研究者詳細 - 岡本　秀毅

論文 - 岡本　秀毅

分割表示 105 件中 61 - 80 件目／全件表示 >>

Characteristics of [6]phenacene thin film field-effect transistor 査読

Noriko Komura, Hidenori Goto, Xuexia He, Hiroki Mitamura, Ritsuko Eguchi, Yumiko Kaji, Hideki Okamoto, Yasuyuki Sugawara, Shin Gohda, Kaori Sato, Yoshihiro Kubozono

APPLIED PHYSICS LETTERS 101 ( 8 ) 2012年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST PHYSICS

Transistor characteristics are studied for field-effect transistors (FETs) with thin films of [6]phenacene, which has six benzene rings and W-shape structure. The molecular alignment preferable for FET transport is found to be formed in [6]phenacene thin films. The transistor shows clear p-channel FET characteristics with field-effect mobility mu as high as 3.7 cm(2) V-1 s(-1). The similar O-2 sensing properties to picene FET are observed in [6]phenacene thin film FET. The bias stress properties are observed in [6]phenacene thin film FET. The pulse-voltage application suppresses the bias-stress effect and it enables a continuous O-2 sensing in [6]phenacene FET. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4747201]

DOI： 10.1063/1.4747201

Unprecedented Temperature-dependent Formation of 3-and 7-Methyl-3H-azepine Derivatives by the Reaction of o-Nitrotoluene with Tributylphosphine in Nucleophilic Media 査読

Siti Mariyah Ulfa, Hideki Okamoto, Kyosuke Satake

CHEMISTRY LETTERS 41 ( 4 ) 400 - 402 2012年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

The reaction of o-methylphenylnitrene in the presence of alcohol and amine was expected to give isomeric pairs of 3- and 7-methyl-3H-azepine derivatives. The formation ratio between these isomers was found to be obviously influenced by reaction temperature, that is, reaction at 150 degrees C gave 7-methyl-3H-azepine derivative, however, it became minor under 70 degrees C in both media. The ratio between 3- and 7-methyl derivatives is explained by a scheme of kinetic- and thermodynamic-controlled product distribution from o-methylphenylnitrene to 3- and 7-methyldehydroazepine intermediates which are trapped by nucleophilic media to give 3- and 7-methyl-3H-azepine derivatives.

DOI： 10.1246/cl.2012.400

Studies on interactions of excited cadmium and mercury atoms with secondary and tertiary alkyl- and silylamines in gas phase

Shunzo Yamamoto, Eriko Kainaga, Omar Ahmed, Hideki Okamoto, Yoshimi Sueishi

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY 228 ( 1 ) 38 - 43 2012年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE SA

The Cd(P-3(1))- and Hg(P-3(1))-photosensitized emissions of some secondary and tertiary alkyl- and silylamines have been investigated under conditions of steady illumination at 493 and 298 K, respectively. The emission bands were observed at around 440 nm in the cadmium-photosensitized reactions of these amines. In contrast, no appreciable emission bands were observed in the mercury-photosensitized reactions of these amines. However, upon addition of tert-butyl alcohol to the amine-mercury system, an emission band evolved at around 350 nm in the mercury-photosensitization. The peak-wavelengths for secondary and tertiary alkyl- and silylamines are slightly shorter than the values predicted from the correlations between the peak wavelength and the first ionization energy obtained in the cadmium- and mercury-photosensitized luminescence of ammonia and primary amines. The quenching efficiencies of the cadmium and mercury resonance lines by secondary alkyl- and silylamines are higher than those by tertiary alkyl- and silylamines. These observations suggest that the steric hindrance by the alkyl and silyl groups to the approach of the nitrogen atom in the amines to excited cadmium and mercury atoms seems to be an important factor for the stabilization of the exciplexes and the quenching of the resonance lines. The behavior of silylamines is similar to that of alkylamines in cadmium- and mercury-photosensitized reactions. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jphotochem.2011.11.010

Fluorescence response of 3-trifluoroacetylaminophthalimide to Li+–I− ion pair induced by 254 nm photolysis in acetonitrile

Chem. Commun. 48 ( 17 ) 2346 - 2348 2012年

STERIC EFFECT ON THE FORMATION OF 3H-AZEPINE DERIVATIVES FROM o-ALKYLPHENYLNITRENE AND ALCOHOL AS A NUCLEOPHILIC MEDIA

Siti Mariyah Ulfa, Hideki Okamoto, Kyosuke Satake

HETEROCYCLES 83 ( 6 ) 1259 - 1265 2011年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The cause of regioselectivity for the formation of 3-alkyl- and/or 7-alkyl-3H-azepine derivatives via the intramolecular insertion reaction of o-alkylphenylnitrene, which is generated by an action of Buy on o-alkylnitrobenzene, in the presence of alcohol found to be elucidated by the steric effects of an alcohol adduct on the dehydroazepine intermediate. Observed selectivity is confirmed both by changing the bulkiness of the o-alkyl group of phenylnitrene and that of alcohol as a nucleophile.

DOI： 10.3987/COM-11-12172

Metal-intercalated aromatic hydrocarbons: a new class of carbon-based superconductors 査読

Yoshihiro Kubozono, Hiroki Mitamura, Xuesong Lee, Xuexia He, Yusuke Yamanari, Yosuke Takahashi, Yuta Suzuki, Yumiko Kaji, Ritsuko Eguchi, Koki Akaike, Takashi Kambe, Hideki Okamoto, Akihiko Fujiwara, Takashi Kato, Taichi Kosugi, Hideo Aoki

PHYSICAL CHEMISTRY CHEMICAL PHYSICS 13 ( 37 ) 16476 - 16493 2011年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

New carbon-based superconductors are synthesized by intercalating metal atoms into the solid-phase hydrocarbons picene and coronene. The highest reported superconducting transition temperature, T-c, of a hydrocarbon superconductor is 18 K for K(3)picene. The physics and chemistry of the hydrocarbon superconductors are extensively described for Axpicene (A: alkali and alkali earth-metal atoms) for x = 0-5. The theoretical picture of their electronic structure is also reviewed. Future prospects for hydrocarbon superconductors are discussed from the viewpoint of combining electronics with condensed-matter physics: modification of the physical properties of hydrocarbon solids is explored by building them into a field-effect transistor. The features of other carbon-based superconductors are compared to clarify the nature of hydrocarbon superconductors.

DOI： 10.1039/c1cp20961b

Phthalide-derived novel fluoroionophores incorporating picolylamino receptors: synthesis and response to metal cations 査読

Hideki Okamoto, Ayako Matsui, Kyosuke Satake

ANALYST 136 ( 15 ) 3164 - 3169 2011年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Phthalide derivatives incorporating mono- and di-picolylamino functionalities at the 6-position have been prepared as novel fluoroionophores and their fluorescence responses to metal cations have been investigated. These phthalides not only exhibited efficient fluorescence in an aqueous medium but also displayed fluorescence on-off response upon addition of transition-metal cations, namely Cu(2+). The 6-aminophthalide fluorophore served as the core of the fluorescent probes although it has rarely been applied to a chemosensor. To the best of our knowledge, these modified phthalides are the first 6-aminophthalide-derived fluorometric probes for metal cations, namely Cu(2+).

DOI： 10.1039/c1an15239d

Quantitative analysis of O-2 gas sensing characteristics of picene thin film field-effect transistors 査読

Xuesong Lee, Yasuyuki Sugawara, Akio Ito, Shuhei Oikawa, Naoko Kawasaki, Yumiko Kaji, Ryoji Mitsuhashi, Hideki Okamoto, Akihiko Fujiwara, Kenji Omote, Takashi Kambe, Naoshi Ikeda, Yoshihiro Kubozono

ORGANIC ELECTRONICS 11 ( 8 ) 1394 - 1398 2010年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

O-2 gas sensing behaviors are studied in picene thin film field-effect transistors (FETs) with hydrophobic polymer (Cytop(TM) or polystyrene) coated SiO2 gate dielectrics. Picene thin film FETs show a rapid reduction of hysteresis in transfer curves recorded in forward and reverse measurement modes, compared to a picene FET with hexamethydisilazane-coated SiO2. The picene FETs show very sensitive O-2 gas sensing effects down to similar to 10 ppm. A quantitative analysis is presented of the gate voltage (V-G) dependent mobility induced by O-2 exposure, i.e., the suppression of drain current at high V-G. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.orgel.2010.06.003

Flexible picene thin film field-effect transistors with parylene gate dielectric and their physical properties 査読

Naoko Kawasaki, Wolfgang L. Kalb, Thomas Mathis, Yumiko Kaji, Ryoji Mitsuhashi, Hideki Okamoto, Yasuyuki Sugawara, Akihiko Fujiwara, Yoshihiro Kubozono, Bertram Batlogg

APPLIED PHYSICS LETTERS 96 ( 11 ) 113305 2010年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST PHYSICS

Flexible picene thin film field-effect transistors (FETs) have been fabricated with parylene gate dielectric on polyethylene terephthalate substrates. The picene thin film FETs show p-channel output/transfer characteristics and the field-effect mobility mu reaches similar to 1 cm(2) V(-1) s(-1) in vacuum. The FET shows a clear O(2) gas sensing effect and negligible hysteresis in the transfer curves, indicating a possible application of the transistor as O(2) selective gas sensor. Furthermore, it has been found that the parylene gate dielectric can eliminate a reduction in on-state drain current caused by continuous bias-voltage application which is observed if a SiO(2) gate dielectric is used.

DOI： 10.1063/1.3360223

Linear response of multiphoton reaction: Three-photon Cycloreversion of anthracene biplanemer in solution by intense femtosecond laser pulses 査読

Yatsuhashi, T., Nakahagi, Y., Okamoto, H., Nakashima, N.

Journal of Physical Chemistry A 114 ( 39 ) 10475 - 10480 2010年

Low voltage operation in picene thin film field-effect transistor and its physical characteristics 査読

Yumiko Kaji, Naoko Kawasaki, Xuesong Lee, Hideki Okamoto, Yasuyuki Sugawara, Shohei Oikawa, Akio Ito, Hiroyuki Okazaki, Takayoshi Yokoya, Akihiko Fujiwara, Yoshihiro Kubozono

APPLIED PHYSICS LETTERS 95 ( 18 ) 183302/1-183302/3 2009年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST PHYSICS

Low voltage operation of picene thin film field-effect transistor (FET) has been realized with 40 nm thick SiO(2) gate dielectrics coated by two polymers, Cytop (TM) and polystyrene. The picene FETs operated in low absolute gate voltage vertical bar V(G)vertical bar below 15 V for Cytop (TM) coated SiO(2) and 30 V for polystyrene coated SiO(2) gate dielectrics, and they showed a significant O(2) gas sensing effect down to similar to 10 ppm. Photoemission spectrum clarified that O(2) molecules penetrate into the thin films at O(2)/picene mole ratio of 1: 1. X-ray diffraction pattern of picene thin films showed highly oriented growth on the polymer-coated SiO(2).

DOI： 10.1063/1.3257373

High-performance C-60 and picene thin film field-effect transistors with conducting polymer electrodes in bottom contact structure 査読

Yumiko Kaji, Ryoji Mitsuhashi, Xuesong Lee, Hideki Okamoto, Takashi Kambe, Naoshi Ikeda, Akihiko Fujiwara, Minoru Yamaji, Kenji Omote, Yoshihiro Kubozono

ORGANIC ELECTRONICS 10 ( 3 ) 432 - 436 2009年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

C-60 and picene thin film field-effect transistors (FETs) in bottom contact structure have been fabricated with poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PED-OT:PSS) electrodes for a realization of mechanical flexible organic FETs. The C-60 thin film FETs showed n-channel enhancement-type characteristics with the field-effect mobility mu value of 0.41 cm(2\) V-1 s(-1), while the picene thin film FET showed p-channel enhancement-type characteristics with the p of 0.61 cm(2) V-1 s(-1). The p values recorded for C-60 and picene thin film FETs are comparable to those for C-60 and picene thin film FETs with Au electrodes. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.orgel.2009.01.006

Trap states and transport characteristics in picene thin film field-effect transistor 査読

Naoko Kawasaki, Yoshihiro Kubozono, Hideki Okamoto, Akihiko Fujiwara, Minoru Yamaji

APPLIED PHYSICS LETTERS 94 ( 4 ) 043310/1-043310/3 2009年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST PHYSICS

Transport characteristics and trap states are investigated in picene thin film field-effect transistor under O(2) atmosphere on the basis of multiple shallow trap and release (MTR) model. The channel transport is dominated by MTR below 300 K. It has been clarified on the basis of MTR model that the O(2)-exposure induces a drastic reduction in shallow trap density to increase both the field-effect mobility mu and on-off ratio. We also found that the O(2)-exposure never caused an increase in hole carrier density. Actually, a very high mu value of 3.2 cm(2) V(-1) s(-1) is realized under 500 Torr of O(2).

DOI： 10.1063/1.3076124

Photochemistry of nitrogen-bridged cyclophanes: 2,11-diaza[32]anthracenoparacyclophane and 2,11-diaza[32]paracyclophane systems 招待査読

Hideki Okamoto, Minoru Yamaji, Kyosuke Satake

Synlett ( 13 ) 1931 - 1945 2008年8月

A convenient synthesis of trifluoroacetamide derivatives of diaza[3(2)]cyclophanes and triaza[3(3)]cyclophanes 査読

Hideki Okamoto, Hiroyuki Takemura, Kyosuke Satake

SYNTHESIS-STUTTGART 44 ( 1 ) 39 - 44 2008年1月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：GEORG THIEME VERLAG KG

The diaza[3(2)]cyclophane skeleton has been constructed by the bis-N-alkylation of 1,4-bis[(4-nitrophenylsulfonylamin o)methyl] benzene with 1,4-bis(halomethyl)benzene in the presence of sodium hydride. The 4-nitrophenylsulfonyl (Ns) amides in the bridge chains of the cyclophane were effectively deprotected by sodium ethanethiolate and the resulting free amine moieties were reprotected as the trifluoroacetamide under mild conditions to afford 3,7-bis(trifluoroacetyl)-3,7-diaza-1,5(1,4)-dibenzenacyclooctaphane in 26% overall yield. This Ns-amide method has also been applied for the preparation of a higher homologue, the trifluoroacetamide derivative of triaza[3(3)]cyclophane, 3,5,7-tris(trifluoroacetyl)-3,7, 10-triaza- 1,5(1,3,5)-dibenzenabicyclo[3.3.3]undecaphane, in 18% overall yield. Thus, the present procedure provides a convenient synthetic route to azacyclophane derivatives possessing trifluoroacetamide groups in the bridge chains.

DOI： 10.1055/s-2007-1000825

Fluorescence properties of 3-and 4-trifluoroacetylamino-1,8-naphthalimides: Solvent-controlled switching of fluorescence color and response to metal-cations 査読

Hideki Okamoto, Kyosuke Satake, Masaru Kimura

ARKIVOC 8 112 - 123 2007年

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ARKAT USA INC

The effects of solvents and metal cations on the fluorescence spectra of 3- ( 1) and 4- ( 2) trifluoroacetylamino-1,8-naphthalimides were investigated. In MeCN, these naphthalimides displayed a violet similar to blue fluorescence based on their neutral amide form ( 1, 2). Whereas in DMSO, they gave off a yellow similar to orange emission due to their amide anions (1(-), 2(-)). In MeOH, naphthalimide 2 emitted a dual fluorescence (lambda(FL) 436 and 556 nm) to display a white luminescence. Naphthalimides 1, 2 are essentially insensitive to metal cations in their neutral amide form. In contrast, the fluorescence of the amide anions 1-, 2- was quenched by metal cations. The efficiency of the quenching correlated with the Lewis acidity of the metal cations; a stronger Lewis acid tended to display a more effective fluorescence quenching. Therefore, the fluorescence color and the sensitivity to metal cations of the naphthalimides were effectively switched by the solvent.

Novel parallel reaction between a [1,5] sigmatropic alkylthio shift and a [1,5] sigmatropic hydrogen shift observed in a 2H-azepine ring 査読

Yasuhiro Kubota, Kyosuke Satake, Hideki Okamoto, Masaru Kimura

ORGANIC LETTERS 8 ( 24 ) 5469 - 5472 2006年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Although heating 2-methoxy-2H-azepine results in a [1,5] sigmatropic hydrogen shift, heating 2-propylthio-2H-azepine results in not only a [1,5] sigmatropic hydrogen shift but also a [1,5] sigmatropic propylthio shift. Kinetic measurements reveal that migratory aptitudes increase in the order of MeO < H, PrS. These [1,5] sigmatropic shifts are discussed on the basis of ab initio DFT calculations.

DOI： 10.1021/ol062131w

Invariom structure refinement, electrostatic potential and toxicity of 4-O-methylalpinumisoflavone, O,O-dimethylalpinumisoflavone and 5-O-methyl-4-O-(3-methylbut-2-en-1-yl)alpinum-isoflavone 査読

Robert Kingsford-Adaboh, Birger Dittrich, Christian B. Huebschle, Winfred S. K. Gbewonyo, Hideki Okamoto, Masaro Kimura, Hiroyuki Ishida

ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62 843 - 849 2006年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：BLACKWELL PUBLISHING

The accurate X-ray single-crystal structures of the isoflavone compounds 4-O-methylalpinumisoflavone, O, O-dimethylalpinumisoflavone and 5-O-methyl-4-O-( 3-methylbut-2-en-1-yl) alpinumisoflavone {alpinumisoflavone = 5-hydroxy7-( 4-hydroxyphenyl)-2,2-dimethyl-2H, 6H-benzo[ 1,2-b: 5,4-b']dipyran-6-one} from data sets measured at cryogenic temperature have been obtained from invariom modelling using theoretically predicted Hansen and Coppens multipole-model form factors, which describe the aspherical electron density distribution. Molecular dipole moments and electrostatic potentials obtained from invariom modelling are discussed and compared with results from ab initio theoretical calculations. All three studied compounds are solvent extracts of root bark or seed powder of Millettia thonningii ( leguminosae), a plant molluscicide and cercaricide used in Franco West Africa as medication against various diseases. The compounds' toxicities to brine shrimp have been determined and their different potencies tentatively related to conformation differences, intramolecular contacts, dipole moments and electrostatic potential features.

DOI： 10.1107/S0108768106019616

Formation of 4H-azepine by the electrophilic reaction of a 2-methoxyazepinium ion and analysis of the sigmatropic isomerization 査読

Christopher E. J. Cordonier, Kyosuke Satake, Hideki Okamoto, Masaru Kimura

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY ( 17 ) 3803 - 3807 2006年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

2-Aryl-2H-, 3-aryl-3H-, and 4-aryl-4H-azepine were formed by the novel, electrophilic, pi(LUMO)-controlled reaction of the 2-methoxyazepinium ion, generated in situ by the reaction of TiCl4 with 2,7-dialkoxy-2H-azepine and an aryl compound, for which the kinetic parameters of the sigmatropic hydrogen rearrangement of the 4H-azepine was measured. The substitution and hydrogen shift of the azepinium ion were analyzed with DFT studies. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).

DOI： 10.1002/ejoc.200600257

Crystal structure of 4ﾕ-O-methylalpinumisoflavone at 90K 査読

Robert Kingsford-Adaboh, E. Ahiano, Birger Dittrich, Hideki Okamoto, Masaru Kimura, Hiroyuki Ishida

Cryst. Res. Technol 41 ( 7 ) 728 - 733 2006年7月

　前のページ - 次のページ　

1
2
3
4
5
6