Synthetic aspects, crystal structure and antibacterial activity of two new Schiff base cobalt(III) complexes

Two new Schiff base complexes of cobalt(III) viz. [Co(L)(L-1)(NCS)]ClO4 (1) and [Co(L-2)(N-3)](2)center dot 4H(2)O (2), where L = propane-1,2-diamine, L-1 = 2-IN-(2-aminopropyl)ethanimidoyllphenolate and L-2 = 2,2'-[propane-1,2-diylbis(nitriloeth-1-yl-1-ylidene)]diphenolate ion, have been prepared and characterized. The syntheses have been achieved by reacting cobalt perchlorate either with the diamine (L) and 2hydroxyacetophenone together or with their Schiff base H2L2 in presence of the respective pseudohalide. The same synthetic system has yielded two complexes of different nuclearity in presence of two different pseudohalides i.e. the mononuclear 1 with thiocyanate and the binuclear 2 with azide ion. The tridentate (L-1) and tetradentate (L-2) Schiff base anions were formed in situ to bind the Co(III) ion in case of the template syntheses. The complexes have been characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction studies. Structural studies reveal that the central Co(III) ions in both the complexes 1 and 2 adopt distorted octahedral geometry and weak intermolecular H-bonding or pi...pi. it interactions are operative to bind the complex units in the solid state. The antibacterial activity of the complexes and related compounds has been tested against some Gram(+) and Gram(-) bacteria. (C) 2011 Elsevier Ltd. All rights reserved.