Impact of Polymer Matrix on Polymer Mechanochromism from Excited State Intramolecular Proton Transfer  

作　　者：Yu Wu Xin Cheng Huan Hu Shui Hu Zhimin Ma Zhiyong Ma 

机构地区：[1]Beijing Advanced Innovation Center for Soft Matter Science and Engineering,Beijing State Key Laboratory of Organic-Inorganic Composites,College of Chemical Engineering,Beijing University of Chemical Technology,Beijing,100029 China [2]Center of Advanced Elastomer Materials,College of Materials Science and Engineering,Beijing University of Chemical Technology,Beijing,100029 China [3]College of Engineering,Peking University,Beijing,100871 China

出　　处：《Chinese Journal of Chemistry》2024年第6期611-616,共6页中国化学（英文版）

基　　金：supported by the National Natural Science Foundationof China(22175015,21704002 and 22375013);the Beijing Natural Science Foundation(2182054);the Big Science Project from BUCT(XK180301);the Fundamental Research Funds forthe Central Universities to Z.Y.M.

摘　　要：Mechanochromic polymers based on non-covalent changes have attracted much attention recently.Herein,we report the impact of inter/intramolecular hydrogen bonds on polymer mechanochromism from the excited state intramolecular proton transfer (ESIPT) process.PhMz-NH2-OH and PhMz=2A are designed and obtained by simple and high-yield synthesis,and are connected into polyurethane and poly(methyl acrylate-co-2-ethylhexyl acrylate),respectively.In the initial state,the PhMz-NH2-OH@PU sample shows blue fluorescence from the excited enol form (E*) excitons,owing to intermolecular hydrogen bonds that interrupt the ESIPT reactions but the PhMz=2A@PMA-2-EA sample expresses cyan fluorescence belonging to the excited keto form (K*) emission,implying that the intramolecular hydrogen bonds matter.Furthermore,under stretching,external force can tune the emission of the PhMz=2A@PMA-2-EA sample from K* to E* state.Though external force can putatively still promote a bond rotation,ESIPT reactions remain equivalently interrupted in both the relaxed and stressed states in a hydrogen-bond donating environment.DFT calculation confirms the force-induced increase in dihedral angle for the transition of ESIPT-on/off.Thus,PhMz-NH2-OH@PU and PhMz=2A@PMA-2-EA showed disparate initial ESIPT states and further different responses/sensitivity to force.This study reports a novel and efficient strategy for enriching mechanochromic investigation and extending the applications of ESIPT reactions.

关 键 词：Polymer mechanochromism Excited state intramolecular proton transfer Hydrogen bonding Supramolecular chemistry Elastomers 

分 类 号：O626[理学—有机化学] O641.3[理学—化学]