Reversible Multistimuli-Response Fluorescent Switch Based on Tetraphenylethene–Spiropyran Molecules

Graphical Unlocking emission : Two tetraphenylethene (TPE)-functionalized spiropyran (SP) molecules were designed and synthesized that exhibit not only aggregation-induced emission properties but also multistimuli-responsive properties, such as photochromism and acidchromism. The reversible and different dual-response fluorescent switches triggered by UV/Vis and acid/base have been realized during the ring-closed (CF) to ring-open (OF) transformation (see scheme). Two tetraphenylethene (TPE)-functionalized spiropyran (SP) molecules with very similar structure were designed and synthesized. The two molecules exhibit aggregation-induced emission (AIE) properties, as well as multistimuli-responsive color-changing properties, such as photochromism and acidchromism. The investigation of their different photochromic and acidchromic characteristics and dual-response fluorescent switch during isomerization indicated that the different link position between TPE and SP will significantly affect the extended π-conjugated system, resulting in completely different photochromic and acidchromic properties.