Anticancer Potential of Diruthenium Complexes with Bridging Hydrocarbyl Ligands from Bioactive Alkynols

[Image: see text] Diruthenacyclopentenone complexes of the general composition [Ru(2)Cp(2)(CO)(2){μ–η(1):η(3)-CH=C(C(OH)(R))C(=O)}] (2a–c; Cp = η(5)-C(5)H(5)) were synthesized in 94–96% yields from the reactions of [Ru(2)Cp(2)(CO)(2){μ–η(1):η(3)-C(Ph)=C(Ph)C(=O)}] (1) with 1-ethynylcyclopentanol, 17α-ethynylestradiol, and 17-ethynyltestosterone, respectively, in toluene at reflux. Protonation of 2a–c by HBF(4) afforded the corresponding allenyl derivatives [Ru(2)Cp(2)(CO)(3){μ–η(1):η(2)-CH=C=R}]BF(4) (3a–c) in 85–93% yields. All products were thoroughly characterized by elemental analysis, mass spectrometry, and IR, UV–vis, and nuclear magnetic resonance spectroscopy. Additionally, 2a and 3a were investigated by cyclic voltammetry, and the single-crystal diffraction method was employed to establish the X-ray structures of 2b and 3a. The cytotoxicity in vitro of 2b and 3a–c was evaluated against nine human cancer cell lines (A2780, A2780R, MCF-7, HOS, A549, PANC-1, Caco-2, PC-3, and HeLa), while the selectivity was assessed on normal human lung fibroblast (MRC-5). Overall, complexes exert stronger cytotoxicity than cisplatin, and 3b (comprising 17α-estradiol derived ligand) emerged as the best-performing complex. Inductively coupled plasma mass spectrometry cellular uptake studies in A2780 cells revealed a higher level of internalization for 3b and 3c compared to 2b, 3a, and the reference compound RAPTA-C. Experiments conducted on A2780 cells demonstrated a noteworthy impact of 3a and 3b on the cell cycle, leading to the majority of the cells being arrested in the G0/G1 phase. Moreover, 3a moderately induced apoptosis and oxidative stress, while 3b triggered autophagy and mitochondrial membrane potential depletion.