Synthesis and Characterization of trans-Dichlorotetrakis(imidazole)cobalt(III) Chloride: A New Cobalt(III) Coordination Complex with Potential Prodrug Properties.

Numerous therapies for the treatment of cancer have been explored with increasing evidence that the use of metal-containing compounds could prove advantageous as anticancer therapeutics. Previous works on Ru(III) complexes suggest that structurally similar Co(III) complexes may provide good alternative, low-cost, effective prodrugs. Herein, a new complex, trans-[Co(imidazole)4Cl2]Cl (2), has been synthesized in high yields utilizing ligand exchange under refluxing conditions. The structure of 2 has been characterized by elemental analysis, 1H and 13C·NMR, ESI-MS, CV, and UV-Vis. The ability of 2 to become reduced in the presence of ascorbic acid was probed demonstrating the likely reduction of the Co(III) metal center to Co(II). In addition, preliminary cell line testing on 2 shows a lack of cytotoxicity.