Synthesis And Chiral Photoactivity Of Luminescent Polypeptide Polymers

Circularly polarized luminescence（CPL）is the differential emission of left-and right-circularly polarized light from chiral luminescent systems,which plays a pivotal role in studying the chiral feature of the emitting excited states.CPL have received increasing attention due to its potential application in 3D display,organic light-emitting diodes（OLEDs）,Chemical probes,information storage and processing.In this paper,a series of chiral polypeptide polymers were synthesized by ring-opening polymerization of AIE molecule with NCA as initiator,in order to provide a new method and theoretical guidance for the study of novel circularly polarized luminescent materials.The main work of this papar includes the following aspects:（1）In this paper,a series of novel polypeptides with different molecular weights and lengths of spacers were synthesized by tetraphenylethene derivatives initiated L-glutamate-NCA ring-opening polymerization.The molecular stuctures,molecular weight and molecular weight distribution of the obtain polymers were confirmed by ¹H NMR,FTIR and GPC analysis.The fluorescence properties of the polymer in DMF/H₂O mixed solvent were studied.The results showed that the polymer had obvious aggregation-induced luminescence activity.When polymer was doped into nemetic liquid crystal 5CB matrix,it was found that the electric field induced the liquid crystal material orientation to change and the fluorescence intensity decreased,indicating that the fluorescence intensity was dependent on the electric field.（2）Using p-hydroxybenzaldehyde and phenylacetonitrile as raw materials,a series of polypeptides of with different molecular weights,lengths of spacers and terminal group lengths were synthesized by four kinds of cyanostilbene derivatives initiated NCA ring-opening polymerization.The molecular stuctures,molecular weight and molecular weight distribution of the obtain polymers were confirmed by ¹H NMR,FTIR and GPC analysis.It was found that the shorter the spacer length,the less controllable the active polymerization.The fluorescence properties of the polymer in DMF/H2O mixed solvent were studied.The results showed that the polymer had obvious aggregation induced luminescence activity.The polymers with small molecular weight showed excellent liquid crystal compatibility and showed obvious cholesteric texture at doping amount up to 30%.