The Synthesis Of Linear Polymer Constructed By Tetraphenyl Ethylene Unit (TPE) And The Study Of Its AIE Properties

The found of aggregation-induced emission(AIE)broke people's understanding to the aggregation-caused quenching before.It's an important discovery in the field of scientific research.At present,scientists have found many compounds with an AIE effect.Among them,tetraphenylethene(TPE)with simple structure is easily to get.It has four benzenes which can rotate freely around C-C bond.This process consumes the energy of the excited molecules,so it has no emission.But,as molecules aggregating,the rotation of the benzene is limited,energy attenuation changes into the form of radiation,so it shows the phenomenon of aggregation-induced emission(AIE).Based on the research results of my research group in the foldamer,we used maleic hydrazide linked by ethylene glycol and dialdehyde derivatives of tetraphenylethene to get soluble linear polymer via forming hydrazone bonds.We contrast the aldehyde hydrogen with the specific hydrogen on the benzene by the NMR to get the degree of polymerization is 20.We got the emission spectra of the linear polymer in good solvent/poor solvent mixtures at different proportions by the fluorescence spectrometer.It shows that as improving the content of poor solvent,the fluorescence of the solution is more and more strong.The polymer shows the effect of aggregation emission enhancement(AEE).At the same time,we check the stacking way of the polymer in different solvents by the UV dilution experiment.The stacking of polymer mainly occurs within the molecule.The soft ethoxy chain can curve in solution,and the polymer can fold into pleated states by ?-? stacking of TPE units within the molecule.Finally,we quench the emission by adding electron-deficient nitro aromatic compound into the solution of polymer.