Di-μ-oxidovanadium(V) di-nuclear complexes: Synthesis, X-ray, DFT modeling, Hirshfeld surface analysis and antioxidant activity

Abstract

In this work, two di-μ-oxidovanadium(V) complexes, [(L1H)VO(μ-O)]2 (C1) and [(L2H)VO(μ-O)]2 (C2), with tridentate Schiff base ligands, [N-(2-hydroxyethylamino)ethyl]-5-methoxysalicylaldimine (L1H) and 2-[(2-(2-Hydroxyethylamino) ethylimino)methyl] phenol (L2H), respectively, were prepared and characterized by various spectroscopic techniques. The X-ray diffraction of C1 showed six-coordinate vanadium in a distorted octahedral geometry with the imine, phenolate and amine donors of the ligand and two oxo-group bonds. Density functional theory (DFT) was carried out using B3LYP level with the 6-31G basis set in order to predict the molecular structure of C1, delineate its vibrational wavenumbers and define the theoretical NMR shifts, which were performed with the GIAO approach. Thereafter, Hirshfeld surface (HS) and 2D fingerprint analysis were used to investigate the intermolecular contacts in the C1 complex. The DPPH free radical scavenging assay was used to evaluate the antioxidant activity of both C1 and C2 complexes.