SYNTHESIS, STRUCTURAL CHARACTERIZATION, AND BIOLOGICAL-ACTIVITY OF 2 DIFFERENT NICKEL(II) COMPLEXES DERIVED FROM PYRIDYL)ETHYLIDENE]MORPHOLINE-4-CARBOTHIOHYDRAZIDE

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