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%.