Synthesis, crystal structure, DFT calculations, protein interaction, anticancer potential and bromoperoxidase mimicking activity of oxidoalkoxidovanadium(V) complexes

The tridentate ONO donor ligand, dipicolinic acid (H2L), upon reaction with [(VO)-O-IV(acac)(2)] in various alcoholic media (ROH = ethanol/n-propanol/n-butanol) yields a series of homologous water soluble mononuclear oxidoalkoxidovanadium(V) complexes 1-3 of general formula [VOL(OR)(H2O)] [R = Et (1), n-Pr (2), and n-Bu (3)]. All the synthesized complexes have been characterized by elemental analysis, various spectroscopic (IR, H-1 NMR, and UV-vis) techniques, cyclic voltammetry and TG/DT analysis. The molecular structures of complexes 1 and 2 are successfully established by the single-crystal X-ray diffraction technique. The vanadium centre occupies a distorted octahedral environment in the complexes. DFT calculations are carried out to estimate the bond parameters, non-covalent interactions and to obtain the frontier orbitals for complexes 1-3. The binding interaction of the complexes with BSA protein is studied by employing spectroscopic methods (absorption, fluorimetric titration, and circular dichroism) and molecular docking. The water soluble complexes 1-3 can be employed as efficient anticancer agents against human breast adenocarcinoma (MCF-7) cancer cells. The bromoperoxidase (VHPO) activities of the complexes 1-3 have been demonstrated through their efficient catalytic performance in the oxidative bromination of thymol. Both the biological and catalytic activities of the complexes are found to show strong dependence on their molecular structures.