SYNTHESIS, SPECTROSCOPIC, CYTOTOXIC, AND DNA-BINDING STUDIES OF BINUCLEAR 2,2'-BIPYRIDINE-PLATINUM(II) AND 2,2'-BIPYRIDINE-PALLADIUM(II) COMPLEXES OF MESO-ALPHA,ALPHA'-DIAMINOADIPIC AND MESO-ALPHA,ALPHA'-DIAMINOSUBERIC ACIDS

Abstract

Four new binuclear complexes of formula [M2(bipy)2(BAA)]Cl2 (where M is Pt(II) or Pd(II), bipy is 2,2'-bipyridine, and BAA is a dianion of meso-alpha-alpha'-diaminoadipic acid (DAA) or meso-alpha-alpha'-diaminosuberic acid (DSA)) have been synthesized. These complexes have been characterized by chemical analysis and ultraviolet-visible, infrared, and H-1 NMR spectroscopy. The mode of binding of ligands in these complexes has been ascertained by infrared and detailed H-1 NMR spectroscopy. These complexes are 1:2 electrolyte in conductivity water. They have also been tested against P388 lymphocytic leukemia cells and their target is DNA molecules. [Pt2(bipy)2(DSA)]Cl2, [Pd2(bipy)2(DSA)]Cl2, and [Pd2(bipy)2(DAA)]Cl2 show I.D.50 values comparable or lower than cis-diamminedichloroplatinum(II) and [Pt(bipy)(Ala)]Cl. In addition, binding studies of [Pt2(bipy)2(DSA)]Cl2 and [Pd2(bipy)2(DAA)]Cl2 to calf thymus DNA have been carried out and the mode of binding seems to be hydrogen bonding, as suggested earlier for analogous mononuclear amino acid-DNA complexes.