Synthesis, characterization and DNA interaction studies of complexes of lanthanide nitrates with tris{2-[(3,4-dihydroxybenzylidene)imino]ethyl}amine

A new tripodal, hydroxyl-rich ligand, tris{2-[(3,4-dihydroxybenzylidene)imino]ethyl}amine (L), and its complexes with lanthanide nitrates were synthesized. These complexes which are stable in air with the general formula of [LnL(NO3)(2)]NO3 center dot H2O (Ln=La, Sm, Eu, Gd, Y) were characterized by molar conductivity, elemental analysis, IR spectra and thermal analysis. The NO3- groups coordinated to lanthanide monodentately, and the coordination number in these complexes may be 8. The interaction of complexes with DNA were investigated by ultraviolet and fluorescent spectra, which showed that the binding mode of complexes with DNA was intercalation, and the binding affinity with DNA were La(III) complex > Sm(III) complex > Eu(III) complex > Gd(III) complex > Y(III) complex. Based on these results, it can be shown that the La(III)complex is promising candidate for therapeutic reagents and DNA probes. (C) 2007 Elsevier B.V. All rights reserved.