研究者詳細 - 大須賀　秀次

論文 - 大須賀　秀次

分割表示40 件中 21 - 40 件目／全件表示 >>

Contact and channel resistances of organic field-effect transistors based on benzodithiophene-dimer films deposited on pentacene crystallinity control layers

Kurokawa, A., Matsumoto, Y., Shibamoto, K., Kajimoto, K., Osuga, H., Yamakado, H., Uno, K., Tanaka, I.

Applied Physics Letters 95 ( 26 ) 2009年 [査読有り]

DOI

Synthesis of Benzo[1,2-b:4,3-b ']dithiophene/triphenylamine Copolymers: Effects of Substituents on Optical and EL Properties

Yosuke Nishide, Hideji Osuga, Kunihiro Iwata, Kazuhiko Tanaka, Hidefumi Sakamoto

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN ( CHEMICAL SOC JAPAN ) 81 ( 10 ) 1322 - 1330 2008年10月 [査読有り]

Benzo[1,2-b:4,3-b']dithiophene/triphenylamine copolymers P-2eh (with no rnethyl substituents) and P-Me and P-2Me (with methyl substituents at triphenylamine sites) were synthesized by Stille coupling reactions. In the ground state, the methyl substituents at the ortho positions to the BDT unit oil the triphenylamine (TPA) moiety in P-Me and P-2Me caused twisting of the polymer structure and clearly limited conjugation of the polymer backbones. However, in their excited states, all of these copolymers were shown to have planar structures, and almost the same emission maxima were observed. This result indicates that, in the excited states, pi-conjugation of the polymer backbone results in the adoption of a more stable planar structure rather than the twisted structure observed in the ground state. The maximum EL efficiencies of devices based on P-Me and P-2Me were about three times higher than that of P-2ch due to restricted pi-stacking/aggregation of the Conjugated copolymers in the solid state and improvements in thermal and electrochemical stability.

DOI

Decay dynamics of photo-luminescence in tris(2-phenylpyridine)iridium phosphor

I. Akimoto, K. Nagao, T. Tashiro, H. Osuga, K. Tanaka, K. Kan'no

JOURNAL OF LUMINESCENCE ( ELSEVIER SCIENCE BV ) 122 ( 1-4 ) 440 - 443 2007年01月

The phosphor material, tris(2-phenylpyridine)iridium (Ir(ppy)(3)), has attracted much attention as an emitter of highly efficient electrophosphorescent devices. In the present work, decay dynamics of photo-luminescence and its temperature dependence have been investigated in the Ir(ppy)(3) emitting center. From the analyses of luminescent decay profiles and time-resolved luminescent spectra, thermally activated population transfer from every triplet sub-level to a singlet state is suggested. (c) 2006 Elsevier B.V. All rights reserved.

DOI

The recognition of higher-order G-quadruplex by chiral cyclic-helicene molecules.

Y. Xu, S. Yamazaki, H. Osuga, H. Sugiyama

Nucleic acids symposium series (2004) ( 50 ) 183 - 184 2006年 [査読有り]

Synthesis and properties of phosphorescent iridium complexes with heterocyclic ligands

T Tashiro, H Osuga, K Tanaka

PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS ( TAYLOR & FRANCIS LTD ) 180 ( 5-6 ) 1481 - 1482 2005年05月

DOI

Synthesis and properties of polyalkylated thiaheterohelicenes

H Osuga, S Nagai, K Tanaka

PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS ( TAYLOR & FRANCIS LTD ) 180 ( 5-6 ) 1499 - 1500 2005年05月

DOI

Synthesis and optical properties of fluorescent materials derived from tricyclic heterocycles

Y Nishide, Y Inagaki, H Osuga, K Tanaka

PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS ( TAYLOR & FRANCIS LTD ) 180 ( 5-6 ) 1479 - 1480 2005年05月

DOI

(P)-helicene displays chiral selection in binding to Z-DNA

Y Xu, YX Zhang, H Sugiyama, T Umano, H Osuga, K Tanaka

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY ( AMER CHEMICAL SOC ) 126 ( 21 ) 6566 - 6567 2004年06月 [査読有り]

DOI

The recognition of Z-DNA by chiral helicene.

Y. Xu, H. Sugiyama, K. Tanaka, H. Osuga

Nucleic acids symposium series (2004) ( 48 ) 87 - 88 2004年 [査読有り]

Clathrate Formation by and Self-Assembled Supramolecular Structures of a "Molecular Spring"

TANAKA K, OSUGA H, KITAHARA Y

Journal of the Chemical Society, Perkin Transactions 2 ( 12 ) 2492 - 2497 2000年

DOI

Clathrate formation by and self-assembled supramolecular structures of a "molecular spring"

K Tanaka, H Osuga, Y Kitahara

JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2 ( ROYAL SOC CHEMISTRY ) ( 12 ) 2492 - 2497 2000年 [査読有り]

The inclusion properties and self-assembly of racemic and optically active helicenediols have been thoroughly investigated. The racemic helicenediol (PM-1) crystallizes with ethanol or 1,2-dichloroethane in different host-guest stoichiometric ratios to form (PM-1).(ethanol) or (PM-1)(2).(1,2-dichloroethane), respectively. Single crystal X-ray analyses of the clathrates show that the helicenediol 1 has greater flexibility to accommodate guest molecules than might have been anticipated. The helical pitch of the helicenediol, which controls the interplanar angle between the terminal thiophene rings, ranges from 38.0, for the ethanol clathrate, to 54.5 degrees for the 1,2-dichloroethane clathrate. This represents an increase of 16.5 degrees or 44%. Testosterone is selectively incorporated into the left-handed helicenediol (M-1) to afford a 1:1 inclusion complex, (M-1).(testosterone), in which the interplanar angle decreases from 54.5 to 46.2 degrees. Without guest molecules, racemic helicenediols self-assemble through a unique supramolecular network of hydrogen bonds to form an alternate-leaf motif, while right-handed helicenediols form a four-leaf clover motif in projection. In the self-assembled structures, the interplanar angle of the helicenediol 1 changes from 44.7, for the racemic case, to 33.8 degrees for the right-handed helical case. All of the above evidence points to the surprising conclusion that helicenediol 1 can expand and contract as a "molecular spring". The maximum elongation of the spring is about 61%.

Non-photochemical route to chiral disubstituted [7]thiaheterohelicenes via biaryl- and carbonyl-coupling reactions

K Tanaka, H Suzuki, H Osuga

JOURNAL OF ORGANIC CHEMISTRY ( AMER CHEMICAL SOC ) 62 ( 13 ) 4465 - 4470 1997年06月

Non-photochemical syntheses of optically active dimethyl[7]thiaheterohelicenes (P)-(+)-14 and (M)-(-)-14 are described. The key transformations in the syntheses are the metal-mediated biaryl coupling reactions between two benzodithiophene units having oxazoline moieties and the intramolecular McMurry coupling reaction of the biaryl dialdehydes (S)-13 and (R)-13. The configuration of the atropisomer 10a obtained from the biaryl coupling reaction was shown to be S by X-ray analysis.

DOI

Practical synthesis of optically pure bifunctionalized heterohelicenes

H Osuga, H Suzuki, K Tanaka

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN ( CHEMICAL SOC JAPAN ) 70 ( 4 ) 891 - 897 1997年04月

Optically active 2-(hydroxymethyl)- and 2-(ethylthiocarbonyl)[1]benzothieno[5',4':2,3][1]benzothieno [4',5:4,5]-thieno[3,2-f]quinolines containing pi-excessive thiophene and iz-deficient pyridine units were prepared by the use of e.ro-3-amino-2-hydroxybornane as a chiral auxiliary. This procedure consists of separation of the helical diastereomers prepared by photocyclization of 1,2-diarylethylenes and removal of the chiral auxiliary by a thiolate ion. Large scale preparation of the helicenes can be accomplished by a modified procedure of the photocyclization reaction. Optical purities of both enantiomers of 2-(hydroxymethyl)- and 2-(ethylthiocarbonyl)[1]benzothieno[5',4':2,3][1]benzothieno[4',5':4,5]-thieno[3,2-f]quinolines were >99.5%. Their absolute configurations were determined by comparison of CD spectra.

DOI

A Novel Non-Photochemical Route to Disubstituted 〔7〕Thiaheterohelicene

Chimia 51 ( 7 ) 450 1997年

Synthesis and Crystal Structure of Chiral Bifunctional Helicenes with π-Deficient Pyridine and π-Excessive Thiophene Units

TANAKA K, KITAHARA Y, SUZUKI H, OSUGA H, KAWAI Y

Tetrahedron Letters ( PERGAMON-ELSEVIER SCIENCE LTD ) 37 ( 33 ) 5925 - 5928 1996年08月

Both enantiomers of new bifunctional helicenes constructed from pi-excessive 2-(hydroxymethyl)thiophene and pi-deficient pyridine rings have been prepared using (1R,2S,3R,4S)-3-amino-2-hydroxybornane as a chiral auxiliary. The X-ray crystal structure reveals the intermolecular hydrogen bond between the hydroxy group of the helicene and the pyridine nitrogen atom of the adjacent molecule. The non-bonded distance between the nitrogen atom and the oxygen atom is 2.72 Angstrom, and the interplanar angle between the terminal rings is 45.3 degrees. Copyright (C) 1996 Elsevier Science Ltd

DOI

ENANTIOSELECTIVE SYNTHESIS OF HELICAL MOLECULES - LIPASE-CATALYZED RESOLUTION OF BIS(HYDROXYMETHYL)[7]THIAHETEROHELICENE

K TANAKA, Y SHOGASE, H OSUGA, H SUZUKI, K NAKAMURA

TETRAHEDRON LETTERS ( PERGAMON-ELSEVIER SCIENCE LTD ) 36 ( 10 ) 1675 - 1678 1995年03月

Lipase (Pseudomonas cepacia)-catalyzed transesterification of racemic 2, 13-bis(hydroxymethyl)dithieno[3,2-e:3',2'-e']benzo[1,2-b:4,3-b']bis[1]benzothiophene by vinyl acetate in dichloromethane proceeded with a high degree of enantioselectivity to give (P)-(+)-bis(hydroxymethyl)[7]thiaheterohelicene (45% yield, 98% ee), and the corresponding monoacetate (37% yield) and diacetate (13% yield). Reduction of the monoester by LiAlH4 gave (M)-(-)-bis(hydroxymethyl)[7]thiaheterohelicene with 80% ee and the diester gave the same enantiomer with 95% ee. The reaction of the racemic helicenediol with Candida antarctica afforded the antipode with 92% ee.

DOI

CONVERGENT SYNTHESIS OF OPTICALLY-ACTIVE BIFUNCTIONALIZED [7]THIAHETEROHELICENE

K TANAKA, H OSUGA, Y SHOGASE, H SUZUKI

TETRAHEDRON LETTERS ( PERGAMON-ELSEVIER SCIENCE LTD ) 36 ( 6 ) 915 - 918 1995年02月

Optically active bifunctionalized [7]thiaheterohelicene was synthesized using (1R, 2R, 3S, 4S)-endo-3-amino-endo-2-hydroxybornane as a chiral element; The photocyclo-dehydrogenation of 1,2-diarylethylene prepared from benzodithiophenecarboxaldehyde 4 and optically active phosphonium salt 8 gave a 38:62 mixture of the chromatographically separable diastereomers of [7]thiaheterohelicene. The removal of the chiral auxiliary from the diastereomers was readily achieved by thiolysis, and subsequent desilylation and reduction gave new helical ligands possessing C-2 symmetry, (P)- and (M)-2,13-bis(hydroxymethyl)dithieno[3,2-e:3',2'-e']benzo[1,2-b:4,3-b']bis[1]benzothiophenes.

DOI

DIASTEREOCONTROLLED SYNTHESIS OF OPTICALLY PURE FUNCTIONALIZED HETEROHELICENES

K TANAKA, H OSUGA, H SUZUKI

TETRAHEDRON-ASYMMETRY ( PERGAMON-ELSEVIER SCIENCE LTD ) 4 ( 8 ) 1843 - 1856 1993年08月

(1R,2S,3R,4S)-exo-3-Amino-exo-2-hydroxybornane (exo-amino alcohol) and (1R,2R,3S,4S)-endo-3-amino-endo-2-hydroxybornane (endo-amino alcohol) were found to be efficient diastereomeric chiral auxiliaries for the preparation of functionalized optically pure heterohelicenes. The diastereoselectivities in the synthesis of the helicenes via photocyclization were controlled by the use of these chiral auxiliaries and the resulting diastereomers were readily separated by column chromatography. Removal of the chiral auxiliaries gave optically pure (+)-(P)- and (-)-(M)-[7]heterohelicenes, whose rotational values were +2830 and -2770, respectively.

DOI

STEREOCONTROLLED DIELS-ALDER REACTIONS WITH CHIRAL TRICYCLIC OXAZOLIDINONES

K TANAKA, H UNO, H OSUGA, H SUZUKI

TETRAHEDRON-ASYMMETRY ( PERGAMON-ELSEVIER SCIENCE LTD ) 4 ( 4 ) 629 - 632 1993年04月

(1R,2R,6S,7S)-5-Aza-1,10,10-trimethyl-3-oxatricyclo[5.2.1.02,6]decan-4-one (endo-oxazolidinone) and (1R,2S,6R,7S)-isomer (exo-oxazolidinone) are found to be efficient diastereomeric auxiliaries for Diels-Alder reactions, which are promoted by Lewis acid catalysts with predictable absolute stereochemistry. Thus, the reaction of cyclopentadiene with N-crotonyl- or N-cinnamoyl-endo-oxazolidinones gave (1R,2R,3S,4S)-3-methyl- or (1R,2S,3S,4S)-3-phenylbicyclo[2.2.1]hept-5-ene-2-carboxylates, while their enantiomers, i.e. (1S,2S,3R,4R)-3-methyl- or (1S,2R,3R,4R)-3-phenylbicyclo[2.2.1]hept-5-ene-2-carboxylates were obtained stereoselectively from the corresponding exo-oxazolidinone derivatives.

DOI

AN EFFICIENT SYNTHETIC METHOD FOR OPTICALLY PURE HETEROHELICENES

K TANAKA, H OSUGA, H SUZUKI, H KISHIDA

TETRAHEDRON LETTERS ( PERGAMON-ELSEVIER SCIENCE LTD ) 33 ( 32 ) 4599 - 4602 1992年08月

(1R,2S,3R,4S)-3-amino-2-hydroxybornane was found to be an efficient chiral auxiliary in the synthesis of functionalized heterohelicenes of high optical purity. Photocyclization of 2-(2-naphtho[2,1-b]thienylvinylene)benzo[1,2-b:4,3-b']dithiophene-5-carboxamide afforded helicenes as a diastereomeric mixture which was readily separated by column chromatography. Removal of the chiral auxiliary from the diastereomers produced 2-methoxycarbonyl[7]heterohelicene with [alpha]D -2770-degrees and its enantiomer with [alpha]D +2830-degrees, respectively.

DOI

　前のページ -次のページ　

<大須賀 秀次>

論文 - 大須賀 秀次

<大須賀　秀次>

論文 - 大須賀　秀次