Synthesis, characterization, antiproliferative and molecular docking study of new half sandwich Ir(III), Rh(III) and Ru(II) complexes

• The new Ir(III), Rh(III) and Ru(II) complexes were synthesized and characterized.
• The Rh(III) complex has a pseudo octahedral “piano-stool” geometry.
• The hydrolysis of the complexes was investigated by 1H NMR.
• The cytotoxicity of the complexes against MCF-7 breast cancer cells was evaluated.
• Cell morphology, apoptosis, cell cycle arrest and molecular docking were studied.

The new carbazole N,N′ ligand containing [(η5-C5Me5)MCl(L)]PF6, (M = Ir (1) and Rh (2)) and [(η6-C6H6)RuCl(L)]PF6 (3) (C5Me5 = pentamethylcyclopentadienyl, L = 9-ethyl-N-(pyridine-2-yl methylene)-9H-carbazole-3-amine) complexes has been synthesized and characterized by 1H NMR, 13C NMR, 2D NMR, melting point analysis, electronic absorption, infrared spectroscopy, HR-Mass spectroscopy and elemental analyses. The crystal structure of the [(η5-C5Me5)RhCl(L)]PF6 has been confirmed by single crystal XRD. The anticancer study of the synthesized complexes 1–3 clearly showed a potent inhibitor of human breast cancer cells (MCF-7) under in vitro conditions. The inhibitory concentrations (IC50) of the complexes 1–3 were determined at low (5, 6 and 8 μM) concentration against the MCF-7 human breast cancer cell line. Further cytotoxic, cell cycle and nuclear studies confirmed that the novel half sandwich Ir(III), Rh(III) and Ru(II) complexes could be effective against MCF-7 human breast cancer cell proliferation. Moreover the results indicate that anticancer in vitro activity of complexes 1–3 falls in the order of 1 > 2 > 3. A molecular docking study of the complexes 1–3 showed the nature of binding energy, H-bond and hydrophobic interactions with the cyclooxygenase-2 (COX-2) receptor.

New Ir(III), Rh(III) and Ru(II) complexes containing a carbazole ligand showed potent cytotoxicity activity against MCF-7 cancer cells. The best cytotoxicity effects were observed for the electron rich Ir(III) and Rh(III) complexes with η5-C5Me5 as ligand (where η5-C5Me5 is the pentamethylcyclopentadienyl ligand), rather than with the η6-benzene Ru(II) complexes.Figure optionsDownload as PowerPoint slide