Title
Photochromic and fluorescence switching properties of oxidized triangle terarylenes in solution and in amorphous solid states
Author
Maki Taguchi, Tetsuya Nakagawa, Takuya Nakashima, Tsuyoshi Kawai
Year
2011
Journal
Journal of Materials Chemistry
Abstract
Three hexatriene-type photochromic compounds 4,5-bis(2,4-dimethyl-5-phenylthiophene-S,S-dioxide-3-yl)-2-phenylthiazole, 1, 4,5-bis(2-methylbenzo[b]thiophene-S,S-dioxide-3-yl)-2-phenylthiazole, 2, and 1,2-bis(2,4-dimethyl-5-phenylthiophene-S,S-dioxide-3-yl)-3,3,4,4,5,5-hexafluorocyclopentene, 3, are synthesized and their photochromic and fluorescence properties are studied, which are analogous to photochromic molecules of triangle terarylene and diarylethene with oxidized aryl units containing S,S-dioxide moieties. These compounds showed photochromic coloration reaction to form a ring-closed form isomer having a cyclohexadiene backbone. Compound 2 showed backward cycloreversion reaction with about 2.4% of photochemical quantum yield, whereas compounds 1 and 3 showed markedly low cycloreversion quantum yields less than 0.1%. Their colored isomers exhibited green or orange fluorescence with relatively high fluorescence quantum yields. Compound 1 also showed similar fluorescence switching nature and fluorescence pattern formation in a stable amorphous film. Intramolecular hydrogen bonding between S,S-dioxide units and methyl groups at photo-reactive carbon atoms is discussed on the basis of molecular structure determined by X-ray single analysis and quantum chemical calculation in the DFT method, which is regarded to contribute to the enhanced emission nature and suppressed cycloreversion photoreactivity of the ring-closed form isomers.
Instrument
FP-6500
Keywords
Fluorescence, Materials