33 Turn-on Mode Photoswitchable Fluorescent Diarylethenes …
565
Fig. 33.1 Photoisomerizaiton of fluorescent diarylethenes 1–8
33.2 Turn-on Mode Photoswitchable Fluorescent
Diarylethenes Having Benzothiophene 1,1-Dioxide
Groups
A
sulfone
derivative
of
1,2-bis(2-methyl-1-benzothiophen-3yl)perfluorocyclopentene, 1, undergoes photochromism and shows fluorescence in
both the open- and closed-ring isomers [29–31]. Open-ring isomer 1a is colorless
and has no optical absorption in the visible-wavelength region. Upon irradiation
with UV light, 1a undergoes a cyclization reaction to produce yellow closed-ring
isomer 1b. The absorption maximum of 1b in ethyl acetate is observed at 398 nm
565
Fig. 33.1 Photoisomerizaiton of fluorescent diarylethenes 1–8
33.2 Turn-on Mode Photoswitchable Fluorescent
Diarylethenes Having Benzothiophene 1,1-Dioxide
Groups
A
sulfone
derivative
of
1,2-bis(2-methyl-1-benzothiophen-3yl)perfluorocyclopentene, 1, undergoes photochromism and shows fluorescence in
both the open- and closed-ring isomers [29–31]. Open-ring isomer 1a is colorless
and has no optical absorption in the visible-wavelength region. Upon irradiation
with UV light, 1a undergoes a cyclization reaction to produce yellow closed-ring
isomer 1b. The absorption maximum of 1b in ethyl acetate is observed at 398 nm