Synthesis and characterisation of platinum(IV) polypyridyl complexes with halide axial ligands

A series of complexes of the type [Pt(PL)(AL)(X)2]2+ (where PL = 1,10-phenanthroline, 5-methyl-1,10-phenanthroline or 5,6-dimethyl-1,10-phenanthroline; AL = 1S,2S-diaminocyclohexane and, X = Cl, Br or I) with anticancer potency, were synthesised in a one pot reaction using N-halogensuccinimide (NXS) as both the source of the ligand and the oxidizing reagent. It was determined that 2.4 equivalents of NXS resulted in 100% oxidation of Pt(II) in a solution of equal parts H2O, ethanol and 1 M HCl. This method of oxidation was 24 times faster than the established peroxide method resulting in the acceleration of the complete synthesis of [Pt(PL)(AL)(X)2]2+. All structures were confirmed using NMR, ESI-MS, CD and UV, while the purity was confirmed by microanalysis. The in vitro cytotoxicity assays revealed that they were more active than analogous complexes with hydroxido axial ligands, and share comparable activity with the corresponding Pt(II) complex.