Faculty Profiles - YAMAGUCHI, Shigehiro

Papers - YAMAGUCHI, Shigehiro

Division display 241 - 260 of about 366 ／ All the affair displays >>

Tetraaryl Tetradecahydroporphyrazins: Novel Porphyrin Derivatives Featuring a Cyclic Benzene-Ring Tetramer

Simon Janich, Roland Froehlich, Atsushi Wakamiya, Shigehiro Yamaguchi, Ernst-Ulrich Wuerthwein

CHEMISTRY-A EUROPEAN JOURNAL Vol. 15 ( 40 ) page： 10457 - 10463 2009

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

Treatment of tetramethylsuccinonitrile 1 with aryl lithium compounds and subsequent quenching with chlorotrimethylsilane yields 5-aryl-3,3,4,4-tetramethyl-N-(trimethylsilyl)-3,4-dihydropyrrol-2-imines 2a-c in 49-71% yield. Attempts to crystallise 2a-c in the presence of wet air yielded the tetraaryl tetradecahydroporphyrazins 3a-c in yields of 4-84% as single diastereomers. X-ray diffraction studies of 3b and c showed that only the isomer with four aryl substituents pointing in the same direction was formed. The resulting four-bladed pinwheel-like structures were characterised by four intramolecular aromatic interactions, in which each phenyl ring points with its edge towards the centre of a neighbouring phenyl moiety, resembling the arrangement of benzene molecules in T-shaped dimers. Temperature-dependent NMR spectra give insight into the dynamic properties of the aryl substituents. Quantum chemical calculations that included dispersion corrections indicated the importance of aryl-aryl interactions for the diastereoselectivity of the reaction and for the structural properties of the single isomers observed.

DOI： 10.1002/chem.200901187

Web of Science

PubMed

Regioselective Unsymmetrical Tetraallylation of C60 through Palladium Catalysis

M. Nambo, A. Wakamiya, S. Yamaguchi, K. Itami

J. Am. Chem. Soc. Vol. 131 page： 15112-15113 2009

Oxidation of End-Capped Pentathienoacenes and Characterization of Their Radical Cations

Reyes Malave Osuna, M. Carmen Ruiz Delgado, Victor Hernandez, Juan T. Lopez Navarrete, Barbara Vercelli, Gianni Zotti, Juan J. Novoa, Yoshitake Suzuki, Shigehiro Yamaguchi, John T. Henssler, Adam J. Matzger

CHEMISTRY-A EUROPEAN JOURNAL Vol. 15 ( 45 ) page： 12346 - 12361 2009

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

A detailed investigation of the optical and electrochemical properties of two pentathienoacene derivatives, 2,6-bis(trimethylsilyl)-alpha-pentathienoacene (TMS-T5-TMS) and 2,6-bis(triisopropylsilyl)-alpha-pentathienoacene (TIPS-T5-TIPS), as the neutral and oxidized species was performed in the temperature range of 80-300 K. The experimental solution UV/Vis and solid-state Raman spectra were interpreted by using time-dependent DFT and DFT quantum chemical calculations at the B3LYP/6-31G** level. Bond lengths, HOMO-LUMO positions, and charge distribution were also predicted by computational methods for both the neutral and oxidized states of each thienoacene. As evidenced by ESR and spectroelectrochemical data, upon oxidation the pentathienoacene derivative with the less sterically hindering trimethylsilyl solubilizing groups, TMS-T5-TMS, undergoes pi dimerization to form [TMS-T5-TMS](2)(2+). In contrast, TIPS-T5-TIPS, with the more bulky triisopropylsilyl solubilizing groups, was oxidized to the radical cation but dimerization was prevented due to steric interactions. These experimental observations are supported by DFT calculations, which were used to investigate [TMS-T5-TMS](2)(2+) and [TIPS-T5-TIPS](2)(2+) pi dimers in the solid state and in solution. The redox potentials and absorption peak locations corresponding to the radical cations and pi dimer of TMS-T5-TMS were identified experimentally.

DOI： 10.1002/chem.200900246

Web of Science

PubMed

Ladder pi-Conjugated Materials Containing Main-Group Elements

Aiko Fukazawa, Shigehiro Yamaguchi

CHEMISTRY-AN ASIAN JOURNAL Vol. 4 ( 9 ) page： 1386 - 1400 2009

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

Ladder pi-conjugated compounds, which have fully ring-fused polycyclic skeletons, are an important class of materials possessing significant potentials for application in organic electronics. The incorporation of main-group elements, such as B, Si P, S, and Se, into the ladder skeletons as bridging moieties is a powerful strategy to endow unusual electronic structures as well as suitable molecular arrangements in the solid state, giving rise to attractive photophysical and electronic properties. Recent efforts have produced a number of fascinating ladder materials, some of which indeed showed high performance as light-emitting materials and charge carrier transporting materials. This Focus Review is an overview of the progress in this chemistry, focusing on several important pi-conjugated skeletons.

DOI： 10.1002/asia.200900179

Web of Science

PubMed

Synthesis and Electronic Spectra of Disilatriptycene Oligomers: Evidence for Electronic Delocalization along the One-Dimensional Arrangement of Bridge-Head Disilanes

Shohei Sase, Yoen-Seok Cho, Atsushi Kawachi, Atsushi Wakamiya, Shigehiro Yamaguchi, Hayato Tsuji, Kohei Tamao

ORGANOMETALLICS Vol. 27 ( 21 ) page： 5441 - 5445 2008.11

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

Reductive coupling of a 9,10-dibromo-9,10-disilatriptycene derivative followed by treatment with chlorotrimethylsilane (TMSCI) affords a series of TMS-capped 9, 10-disilatriptycene oligomers DSiT[n]. Each isomer, up to the pentamer (n = 5), can be separated using recycling gel permeation chromatography. The X-ray structural analysis of DSiT[2] shows that the six silicon atoms are linearly aligned in a rigid array structure. While the ultraviolet (UV) absorption maximum remains constant at 230 nm, irrespective of the chain length, the magnetic circular dichroism (MCD) spectra exhibit a red shift band near 245 nm, and the emission maximum steadily shifts from 319 to 337 nm as the number of silicon atom increases. These spectra indicate the occurrence of electronic delocalization along the one-dimensional arrangement of bridge-head disilane moieties.

DOI： 10.1021/om701283e

Web of Science

Red-emissive Polyphenylated BODIPY Derivatives: Effect of Peripheral Phenyl Groups on the Photophysical and Electrochemical Properties

Atsushi Wakamiya, Naoya Sugita, Shigehiro Yamaguchi

CHEMISTRY LETTERS Vol. 37 ( 10 ) page： 1094 - 1095 2008.10

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

A series of red-emissive BODIPY derivatives 2-4 having five to seven phenyl groups on their periphery were synthesized., and their photophysical and electrochemical properties were investigated. While the 8-phenyl-substituted derivatives only have moderate fluorescence quantum yields in solution, they can show intense red fluorescence in the PMMA films. The peripheral phenyl groups also affect the redox reversibility in cyclic voltammetry.

DOI： 10.1246/cl.2008.1094

Web of Science

Design and synthesis of boron-containing functional pi-electron materials

Atsushi Wakamiya, Shigehiro Yamaguchi

JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN Vol. 66 ( 9 ) page： 858 - 868 2008.9

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

Utilization of boron, a group 13 element, as a key element for developing new functional electronic and optoelectronic materials is an important direction in the organoboron chemistry. Boron has several characteristic features, such as trigonal planar geometry for trivalent boron compounds, high Lewis acidity, and effective orbital interaction with pi-conjugated frameworks through the vacant p-orbital (i.e., p(pi)-pi* conjugation). Exploiting these features of the boron element for molecular designs allows us to create sophisticated pi-electron materials having attractive photophysical and electronic properties. We here present some progress in our chemistry, including B,B',B"-trianthrylborazine (B3N3)-based molecular bundles, boryl-substituted thienylthiazole pi-electron systems with intramolecular B-N coordination, borole- and dibenzoborole-based pi-conjugated compounds, and boryl-substituted emissive organic solids.

DOI： 10.5059/yukigoseikyokaishi.66.858

Web of Science

Scopus

Electronic modulation of fused oliglothiophenes by chemical oxidation

Yoshitake Suzuki, Toshihiro Okamoto, Atsushi Wakamiya, Shigehiro Yamaguchi

ORGANIC LETTERS Vol. 10 ( 16 ) page： 3393 - 3396 2008.8

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

The reaction of pentathienoacene (f-5T) with mCPBA produced a series of oxidized derivatives containing one or two thiophene-S,S-dioxide rings. The regioselectivity of the oxidation reflects the aromaticity of each thiophene ring in the f-5T skeleton, and the extent of the oxidation significantly affects the fluorescence and redox properties.

DOI： 10.1021/ol801136k

Web of Science

PubMed

Highly electron-donating 3,3 '-diaryl-1,1 '-bi(isobenzofuran)s synthesized by photochemical exocyclic [2+2+2] cycloaddition

Hongyu Zhang, Atsushi Wakamiya, Shigehiro Yamaguchi

ORGANIC LETTERS Vol. 10 ( 16 ) page： 3591 - 3594 2008.8

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

Facile photochemical exocyclic [2 + 2 + 2] cycloaddition produced a series of electron-donating 1,1'-bi(isobenzofuran)s having various aryl groups at the 3,3' positions. The 1,1'-bi(isobenzofuran) skeleton with a highly coplanar structure is a useful building unit to construct the narrow bandgap pi-conjugated systems with low oxidation potentials.

DOI： 10.1021/ol801358c

Web of Science

PubMed

Synthesis and structural characterization of pentaarylboroles and their dianions

Chcuk-Wai So, Daisuke Watanabe, Atsushi Wakamiya, Shigehiro Yamaguchi

ORGANOMETALLICS Vol. 27 ( 14 ) page： 3496 - 3501 2008.7

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

A series of l-aryl-2,3,4,5-tetraphenylboroles [Ph(4)C(4)BAr] [Ar = p-MeC(6)H(4) (2), p-Me(3)SiC(6)H(4)(3), p-FC(6)H(4) (4)] were synthesized. The X-ray crystallography of 2-4 revealed that they have short distances between the borole boron atom and the phenyl rings of the neighboring molecules, suggesting the existence of certain intermolecular interaction. Despite this interaction, the borole rings in 2-4 remain planar and contain substantial bond alternation in the butadiene skeleton, which is consistent with the theoretically optimized structures of the singlet boroles. These results demonstrated that the boroles still have antiaromatic character in the crystalline state. Compound 3 and pentaphenylborole [Ph(4)C(4)BPh] (5) were further reacted with potassium or potassium graphite to form potassium borole dianion salts [K(2){Ph(4)C(4)B(p-Me(3)SiC(6)H(4)))] (6) and [K(2){Ph(4)C(4)BPh)] (7), respectively. In their X-ray crystal structures, compounds 6 and 7 are polymeric and have two K(+) ions lying on both sides of the borole plane With eta(5)-coordination.

DOI： 10.1021/om8002812

Web of Science

Bis-phosphoryl-bridged stilbenes synthesized by an intramolecular cascade cyclization

Aiko Fukazawa, Masanao Hara, Toshihiro Okamoto, Eun-Cheol Son, Caihong Xu, Kohei Tamao, Shigehiro Yamaguchi

ORGANIC LETTERS Vol. 10 ( 5 ) page： 913 - 916 2008.3

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

Bis-phosphoryl-bridged stilbenes have been synthesized using an intramolecular cascade cyclization. They show intense blue fluorescences at longer wavelengths with higher quantum yields compared to those of the known element-bridged stilbenes. In addition, they have much lower reduction potentials due to the inductive effect of phosphoryl groups. The incorporation of the phosphoryl moiety is an effective way for the construction of highly electron-accepting pi-conjugated systems.

DOI： 10.1021/ol7030608

Web of Science

PubMed

Synthesis and Electronic Spectra of Disilatriptycene Oligomers: Evidence for Electronic Delocalization along the One-Dimensional Arrangement of Bridge-Head Disilanes

S. Sase, Y.-S. Cho, A. Kawachi, A. Wakamiya, S. Yamaguchi, H. Tsuji, and K. Tamao

Organometallics Vol. 27 page： 5441-5445 2008

*Phosphonium and Borate-Bridged Zwitterionic Ladder Stilbene and Its Extended Analogues Reviewed

A. Fukazawa, H. Yamada, and S. Yamaguchi

Angew. Chem. Int. Ed. Vol. 47 page： 5582-5585 2008

Kinetically Stabilized Dibenzoborole as an Electron-Accepting Building Unit

A. Wakamiya, K. Mishima, K. Ekawa, and S. Yamaguchi

Chem. Commun., page： 579-581 2008

Bis-Phosphoryl-Bridged Stilbenes Synthesized by an Intramolecular Cascade Cyclization

A. Fukazawa, M. Hara, T. Okamoto. E.-C. Son, C. Xu, K. Tamao, and S. Yamaguchi

Org. Lett. Vol. 10 page： 913-916 2008

Synthesis and Structural Characterization of Pentaarylboroles and Their Dianions

C.-W. So, D. Watanabe, A. Wakamiya, and S. Yamaguchi

Organometallics Vol. 27 page： 3496-3501 2008

Disilylphenylene and Tetrasilylphenylene as a New Building Unit for Highly Fluorescent Poly(aryleneethynylene)s

A. Iida, K. Nagura, and S. Yamaguchi

Chem. Asian J. Vol. 3 page： 1456-1464 2008

Electronic Modulation of Fused Oligothiophenes by Chemical Oxidation

Y. Suzuki, T. Okamoto, A. Wakamiya, and S. Yamaguchi

Org. Lett. Vol. 10 page： 3393-3396 2008

Highly Electron-Donating 3,3'-Diaryl-1,1'-Bi(isobenzofuran)s Synthesized by Photochemical Exocyclic [2+2+2] Cycloaddition

H. Zhang, A. Wakamiya, and S. Yamaguchi

Org. Lett. Vol. 10 page： 3591-3594 2008

Design and Synthesis of Boron-Containing Functional pi-Electron Materials

A. Wakamiya, and S. Yamaguchi

J.Syn. Org. Chem., Jpn. Vol. 66 page： 858-868 2008

　 PREV - NEXT 　

<YAMAGUCHI, Shigehiro>

Papers - YAMAGUCHI, Shigehiro