Faculty Profiles - YAMAGUCHI, Shigehiro

Papers - YAMAGUCHI, Shigehiro

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Field effect transistors of single crystal benzo-annulated fused oligothiophenes and oligoselenophenes Reviewed

Y. Tominari, K. Yamada, M. Yamagishi, Jun Takeya, T. Okamoto, K. Kudoh, A. Wakamiya, S. Yamaguchi

Materials Research Society Symposium Proceedings Vol. 1003 page： 112 - 117 2007

Publishing type：Research paper (international conference proceedings)

Recently synthesized benzo-annulated fused oligothiophenes and oligoselenophenes are introduced as air-stable organic semiconductors for high-performance organic field-effect transistors. To evaluate electronic mobility intrinsic to the materials, single-crystal transistors are prepared for two representative compounds of benzo-annulated pentathienoacene f-B5TB and its selenium analogue f-BT3STB. High mobility of more than 1 cm2/Vs is achieved for the selenium compound, due to its considerable Se- - -Se orbital interactions. The transistor performances have been stable for two months, indicating high duration of the compound in the ambient atmosphere. Copyright © 2007 Materials Research Society.

Scopus

General synthesis of extended fused oligothiophenes consisting of an even number of thiophene rings

Toshihiro Okamoto, Kenichi Kudoh, Atsushi Wakamiya, Shigehiro Yamaguchi

CHEMISTRY-A EUROPEAN JOURNAL Vol. 13 ( 2 ) page： 548 - 556 2007

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

The intramolecular double cyclization of bis(3-bromo-2-thienyl)acetylenes though a lithium-halogen exchange reaction with tBuLi followed by treatment with elemental sulfur produces two thiophene-fused thieno[3,2-c](1,2-dithiin)s. The subsequent dechal-cogenation from the 1,2-dithiins with copper nanopowder affords tetrathienoacenes. On the basis of this two-step procedure, a series of trialkylsilyl-terminated, fused oligothiophenes, including hexathienoacene (a six thiophene-fused system) and octathienoacene (an eight thiophene-fused system), were synthesized. In the UV/Vis absorption and fluorescence spectra of the fused oligothiophenes, the absorption and emission maxima shift to longer wavelengths, as the pi-conjugation length increases. Their maximum wavenumbers have linear relationships with the reciprocal number of thiophene rings consisting of the it-conjugated frameworks. In the cyclic voltammograms, all the compounds show reversible oxidation waves, the first oxidation potential of which shifts to less positive as the conjugation length increases. Among them, the octathienoacene also shows a reversible second oxidation process. Indeed, its chemical oxidation with an excess amount of NO+SbF6- produces the dication as a golden crystal. The crystal structures of the neutral octathienoacene and its dication were determined by X-ray crystallography. While in the neutral state, the octathienoacene has a benzenoid structure with a large bond alternation of about 0.04 angstrom, its dication has a quinoid structure in which two cationic charges are mainly localized on the terminal rings.

DOI： 10.1002/chem.200601064

Web of Science

PubMed

Highly emissive organic solids containing 2,5-diboryl-1,4-phenylene unit

Cui-Hua Zhao, Atsushi Wakamiya, Yuko Inukai, Shigehiro Yamaguchi

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Vol. 128 ( 50 ) page： 15934 - 15935 2006.12

High fidelity self-sorting assembling of meso-cinchomeronimide appended meso-meso linked Zn(II) diporphyrins

Taisuke Kamada, Naoki Aratani, Toshiaki Ikeda, Naoki Shibata, Yoshiki Higuchi, Atsushi Wakamiya, Shigehiro Yamaguchi, Kil Suk Kim, Zin Seok Yoon, Dongho Kim, Atsuhiro Osuka

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Vol. 128 ( 23 ) page： 7670 - 7678 2006.6

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

In noncoordinating solvents, meso-cinchomeronimide appended Zn(II) porphyrin 2 forms a cyclic trimer, while diporphyrins 7 exhibit high-fidelity self-sorting assembling to form discrete cyclic trimer, tetramer, and pentamer with large association constants from 7(in-in), 7(in-out), and 7(out-out), respectively, through almost perfect discrimination of enantiomeric and conformational differences of the meso-cinchomeronimide substituents. In the latter self-sorting processes, the dihedral angles dictated by the two pyridyl nitrogen atoms control the size of the aggregates; the trimer from 7(in-in), the tetarmer from 7(in-out), and the pentamer from 7(out-out). Cyclic structures of (2) 3 and (R-7(out-out)) 5 have been determined by single-crystal X-ray diffraction analysis.

DOI： 10.1021/ja0611137

Web of Science

PubMed

Reactions of fused polycyclic 1,2-dithiins with transition metals: Synthesis of heteroacenes via desulfurization

K Kudoh, T Okamoto, S Yamaguchi

ORGANOMETALLICS Vol. 25 ( 9 ) page： 2374 - 2377 2006.4

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

Bis(thieno[3,2-b]thiophene)-fused 1,2-dithiin reacts with a stoichiometric amount of Ni(cod)(2)/2PPh(3) to produce a dimeric Ni(II) complex via the oxidative addition of the disulfide bond in the 1,2-dithiin skeleton to the Ni(0) center. An X-ray crystal structure analysis revealed that this complex has a dimeric structure in which one sulfur atom derived from the disulfide bond bridges two metal centers. The resultant Ni complex undergoes desulfurization at elevated temperature to produce a fully fused thiophene-based heteroacene.

DOI： 10.1021/om051000g

Web of Science

Ladder pi-conjugated materials with main group elements

S Yamaguchi, CH Xu, T Okamoto

PURE AND APPLIED CHEMISTRY Vol. 78 ( 4 ) page： 721 - 730 2006.4

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：INT UNION PURE APPLIED CHEMISTRY

Ladder-type pi-conjugated skeletons are promising building units for new materials for organic electronics, wherein their annelated coplanar structures enhance the pi-conjugation, leading to a set of desirable properties such as intense fluorescence and high carrier mobility. As a new entry into this class of skeletons, we now disclose two series of ladder molecules, i.e., silicon- and carbon-bridged oligo(p-phenylenevinylene)s and thiophene- and selenophene-based heteroacenes. The former ladder molecules contain the silole substructure in which the silicon bridges affect the electronic structure and thus photophysical properties through the sigma*-pi* conjugation. The latter heteroacenes can be recognized as the heteroatom analogs of acenes and may be promising materials for organic thin film transistors. These two series of molecules have been synthesized based on newly developed intramolecular cyclizations of acetylenic compounds.

DOI： 10.1351/pac200678040721

Web of Science

Highly Emissive Organic Solids Containing 2,5-Diboryl-1,4-Phenylene Unit

C. -H. Zhao, A. Wakamiya, Y. Inukai, and S. Yamaguchi

J. Am. Chem. Soc. Vol. 128 page： 15934-15935 2006

Highly Fidelity Self-Sorting Assembling of meso-Cinchomeronimide Appended meso-meso Linked Zn(II) Diporphyrins

T. Kamada, N. Aratani, T. Ikeda, N. Shibata, Y. Higuchi, A. Wakamiya, S. Yamaguchi, K. S. Kim, Z. S. Yoon, D. Kim, A. Osuka

J. Am. Chem. Soc. Vol. 128 page： 7670-7678 2006

Reactions of Fused Polycyclic 1,2-Dithiins with Transiton Metals: Synthesis of Heteroacenes via Desulfurization

K. Kudoh, T. Okamoto, and S. Yamaguchi

Organometallics Vol. 25 page： 2374-2377 2006

Boron as a Key Component for New pi Electron Materials

S. Yamaguchi and A. Wakamiya

Pure Appl. Chem. Vol. 78 page： 1413-1424 2006

Ladder pi-Conjugated Materials with Main Group Elements

S. Yamaguchi, C. Xu, and T. Okamoto

Pure Appl. Chem. Vol. 78 page： 721-730 2006

Intramolecular B-N Coordination as a New Scaffold for Design of Electron Transporting Materials: Synthesis and Properties of Boryl-Substituted Thienylthiazoles

A. Wakamiya, T. Taniguchi, and S. Yamaguchi

Angew. Chem. Int. Ed. Vol. 45 page： 3170-3173 2006

Boron as a Key Component for New pi Electron Materials

S. Yamaguchi, A. Wakamiya

Pure Appl. Chem. Vol. 78 page： 1413-1424 2006

Intramolecular B-N coordination as a scaffold for electron-transporting materials: Synthesis and properties of boryl-substituted thienylthiazoles

Atsushi Wakamiya, Takuhiro Taniguchi, Shigehiro Yamaguchi

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Vol. 45 ( 19 ) page： 3170 - 3173 2006

Synthesis and photophysical properties of new π-electron systems containing boryl groups at the side positions Reviewed

A. Wakamiya, C.-H. Zhao, K. Mori, S. Yamaguchi

Polymer Preprints, Japan Vol. 55 ( 2 ) page： 3023 - 3024 2006

Synthesis, structures, and photophysical properties of silicon and carbon-bridged ladder oligo(p-phenylenevinylene)s and related pi-electron systems

S Yamaguchi, CH Xu, H Yamada, A Wakamiya

JOURNAL OF ORGANOMETALLIC CHEMISTRY Vol. 690 ( 23 ) page： 5365 - 5377 2005.11

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

A series of partially or fully fused ladder oligo(p-phenylenevinylene)s (LOPVs) and related pi-electron systems has been synthesized. Thus, the intramolecular reductive cyclization of o-silyl-substituted bis(phenylethynyl)benzenes with lithium naphthalenide produces partially silicon-bridged bis(styryl)benzenes consisting of silaindene or disilaindacene skeletons. By combining this cyclization with the Friedel-Crafts type electrophilic cyclization, a homologous series of the fully fused LOPVs and related compounds, bearing silicon and carbon bridges, has been synthesized in fairly good yields. The longest example of the LOPVs is the 13-ring-fused system that has a nearly flat pi-conjugated framework with a length of 2.9 nm, as proven by X-ray crystallography. All the produced ladder pi-electron systems show intense fluorescence in the visible region with high quantum yields as well as relatively small Stokes shifts. As the silicon contents increase or the disilaindacene skeleton is incorporated, the emission maxima shift to the longer wavelengths and the fluorescent quantum yields slightly decrease. These trends can be rationalized as due to the sigma* effect of silicon, wherein the silicon bridges contribute to the electronic structure through sigma*-pi* orbital interaction that cause the red-shifts ill the emission maxima and suppress the radiative decay process from the singlet excited state. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jorganchem.2005.05.019

Web of Science

General synthesis of thiophene and selenophene-based heteroacenes

T Okamoto, K Kudoh, A Wakamiya, S Yamaguchi

ORGANIC LETTERS Vol. 7 ( 23 ) page： 5301 - 5304 2005.11

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

A new intramolecular triple cyclization of bis(o-haloaryl)diacetylenes, via dilithiation followed by reaction with chalcogen elements, produces pi-conjugated compounds containing heterole-1,2-dichalcogenin-heterole fused tricyclic skeletons. The subsequent dechalcogenation with copper metal affords a series of thiophene- and selenophene-based heteroacenes.

DOI： 10.1021/ol0523650

Web of Science

PubMed

The chemistry of silicon-containing ladder pi-conjugated systems

Yamaguchi S, Xu CH

JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN Vol. 63 ( 11 ) page： 1115 - 1123 2005.11

The chemistry of silicon-containing ladder pi-conjugated systems

S Yamaguchi, CH Xu

JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN Vol. 63 ( 11 ) page： 1115 - 1123 2005.11

Language：English Publishing type：Research paper (scientific journal) Publisher：SOC SYNTHETIC ORGANIC CHEM JPN

The intramolecular reductive cyclization of bis(o-silylphenyl)acetylenes with lithium naphthalenide produces bis-silicon-bridged stilbenes. Based on this new cyclization, a series of silicon-bridged ladder pi-conjugated systems consisting of the p-phenylenevinylene framework have been synthesized, including the partially or fully silicon-bridged bis (styryl) benzenes, extended ladder oligo(p-phenylenevinylene)s, and bis-silicon-bridged stilbene-based pi-conjugated polymers. All the ladder pi-electron systems show intense fluorescence in the visible region. The detailed elucidation of their photophysical properties revealed the significant effect of the silicon moieties on the fluorescence properties.

Web of Science

Toward pi-conjugated molecule bundles: Synthesis of a series of B,B ',B ''-trianthryl-N,N ',N ''-triarylborazines and the bundle effects on their properties

Wakamiya A, Ide T, Yamaguchi S

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Vol. 127 ( 42 ) page： 14859 - 14866 2005.10

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Papers - YAMAGUCHI, Shigehiro