Synthesis, Structural Characterization, and Biological Activity of Two Different Nickel(II) Complexes Derived from <i>N</i>′-[1-(2-pyridyl)ethylidene]morpholine-4-carbothiohydrazide

Abstract

Abstract The reaction of Ni(OAc)2 with N′-[1-(2-pyridyl)ethylidene]morpholine-4-carbothiohydrazide (HL) afforded two nickel(II) complexes, [Ni(L)2] (1) and [Ni(L)(OAc)] (2), depending on reaction temperature and starting molar ratio; the former was a 6-coordinate, paramagnetic complex and the latter a 4-coordinate, diamagnetic complex. X-ray analysis of the complex 2 revealed that the ligands, L and OAc, were coordinated to the central metal ion to form a square-planar geometry. The complex 2 showed enhanced antimicrobial activities against selected Gram-positive bacteria, compared with those of the ligand alone, whereas the other complex 1 showed no activity.