Spectral Analysis and Synthesis of a Series of Europium and Benzoic Acid,1,10-Phenanthroline Complexes

Binary complex was synthesized with ligands of europium and benzoic acid(BA),and ternary complex was synthesized with ligands of europium and benzoic acid(BA) and 1,10- phenanthroline(Phen).Their infrared absorption spectra,UV absorption and fluorescence spectra were studied.The results showed that UV spectra of the complexes mainly showed as a ligand absorption,energy was absorbed by ligand to transfer to center ion En~(3+).The infrared spectra of complexes were different from the ligand,the symmetry telescopic vibration of carboxyl v_s(coo-) to 1418cm~(-1),then the against symmetry stretching vibration of carboxyl v_(as)(coo-) shifted to 1562cm~(-1), that showed coordination bond was formed between europium and the ligand.Determination of fluorescence performance of the complexes and fluorescence security printing ink,ternary complex showed the fluorescence characteristics of centre ion Eu~(3+),the strongest peak of 616nm fluorescence emission spectral corresponded to ~5D_0→~7F_2 of Eu~(3+).The preparation of the fluorescence security printingink of rare earth is colorless in the visible,but it showed obvious red fluorescent in UV lamp.