Synthesis, crystal structures, and antibacterial activities of manganese(II) and copper(II) complexes derived from 2-bromo-4-chloro-6-[(2-hydroxyethylimino)methyl]phenol

Abstract

ABSTRACTReaction of the tridentate Schiff base 2-bromo-4-chloro-6-[(2-hydroxyethylimino)methyl]phenol (HL) with manganese and copper salts in the presence of ammonium thiocyanate in methanol afforded a new mononuclear complex, [MnL2]·0.5H2O (1), and a new dinuclear complex, [Cu2L2(NCS)2] (2). The complexes were characterized by single-crystal X-ray diffraction, FT-IR, and elemental analysis. The Mn atom in complex 1 is coordinated by two tridentate Schiff base ligands, forming octahedral coordination. The Cu atom in complex 2 is coordinated by one tridentate Schiff base ligand, and two thiocyanate ligands, forming square pyramidal coordination. The free Schiff base and the complexes were assayed for antibacterial activities. Both complexes are more active against the bacteria than the free Schiff bases. Complex 2 has the MIC value of 0.20 μg mL−1 against Bacillus subtilis.