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 [(eta(6)-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 [(eta(6)-arene) Ru(mu-Cl)Cl](2) (arene = C6H6, p-iPrC(6)H(4)Me or C6Me6) and [Cp*M(l-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. (C) 2014 Elsevier B.V. All rights reserved.