A Versatile BenzimidazoleSubstituted Spirolactam Mechanophore:When Excited State Intramolecular Proton Transfer Couples with Rhodamine  

作　　者：Huan Hu Xin Cheng Zhimin Ma Qingyuan Yang Rint PSijbesma Zhiyong Ma 

机构地区：[1]Beijing Advanced Innovation Center for Soft Matter Science and Engineering,State Key Laboratory of Organic-Inorganic Composites,College of Chemical Engineering,Beijing University of Chemical Technology,Beijing 100029 [2]College of Engineering,Peking University,Beijing 100871 [3]Department of Chemical Engineering and Chemistry,Institute for Complex Molecular Systems,Eindhoven University of Technology,5600 MB,Eindhoven

出　　处：《CCS Chemistry》2024年第7期1798-1809,共12页中国化学会会刊（英文）

基　　金：financially supported by the National Natural Science Foundation of China (grant nos.22375013,22175015,and 21704002);the Beijing Natural Science Foundation (grant no.2182054);the Big Science Project from BUCT (grant no.XK180301);the Fundamental Research Funds for the Central Universities to Z.Y.Ma.

摘　　要：Exploration of multicolor mechanochromic bulk polymers based on a single mechanophore is a big challenge to date.Herein,we report a versatile benzimidazole-substituted spirolactam mechanophore where excited state intramolecular proton transfer(ESIPT)coupled with rhodamine.The mechanophore was facilely synthesized and then covalently linked to polyurethane(PU)chains.The PU film containing the mechanophore(1@PU)showed cooperative photochromism upon irradiation involving simultaneous enhancement of normalized enol and rhodol emissions based on a cooperative ESIPT process and the ring-opening reaction of spirolactam.Moreover,the film exhibited dual-mode multicolor mechanochromism upon stretching and compression.The normalized intensity of enol emission increased and the fluorescence turned from light green to cyan after stretching,then red coloration appeared from colorless after compressing.Control experiments and density functional theory calculations confirmed that the stretch-induced increase of enol emission was attributed to torsion of the dihedral angle between xanthene and benzimidazole in the mechanophore via force-induced disaggregation and direct force action on the isolated mechanophore.Torsion of the dihedral angle and the ring-opening reaction of spirolactam in a single mechanophore occurred sequentially during compression,resulting in an observed red coloration.This study might provide a glimpse into the design of novel multicolor mechanochromic mechanophores.

关 键 词：mechanophore RHODAMINE excited state intramolecular proton transfer cooperative photochromism dual-mode mechanochromism 

分 类 号：O62[理学—有机化学]