Effective and Selective Ru(II)-Arene Complexes Containing 4,4'-Substituted 2,2' Bipyridine Ligands Targeting Human Urinary Bladder Cancer Cells

Cisplatin-based chemotherapy is a common regimen for bladder cancer, a life-threatening cancer with more than 500,000 new cases worldwide annually. Like many other metallodrugs, cisplatin causes severe side effects for its general toxicity. Organoruthenium is known for its structural stability, good anticancer activity, and possible low general toxicity. Here, we have prepared and characterized a series of water-soluble ruthenium-arene complexes with N,N'-chelating ligands: [Ru(II)-η6-arene-(4,4'-(X)2-2,2'-bipyridine)Cl]Cl (arene = p-cymene, X = C4H9 (1), COOH (2), COOCH3 (3), COOC2H5 (4); arene = benzene, X = C4H9 (5), COOCH3 (6), COOC2H5 (7)). These complexes are carefully characterized using single-crystal X-ray diffraction, UV-vis, IR, 1H NMR, and MALDI-TOF MS spectroscopy. Their DFT-calculated structural and thermodynamic properties are consistent with the experimental observations. Biophysicochemical studies of complex interaction with CTDNA and BSA supported by molecular docking simulations reveal suitable properties of 1-7 as anticancer agents. Cytotoxicities of 1-7 are evaluated on healthy human MCF-10a-breast epithelial and African green monkey Vero cells, and carcinoma human HepG-2-hepatic, T24-bladder, and EAhy-926-endothelial cells. All complexes exhibit much higher cytotoxicity for T24 than cisplatin. Particularly, 1 and 2 are also highly selective toward T24. Fluorescence imaging and flow cytometry demonstrate that 1 and 2 penetrate T24 cell membrane and induce early apoptosis at their respective IC50 concentrations, which ultimately lead to cell death. Statistical analysis suggests that the order of importance for T24 cell antiproliferation is protein binding, Log p, Ru-Cl bond length, while DNA binding is the least important. This study is the first to report the anti-bladder cancer efficacy of Ru-arene-2,2'-bipyridine complexes, and may provide insights for rational design of organoruthenium drugs in the enduring search for new chemotherapeutic agents.

Design, Synthesis, DNA/HSA Binding, and Cytotoxic Activity of Half-Sandwich Ru(II)-Arene Complexes Containing Triarylamine-Thiosemicarbazone Hybrids

Organoruthenium complexes are potent alternatives for platinum-based complexes because of their superior anticancer activity. In this investigation, a series of new Ru(II)-arene complexes with triarylamine-thiosemicarbazone hybrid ligands with higher anticancer activity than cisplatin are reported. The molecular structure of the ligands and complexes was confirmed spectroscopically and supported by single-crystal X-ray crystallography. These complexes adopted a three-leg piano stool geometry. All the Ru(II)-arene complexes were systematically investigated for their in vitro cytotoxicity against human cervical (HeLa S3), lung (A549) cancer, and human normal lung (IMR-90) cell lines using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Interestingly, a pyrrolidine-attached Ru(II)-benzene complex exhibited superior activity against cancer cells with low IC₅₀ values, and colony formation study showed complete inhibition at 5 and 10 μM concentration. Furthermore, morphological changes assessed by acridine orange and propidium iodide staining revealed that the cell death occurred by apoptosis. In addition, the interaction between synthesized Ru(II)-arene complexes and DNA/protein was explored by absorption and emission spectroscopy methods. These synthesized new organoruthenium complexes can be used for developing new metal-based anticancer drugs.

Multi-ion detection and molecular switching behaviour of reversible dual fluorescent sensor

The selective chemosensing behaviour of imidazole bisthiocarbohydrazone (IBTC) towards F^- and Cu²⁺ are studied via colorimetric, UV-Visible, fluorescence spectra studies, and binding constants were calculated. The ¹H NMR titration study strongly support that the deprotonation of IBTC followed by the hydrogen bond formation via N1H1 and N2H2 protons with fluoride ion. The fluorescence inactive IBTC-Cu complex became fluorescence active in the presence of perchlorate (ClO₄^-) ion. The selective detection of perchlorate ion was also explained. The F^- sensing mechanism of IBTC has been investigated by Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TDDFT) methods. The theoretical outcomes well reproduce the experimental results. And it concluded the NH protons, nearby the imine group was first captured by the added F^- ion and then deprotonation happened followed by the formation of hydrogen bond. The IBTC found good reversibility character with the alternative addition of Ca²⁺ and F^-. The multi-ion detection of IBTC was used to construct the NOR, OR and INHIBITION molecular logic gates.

Crystal structure of 3-[(E)-(2-hy-droxy-3-meth-oxy-benzyl-idene)amino]-1-methyl-1-phenyl-thio-urea

In the asymmetric unit of the title compound, C16H17N3O2S, there are two independent mol-ecules (A and B), which show an E conformation with respect to the C=N bond. An intra-molecular O-H⋯N hydrogen bond with an S(6) motif stabilizes the mol-ecular structure. The terminal phenyl and benzene rings are almost orthogonal to each other, the dihedral angle being 87.47 (13)° for mol-ecule A and 89.86 (17)° for mol-ecule B. In the crystal, weak bifurcated N-H⋯(O,O) hydrogen bonds link the two independent mol-ecules, forming a supra-molecular chain with a C (2) 1(14)[R (2) 1(5)] motif along the b axis. A weak C-H⋯O inter-action is also observed in the chain.

Synthesis, X-ray crystal structure, DNA/protein binding and DNA cleavage studies of novel copper(ii) complexes of N-substituted isatin thiosemicarbazone ligands

Copper(ii) complexes containing isatin thiosemicarbozone ligands have been synthesized and evaluated for its biological applications like DNA/protein binding and DNA cleavage studies.