Thermochromic Behavior of Azobenzene-based Coordination Polymer with Reversible Breathing Process

摘要

A multiple stimuli-responsive coordination polymer,namely,[Zn(H2O)6][Zn4Na2L4(H2O)_(12)](H2O)_(12)(1)(H3L=5-(4-Sulfophenylazo)salicylic acid),was synthesized by a simple hydrothermal method.It reveals a 2D elastic layer-structured framework,forming a three-dimensional(3D)interlinked networks driven by extensive π…π stacking interactions.Removing water molecules by heating or vacuum freeze drying,it not only shows a reversible thermo-chromism but also exhibits a selective gas absorption and breathing effect.In addition,this material exhibits skeleton stability under reversible dehydration/hydration.The reversible thermochromic behaviour is mainly attributed to the change of the coordination environment of Zn~(2+)ions during the dehydration/hydration process.Furthermore,the film of 1 on the polylactic acid(PLA)support displayed similar reversible thermochromic behaviour with high sensitivity(large color-change and rapid response upon cooling or heating),promoting its application in switching fibres and devices,and naked-eye colorimetric sensor in the future.