Design And Synthesis Of Ladder-Type Conjugated Polymers Containing Carbazole Groups Via BO-Bidges

As a semiconductor material,conjugated polymers have excellent photoelectric properties.Due to they are a kind of polymer material,so conjugated polymers are also characterized by light weight,easy processing and various kinds of conjugated polymers.Design synthesis has always been a hot topic of research.Because of the ladder-type conjugated polymer is?-conjugated in its main chain,the photoelectricity and other properties are better than ordinary conjugated polymers.Therefore,the design and synthesis of ladder-type conjugated polymers have attracted the attention of researchers.The main work of this thesis is to prepare ladder-type conjugated polymers by designing a synthetic route,and carry out a series of characterization studies on its structure and properties.At the same time,it provides some method routes for the synthesis of new ladder-type polymers,and the application in the field of optoelectronic materials provides a certain scientific basis.The main contents of this article are as follows:1.This thesis mainly uses carbazole compounds as raw materials to prepare conjugated polymers and corresponding small molecule compounds a2 by Suzuki coupling reaction.After complexation of small molecular compounds,it is found that the intramolecular ring formation rate is high,so the prepared polymer was also cyclized by B-O complexation to obtain a fully conjugated ladder BO-embedded heterocyclic polymer.In the second chapter,2,7-dibromocarbazole was used as the staring material.First,the alkyl chain was attached to ensure the solubility of the compound.Then,bromine is converted into boric acid,and NBS is substituted at the 3,6-position to prepare compound a6.Oxidation of boric acid to obtain compound a7 having a hydrocyl group,since the compound having a hydroxyl group direclty has a poor polymerization effect,the hydroxyl group of compound a7 is subjected to a dehydration reaction to form an ester group,follwed by polymerization,and the time required for the polymerizaton is carried out.Short time and high yield,the obatined polymer P1 is deprotected and the ester group is changed back to the hydroxyl group,and then B-O complexes with phenyldichloroboron to final obtain the priduct P3 was 7.77×10~3 g/mol.The maximum ultravloet absorptiom peaks of ladder-type compound a3 and ladder-type polymer P3 were 366 nm and 390 nm,respectively.And the fluorescence emission peaks were 407 nm and 435 nm,respectively.The fluorescence quantum yield of P3 was 0.96.The HOMO values of the compound a3 and the ladder-type conjugated polymer P3 were-5.69 eV and-5.62 eV.The ladder-type conjugated polymer P3 has good thermal stabillity and is easily soluble in organic solvents such as dichloromethane and tetrahydrofuran,and has good photoelectric properties.2.Due to the structural characteristics of the poly(2,7-carbazole)derivative,its photoelectric properties are superior to those of poly(3,6-carbazole)derivatives,but the synthesis is difficult.This third chapter mainly synthesizes poly(2,7-carbazole)derivatives.Although it is combined with the second chapter to prepare fully conjugated ladder polymers by Suzuki coupling reaction and B-O complex intermolecuar ring formation reaction,but the use of different raw materials,this chapter is the use of o-dianisidine as the starting material,through the iodine A series of reactions such as iodine substitution,nitrification,ring closure and winding are used to prepare compound b4.As in the second chapter,it is necessary to react a methoxy group to form a hydroxyl group,and then react to form an ester group to repolymerized to prepare a polymer M1.The position of the functional group is opposite to the position of the functional group of the polymer P1,and finally the B-O complex is entangled to form a polymer M3.The number average molecular weight of the ladder-type conjugated polymer M3 was 1.08×10~4 g/mol.The maximum ultraviolet absorption peak was435 nm,the fluorescence emission peak was 476 nm,and the fluorescence quantum yield was0.98.The HOMO value of the ladder-type conjugated polymer M3 was-5.68 eV.The trapezoidal conjugated polymer M3 also has good thermal stability and is easily soluble in organic solvents such as dichioromethane and tetrahydrifuran.The two fully comjugated ladder-type BO-embedded polymers prepared in the thesis all show good performance in terms of photoelectricity,and provide a certain theoretical data basis for the development of organic photoeletric materials.