Synthesis, characterization of α-oxopentanedioic acid-isonicotinoyl hydrazone rare earth-complexes and relaxivity of Gd-complex

alpha-Oxopentanedioic acid isonicotinoyl hydrazone (H2L) and its five rare earth complexes were synthesized with a view to further investigating MRI activities of the polyearboxylic Schiff base complexes. The complexes were characterized on the basis of elemental analyses, IR, UV, H-1 NMR spectra and thermal analyses. The general formula of the complexes is [Ln(HL) (H2O)(2)](Cl2H2O)-H-. (where Ln(III) = La, Pr, Nd, Eu and Gd). In addition, the relaxivity (R-1) of the Gd-complex was determined by INVREC Au program.