Mononuclear half-sandwich cyclic-p-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 [(g6-arene)Ru(L)Cl]+ and [Cp⁄M(L)Cl]+ have been isolated by the reaction of bithiazole ligands {2,20 -dimethyl-4,40 -bithiazole (dm4bt), 2,20 -diamino-4,40 -bithiazole (da4bt), and 2,20 -diphenyl-4,40 - bithiazole (dp4bt)} with the precursor compounds [(g6-arene)Ru(l-Cl)Cl]2 (arene = C6H6, p-iPrC6H4Me or C6Me6) and [Cp⁄M(l-Cl)Cl]2 (M = Rh, Ir). These compounds were isolated as SbF6 salts and fully char- acterized 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.