Eight new organometallic Ru(II)–arene complexes of the type [RuCl 2 (η 6 -arene)(η 1 - S -aroylthiourea)] (arene = p -cymene or benzene) were synthesized in order to evaluate the effect of the arene moiety and the substituent of the aroylthiourea ligand on the cytotoxicity of the complexes. The ligands (L1 and L2) and complexes ( 1–8 ) were characterized using analytical and spectroscopic (UV–visible, infrared, 1 H NMR, 13 C NMR, and mass) methods. The structure of the ligands (L1 and L2) and complexes ( 1 and 3–6 ) was obtained from single-crystal X-ray diffraction studies. The cytotoxicity of the complexes was evaluated against four different cancer cell lines: MCF-7 (breast), COLO 205 (colon), A549 (lung), and IMR-32 (neuroblastoma). All the complexes showed good cytotoxicity and the highest was in the IMR-32 cell line, which articulates the specificity of these complexes toward the IMR-32 cancer cell line. The complexes 5 , 7 , and 8 exhibited remarkable cytotoxicity in the entire cancer cell lines tested, which was comparable with the standard drug, cisplatin. The anticancer mechanism of the complexes 3 and 7 in IMR-32 cells was evaluated by bright-field microscopy, intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP), DNA damage, and caspase-3 analyses. The cells treated with the complexes showed upregulated caspase-3 compared to the control, and it was found that ROS and MMP were dose-dependent on analysis. Also, bright-field microscopy and 4′,6-diamidino-2-phenylindole (DAPI) staining have correspondingly shown cellular membrane blebbing and DNA damage, which were morphological hallmarks of apoptosis. The study concluded that the complexes promoted the oxidative stress-mediated apoptotic death of the cancer cells through the generation of intracellular ROS, depletion of MMP, and damage of the nuclear material.

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Fourteen new RuII–arene (p‐cymene/benzene) complexes (C1–C14) have been synthesized by varying the N‐terminal substituent in the furoylthiourea ligand and satisfactorily characterized by using analytical and spectroscopic techniques. Electrostatic potential maps predicted that the electronic effect of the substituents was mostly localized, with some influence seen on the labile chloride ligands. The structure–activity relationships of the Ru–p‐cymene and Ru–benzene complexes showed opposite trends. All the complexes were found to be highly toxic towards IMR‐32 cancer cells, with C5 (Ru–p‐cymene complex containing C6H2(CH3)3 as N‐terminal substituent) and C13 (Ru–benzene complex containing C6H4(CF3) as N‐terminal substituent) showing the highest activity among each set of complexes, and hence they were chosen for further study. These complexes showed different behavior in aqueous solutions, and were also found to catalytically oxidize glutathione. They also promoted cell death by apoptosis and cell cycle arrest. Furthermore, the complexes showed good binding ability with the receptors Pim‐1 kinase and vascular endothelial growth factor receptor 2, commonly overexpressed in cancer cells.

The synthesized Cu(ii) complexes, especially bimetallic complexes, exhibited versatile anticancer and enzyme-like activities.

Six different acylthiourea ligands (L1-L6) and their corresponding Ru(II)-p-cymene complexes (P1-P6) were designed to explore the structure-activity relationship of the complexes under the influence of aliphatic chain length and aromatic...