Photochromism of diarylethenes having thiophene oligomers as the aryl groups

Diarylperfluorocyclopentenes having thiophene oligomers as the aryl groups were synthesized and their photochromic reactivity was examined. The cylization quantum yields were scarcely affected by the oligomer chain length, while the ring-opening quantum yields dramatically decreased with the increasing number of the thiophene rings, The low quantum yield of a 1,2-bis(5 ''-cyano-2,4-dimethyl-5,2':5',2 ''-terthiophen-3-yl)perfluorocyclopentene closed-ring form was increased as large as 34 times by raising the reaction temperature from 25 degrees C to 150 degrees C. (C) 1997 Elsevier Science Ltd.