Synthesis, crystal structure and antibacterial activity of a group of mononuclear manganese(II) Schiff base complexes

Abstract

Five mononuclear complexes of manganese(II) of a group of the general formula, [MnL(NCS)2] where the Schiff base L=N,N′-bis[(pyridin-2-yl)ethylidene]ethane-1,2-diamine (L1), (1); N,N′-bis[(pyridin-2-yl)benzylidene]ethane-1,2-diamine (L2), (2); N,N′-bis[(pyridin-2-yl)methylidene]propane-1,2-diamine (L3), (3); N,N′-bis[(pyridin-2-yl)ethylidene]propane-1,2-diamine (L4), (4) and N,N′-bis[(pyridin-2-yl)benzylidene]propane-1,2-diamine (L5), (5) have been prepared. The syntheses have been achieved by reacting manganese chloride with the corresponding tetradentate Schiff bases in presence of thiocyanate in the molar ratio of 1:1:2. The complexes have been characterized by IR spectroscopy, elemental analysis and other physicochemical studies, including crystal structure determination of 1, 2 and 4. Structural studies reveal that the complexes 1, 2 and 4 adopt highly distorted octahedral geometry. The antibacterial activity of all the complexes and their respective Schiff bases has been tested against Gram(+) and Gram(−) bacteria.