Synthesis, characterization and in vitro antidiabetic activity of anionic dioxidovanadium(V) complexes

The hydrazone Schiff base ligand isonicotinic acid (2-hydroxy-3-methoxy-benzylidene)-hydrazide ligand (H2L) has been synthesized. This ligand has been used to synthesized the six dioxidovandium(V) complexes [V(O)2(L)]ImH (1), [V(O)2(L)]2-MeImH (2), [V(O)2(L)]2-EthImH (3), [V(O)2(L)]1-MeImH (4), [V(O)2(L)]BezImH (5) and [V(O)2(L)]2-MeBenzImH (6). The ligand and complexes were characterized by FTIR, UV–Vis and other spectroscopic techniques. The used hydrazone Schiff base was also characterized by 1H NMR, 13C NMR and single-crystal X-ray analysis. The Hirshfeld analysis of ligand gives the most important interactions in the ligand is the O⋯H/H⋯O interactions and N⋯H/H⋯N interactions. The contribution of these interactions to the total Hirshfeld surface area is 18.7 and 8.1% respectively. The stability of vanadium was studied using cyclic voltammetry and differential pulse voltammetry. DFT calculations were carried out to correlate the electronic structures of complexes. The geometry of the vanadium(V) centre is distorted square pyramidal and distorted trigonal pyramidal. The VO2+ entity accommodated in the ONO binding site of tridentate ligand yields [V(O2)L]- anion.The τ5 ​= ​0.759–0.770 value for 1, 2 and 3 are very close to 1 authenticating the distorted trigonal bipyramidal geometry around the V(V) centre. For complexes 4, 5 and 6 the value of τ ​= ​0.385, 0.198 and 0.010 suggesting the distorted square pyramidal geometry of V(V) centers. Antidiabetic properties of complexes were also explored using α-glucosidase, β-glucosidase and α-amylase inhibition methods. [Display omitted] •Vanadium complexes with NNO donor ligand.•Distorted octahedral geometry of complex.•Molecular Docking to study the molecular binding behaviour of all complexes.•Antidiabetic activity.