Mononuclear half-sandwich cyclic-π-perimeter platinum group metal complexes having bithiazole ligands: Synthesis, molecular and anti-cancer studies

Mononuclear cationic half-sandwich arene Ru(II) and Cp∗Rh(III)/Cp∗Ir(III) compounds with the general formula [(η6-arene)Ru(L)Cl]+ and [Cp∗M(L)Cl]+ have been isolated by the reaction of bithiazole ligands {2,2′-dimethyl-4,4′-bithiazole ( dm4bt ), 2,2′-diamino-4,4′-bithiazole ( da4bt ), and 2,2′-diphenyl-4,4′-bithiazole ( dp4bt )} with the precursor compounds [(η6-arene)Ru(μ-Cl)Cl]2 (arene=C6H6, p-iPrC6H4Me or C6Me6) and [Cp∗M(μ-Cl)Cl]2 (M=Rh, Ir). These compounds were isolated as SbF6 salts and fully characterized by spectral studies. Some representative compounds were confirmed by single crystal X-ray crystallographic studies. Chemo-sensitivity activities of compounds 1, 5, 11, 12, 14 and 15 were evaluated against two human breast carcinoma cell lines (MDA-MB-231 and T47D). There is a clear SAR seen, where the iridium-based complexes with the dp4bt ligand are much more potent than the ruthenium and rhodium complexes.