Photoswitchable "Turn-on" Fluorescence Diarylethenes: Substituent Effects on Photochemical Properties and Electrochromism.

A series of "turn-on" fluorescence diarylethenes derived from 2,3-bis(2-methylbenzo[b]thiophen-3-yl)-5,6-dihydro-4H-thieno[2,3-b]thiopyran-4-one (1) with alkyl and acetyl substituents were synthesized. The photochemical and photophysical properties of these derivatives, including the photoreaction of crystalline 1, were thoroughly investigated to reveal substituent effects on their properties. The results indicated that alkyl substituents did not significantly affect the absorption and emission spectra of the diarylethenes.

The effect of a "push-pull" structure on the turn-on fluorescence of photochromic thio-ketone type diarylethenes.

a series of diarylethene compounds with a thiophene bridging unit have been synthesized to investigate the relationship between molecular structure and photochromic properties. In particular, the fluorescence properties related to compound 1 were investigated. The results showed that a six-membered ring carrying an electron-donating sulfur atom and an electron-withdrawing carbonyl group is necessary to form a "push-pull" system for the fluorescence of 1.

Photoswitchable fluorescent diarylethene in a turn-on mode for live cell imaging.

A new diarylethene-derived photochromic compound, with little cytotoxicity, plasma membrane-permeability, and efficient photoswitchability in cells upon alternative UV and visible light irradiation, was synthesized and applied to live cell imaging.