Study On The Construction Of Novel Functional Polymers Containing Pyridine Structure By Multi-component Polymerization

Ideal polymerization reactions are expected to generate polymeric products with desired structures in high yields from readily accessible reactants through fast and facile procedures.However,conventional polymerization methodologies possess disadvantages including pre-activation,harsh reaction conditions,tedious protection–deprotection procedures,and toxic byproducts.Therefore,development of novel and efficient polymerization method to functional polymers with well-defined structures and unique properties has important academic significance and potential industrial application value.Multi-component reactions?MCRs?or multi-component tandem reactions?MCTRs?with advantages such as simple operation and high atom economy,have be recognized as very powerful techniques for rapid synthesis of structurally diverse organic compounds.Based on our own previous study results,and inspired the recent develop ments in MCRs and MCTRs,a series of novel functional polymers containing4-aryl-2,6-diphenylpyridyl moieties such aromatic polyamides,hyperbranched p olyamides,poly?aryl cyano diyne?s and hyperbranched poly?aryl cyano triyne?s have be developed through one-pot,multi-component or multi-component tande m polymerization reaction based on new internal alkynes,as well as dibromide,tribromide and diiodide monomers containing 4-aryl-2,6-diphenylpyridyl unit i n this study,respectively.The main research content includes four parts as follows:1.Aromatic benzaldehyde,4-bromoacetophenone and ammonium acetate ar e used as raw materials to synthesize 4-bromo-2,6-diphenylpyridine dibromide compound through the reaction of qiqibabine,and then separate them Coupling with phenylacetylene to produce internal diyne monomer containing 4-aryl-2,6-diphenylpyridine structure.Then,the internal diyne and p-dibromobenzene,as well as K₄[Fe?CN?₆]were subjected to three-component polymerization reaction to synthesize a series of poly?aryl cyano diyne?s functional polymers with A IE phenomenon.Studies have shown that the synergistic effect of trifluorometh yl,methoxy and methyl,as well as the pyridine ring,gives this type of poly mer higher solubility and heat resistance?5%of the weight loss temperature i s above 260°C?In addition,this series of polymers exhibits obvious ultraviol et absorption in the range of 302-331 nm,has good fluorescence properties,a nd has a quantum yield of 17.06-19.73%.2.Using 4-trifluoromethyl benzaldehyde,4-nitroacetophenone and ammoniu m acetate as raw materials,4-?4-trifluoromethylphenyl?-2,6-was synthesized thr ough the reaction of zizibabin bis?4-nitrophenyl?pyridine,followed by Pd/C and hydrazine hydrate as catalyst,to prepare 4-?4-trifluoromethylphenyl?-2,6-bis?4-a minophenyl?pyridine Then,4-?4-trifluoromethylphenyl?-2,6-bis?4-iodophenyl?pyrid ine?MPIPP?is obtained by diazotization and iodine"one pot"method;on this basis,Through carbonylation polycondensation reaction,MPIPP and six diffe rent aromatic diamines and carbon monoxide were condensed in three compon ents to prepare a series of polyaromatics containing 4-aryl-2,6-diphenylpyridine structural unit in the main chain Amide.The prepared polymer has high mol ecular weight and good solubility.It can be dissolved in strong polar solvents such as DMF,DMAc,NMP,DMSO,etc.at room temperature,and has good solubility in medium polar solvent THF.In nitrogen atmosphere,the 5%ther mal weight loss temperature is above 301.3°C,and the carbon residual rate a t 800°C is above 42.2%;when the wavelength is 500 nm,the light transmit tance of the polymer is above 74.2%,indicating that the polymer Has better li ght transmission.3.Using 4-bromobenzaldehyde,4-bromoacetophenone and ammonium aceta te as raw materials,2,4,6-tris?4-bromophenyl?pyridine was prepared by the reac tion of zizibabin.Then,according to the similar polymerization method describ ed above,a series of hyperbranched polyaramides containing pyridine structure s were synthesized.This series of polymers has good heat resistance and solu bility.In addition,this series of polymers has UV absorption in the range of326-349 nm.The UV absorption caused by the carbonyl n-?*transition cause s the polymer to show double absorption peaks.4.Using the synthesized 2,4,6-tris?4-ethynylphenyl?pyridine as the monomer,and using the similar three-component polymerization method described above,the hyperbranched poly?aryl cyano triyne?s with pyridine structure and AIE p henomenon was also obtained Triyne.Compared with the above polyarylcyandi enediynes,the solubility and heat resistance of this series of polymers have be en significantly improved;all polymers exhibit ultraviolet absorption around 316 nm;in addition,the polymers are crystalline substances.