Synthesis And Properties Of Novel Polyesters Containing 8-Hydroxyquinoline Side Groups And Zinc And Aluminum Complexes

Seven novel polyesters containing 8-hydroxyquinoline side groups（P15～P21） have been synthesized through nitration,acyl chloride,polycondensation,reduction and condensation reactions using isophthalic acid as the starting material.And then they are reacted with zinc acetate and aluminum chloride respectively to obtain fourteen kinds of zinc complexes（P15-Zn～P21-Zn）and aluminum complexes（P15-Al～P21-Al）.Structure and property of the polyesters and zinc and aluminum complexes have been characterized by elemental analysis,ICP,FT-IR,UV-vis,¹H NMR,GPC,TG,DSC and fluorescence spectroscopy.P15～P18 are partially soluble in CH₃OH,CH₂Cl₂,CHCl₃and THF（P18 are soluble in THF）.P19～P21 can be partially dissolved in CH₃OH and soluble in CH₂Cl₂,CHCl₃ and THF.P15～P21 are all soluble in DMF,DMSO,DMAC and NMP.After coordinated with zinc and aluminum,the solubility of polyesters decreased,P19-Zn～P21-Zn and P15～Al～P18-Al are partially dissolved in CH₃OH,CH₂Cl₂,CHCl₃ and THF.P15-Zn～P21-Zn and P15～Al～P18-Al are partially dissolved in DMF,DMSO,DMAC and NMP.P19～Al～P21-Al are soluble in DMF,DMSO,DMAC and NMP.Introducing ether chains can improve solubility of polyesters and their zinc and aluminum complexes.Solubility of aluminum complex is better than zinc complex.The mass average molar mass（M_w）of P15～P21 is between17887～32212 g/mol,while their polymer dispersity index（PDI）is at around 1.20～2.04.The5%decomposition temperature(T_5d)of seven polyesters is between 265.4～308.3°C,while T_5dof fourteen metal complexes is at around 287.4～352.5°C.T_5d of aluminum complex is greater than corresponding zinc complex and T_5d of metal complexes is higher than corresponding polyesters,indicate that their thermal stability have been improved after coordination.The glass transition temperature（T_g）of polyesters is at around 62.3～121.8°C,and T_g of metal complexes is all higher than 180°C,which is beneficial to used as optoelectronic functional materials.The DMF solutions(5×10^-5 mol/L)of P15～P21 emit purple fluorescence at around413～425 nm.The DMF solutions(5×10^-5 mol/L)of P15-Zn～P21-Zn and P15-Al～P21-Al emit intense green fluorescence at around 508～522 nm and 485～505 nm,respectively.P15-Zn～P21-Zn and P15-Al～P21-Al in solid state emit strong green fluorescence at around525～537 nm and 502～527 nm,respectively.The fluorescence quantum yields of P15～P21,P15-Zn～P21-Zn,P15-Al～P21-Al are 5.5～10.9%,21～31%and 23～35%,respectively.The fluorescence emission wavelength of polyesters has been significantly red-shifted,meanwhile intensity of their emission peak and fluorescence quantum yields have been increased to achieve purpose of modification after coordination.In this paper,seven novel polyesters containing 8-hydroxyquinoline side groups（P15～P21）and fourteen metal complexes（P15-Zn～P21-Zn and P15-Al～P21-Al）were synthesized.They all have good solubility and thermal stability.The zinc complexes and aluminum complexes have good green-light emitting performance and provide new light-emitting materials for the field of photoelectric materials.