Synthesis, characterization, and antitumor properties of some metal complexes of 2,6-diacetylpyridine bis(N4-azacyclic thiosemicarbazones).

Complexes of Mn(II), Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Pt(II) with 2,6-diacetylpyridine bis(N4-azacyclic thiosemicarbazones), abbreviated as H2L, have been prepared and characterized by elemental analysis, molar conductance, magnetic moments (300-78 K) and spectral studies. On the basis of these studies, a distorted six-coordinate structure for Fe(L)Cl and a distorted five-coordinate structure for M(L) (M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), or Pt(II] are suggested. The ligands undergo deprotonation and appear to coordinate through the thione sulphur, the imine nitrogen and pyridyl nitrogen. All the ligands and metal complexes were screened for their antitumor activity against P 388 lymphocytic leukemia test system in mice, and it was found that a few of them possess significant activity at the dosages used.