An EXAFS spectroscopic study of Europium (III) complexation with dafone

Abstract An extended x-ray absorption fine structure (EXAFS) for L III Eu crystal edge at 6977 eV energy was studied on an original complex based on europium. The ligand was coordinated entirely with respect to europium atom for [Eu(dafone) 2 Cl 2 .(H 2 O) 2 ](Cl)(H 2 O), where dafone is 4,5-diazafluoren-9-one. The EXAFS spectra showed close-neighbor correlations between europium and nitrogen atoms as well as to the adjoining carbon backbones on macrocyclic cages, which resulted in the bond lengths, the Debye-Waller factor, and coordination numbers. The Eu (III) complex in vitro antibacterial efficacy on a set of Gram-negative bacteria and Gram-positive bacteria showed that the complex displays marked antibacterial behavior. The minimum complex inhibitory concentrations showed that the Eu complex displays significantly higher antibacterial impact on conventional Staphylococcus aureus and Escherichia coli bacterial strains compared to those of silver sulfadiazine and europium nitrate. The Eu (III) bacterial inhibitions are closely linked to relevant DNA binding affinities.