Design And Synthesis Of Ladder Conjugated Polymer Containing Carbazolyl Benzopyrazine

Ladder conjugated polymers are unique in which their main chain structure is composed of fused rings,and adjacent rings share two or more atoms.The restriction of bond rotation in rigid ladder-shaped polymers greatly limits their conformational freedom,so the ladder-shaped conjugated polymers have excellent properties.Ladder-shaped conjugated polymers have received extensive attention from scientific researchers.Ladder polymers consist of nonconjugated(twisted structure type)and conjugated(planar configuration)structure.Their synthesis can be divided into two general strategies: direct method and indirect method.Laddershaped conjugated polymers have been widely used in all kinds of applications,such as light emitting diodes(OLED)and organic field effect transistors(OFET).The ladder-shaped conjugated polymers have important research value and broad application in the future.The main of this paper is design and synthesis of ladder-shaped conjugated polymers containing carbazolyl benzopyrazine,providing a new route for designing and synthesising of laddershaped conjugated polymers.Main content of the paper is as follows.1.This article mainly uses a series of common organic reactions such as Friedel-Crafts acylation reaction,oxidation reaction and Suzuki coupling reaction to prepare conjugated polymers and small molecule model compounds using carbazole monomers.the model compound undergoes Friedel-Crafts acylation with a higher yield.And the Maillard reaction with phenylenediamine still has a high yield.Therefore,using these two reactions to prepare ladder-shaped conjugated polymers containing benzopyrazine bridges.Chapter 2 and Chapter3 both use 2,7-dibromocarbazole as the material.First We used the Friedel-Crafts acylation reaction,the oxidized acyl group is ?-carbonyl acid,and the esterification protects the carboxyl group to get to Suzuki reaction.Through cyclization and addition,the ladder-shaped conjugated benzopyrazine bridge-connected heterocyclic polymers.2.There may be by-products of ortho-substitution,when 2,7-bromocarbazoles undergo the Friedel-Crafts acylation reaction.This problem seriously affect the regularity of the polymer ladder-shaped conjugated polymer structure,and affecting the performance of material.Chapter4 uses 2,7-dibromocarbazole and 2-bromocarbazole as materials to prepare model compounds through a series of reactions such as Friedel-Crafts reaction,addition,Cyclization reaction and flexible side chain modification.Similar to the previous two chapters,First using the FriedelCrafts acylation reaction,the oxidized acyl group being ?-carbonyl acid,and the esterification protects the carboxyl group to get to Suzuki reaction.Finally,the model compound is synthesized.Discuss the problem of ring closure site by NMR.In order to verify the correctness of the synthesis of monomers,molecule compounds and polymers,the compounds and polymers in the three chapters were characterized by NMR,MS,GPC,and ultraviolet-fluorescence spectroscopy,using DSC,TGA and electrochemical workstation to test the thermal stability and electrochemical performance of polymers.Obviously,the poor solubility problem in the preparation process of the ladder-shaped conjugated polymers.In order to enhance the solubility,modifing the side chain of the carbazole unit.The modified compounds and polymers have good solubility in common organic solvents.