Biological and Catalytic Evaluation for Nickel (II) and Oxyvanadium (II) Chelates of tri-Dentate Hydrazone-Quinoxalyl Ligand

Formation of a tridentate mono-basic hydrazone-quinoxalyl ligand was done through condensation of quinoxalyl-2-carbohydrazide with 2-hydroxy-1-naphthaldehyde (H₂dip). The coordination capability of H₂dip with Ni (II) and V (IV) ions was examined at molar ratios of 1:1 leading to the synthesis of two distinct complexes, Ni(dip) and VO(dip), respectively. The chemical structure was validated by many spectroscopic techniques. The characterization included carbon, hydrogen, and nitrogen elemental analyses and assessments of magnetic properties and conductivity behavior. The inhibited effects of H₂dip (organic molecules) and its Ni (II) and V (IV) chelating agents on the constrained proliferation of three specific bacterial/fungal types, beside three established human cancer cell lines, have been evaluated in relation to the structural impact of Ni(dip) and VO(dip) compared with their free ligand (H₂dip). The research aimed to determine the nature influence of Ni (II) and V (IV) ions and the structure of their metal chelates on the binding affinity of H₂dip, Ni(dip), and VO(dip) for ct-DNA, that is, calf thymus DNA, depending on the viscometric/spectrophotometric alterations in characters. Furthermore, the assessment of binding constants (13.12, 15.19, and 14.88 × 10⁷ mol⁻¹ dm³), Gibbs free energy (−40.21, −44.51, and −45.01 kJ mol⁻¹), and chromism modes for H₂dip, Ni(dip), and VO(dip), respectively, was used to examine the interaction mechanisms of Ni(dip) and VO(dip), attributing the increased binding affinity to ct-DNA in comparison with H₂dip. The antioxidant potential was examined for H₂dip, Ni(dip), and VO(dip) within SOD (superoxide dismutase) and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays, reporting respectable antioxidant reactivity. Ni(dip) and VO(dip) chelating catalysts represented superior catalytic oxidative activity for 1,2-cyclooctene (unsaturated hydrocarbons, CyO) using hydrogen peroxide in a homogenous manner. At 80°C, the yield percentage of selective epoxy-cyclooctane (CyOO) was 90% after 3 h and 93% after 3 h in acetonitrile (the best solvent) using Ni(dip) and VO(dip), respectively. The disparity in optimum actions for these catalysts pertained to the differences in their electronegativity and Lewis's acidity, with a suggested mechanistic pathway.