Synthesis, Characterization and Properties of Complexes based on Ligand Ethylenediamine -N,N-di(4-acetamide benzoic acid)-diacetate

The ligand ethylenediamine-N,N-di(4-acetamide benzoic acid)-diacetate(H4L) is synthesized by acylation reaction of ethylenediamine tetraacetic acid dianhydride and p-amniobenzoic acid. A series complexes were prepared after the reaction of the ligand with rare earth ions Gd3+，Sm3+，Eu3+ and transition metal ions Mn2+,Fe3+ respectively. The complexes were characterized by IR, UV-Vis, element analysis and TG-DTA. The results showed that the chemical composition of the complexes is confirmed to be M(HL)?3H2O（M=Sm3+, Eu3+,Gd3+,Fe3+）or M(H2L)?3H2O（M=Mn2+）. The fluorescence emission spectra of the complexes were measured and investigated, there is no characteristic emission peak of ion in fluorescence emission spectrum for Gd(HL)?3H2O, while emission peak of 5D07F3 transition is the strongest at 618 nm for the complex Eu(HL)?3H2O. The longitudinal relaxivity time T1 of Gd complex was 7.43 mmol/(L?s),which was more greater than small molecular weight complex Gd-DTPA.