Synthesis of fluorescent amorphous diarylethenes

1,2-Bis(2-methyl-1-benzothiophen-3-yl)perfluorocyclopentene derivatives having 2,4-diphenylphenyl substituents at 6 and 6 ' positions of the benzothiophene rings were synthesized. Both mono- and di-substituted derivatives, compounds la and 2a, formed amorphous states at room temperature and their glass transition temperatures were observed at 88 degreesC and 127 degreesC, respectively. Remarkable spectral shift of the fluorescence from 650 nm to 450 nm was observed for the amorphous film of closed-ring isomer 2b upon visible (lambda > 450 nm) light irradiation.