DFT studies and antioxidant activity of Schiff base metal complexes of 2-aminopyridine. Crystal structures of cobalt(II) and zinc(II) complexes

A series of metal complexes of cobalt(II) (1), copper(II) (2), nickel(II) (3), and zinc(II) (4) with Schiff base derived from 2-aminopyridine was synthesized and characterized. Molecular structures of complexes (1) and (4) were determined by single X-ray diffraction studies. The structure and electronic properties of the complexes were analyzed using DFT calculations. To determine the antioxidant properties of transition metal complexes, the anti-hemolytic and FRAP methods of antioxidant assays were used. [Display omitted] •The crystal structures of Zn(II) and Co(II) were determined by X-ray diffraction.•Electronic study of the molecule was performed aided by DFT computations.•Metal complexes exhibited significant in vitro antioxidant activity. Metal(II) complexes of cobalt(II) (1), copper(II) (2), nickel(II) (3), and zinc(II) (4) with Schiff base derived from 2-aminopyridine were synthesized and characterized. Molecular structures of complexes (1) and (4) were determined by single X-ray diffraction studies. Crystal structures of these two complexes were mononuclear. Furthermore, the metal ions were in a distorted tetrahedral environment though they were quite different. Complex 1 was made up of two ligand molecules and Co ion (CoIIL2), while complex 4 can be described as ZnL(O-NH2-Py) Br. The structure and electronic properties of the complexes were analyzed using DFT calculations. Moreover, all four complexes were studied with respect to their antioxidant activities.