Half-sandwich ruthenium (II) p-cymene complexes based on organophosphorus ligands: Structure determination, computational investigation, in vitro antiproliferative effect in breast cancer cells and antimicrobial activity
Klaimanee, E; Nhukeaw, T; Saithong, S; Ratanaphan, A; Phongpaichit, S; Tantirungrotechai, Y; Leesakul, N
Three novel organometallic ruthenium(II) p-cymene complexes based on organophosphorus ligands, [Ru2(p-cymene)2(dppp)Cl4] (1), [Ru2(p-cymene)2(dpppe)Cl4] (2), and [Ru2(p-cymene) (dppbe)Cl4] (3), were successfully synthesized by complexation of [RuCl(p-cymene) (μ-Cl)]2 dimer with bis(diphenylphosphino)propane (dppp), bis(diphenylphosphino)pentane (dpppe), and bis(diphenylphosphino)benzene (dppbe). Complexes 1 and 2 were homo-binuclear metallic complexes comprising two distorted tetrahedral Ru(II) centers with η6-p-cymene, two chloro ligands, and the related P-donor ligand. On the other hand, complex 3 was a half-sandwich homo-binuclear metallic complex comprising a distorted tetrahedral Ru(II) center and an octahedral Ru(II) center. The complexes were characterized by single crystal x-ray diffraction, 1H NMR, ES-MS, FTIR, elemental analysis, and density functional theory. The complexes exhibited in vitro anticancer activity towards MCF-7, HCC1937, and MDA-MB-231 human breast cancer cell lines, with a much higher sensitivity than cisplatin. Complex 1 was especially effective towards these cancer cell lines, giving IC50 values of 0.3520 ± 0.02, 0.5386 ± 0.01 and 0.8944 ± 0.03 μM, respectively. Moreover, all complexes showed significant activity against the Gram-positive bacteria, Staphylococcus aureus ATCC25923 (SA) and methicillin–resistant Staphylococcus aureus (MRSA). Complex 2 shows the greatest MIC/MBC values of 1/8 μg.mL−1 and 0.5/8 μg.mL−1 for SA and MRSA inhibition, respectively. Interesting antifungal activity and antifilamentous fungal activity was also observed in complex 2. © 2021 Elsevier Ltd