Biological Potential and Structure Activity Relationships in Organotin (IV) and Pd(II) Compounds
Organotin(IV) and palladium(II) complexes are mainly synthesized by treating a N,O or S donor ligand with an organotin halide and PdCl2, respectively. The structures of the complexes can be elucidated by various characterization techniques such as microanalysis (CHNS), FTIR spectroscopic analysis, UV-Visible spectroscopy, NMR (1H & 13C) and single crystal XRD. Organotin compounds are applied in numerous biocidal formulations as wood preservatives, surface disinfectants, antitumor agents, insecticides, marine antifouling paints, mollucides, miticides and fungicides. The biochemical activity is mainly affected by coordination number of tin, number and nature of the organic group bonded to tin and the chain length of an alkyl groups. Organotin(IV) dithiocarbamates are famous for their acaricidal, antifungal, tuberculostatic, antibacterial and anticarcinogenic activities. Cisplatin which is a famous Pt(II) drug, is successfully applied either alone or in various combinations to treat cancer. However, There is also a growing interest in the discovery of alternate drugs with palladium(II) because there are considerable similarities between the coordination chemistry of palladium(II) and platinum(II) compounds. However, the palladium complexes dissociate readily and form reactive species which could not reach their pharmacological targets. This drawback can be overcome by synthesizing Pd(II) complexes with chelating ligands such as dithiocarbamates. Pd(II) and Pt(II) compounds with bioactive ligands are of special interest due to their possibility of oral administration, lower toxicity and their ability to coordinate with DNA. Organotin(IV) derivatives possess strong antibacterial and antifungal potential while palladium(II) complexes are chiefly famous for their antitumor and anticancer activities. The nature of a metal coordinated to the ligand, has a decisive role in biological activities of both kinds of compounds.