Synthesis And Properties Of Circularly Polarized Light-emitting Isocyanide Copolymer

Circularly polarized luminescence materials have attracted more and more attention in recent years because of their wide application in many fileds.However,there are still few types of circularly polarized luminescence materials available,and some small molecules of circularly polarized luminescence materials can not be applied in practice.Therefore,the preparation of new and efficient circularly polarized luminescence materials has very positive significance.In this paper,an optically active material with circularly polarized luminescence was constructed by using the strategy of copolymerization of chiral monomers and achiral fluorescent monomers.Random copolymerization of chiral isocyanide monomer and achiral fluorescent isocyanide monomer under the initiation of monometallic palladium catalyst,the copolymer with controllable molecular weight and narrow molecular weight distribution were obtained,and the copolymers could emit circularly polarized luminescence.It is worth mentioning that this is the first time circularly polarized luminescence material prepared by isocyanide monomer.There are two main roles that chiral monomers play here,the first is to provide a helical structure for the formation of CPL,the larger the proportion of chiral monomers,the stronger the circular dichromatic signal of copolymer;secondly,the long alkyl chain on the chiral isocyanide can make the copolymer easier to dissolve in variety of common solvents.The role of fluorescent molecules is naturally to act as chromophore to enable polymers to emit fluorescence,the higher the proportion of fluorescent components,the stronger the fluorescence intensity of copolymer.Subsequently,we found that the circular dichromatic signal of the copolymer strongly affects the CPL signal.When the CD strength of the copolymer is higher,there will be a more obvious CPL signal.On the contrary,When the CD strength of the copolymer is relatively weak,the CPL signal will be weaker or even can not be detected.Here,we have prepared copolymers which can emit red,green and blue fluorescence.According to the RGB principle,white fluorescence can be obtained by blending copolymer solutions of three different colors.