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178 results on '"Mutai, Toshiki"'

23. Synthesis of Imidazopyridine Derivatives Showing Efficient Luminescence in the Solid State—ESIPT Luminescence Properties and their Crystal-structure Dependence

Author

Mutai Toshiki and Araki Koji

Subjects
Imidazopyridine, Chemical substance, Chemistry, Organic Chemistry, Solid-state, Nanotechnology, 02 engineering and technology, Crystal structure, 010402 general chemistry, 021001 nanoscience & nanotechnology, Photochemistry, 01 natural sciences, 0104 chemical sciences, 0210 nano-technology, Luminescence, Science, technology and society
Published
2017

25. Photochromic diarylethene with turn-off fluorescent switching property

Author

Kono, Luna, primary, Nakagawa, Yuma, additional, Fujimoto, Ayako, additional, Nishimura, Ryo, additional, Hattori, Yohei, additional, Mutai, Toshiki, additional, Yasuda, Nobuhiro, additional, Koizumi, Kenichi, additional, Yokojima, Satoshi, additional, Nakamura, Shinichiro, additional, and Uchida, Kingo, additional

Published
2019
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29. Locking of helicity and shape complementarity in diarylethene dimers on graphite

Author

Katsonis, Nathalie, Minoia, Andrea, Kudernac, Tibor, Mutai, Toshiki, Hong Xu, Uji-i, Hiroshi, Lazzaroni, Roberto, De Feyter, Steven, and Feringa, Ben L.

Subjects
Ethylene -- Atomic properties, Ethylene -- Chemical properties, Graphite -- Chemical properties, Molecular dynamics -- Analysis, Scanning tunneling microscopy -- Technology application, Technology application, Chemistry
Abstract

Chiral domains are formed at liquid/solid interface by achiral diarylethenes due to surface-induced atropoisomerism. Molecular dynamics have shown that these dimers of diarylethenes are chiral dimers, rather than prochiral dimers.

Published
2008

30. Material design for piezochromic luminescence: Hydrogen-bond-directed assemblies of a pyrene derivative

Author

Sagara, Yoshimitsu, Mutai, Toshiki, Yoshikawa, Isao, and Araki, Koji

Subjects
Luminescence -- Analysis, Hydrogen bonding -- Research, Polycyclic aromatic hydrocarbons -- Optical properties, Chemistry
Abstract

A novel design principle was adopted to incorporate two strongly demanding factors for molecular packing, a planar aromatic core and multiple hydrogen-bonding sites into a single molecule structure. The designed molecule, an amide-substituted tetraphenylpyrene derivative C6TPPy, successfully showed a piezochromic luminescence by pressure-induced alteration of the molecular packing and subsequent heating-induced restoration.

Published
2007

34. Highly stable host-guest photorefractive polymer composite with low glass transition temperature

Author

Jung, Gyeong Bok, Akazawa, Takayuki, Mutai, Toshiki, Fujimura, Ryushi, Ashihara, Satoshi, Shimura, Tsutomu, Araki, Koji, and Kuroda, Kazuo

Subjects
Materials science, Photorefractive materials, Physics and Astronomy (miscellaneous), Composite number, General Physics and Astronomy, Diffraction efficiency, law.invention, Organic photorefractive materials, Optics, law, Plasticizers, Crystallization, chemistry.chemical_classification, business.industry, Organic polymers, General Engineering, Electric field effects, Polymer, Photorefractive effect, Composite materials, Chromophore, chemistry, Chemical engineering, business, Glass transition
Abstract

We studied the phase stability and photorefractive properties of a new poly(N-vinylcarbazole) (PVK)-based photorefractive polymer composite by modifying the structure of a nonlinear optical chromophore (NLO), 4-butoxy-3-propyl-1-(4-nitrophenyazo)benzene. The shelf life of a sample with a modified NLO, 4-(2-ethylhexyloxy)3-propyl-1-(4-nitrophenyazo) benzene was extended by more than five months even though it had a low glass transition temperature (Tg) of -19C. This material also had a short photorefractive response time constant of 33 ms and a high diffraction efficiency of 49% at an electric field of 100V/m and a total writing intensity of 942mW/cm2. These desirable characteristics are believed to be due to the following reasons: first, the new chromophore acts as a plasticizer, thereby enhancing the orientation of the NLO and second, the solubility of the chromophore in a polymer matrix increases, inhibiting crystallization and providing a high optical quality. 2006 The Japan Society of Applied Physics.

Published
2006

35. Temperature dependence of photorefractive properties of PVK-based composites

Author

Jung, Gyeong Bok, Mutai, Toshiki, Fujimura, Ryushi, Ashihara, Satoshi, Shimura, Tsutomu, Araki, Koji, and Kuroda, Kazuo

Subjects
Birefringence, Materials science, Nonlinear optics, Physics and Astronomy (miscellaneous), Photoconductivity, Organic polymers, Composite number, General Engineering, Electric field effects, General Physics and Astronomy, Photorefractive effect, Composite materials, Chromophore, Conductivity, Chromophores, Thermal effects, Reduced properties, Glass, Composite material, Glass transition
Abstract

We studied the temperature dependencies of electric field-induced birefringence, conductivity, and photorefractive properties of two poly(n-vinylcarbazole) (PVK)-based composites with different nonlinear optical chromophores: 2,5-dimethyl-4-(4'-nitrophenylazo)anisole (DMNPAA) and its derivative, 4-butoxy-3-propyl-1-(4'-nitrophenyazo) benzene (m3p4). Both composites showed similar temperature dependencies; the photorefractive responses were faster at higher temperatures and the diffraction efficiencies increased with temperature and then began to decrease. Such behavior is consistent with the measured temperature dependencies of the field-induced birefringence and the conductivity. We found that the m3p4 composite exhibited a faster photorefractive response rate than the DMNPAA composite when compared at the same reduced temperature T-Tg, where T is the temperature of the measurement and Tg is the glass transition temperature. The results indicate that one can enhance the total photorefractive response rate by changing the nonlinear optical chromophore.

Published
2004

36. High-speed TPD-based photorefractive polymer composites

Author

Jung, Gyeong Bok, Yoshida, Masashi, Mutai, Toshiki, Fujimura, Ryushi, Ashihara, Satoshi, Shimura, Tsutomu, Araki, Koji, and Kuroda, Kazuo

Subjects
Birefringence, Photorefractive materials, Photoconductivity, Temperature programmed desorption, Polystyrenes, Composite materials
Abstract

We studied the electric-field-induced birefringence, the photoconductivity and the photorefractive properties of photorefractive polymer composites based on N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine (TPD). Photorefractive response rate is improved in TPD-based photorefractive polymer, composed of TPD, polystyrene (PS), 4-butoxy-3-propyl-1-(4'-nitrophenylazo)benzene (m3p4) and C60. We obtained the photorefractive response time of as fast as 3.2 ms (@I = 837 mW/cm2, E = 40 V/m). The photoconductivity of TPD-based photorefractive polymer is found to be greater than that of the PVK-based one.

Published
2004

37. High-speed TPD-based Photorefractive Polymer Composites

Author

G.B. Jung, Tsutomu Shimura, Kazuo Kuroda, Mutai Toshiki, Koji Araki, Ryushi Fujimura, Masashi Yoshida, and Satoshi Ashihara

Subjects
Biphenyl, chemistry.chemical_compound, Materials science, Birefringence, chemistry, Diamine, Photoconductivity, General Medicine, Photorefractive effect, Polystyrene, Photorefractive polymer, Composite material, Benzene
Abstract

We studied the electric-field-induced birefringence, the photoconductivity and the photorefractive properties of photorefractive polymer composites based on N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine (TPD). Photorefractive response rate is improved in TPD-based photorefractive polymer, composed of TPD, polystyrene (PS), 4-butoxy-3-propyl-1-(4'-nitrophenylazo)benzene (m3p4) and C 6 0 . We obtained the photorefractive response time of as fast as 3.2 ms (@I = 837 mW/cm 2 , E = 40 V/μm). The photoconductivity of TPD-based photorefractive polymer is found to be greater than that of the PVK-based one.

Published
2004

40. Influence of intermolecular interactions on solid state luminescence of imidazopyridines: theoretical interpretations using FMO-TDDFT and ONIOM approaches

Author

Shigemitsu, Yasuhiro, Mutai, Toshiki, Houjou, Hirohiko, Araki, Koji, Shigemitsu, Yasuhiro, Mutai, Toshiki, Houjou, Hirohiko, and Araki, Koji

Abstract

6-Cyano-2-(2′-hydroxyphenyl)imidazo[1,2-a]-pyridine (6CN-HPIP) shows polymorph-dependent luminescence with the three different crystal forms exhibiting the packing-controlled tuning of bright colors, orange, yellow, and red. The distinctive emission in aggregated states was treated with finite cluster models and analyzed by means of quantum chemistry calculations. The influence of structural displacements and intermolecular interactions in the crystalline state on solid state luminescence was examined in detail using the Fragment Molecular Orbital (FMO) scheme, suitable for studies of aggregated molecular systems. The FMO pair interaction analysis of the S1-S 0 emission maxima indicated that the intermolecular side-to-side interactions cause hypsochromic shifts; facial interactions induce bathochromic shifts; and crystal packing effects in total induce hypsochromic shifts. The FMO predictions of the emission maxima offered qualitatively satisfactory agreements with the experiments. However, the small cluster models including up to 17 molecules did not reach quantitative convergence, i.e., the emission colour order among them was not well reproduced., Physical Chemistry Chemical Physics, 16(28), pp.14388-14395; 2014

Published
2014

41. Effects of interaction between the chelate rings and π-conjugated systems in fused salphen complexes on UV-Vis-NIR spectra.

Author

Houjou, Hirohiko, Yagi, Keisuke, Yoshikawa, Isao, Mutai, Toshiki, and Araki, Koji

Subjects
CHELATES, METAL complexes, BIOCONJUGATES, NEAR infrared spectroscopy, ISOMERS
Abstract

Dinuclear (Zn2, Ni2, and NiZn) complexes of fused salphen with acene-type annelation were synthesized from 3,7-diformyl-2,6-dihydroxynaphthalene. The spectroscopic properties of these complexes were compared with those of their constitutional isomers with phene-type annelation. The acene-type complexes exhibited a characteristic absorption band in the near-infrared region that showed a noticeable solvent effect. Time-dependent density functional theory calculations suggested that the absorption arose from a π → π* transition localized at the naphthalene ring, which was perturbed by the adjoining chelate rings. Effects of the connection topology in the fused salphen complexes are discussed by comparison with those of polycyclic aromatic hydrocarbons. [ABSTRACT FROM AUTHOR]

Published
2017
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