Study On The Synthesis Of Cyanofunctionalized 1,4-bis?(E)-2-(1H-indol-3-yl)vinyl?benzenes And Their Thermochromism

Stimuli-responsive materials have attracted considerable attention due to their promising applications in sensors,data storage and optoelectronic devices.The finding of the aggregation induced emission(AIE)effect(Tang et al,2001)promotes the development of new stimuli-responsive materials.Recently,cyano substituted oligo(pphenylene vinylene)(CN-OPV)derivatives have been reported to possess AIE properties and display stimuli-sensitive behaviour including mechano-,piezo-,thermo-,vapour-and electro-induced fluorescence changes.In this work,on the basis of a CNOPV skeleton,five cyano-functionalized 1,4-bis((E)-2-(1H-indol-3-yl)vinyl)benzenes(CN-BIVBn,n = 8,10,12,14,16)have been constructed by introducing two strong electron donating N-alkyl indole groups which are linked by a conjugated unit.Their TICT and AIE effect and fluorescent thermochromism were examined,and their structure-property relationships were intensively investigated.The morphology and the optical waveguide property were also tested.1)Being characterized by UV-visible absorption spectrum and PL spectrum,all of the five CN-BIVBn were found to show TICT effect and AIE property2)Being characterized by PL spectrum in different temperatures,the five constructed luminophores present chain length-dependent thermochromic behaviour:i)almost no thermochromism is observed for the three luminophores with relatively short alkyl chains(CN-BIVB8,CN-BIVB10 and CN-BIVB12);ii)as for CN-BIVB14,it initially exhibits greenish-yellow fluorescence which turns to orange upon heating and the orange emission is retained after cooling;iii)CN-BIVB16 extraordinarily displays three-colour emissions including greenishyellow,orange and salmon pink fluorescence in initial,heated and cooled states,respectively3)Being characterized by DSC?PXRD and SEM,we have investigated their structureproperty relationships,proposed their thermochromic mechanism4)Being characterized by fluorescence microscopy,CN-BIVB8,CN-BIVB10 and CNBIVB12 were found to show optical waveguide propertyThe results provide a new method to design novel thermochromic CN-OPV derivatives materials.