Synthesis and photochromism of new asymmetrical diarylethenes with a variableheteroaryl ring and a quinoline unit

Abstract

Three new asymmetrical photochromic diarylethenes containing a variable heteroaryl ring and a quinolineunit were synthesized and their structures were determined by single-crystal X-ray diffraction analysis. Their properties,including photochromism, acidichromism, and uorescence, were investigated systematically. For these diarylethenes,the one with an indole moiety had the largest absorption maximum, cyclization quantum yield, photoconversion ratio,emission peak, and uorescent modulation efficiency. In addition, these diarylethenes exhibited an evident dual switchingbehavior induced by the stimulation of acid/base and UV/Vis. Addition of tri uoroacetic acid to solution of thediarylethenes produced protonated derivatives with notable changes in their absorption spectra. These results indicatedthat the effect of the heteroaryl rings played a very important role during the process of photoisomerization for thesediarylethene derivatives.