Synthesis And Properties Of Rare Earth Coordination Polymers Containing Tridentate Ligand Polyester Of1,3,4-oxadiazole

In this paper,2,6-bis-(2-methyl acetate sulfide-1,3,4-oxadiazole)-pyridine (4) wassynthesized by esterifation, alkylation, cyclization, substitution with2,6-pyridinedicarboxylicacid as raw materials. Polyester (P) containing1,3,4-oxadiazole was synthesized bytransesterification with the1,6-hexylene glycol. Rare earth coordinate polymers, P-Sm-Q,P-Eu-Q, P-Tb-Q, P-Dy-Q, were synthesized by coordination with polyester P,8-hydroxyquinoline and rare earth metal iones as the ratio of2:1:1. The structure andproperties of the rare earth coordinate polymers were confirmed by IR, UV-vis,1H NMR, MS,GPC, EL and fluorescence. Mwof P is11240g/mol, and PDI is2.14. The results of IR,1HNMR and EL showed that the ratio of P,8-HQ and rare earth was2:1:1. The rare earthcoordinate polymers, P-Sm-Q, P-Eu-Q, P-Tb-Q, P-Dy-Q, can be dissolved in DMF, DMSO,DMAc and NMP, indicating that they showed well solubility. Tested by TG,5%weight losstemperature of the rare earth coordinate polymers were at the172.7-208.6℃. There weretwo steps in the process of weight loss of rare earth coordinate polymers. First, the maximumweight loss temperature at the347.7-394.2℃, char yield in the11.2-11.6%; second, themaximum weight loss temperature at the600.2-639.2℃, char yield in the42.8-43.9%,indicating that they showed considerable thermal stability. The fluorescence spectra of rareearth coordinate polymers showed that the wavelength fluorescent maximum emission peaksof rare earth coordinate polymers were at550nm indicating that they emited yellowgreen andcolor of rare earth metal ions, and598nm,619nm,491nm and482nm, the fluorescence colorof Eu3+, Tb3+, Sm3+, Dy3+were red, green, orange red and bluish green, respectively. Thepolymester containing1,3,4-oxadiazole has many advantages of easy processing, considerablethermal stability. Rare earth coordination polymers show good solubility, considerablethermal stability, and fluorescence property, which can be used in the field of opticalfunctional polymer material.