X-ray crystal structure of the cytotoxic planar Ni(II) complex of N-4-dimethyl-2-acetylpyridine thiosemicarbazone

Transition metal complexes of thiosemicarbazone ligands are emerging as a n ew class of non-platinum experimental anticancer chemotherapeutic compounds .(1-3) The observed cytotoxicities of the active complexes have been though t to arise from their interaction with intracellular thiols such as glutath iones (GSH) generating a thiolato Complex of the type [ML](+) which in turn is capable of promoting redox reactions with other thiols and oxygen gener ating the disulphide species (GSSG) alongwith superoxide and hydroxyl radic als.(4) The other possibility involves the binding of the drug to the enzym e, viz., ribonucleotide reductase, an obligatory enzyme for DNA synthesis, thereby hindering or blocking the DNA replication.