The new chiral ligands (R)-/(S)-N-((1-phenylethyl)carbamothioyl)benzamide (L1/L2), (R)-/(S)-N-((1-phenylethyl)carbamothioyl)thiophene-2-carboxamide (L3/L4), and (R)-/(S)-N-((1-phenylethyl)carbamothioyl)furan-2-carboxamide (L5/L6) were synthesized, characterized, and used to prepare novel chiral Ru(II) complexes. The chiral Ru(II) complexes 1–6 were obtained from reactions between the chiral ligands L1–L6 and [RuCl2(p-cymene)2]2. The complexes were characterized by analytical and spectroscopic (NMR, FT-IR, electronic) techniques. The solid-state structures of the ligands L1 and L3 and complexes 1, 4, and 6 were determined by single-crystal X-ray diffraction methods. In all of the complexes, the ligand is bound to the Ru(II) center only via the sulfur donor atom. This monodentate coordination of the acylthiourea ligands was observed for the first time with ruthenium. The Ru(II) complexes 1–6 all act as efficient catalysts for the asymmetric transfer hydrogenation of aromatic ketones in the presence of 2-propanol and KOH to produce chiral alcohols. All of the catalysts showed excellent conversions of up to 99% and enantiomeric excesses of up to 99%.

Indole thiosemicarbazone ligands were prepared from indole-3-carboxaldehyde and N-(un)substituted thiosemicarbazide. The Ru(η 6 -p-cymene) complexes [Ru(η 6 -pcymene)(HL1)Cl]Cl (1) and [Ru(η 6 -p-cymene)(L2)] 2 Cl 2 (2*) were exclusively synthesized from thiosemicarbazone (TSC) ligands HL1 and HL2, and [RuCl 2 (p-cymene)] 2 . The compounds were characterized by analytical and various spectroscopic (electronic, FT-IR, 1D/2D NMR, and mass) tools. The exact structures of the compounds (HL1, HL2, 1, and 2*) were confirmed by single-crystal X-ray diffraction technique. In complexes 1 and 2*, the ligand coordinated in a bidentate neutral (1)/monobasic (2*) fashion to form a fivemembered ring. The complexes showed a piano-stool geometry around the Ru ion. While 2* existed as a dimer, 1 existed as a monomer, and this was well explained through free energy, bond parameter, and charge values computed at the B3LYP/SDD level. The intercalative binding mode of the complexes with calf thymus DNA (CT DNA) was revealed by spectroscopic and viscometric studies. The DNA (pUC19 and pBR322 DNA) cleavage ability of these complexes evaluated by an agarose gel electrophoresis method confirmed significant DNA cleavage activity. Further, the interaction of the complexes with bovine serum albumin (BSA) was investigated using spectroscopic methods, which disclosed that the complexes could bind strongly with BSA. A hemolysis study with human erythrocytes revealed blood biocompatibility of the complexes. The in vitro anticancer activity of the compounds (HL1, HL2, 1, and 2*) was screened against two cancer cell lines (A549 and HepG-2) and one normal cell line (L929). Interestingly, the binuclear complex 2* showed superior activity with IC 50 = 11.5 μM, which was lower than that of cisplatin against the A549 cancer cell line. The activity of the same complex (IC 50 = 35.3 μM) was inferior to that of cisplatin in the HepG-2 cancer cell line. Further, the apoptosis mode of cell death in the cancer cell line was confirmed by using confocal microscopy and DNA fragmentation analysis.

A series of 4‐substituted N‐(2‐mercaptophenyl)salicylideneimine Schiff bases were synthesized and investigated for corrosion inhibition of mild steel in hydrochloric acid medium. Inhibition through adsorption mechanism is proposed for these inhibitors, which is well supported by electrochemical impedance spectroscopy, the Langmuir adsorption isotherm and Scanning Electron Microscope morphologies of inhibited and uninhibited mild steel specimens. The negative ∆Gads indicates the spontaneous adsorption of the inhibitor on a mild steel surface. Among all the examined inhibitors, 5‐bromo‐N‐(2‐mercaptophenyl)salicylideneimine showed a higher inhibition efficiency. In order to reveal the usefulness of these Schiff bases as corrosion inhibitors under various circumstances, weight loss measurements were performed at various temperatures, acid concentrations and immersion times.

Palladium(ii) complexes featuring bidentate heterocyclic thiosemicarbazones have been synthesized, characterized and evaluated for their biomolecular interactions. The complexes induced in vitro anticancer activity through apoptosis.

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The reactions of [RuCl 2 (η 6 -C 6 H 6 )] 2 with chiral aroylthiourea ligands yielded pseudo octahedral half-sandwich "piano-stool" complexes. All the Ru(II) complexes were characterized by analytical and spectral (UV-visible, FT-IR, 1 H NMR and 13 C NMR) studies. The molecular structure of the ligands (L2 and L4) and the complexes (2, 4 and 5) was confirmed by single crystal XRD. All the complexes were successfully screened as catalysts for the asymmetric transfer hydrogenation (ATH) of ketones using 2-propanol as the hydrogen source in the presence KOH. The ATH reactions proceeded with excellent yields (up to 99%) and very good enantioselectivity (up to 99% ee). The scope of the present catalytic system was extended to substituted aromatic ketones and few hetero aromatic ketones. Density functional theory (DFT) calculations predicted non-classical, concerted transition states for the ATH reactions. The catalytic activity of Ru-benzene complexes toward asymmetric reduction of ketones was significantly higher compared to analogues p-cymene complexes. Such enhanced efficiency and the product selectivity for Ru-benzene complexes compared to Ru-p-cymene complexes were rationalized by the computational study.Electronic supplementary information (ESI) available: A table of the X-ray crystallographic data, atomic coordinates in CIF format, the molecular structure of ligands L2 & L4, 1 H NMR and 13 C NMR spectra of all the ligands and complexes, GC and HPLC data are included. Cartesian coordinates, energies, and vibrational frequencies for all the reported structures, and optimized geometries and activation free energies for high energy TSs.

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