| Co-Investigator(Kenkyū-buntansha) |
MIKI Sadao Faculty of Engineering Synthetic Chemistry Lecturer, 工学部, 助手 (30135537)
SUGIMOTO Toyonari Faculty of Engineering Synthetic Chemistry Assoc. Prof., 工学部, 助教授 (30093256)
安西 弘行 通産省, 工技院電総研, 主任研究員
小林 常利 理化学研究所, 研究員 (30109798)
田丸 良直 長崎大学, 工学部, 教授 (80026319)
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| Budget Amount *help |
¥11,300,000 (Direct Cost: ¥11,300,000)
Fiscal Year 1989: ¥4,300,000 (Direct Cost: ¥4,300,000)
Fiscal Year 1988: ¥7,000,000 (Direct Cost: ¥7,000,000)
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| Research Abstract |
This research has been carried out with aim of developing both multi-color organic electrochromic systems and highly sensitive photochromic systems by use of novel pi conjugated compounds. The newly prepared tetrakis(4-hydroxyphenyl)thienothiophene and 1,3-dithiole- radialenes and dendralenes constructed reversible redox systems with their corresponding oxidized species, and vivid three color change was observed. Anthraquinone was chosen as a fundamental molecular skeleton for photochromic molecule, because of its intrinsic spectral sensitivity at long wavelength region as well as its resistibility toward photo-degradation. We employed steric strain, which forces bending of the aromatic ring in a vibrational mode operative for photochemical formation of valence isomers such as Dewar and valene isomers. Thus, 1,2,3-tri-t-butyl anthraquinone was synthesized. Comparing to the electronic spectrum of the parent molecule, the spectrum of 1,2,3-tri-t-butylanthraquinone was characteristic having a longest absorption band with a large extinction coefficient of 3500. The bathochromic shift of the band is also notable, and its absorption cut-off reaches to ca. 550 nm. Upon irradiation, the molecule undergoes reversible valence isomerizations between the corresponding hemi-Dewar anthraquinone derivative. The substitutional modification was employed in naphthacenequinone in order to improve spectitral sensitivity. 1,2,3-tri-t-butylnaphthacenequinone gave the corresponding hemi-Dewar isomer, whereas the 7,8,9-tri-t-butyl system gave the valene isomer. Both the photochemical isomerizations was reversible and quantitative. These new photochromic systems would be practically of practical use.
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