SYNTHESIS AND CHARACTERIZATION OF PALLADIUM(II) COMPLEXES WITH THIOUREAS, HETEROCYCLIC THIONES AND PHOSPHINE DERIVATIVES

Abstract

The interaction of thioureas with metal ions has been the subject of numerous recent investigations because of their variable binding modes and because of the relevance of their binding sites to those in living systems. The complexes of palladium(II) in this regard are particularly important because of its similarity to platinum(II) complexes. Forty palladium compounds of formula [Pd(L1)2(L2)2]Cl2, where L1 = thioureas (Tu), Methylthiourea (Mtu), dimethylthiourea (Dmtu), tetramethylthiourea (Tmtu), 2-mercaptopyridine (2Mpy) and 2-mercaptopyrimidine, 6-mercaptopurine and 4-mercaptopyrimidine, L2 = Tri-p-tolylphosphine, Tri-o-tolylphosphine, Benzyldiphenylphosphine, Tris-4-chlorophenylphosphine and cyclohexyldiphenylphosphine have been synthesized by the reaction of K2[PdCl4] to phosphine and after that thiones ligands. The complexes (1), (2) and (3) were also characterized by single crystal X-ray diffraction technique. The spectral and crystallographic data suggest that the complexes show sulphur coordination of thioureas/heterocyclic thiones and phosphorous coordination of phosphines to palladium(II). The geometry of palladium(II) is distorted square planar. The antibacterial activities against bacterial strains were checked using Imipenum as reference. The antitumor ability for MCF7 tumor cell line was found comparable to that of doxorubicin. The investigated compounds have shown a relatively less cytotoxic effect in brine shrimp bioassay study. The antioxidant activity indicate potential for further study. The results designate that palladium complexes with thiones and phosphines ligands should be studied further for their use as anticancer palladium drugs in future.