Synthesis, physicochemical characterization, and cytotoxic screening of new zirconium complexes with coumarin derivatives

Zirconium complexes of mendiaxon, warfarin, coumachlor, and niffcoumar have been synthesized by reaction of the ligands with zirconium chloride in sto ichiometric ratio 1:2. The formation of the complexes has been proved on th e basis of elemental analysis, IR-spectroscopy. IH-NMR spectroscopy, and th ermal studies. Differential thermal analyses and thermogravimetric analyses have been applied to study the compositions of the new complexes. It is co ncluded that the lactone- and the keto-carbonyl groups of warfarin, coumach lor, and niffcoumar are bonded to the metal ion as bidentate ligands, but m endiaxon is bonded as monodentate ligand. Cytotoxic screening by MTT-assay was carried out. Among these compounds the zirconium complex of mendiaxon s howed highest cytotoxic activity against human promyelocytic leukemic HL-60 cells. The inorganic salt was found to be active against this cell line.