Syntheses, characterization and molecular structures of novel Ru(ii), Rh(iii) and Ir(iii) complexes and their possible roles as antitumour and cytotoxic agents

Abstract

A series of organometallic arene platinum group metal complexes of the type [(η⁶-arene)Ru(L)Cl]PF₆ {arene = benzene; p-cymene and hexamethylbenzene, L = N, N′ ligands} and [(η⁵-Cp*)M(L)Cl]PF₆ (where M = Rh(III) and Ir(III), L = N, N′ ligands) were synthesized. All complexes were isolated as hexafluoridophosphate salts and characterised by elemental analysis, infrared and NMR spectroscopy. The molecular structures of three representative complexes 1, 4 and 9 were determined by single crystal X-ray crystallography. They have a “piano stool” geometry with η⁵ and η⁶ coordination of the arene ligands. Trypan blue exclusion and DNA fragmentation assays of the synthesized complexes displayed the potent anticancer properties of complexes 5, 6 and 9. Compound 6 shows the highest antitumor activity with a T/C value of 211%.