Study of photochemically photochromism of 1,2-bis[5'-(4'-methoxyphenyl)-2'-methylthien-3'-yl]perfluorocyclopentene using two-dimensional FT-IR spectroscopy

摘要

The mechanism of the UV-induced photochemically photochromic process of 1,2-bis[5'-(4"-methoxyphenyl)-2'-methlthien-3'-yl]-perfluorocyclopentene (Daeome) was investigated using two-dimensional (2D) FT-IR spectroscopy. Dynamic changes of IR absorption bands in the characteristic spectral regions for phenyl ring (1609, 1601 and 1494 cm~(-1)) and thiophene ring (1556 and 1516 cm~(-1)) were studied in detail to reveal conformational transformations taking place in this reaction. 2D correlation analysis successfully revealed that IR intensity decrease at 1556 and 1516 cm~9-1) occurs somewhat ahead of the intensity increase at 1601 and 1491 cm~(-1), indicating that the first step of this photochromic reaction was the weakening of aromaticity of the thiophene ring.