Spectral, electrochemical, thermal, DNA binding ability, antioxidant and antibacterial studies of novel Ru(III) Schiff base complexes

•Novel Ru(III)-NOON Schiff bases complexes.•Spectral, electrochemical and thermogravimetric studies.•Binding ability of Ru(III) complexes with calf thymus DNA.•Antioxidant activity of the novel complexes.•Antibacterial screening.

Four new air stable low spin Ru(III) complexes of the type [Ru(L1–4)(H2O)2]Cl have been synthesized, where L = dianion of the tetradentate Schiff base ligands namely N,N′bis(salicylaldehyde)4,5-dimethy-l,2-phenylendiammine (L1H2), N,N′bis(salicylaldehyde)4,5-dichloro 1,2-phenylendiammine (L2H2), N,N′bis(o-vanillin)4,5-dimethy-1,2-phenylendiammine (L3H2) and N,N′bis(o-vanillin)4,5-dichloro-1,2-phenylendiammine (L4H2). The complexes have been fully characterized by elemental analysis, infrared spectroscopy, electronic spectroscopy, magnetic susceptibility and electron spin resonance spectroscopy. Elemental analyses and spectroscopic data have been showed that, the stoichiometries of complexes were 1:1 with an octahedral geometry for all the complexes. Thermal analysis measurements indicated that the complexes have good thermal stability. The redox behavior of the complexes has been investigated by the cyclic voltammetric technique. The interaction of these complexes with calf thymus DNA (CT-DNA) was explored by different techniques which revealed that the complexes could bind to CT-DNA through an intercalative mode. Furthermore, the antioxidant activity of the Ru(III) complexes against superoxide and hydroxyl radicals was evaluated by using spectrophotometer methods in vitro. The experiments on antioxidant activity show that the complexes were found to possess potent antioxidant activity. Additionally, as a potential application the antibacterial activity of the complexes was assessed by testing their effect on the growth of various strains of bacteria.

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