.5) (M = Fe, Ga; X = Cl, Br) are dimerized insulators, whereas when the halogenes (Cl/Br) or the metals (Fe/Ga) are alloyed, metallic salts with uniform columns are obtained.

DOI： 10.1080/10587250290101513

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Most of the organic conductors based on CH-TTP derivatives, where CH-TTP is 2-(4,5-cyclohexeno-1,3-dithiol-2-ylidene)-5-(1,3-dithiol-2-ylidene)- 1,3,4,6-tetrathiapentanlene, behave metallic down to low temperatures. An X-ray crystal structure analysis of CHEO-TTP(RcO(4))(0.38) revealed that the arrangement of the donors is close to that of the kappa-BEDT-TTF salts. The band structure calculated with the tight-binding approximation suggests that the ReO4- salt has a closed Fermi surface similar to those of the kappa-type superconductors.

DOI： 10.1080/10587250290101531

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θ-(BDT-TTP)2Cu(NCS)2 (BDT-TTP=2,5-bis(1,3- dithiol-2-ylidene)-1,3,4,6-tetrathia-pentalene) is a highly correlated organic conductor with a quasi-two-dimensional electronic structure. This compound undergoes a second-order phase transition at 250K. Below the phase transition temperature, the optical gap significantly broadens. From the analysis of the Roman spectrum, we found that the phase transition was accompanied by a disproportionation of charge. The separated charge forms a vertical stripe along the b-axis, and the b-axis is likely to be doubled at 5K.

DOI： 10.1080/10587250290101360

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We have obtained a new molecular metal containing a rare-earth complex anion, β″-(BO)2[YbCl4(H2O) 2]. This salt retains metallic conductivity down to 4 K. This crystal is metastable at room tmperature; it gradually tranforms into another phase, α-(BO)2[YbCl4(H2O)x], which becomes insulating below 210 K. The β″-phase crystal have a chain structure of the anions, formed by OH⋯Cl hydrogen bonding. This is the first example of a π molecular conductor based on an assembled rare-earth complex. Preparation, structure and resistivity of (BO)2[YbCl 4(H2O)x] system is reported.

DOI： 10.1080/713738629

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We present the polarized Raman spectra and magnetic susceptibility of (formula presented) which undergoes a charge-ordering phase transition at (formula presented) From the splitting of the (formula presented) band, the charge-disproportionation ratio δ is estimated as 0.4 at 10 K. The linewidth of (formula presented) suggests the fluctuation in charge distribution above (formula presented) The magnetic susceptibility of (formula presented) follows the Curie-Weiss Law with the Curie constant of 0.154 emuK/mol and Weiss temperature of -29 K. The single-crystal ESR experiment shows a magnetic phase transition to a spin-singlet state at 5 K. The polarized Raman spectra and magnetic property suggest the view that the positive charge is vertically ordered along the b-axis. © 2002 The American Physical Society.

DOI： 10.1103/PhysRevB.66.235102

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DOI： 10.1103/PhysRevB.66.235102

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Several TM-PDT analogous donors, where TM-PDT is 2-[4,5-bis(thiomethyl)-1,3-dithiol-2-ylidene]-5-(pyran-4-ylidene)-1,3,4,6-tetrathiapentalene, have been prepared. Cyclic voltammetry demonstrated that chalcogen atom exchange at chalcogenopyran moiety in donors strongly influenced their redox potentials. Electrical conductivity of all their salts showed a semiconducting behavior with relatively small activation energy. Crystal structure of (SM-PDT)(TCNQ), where TM-PDT is 2-[4,5-bis(selenomethyl)-1,3-dithiol-2-ylidene]-5-(pyran-4-ylidene)-1,3,4,6-tetrathiapentalene, has been revealed to compose of the D-A type mixed stacks.

DOI： 10.1080/10587250210766

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Fluorescence carbon Kα x-ray emission spectra (XES) of low-dimensional charge transfer salts [(TMTSF) 2 PF 6 , (BETS) 2 FeBr 4 , and (CPDT-STE) (TCNQ)] are presented. The Fermi energy positions are determined for these spectra using XPS binding energies of the C 1s core level. The absence of metallic Fermi edges in the carbon Kα XES data is reminiscent of Luttinger-liquid behavior predicted for one-dimensional metals, but the observed suppression of spectral weight near the Fermi level occurs on a surprisingly large energy scale. An additional low-energy subband found in carbon Kα XES of (BEDT-TTF) 4 [(H 3 O)Fe (C 2 O 4 ) 3 ] C 5 H 5 N is attributed to strong cation-anion interaction in this organic super-conductor.

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The novel silver(I) coordination polymer with 2,5-bis(4',5'-bis(methylthio)-1',3'-dithiol-2'ylidene)-1,3,4,6-tetrathiapentalene (TTM-TTP), [Ag(TTM-TTP)(CF3SO3)](n) (1), which consists of 1-D waving chains, was synthesized and characterized. Polymer 1 can be also regarded as a 3-D supramolecular network formed via many shorter side-by-side and face-to-face (SS)-S-... contacts. This polymer and its iodine-doped compound 2 behave as semiconductors with &sigma;(25&DEG;C) values of 7.1 x 10(-6) and 0.85 S cm(-1), respectively.
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DOI： 10.1021/ic010630h

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

Fluorescence carbon Ka x-ray emission spectra (XES) of low-dimensional charge transfer salts [(TMTSF)(2)PF6, (BETS)(2)FeBr4, and (CPDT-STE) (TCNQ)] are presented. The Fermi energy positions are determined for these spectra using XPS binding energies of the C 1s core level. The absence of metallic Fermi edges in the carbon K alpha YES data is reminiscent of Luttinger-liquid behavior predicted for one-dimensional metals, but the observed suppression of spectral weight near the Fermi level occurs on a surprisingly large energy scale. An additional low-energy subband found in carbon K alpha XES of (BEDT-TTF)(4)[(H3O)Fe(C2O4)(3)]C5H5N is attributed to strong cation-anion-interaction in this organic superconductor.

DOI： 10.1103/PhysRevB.64.233107

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A new diethyl-substituted organic donor, Et2BEDT-TTP, has been synthesized. The radical-cation salt, (Et2BEDT-TTP)(2)HgI3 has a unique crystal structure where the stereochemical cis- and rrans-isomers are arranged regularly to make tetramerized columns. (C) 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4039(01)01072-3

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Four kinds of (1:1) and (1:2) salts of 3-(4- and 3-ethyl-pyridinium)-1,5-diphenylverdazyl radical cations with tetra-cyanoquinodinlethanide (TCNQ) anion ([p-EtPyDV](+)[TCNQ](-) (1), [m-EtPyDV](+)[TCNQ](-) (2), [p-EtPyDV](+)[TCNQ](2)(-) (3), and [m-EtPyDV](+)[TCNQ](2)(-) (4)) have been prepared, and the magnetic susceptibilities (chi (M)) measured between 1.8 and 300 K. The values of chi T-M at 300 K are 0.437, 0.383, 0.620, and 0.482 K emu mol(-1) for the salts (1), (2), (3), and (4), respectively, and decrease by lowering the temperature. The chi (M) of the salt (2) follows the Curie-Weiss law with a Curie constant of 0.374 K emu mol(-1) and a negative Weiss constant of - 2.4 +/- 0.2 K in the temperature region 1.8-300 K, indicating disappearance of a net magnetic moment due to the formation of strong spin pairs in TCNQ anion molecules. The chi (M) of the salt (3) shows a broad maximum at T-max = 118 +/- 2 K, and can be well explained by a singlet-triplet equilibrium model with 2J/k(B) = - 190 K. The chi (M) of the salt (4) shows a broad maximum at T-max = 9.3 +/- 0.5 K. The chi (M) can be well reproduced by the sum of the contributions from: (i) a one-dimensional (1D) Heisenberg antiferromagnetic alternating-chain system with 2J/k(B) = - 15.2 K (alternation parameter alpha = J(2)/J(1) = 0.4); and (ii) the dimer system with 2J/k(B) = - 741 K. The magnetic property of (4) was discussed based on the results obtained by crystal structure analysis of (4). On the other hand, the susceptibility of the salt (!) showed anomalous magnetic behavior that cannot be explained by a simple model. The (1:1) salts (1) and (2) are insulators. On the other hand, the pressed pellet conductivity (sigma) of the (1:2) salts (3) and (4) at 20 degreesC was sigma = 6.9 x 10(-2) and 1.5 x 10(-3) S cm(-1) with activation energy E-A= 0.072 acid 0.25 eV, respectively, showing the property as semiconductor. The two (1:2) salts (3) and (4) are new, genuine organic magnetic semiconductors. (C) 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0277-5387(01)00651-9

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We present spectroscopic evidence for the charge disproportionation below the phase transition of the crystal of θ-(BDT-TTP)2Cu(NCS)2. This compound is a highly correlated quasi-2D organic conductor. Below the phase transition, the electronic transition in the mid-infrared region shifts to high-frequency side and the C=C stretching ag modes v2, v3, and v4, which are sensitive to the charge on BDT-TTP, split into two groups. At 5 K these groups are reasonably assigned to charge-poor and charge-rich BDT-TTP molecules.

DOI： 10.1016/S0379-6779(00)00672-X

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Organic donor TTM-TTP forms 1:1 composition salts with MX4- (M = Fe, Ga; X = Cl, Br), which have dimerized one-dimensional columns and are insulators even at room temperature. On the Contrary, (TTM-TTP)FeBr2Cl2 shows high electrical conductivity of about 1000 Scm(-1) at room temperature and metallic behaviour down to 160 K. This salt has uniform one-dimensional donor columns. This is the first 1:1 composition organic metal with magnetic anion. The FeX4- salts exhibit weak magnetic interactions between the anions; the Weiss temperatures are less than 2.6 K.

DOI： 10.1016/S0379-6779(00)01143-7

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Six kinds of novel TTP derivatives including BETS skeleton (1a-1f) have been prepared. The crystal structures of (1b)(SbF6)(0.36) and (1c)(Au(CN)(2))(0.36) were determined and these donor arrangements are so-called kappa -type. Temperature dependence of resistivity of (1f)(SbF6)(0.32) revealed selenium atom substitution may suppress a metal-insulator transition.

DOI： 10.1016/S0379-6779(00)00641-X

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Ground states of one-dimensional organic conductors based on ChTM-TTP (2-(4,5-cyclohexylenedithio-1,3-dithiol-2-ylidene)-5-[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene) have been investigated. (ChTM-TTP)(2)X (X = AuBr2, Au(CN)(2), GaCl4) shows antiferromagnetic phase transition around 30 K. The phase sequence of(ChTM-TTP)(2)X is similar to that of (TMTTF)(2)Br. The strength of the dimerization and the one-dimensionality controls the ground states of not only (ChTM-TTP)(2)X but also (TMTCF)(2)X.

DOI： 10.1016/S0379-6779(00)00974-7

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Using the heavy rare-earth complex anions, [Ln(NCS)(6)](3-) (Ln = Ho, Er, Yb and Y), we have synthesized three series of metallic compounds, (BO)(x)[Ln(NCS)(6)], (TTP)(x)[Ln(NCS)(6)] (x approximate to 8) and (DIEDO)(6)[Ln(NCS)(6)]. The BO and TTP salts are metallic down to very low temperature, while the resistivity of the DIEDO salts increases below about 40 K. These are the first examples of stable metals based on organic pi -donors and rare-earth 4f ions.

DOI： 10.1016/S0379-6779(00)01159-0

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Properties of metallic TTM-TTp (2,5-bis[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene) salts with 1:1 composition, in particular magnetic properties of (TTM-TTP)[C(CN)(3)], are reported. The results are discussed on the basis of molecular orbital calculations of on-site and off-site Coulomb integrals, U and V.

DOI： 10.1016/S0379-6779(00)01134-6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERLAG Z NATURFORSCH  

The preparation and characterization of some pi -donors with a pyrazine-edge-group as well as with tetrathiapentalene-, thiophene-, and dihydrobenzoselenophene- spacer-groups are described. Some of these donors give conducting charge transfer complexes with TCNQ and/or cation radical salts with I-3(-), BF4- and PF6- as counter anions.

DOI： 10.1515/znb-2001-0313

DOI： 10.1088/1468-6996/10/2/024301_references_DOI_3nBePCrXG3VOH51G9MDvV5I9obH

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New type TTP donors. alkyl-DH-TTPs (2-alkylidene-5-(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene) were newly synthesized. From the electrochemical study, these donors have larger onsite Coulomb repulsion compared with the previously known his-fused type TTP donors in accordance with reduction of the pi -system. Nevertheless Me-DH-TTP makes metallic salts down to quite low temperature.

DOI： 10.1016/S0379-6779(00)00957-7

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C-13-NMR measurements have been carried out to investigate the nature of the electronic properties of the one-dimensional half-filled band system, (TTM-TTP)I-3. It is known that this compound is metallic down to 160K. The metal-insulator transition into a non-magnetic ground state was confirmed from the temperature dependence of NMR relaxation rate. In addition, it was found that C-13-NMR spectra split into two in the insulating state. This is a evidence of charge disproportionation among the organic molecules. It may be considered as a typical CDW formation in a 1D half-filled system with large intersite Coulomb repulsion.

DOI： 10.1016/S0379-6779(00)01069-9

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Magnetic investigation of organic conductors based on TTP derivatives, (BDT-TTP)(2)SbF6 and (EO-TTP)(2)AsF6, was carried out by H-1-NMR measurements. The NMR spin-lattice relaxation rates, H-1-T-1(-1), of the present salts deviate from the Korringa-like behavior at low temperatures. The low-temperature electronic states of the TTP family will be discussed from microscopic points of view.

DOI： 10.1016/S0379-6779(00)00784-0

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Language：English   Publisher：AMERICAN PHYSICAL SOC  

DOI： 10.1103/PhysRevB.63.054301

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

We present spectroscopic evidence for the charge disproportionation in the crystal theta-(BDT-TTP)(2)Cu(NCS)(2) (BDT-TTP=2,5-bis(1',3'-dithiol-2 '-ylidene)-1,3,4,6-tetrathia-pentalene). theta-(BDT-TTP)(2)Cu(NCS)(2) is a highly correlated organic conductor with a quasi-two-dimensional electronic structure. In the electrical resistance of this compound, we found a second-order phase transition at 250 K. Below this phase-transition temperature, the optical absorption in the midinfrared region exhibits a high-frequency shift, and the Raman-active C=C stretching modes nu (2), nu (3), and nu (4), which are sensitive to the charge on BDT-TTP, split into 12 bands at 5 K. Based on the excitation-light dependence of the Raman spectrum, we propose that a disproportionation of charge occurs below the phase-transition temperature.

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

C-13 NMR measurements have been carried out to investigate the nature of the electronic state of the one-dimensional half-filled band system, (TTM-TTP)I-3. Metal-insulator transition at around 120 K was observed through the temperature dependence of NMR relaxation rate, 1/T-1. From the analysis of NMR spectra in the insulating state, it is strongly suggested that charge disproportionation with the valences of the TTM-TTP molecules 2-0-2-0 exists along the stacking axis. (C) 2000 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0022-3697(00)00176-1

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

We have prepared TTM-TTP-based (TTM-TTP=2,5-bis[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene) organic conductors with 1 : 1 composition including tetrahedral anions in order to elucidate electronic properties of half-filled conductors. We have obtained three new 1 : 1 composition salts (TTM-TTP)GaCl4(PhCl)(0.5), (TTM-TTP)GaBr4(PhCl)(0.5), and (TTM-TTP)GaBr2.0Cl2.0(PhCl)(0.5), which have dimerized donor columns. (TTM-TTP)GaCl4(PhCl)(0.5) shows paramagnetism in spite of the apparent band-insulating electronic structure, In addition we have obtained a metal alloy salt, (TTM-TTP)Fe0.9Ga0.1Cl4. This salt has uniform donor columns and shows high electrical conductivity.

DOI： 10.1039/b101542g

DOI： 10.1088/1468-6996/10/2/024301_references_DOI_3W90nTYlInJBRbSg1aLoSX2LaHY

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

The title donor, where SM-PDT is 2-[4,5-bis(selenomethyl)-1,3-dithiol-2-ylidene]-5-(pyran-4-ylidene)-1,3,4,6-tetr athiapentalene, formed semiconducting 1:1 salts with various anions. The crystal structure analysis of (SM-PDT)PF6(PhCl)x has revealed that an edge-to-edge chalcogen interaction gave two-dimensional sheet-like structure.

DOI： 10.1246/cl.2001.162

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Georg Thieme Verlag  

A facile and effective synthetic procedure for 1,3-diselenole-2-selone-4,5-diselenolate (dsis, 2) has been established. The utilization of 2 for the synthesis of selenocycle-fused tetraselenafulvalene derivatives is also reported.

DOI： 10.1055/s-2001-16755

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Fluorescence carbon (formula presented) x-ray emission spectra (XES) of low-dimensional charge transfer salts (formula presented) (formula presented) and (CPDT-STE) (TCNQ)] are presented. The Fermi energy positions are determined for these spectra using XPS binding energies of the C (formula presented) core level. The absence of metallic Fermi edges in the carbon (formula presented) XES data is reminiscent of Luttinger-liquid behavior predicted for one-dimensional metals, but the observed suppression of spectral weight near the Fermi level occurs on a surprisingly large energy scale. An additional low-energy subband found in carbon (formula presented) XES of (formula presented) is attributed to strong cation-anion interaction in this organic superconductor. © 2001 The American Physical Society.

DOI： 10.1103/PhysRevB.64.233107

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

(TTM-TTP)AuI2 (TTM-TTP: 2,5-bis[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetra-thiapentalene) has it dimerized structure along the donor stacking direction. and shows semiconducting behavior below room temperature. ESR, static magnetic susceptibility, and optical reflectance of this salt hare been measured to investigate the spin state and the electronic correlation. The ESR signal. has been observed from room temperature to 3 K, and the spin susceptibility shows paramagnetic behavior with a rapid decrease below 10 K. The static magnetic susceptibility is paramagnetic and has an anomaly around 10 K in agreement with the ESR result. The chain axis optical reflectance spectra show clear optical gap in the mid-infrared region. An: attempt is undertaken to analyze the optical spectrum by means of the one-dimensional dimerized Hubbard model, which suggests that the on-site Coulomb repulsion, U, is small and the spin polarization is located at the marginal paramagnetic boundary. These results indicate that this compound is not a band-insulator but the Mott insulator with a small spin gap.

DOI： 10.1143/JPSJ.69.4066

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

An organic donor, TTM-TTP (TTM-TTP = 2,5-bis[4,5-bis(methylthio)-1,3-dithiolylidene]-1,3,4,6-tetrathiapentalene), forms 1:1 donor/anion salts with FeCl4- and FeBr4-, (TTM-TTP)FeX4(PhCl)(0.5) (X = Cl, Br), which have one-dimensional dimerized columns and are insulators even at room temperature. In contrast, the salt with an alloyed anion, (TTM-TTP)FeBr1.8Cl2.2, shows high electrical conductivity of about 1000 S cm(-1) at room temperature and remains metallic down to 160 K. This salt has uniform, one-dimensional, donor columns. This is the first 1:1 donor/anion composition organic metal with a magnetic counteranion. These compounds exhibit weak magnetic interactions; the Weiss temperatures are around 1-3 K.

DOI： 10.1021/cm000404q

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

The conduction behavior down to low temperatures is emphasized in the study reported here of the title TCNQ complex of TMET-TS-TTP (shown in the Figure: X = Se, Y = S) because radical cation salts of TTP are promising organic conductors. The preparation, crystal structure, and electron spin resonance investigation of the TCNQ complex are presented.

DOI： 10.1002/1521-4095(200006)12:13<983::AID-ADMA983>3.0.CO;2-7

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

Magnetic properties of the title compounds are investigated by ESR measurements, and from the temperature dependence of the g-values, the spin susceptibility is separated into donor and TCNQ contributions. For (DTM-TTP)(TCNQ) (TCE), the overall. spin susceptibility decreases gradually from room temperature to 200 K, and more rapidly below 200 K, indicating a gradual crossover from a metallic to nonmagnetic insulating state. For (TME-TTP)(2) (TCNQ), the spin susceptibility exhibits a gradual increase from room temperature to 50 K, followed by a rapid Curie-like increase that is attributed to the isolated TCNQ molecules. The donors remain paramagnetic even in the insulating state in accordance with the two-dimensional theta-type arrangement of the donor conducting sheet.

DOI： 10.1143/JPSJ.69.1845

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

Communication: Two new phases for the metallic salts based on 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene have been prepared and shown to exhibit metallic conductivity down to low temperature. The organic slab topology and band structure are identical to previously determined 2:1 salts of the same donor with smaller monoanions-only the Fermi surface (see Figure) is modified by changing the anion volume and charge.

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

Three selenium analogues of DTEDT [2-(1,3-dithiol-2-ylidene)-5-[2-(1,3-dithiol-2-ylidene)ethylidene]-1,3,4,6-tetrathiapentalene] have been synthesized. They showed four pairs of single-electron redox waves. The E-1 values are a little higher by 0.02-0.05 V than that of DTEDT. On the other hand, the E-2-E-1 values are almost equal to that of DTEDT. Their TCNQ complex and cation radical salts show fairly high electrical conductivities and several salts exhibit metallic conductivities. In particular the ReO4- and Au(CN)(2)(-) salts of DTEDS and the SbF6-, TaF6- and I-3(-) salts of DSEDS exhibited stable metallic behaviour down to 1.5-4.2 K. An X-ray crystal structure analysis of the metallic salt (DSEDS)(3)TaF6 reveals that this salt has a two-dimensional beta-type packing motif of the donor molecules similar to the superconducting (DTEDT)(3)Au(CN)(2). The calculated Fermi surface of (DSEDS)(3)TaF6 is a two-dimensional closed ellipsoid.

DOI： 10.1039/b002790l

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

Several gold(III) complexes with TTF dithiolato ligands have been prepared as the tetrahexylammonium salts. The cyclic voltammograms in DMF showed two or three pairs of redox waves. X-Ray structure analysis of Ph4P . Au(eodt)(2)(DMF)(2) reveals that the Au(eodt)(2) anion takes a significantly folded chair conformation. Charge-transfer salts of Au(dt)(2) derivatives with TCNQ showed high conductivity (sigma(rt) = 10(0)-10(1) S cm(-1) on a compressed pellet).

DOI： 10.1080/10587250008023503

DOI： 10.1088/1468-6996/10/2/024301_references_DOI_A3uawcrvZUQTcC9q8U6fhF1AlQT

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

The title material, where TM-TPDS is 2-[4,5-bis(methylthio)-1,3-diselenol-2-ylidene]-5-(thiopyran-4-ylidene)-1,3,4,6- tetrathiapentalene, has three-dimensional (3D) donor array, in which 1D donor columns are tetragonally arranged with each other. It shows metal-like conducting behavior down to TMI = 100 K.

DOI： 10.1246/cl.2000.1274

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

The electron-molecular vibration (EMV) coupling constants and the accompanying vibronic energy values of five kinds of organic donor molecules (TTF+1, TTP+1, TTPY+1, TOF+1 and TSF+1) are crucial ingredients of metallic organic salts, and have been theoretically estimated in order to systematically investigate their dependencies on the molecular structures. The effect of the replacement of sulfur atoms in TTF+1 with oxygen and selenium atoms (TOF+1 and TSF+1) has been paid particular attention. It has been found that the EMV coupling constant decreases in the order of TOF+1 &gt; TTF+1 &gt; TSF+1 &gt; TTP+1 &gt; TTPY+1. That is, the smaller coupling constants appear in the larger-sized molecule with heavier atoms. (C) 2000 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0038-1098(00)00008-9

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The compounds (TTM-TTP)(I 3 ) 5/3 and (TSM-TTP)(I 3 ) 5/3 which have polyiodide chains along the donor stacking direction and show characteristic &quot;copper&quot; luster, exhibit metallic behavior above T MI ≈20 K. High-pressure resistivity, the Raman spectra, and optical reflectance of these salts have been measured to investigate the origin of the low-temperature insulating state and the iodine species. For (TSM-TTP)(I 3 ) 5/3 two kinds of conducting behavior have been observed; below 20 K some low-conducting samples have shown an increase of the resistivity of more than 10 3 times, but other high-conducting samples have shown an increase of less than 10 times. The increase of resistivity is almost suppressed under a pressure of 11.5 kbar in the high-conducting phase of (TSM-TTP)(I 3 ) 5/3 . The Raman spectra provide clear evidence that the polyiodide chain is composed of I 3 - in these compounds. The Raman spectra and the x-ray photographs indicate that the increase of resistivity originates in the disorder. The chain axis optical reflectance spectra show plasma edges appearing in the infrared region and three peaks from the infrared to the visible range; the latter originate from the intramolecular transition and polyiodide ions. Temperature dependence of optical conductivity is metallic even below T MI . From these results, the origin of the low-temperature insulating state is attributed to disorder driven localization. ©1999 The American Physical Society.

DOI： 10.1103/PhysRevB.60.4635

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A bis-fused π-electron donor incorporating a pyran-4-ylidene moiety, 2-(1,3-dithiol-2-ylidene)-5-(pyran-4-ylidene)-1,3,4,6-tetrathiapentalene (PDT-TTP, 1a), and its derivatives (1b-d) have been synthesized. The cyclic voltammograms of PDT-TTPs are composed of three pairs of redox waves. Comparison of the first oxidation potentials (E 1 ) suggests PDT-TTP (+0.42 V vs SCE in benzonitrile) is a weaker donor than TTF (+0.35 V). The present donors have produced a large number of highly conducting (σ rt = 10 0 -10 2 S cm -1 ) molecular complexes. Among them, conducting salts based on the ET-PDT (1d) are metallic down to liquid helium temperature. The metallic PF 6 - salt of ET-PDT has a composition of (ET-PDT) 4 PF 6 (cn), where en is 1-chloronaphthalene, in which two crystallographically independent ET-PDT molecules A and B form a face-to-face stack with a four-folded period as A′ABB′. In the present salt, the head-to-tail overlap of the unsymmetrical π-electron framework of PDT-TTP prevents an effective intrastack overlap and produces a strongly dimerized electronic structure along the stack direction. Tight-binding band calculations indicate that it has opened Fermi surfaces characteristic of quasi-one-dimensional metals. © 1999 American Chemical Society.

DOI： 10.1021/cm981035p

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PHYSICAL SOCIETY JAPAN  

DOI： 10.1143/JPSJ.68.3748

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

The compounds (TTM-TTP)(I-3)(5/3) and (TSM-TTP)(I-3)(5/3) which have polyiodide chains along the donor stacking direction and show characteristic ''copper'' luster, exhibit metallic behavior above T(MI)approximate to 20 K. High pressure resistivity, the Raman spectra, and optical reflectance of these salts have been measured to investigate the origin of the low-temperature insulating state and the iodine species. For (TSM-TTP)(I-3)(5/3) two kinds of conducting behavior have been observed; below 20 K some low-conducting samples have shown an increase of the resistivity of more than 10(3) times, but other high-conducting samples have shown an increase of less than 10 times. The increase of resistivity is almost suppressed under a pressure of 11.5 kbar in the high-conducting phase of (TSM-TTP)(I-3)(5/3). The Raman spectra provide clear evidence that the polyiodide chain is composed of I-3(-) in these compounds. The Raman spectra and the x-ray photographs indicate that the increase of resistivity originates in the disorder. The chain axis optical reflectance spectra show plasma edges appearing in the infrared region and three peaks from the infrared to the visible range; the latter originate from the intramolecular transition and polyiodide ions. Temperature dependence of optical conductivity is metallic even below T-MI. From these results, the origin of the low-temperature insulating state is attributed to disorder driven localization. [S0163-1829(99)06331-6].

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Sequoia SA  

Well-defined plasma edges appeared in the polarized reflection spectra polarized parallel (//a) and perpendicular (⊥a) to the molecular stack. The intra- and inter-stack transfer integrals were estimated from the plasma frequencies in the framework of tight-binding model. Based on these transfer integrals, the energy dispersion, density of state, and Fermi surface were calculated. The Fermi surfaces of both compounds were open in the kc direction. At low temperature the intra-stack transfer integral increased by about 30% whereas the enhancement of inter-stack transfer integral was very weak.

DOI： 10.1016/S0379-6779(98)00923-0

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

Several derivatives of 2,2'-ethanediylidenebis(1,3-dithiole) fused with 1,3-dithiol-2-ylidenes (DT-EBDTs) have been prepared. Their cyclic voltammograms consist of three single-electron redox waves. The first redox potential of MeDT-EBDT (+0.37 V vs. SCE in PhCN) is lower by 0.08 V than those of the corresponding TTF, MeDT-TTF. On the other hand, the E-2-E-1 value (0.13 V) is smaller by 0.18 V than that of MeDT-TTF. The present donors afford semiconducting AsF6- salts, TCNQF(4) and DDQ complexes (sigma(rt) = 10(-5)=10(-1) S cm(-1), E-a, = 0.03-0.19 eV).

DOI： 10.1016/S0379-6779(98)00573-6

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A selenium analogue of dimethyl substituted TTP (DM-TS-TTP) was prepared. (DM-TS-TTP)(2)PF6 showed metallic temperature dependence down to 4.2 K. X-Ray crystal structure analysis of this salt reveals that the arrangement of donors is similar to beta-type BEDT-TTF salts. The band structure calculated by a tight-binding method suggests that it has a quasi one-dimensional Fermi surface.

DOI： 10.1016/S0379-6779(98)00895-9

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

Radical cation salts of EOPT-TTP, where EOPT-TTP is 2-(4,5-ethylenedioxy-1,3-dithiol-2-ylidene)-5-(4,5-propylenedithio-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene have been prepared. All the salts obtained so far exhibited metallic temperature dependence of resistivity down to low temperature regardless of shape and size of counter anions.

DOI： 10.1016/S0379-6779(98)00893-5

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

TTP (tetrathiapentalene) series donors have been prepared by two steps of phosphite-mediated cross-couplings. By using cyanoethyl groups instead of acetoxybenzyl as a protecting group, we have succeeded in improving the yields. The applicability of this method will be discussed.

DOI： 10.1016/S0379-6779(98)00391-9

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

A new ST-TTP donor TMEO-ST-TTP, where TMEO-ST-TTP is 2-[4,5-bis(methylthio)-1,3-diselenol-2-ylidene)-5-(4,5- ethylendioxy-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene, has been prepared. It affords highly conducting PF6- and AsF6- salts retaining metallic conductivity down to 4.2 K, while the TCNQ complex and ClO4- salt are low conductive semiconductors. X-Ray structure analyses reveal that (TMEO-ST-TTP)(TCNQ)(PhCl) has a DA type mixed stack, and that the donor array of (TMEO-ST-TTP)(2)ClO4(DCE) in the conducting sheet resembles beta-BEDT-TTF salts.

DOI： 10.1016/S0379-6779(98)00320-8

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Preparation of a series of unsymmetrical tetrathiafulvalenes substituted with two methoxy groups (2a-f), and their electrochemical properties are described. X-Ray crystal structure analysis of methylenedithio derivative 2c reveals that there are side-by-side S...S contacts shorter than the sum of the van der Waals radii (3.70 Angstrom). The TCNQ complex of ethylendithio-2 (2d) and I-3 salt of 2e showed low conductivity of 10(-5) S cm(-1) at room temperature.

DOI： 10.1016/S0379-6779(98)00609-2

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Magnetic measurements of (CPDT-STF)-TCNQ were performed. We try to separate the spin susceptibility into the contributions of the two spin species.

DOI： 10.1016/S0379-6779(98)00601-8

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(TTM-TTP)I-3 in sprite of its 1-D half-filled band, exhibits the metallic conduction at room temperature. Resistance, susceptibility, X-ray diffuse scattering studies revealed a phase transition at T-c approximate to 110 K below which the resistivity increases rapidly, the susceptibility decreases and the 2 k(F) = 0.5 c(*) superstructure sets in. The nature of the transition is discussed in the light of the band structure and the precursor effect at higher temperatures.

DOI： 10.1016/S0379-6779(98)00470-6

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A 1:1 composition organic conductor (TTM-TTP)I-3 has a highly one-dimensional half-filled band, but shows a metallic conductivity down to 160 K. Another 1:1 composition organic conductor (TTM-TTP)[C(CN)(3)] has been prepared. This compound has a one-dimensional column similar to the I-3(-) salt, but the packing pattern of the columns is different. This compound exhibits a metallic conductivity down to 70 K, an even lower temperature.

DOI： 10.1016/S0379-6779(98)00586-4

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(TTM-TTP)(I-3)(5/3) (TTM-TTP: 2,5-bis[4,5-(methylthio)-1,3-dithiol-2-ylidene]- 1,3,4,6-tetrathiapentalene) and its isostructual methylseleno-substituted compounds show metallic behavior above T-MI approximate to 20 K in spite of large positive charge +5/3. High pressure resistivity and ESR measurements have been carried out. Both salts remain paramagnetic down to 2.9 K; no evidence of spin-Peierls or antiferromagnetic transition is obtained.

DOI： 10.1016/S0379-6779(98)00482-2

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(TTM-TTP)I-3 which has been considered as the typical one-dimensional half-filled band system, has been critically restudied by structural and magnetic measurements. X-ray diffuse scattering study reveals the formation of 2k(F) CDW superstructure with the wave vector q(1) =(0, 0, 0.5) below 160 K of the metal-insulator transition temperature. Another structural modulation with q(2) = (0.5, 0, 0.5) is observed below 90-100 K. modulated structure analysis using the q(2) satellite reflections and the Bragg reflections shows the large displacement in I-3 anion. Anomalies in chi line width and g-value of ESR measurements which correspond to the structural anomaly, are also reported.

DOI： 10.1016/S0379-6779(98)00473-1

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The AsF6- salts based on TTP and its selenium analogues ST-TTP and BDS-TTP are isostructural with each other, in which the donor are arranged in the so-called B-type packing.

DOI： 10.1016/S0379-6779(98)00574-8

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We have synthesized several TTP (tetrathiapentalene) derivatives with a cyclohexane ring. Some of their salts show metallic conductivity, and have uniform stacks in spite of the bulky cyclohexane group. Among them (ChTM-TTP)(2)Au(CN)(2) exhibits a metal-insulator transition at 120 K, followed by a spin-Peierls or antiferromagnetic transition at 40 K. In addition thermoelectric power is consistent with semiconducting behavior and shows that the carriers are holes on the donors.

DOI： 10.1016/S0379-6779(98)00393-2

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

2-(1,3-Diselenol-2-ylidene)-5-(pyran-4- ylidene)- 1,3,4,6-tetrathiapentalene (PDS-TTP), its thiopyran analogue (TPDS-TTP), and their bis(methylthio) derivatives have been prepared. Their first and second oxidation potentials are comparable to those of the corresponding sulfur analogues. The PF6 and AsF6 salt of PDS-TTP displayed metallic conductivity down to 4.2 K, and TCNQ complex was semiconductor with a low activation energy (0.006 eV).

DOI： 10.1016/S0379-6779(98)00469-X

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