[Synthesis and spectroscopic characterization of complexes of trivalent lanthanide ions Eu(III) and Tb(III)].

Two coordination compounds formed between Eu(III) and Tb(III) with ofloxacin have been synthesized. Molecular formula Ln(oflo)3Cl3.8H2O has been deduced from elemental chemical analysis and ICP.FTIR spectroscopy shows that both carbonyl and carboxy groups may coordinate the lanthanide cation(Eu3+/Tb3+) to form a stable six-membered ring. The reaction between lanthanide and ofloxacin can be accomplished without any additional base since FTIR suggests the proton transportation from the carboxyl group to the tertiary nitrogen. The complex containing Eu3+ was proved to be excited with the broad band from 200 to 450 nm. Between the two complexes is studied, Eu3+ is the most efficiently sensitized by ofloxacin, while Tb3+ is the least. The disappearance of the ligand fluorescence and the strong emitting of Eu3+ in the complex, which is ascribed to the transitions 5D0-7F0, 5D0-7F1, 5D0-7F2 respectively, make it clear that some well energy transfer has happened. But complex Tb(oflo)3Cl3.8H2O irradiates lights from both ligand and Tb3+.