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A new series of pincer type ruthenium(II) Schiff base complexes namely [Ru(CO)(PPh3)2(L1‒6)] (1–6) (where, L1‒6 ​= ​NOO ‒ donors of tri-dentate ligands) have been synthesized from ruthenium precursor such as [RuHCl(CO)(PPh3)3] containing tri-dentate Schiff bases ligands (H2L1‒H2L6). These ruthenium complexes were analyzed by elemental analysis and diverse characterizations such as FT‒IR, UV–Vis and NMR (1H and 31P) spectroscopy studies. The crystal structure of one of the complexes 5 ([Ru(CO)(PPh3)2L5]) was determined by single crystal X‒ray crystallography that revealed pincer type of coordination mode of complexes. Furthermore, complexes 1–6 have been utilized for transfer hydrogenation of aromatic ketones to secondary alcohols in the presence of i‒PrOH/KOH. The catalytic efficiency of complexes showed an efficient for transfer hydrogenation of ketones with alcohol as moderate to high conversions.

N, N-[(diethylamino)(thiocarbonyl)]-substituted benzamidine ligands have been synthesized from the reaction of N, N-[(diethylamino)(thiocarbonyl)]benzimidoyl chloride with functionalized amines such as 2-aminophenol and 2-picolylamine. The reaction of N, N-[(diethylamino)(thiocarbonyl)]-2-hydroxyphenylbenzamidine ( H 2 L 1) with ruthenium(II) precursor [RuHCl(CO)(PPh3)3] afforded complex 1 of the type [Ru(L1)(CO)(PPh3)2] in which the ligand coordinated in tridentate ONS mode. The reaction of H 2 L 1 with copper precursor [Cu(CH3COO)(PPh3)2] induced C═N bond cleavage of the ligand and afforded complex 3 of the type [Cu(1,1-DT)(Cl)(PPh3)2] (1,1-DT = 1,1-diethylthiourea) in which the ligand coordinated in a monodentate fashion. The ligand N, N-[(diethylamino)(thiocarbonyl)]-2-picolylbenzamidine ( HL 2) reacted with ruthenium(II) and copper(I) precursors to form complex 2 of the type [Ru(1,1-DT)(Cl2)(CO)(PPh3)2] and complex 3, respectively, in which the ligand underwent C═N cleavage and coordinated in a monodentate fashion via C═S group. In complexes 1 and 2, the two triphenylphosphine co-ligands coordinated in trans position whereas, in complex 3, the two triphenylphosphine co-ligands coordinated in cis position. All the compounds were characterized using infrared, UV-visible, (1H, 13C, 31P) NMR, ESI-MS and elemental analyses. The molecular structures of ligand H 2 L 1 and complexes 1- 3 were determined using X-ray crystallography, which confirmed the coordination mode of the ligands with metals. The crystal structure of complexes 1 and 2 revealed a distorted octahedral geometry around the ruthenium ion and the structure of complex 3 indicated a tetrahedral geometry around the copper ion. With the X-ray structures, density functional theory computations were carried out to determine the electronic structure of the compounds. The interactions of complexes 1- 3 with calf thymus DNA and bovine serum albumin protein were investigated using UV-visible and fluorescence spectroscopic and viscometric methods. Catecholase- and phosphatase-like activities promoted by complexes 1- 3 under physiological conditions have been studied. In vitro anticancer activities have been demonstrated by MTT assay, acridine orange/ethidium bromide and diamidino-2-phenylindole staining against various cancerous cell lines. [ABSTRACT FROM AUTHOR]

A serious of new dissymmetric ruthenium(II) carbonyl complexes of the type [Ru(CO)(EPh3)(L1-2)] (1-4), [E = P or As; L1 = N4-(2-Hydroxy-5-chlorobenzylidene)-2-amino-5-chlorobenzophenone thiosemicarbazone; L2 = N4-(2-Hydroxynaphthalene-1-carbaldehyde)-2-amino-5-chlorobenzophenone thiosemicarbazone] have been synthesized and characterized by several spectroscopic studies. The molecular structure of the ligand L1 and the ruthenium(II) carbonyl complexes (2, 4) have been analyzed by single crystal X-ray studies, and found that the ruthenium(II) complexes possess a distorted octahedral geometry. The DNA binding studies such as emissive titration, Ethidium bromide/Methylene blue (EB/MB) displacement assay and viscometry measurements revealed that the ruthenium(II) complexes bound with calf thymus DNA through intercalative mode with relatively high binding constant values. Further, the interactions of the complexes with bovine serum albumin (BSA) were also investigated using fluorescence spectroscopic methods, which showed that the new complexes could bind strongly with BSA. The complexes (1-4) were tested for DNA and BSA cleavage activities, and the results showed that the complexes exhibited good cleavage properties. In addition, the newly synthesized ruthenium(II) complexes possess better in vitro cytotoxic activities against various cell lines (MCF-7, Hop62, MDA-MB-435) and AO/EB staining method showed that these complexes induced apoptosis of MCF-7 cell lines. [ABSTRACT FROM AUTHOR]

The complete mol-ecule of the title compound, C22H16N2O2, is generated by a crystallographic inversion centre at the mid-point of the central N-N bond. Two intra-molecular O-H⋯N hydrogen bonds occur.