Dioxidovanadium(V)-Schiff base complexes: synthesis, structural elucidation, DNA interactions and photocatalytic dye degradation

Two dioxidovanadium(V) complexes, [VO2LH] (1) and [{VO2L}K(H2O)3] (2), containing a tridentate O, N, O donor Schiff base ligand salicylaldehyde–isonicotinoylhydrazone (H2L), have been synthesized. The synthesized ligand and corresponding complexes were structurally characterized by elemental analyses, FT-IR, UV–visible, and 1H NMR spectroscopy. Single crystal X-ray diffraction studies of the complexes (1, 2) show a distorted square pyramidal coordination environment around the metal centre. The synthesized dioxidovanadium(V) complexes were found to bind with CT-DNA in intercalative mode, with binding constant values for 1 and 2 calculated to be 1.16 × 104 M−1 and 1.08 × 104 M−1, respectively. The complexes show photocatalytic activity under visible light in the degradation of toxic cationic and anionic dyes, viz., methylene blue (MB) and rhodamine B (RhB), brilliant blue (BB), Congo red (CR), methyl orange (MO), and xylenol orange (XO) in aqueous medium.