Stereochemistry and antitumour activity of platinum metal complexes of 2-acetylpyridine thiosemicarbazones

Complexes, [M(HL)(2)], where M = Pd-II, Pt-II and HL = neutral 2-acetylpyridine-(2-methylthiosemicarbazone), 2-acetylpyridine-(4-methylthiosemicarbazone) and 2-acetylpyridine-(4-phenylthiosemicarbazone) as well as [M(HL)(2)]Cl-3, where M Ru-III, Rh-III and Ir-III, have been prepared and characterized by elemental analyses, conductivity measurements, magnetic susceptibility measurements and spectroscopic (i.r., Raman, u.v.-vis. and H-1 and C-13-n.m.r) studies. The ligands behave as neutral bidentate components in the Pd-II and Pt-II complexes, whereas in Ru-III, Rh-III and Ir-III complexes the ligands exist as neutral tridentates. Various ligand and nephelauxetic parameters have been calculated :br the metal complexes. The Ru-III, Rh-III and Ir-III complexes are six-coordinate distorted octahedral, whereas Pd-II and Pt-II are four coordinated. The ligands and their platinum group complexes exhibit a potent cytotoxic activity against Ehrlich ascites tumour cells in vitro but appear to be more in vivo.