Syntheses, characterizations, X-ray crystal structures, and antibacterial activities of Co(II), Ni(II), and Zn(II) complexes of the Schiff base derived from 5-nitro-2-hydroxybenzaldehyde and benzylamine

Abstract

Three new complexes, [CoIIL2(bzln)2] (1), [NiIIL2(DMF)2] (2), and [ZnIIL2] (3), with the bidentate (NO) Schiff base HL = 2-((E)-(benzylimino)methyl)-4-nitrophenol have been synthesized and characterized. [CoIIL2(bzln)2] (1) was initially formed from the reaction of H2L1 (N,N′-bis(5-nitrobenzaldehyde)-2-aminobenzylamine = H2L1), with CoII(CH3COO)2·4H2O in the presence of benzylamine. The X-ray crystal structure of 1 revealed that HL was formed from the hydrolysis of H2L1 and the recondensation of benzylamine with 2-hydroxy-5-nitrobenzaldehyde produced in H2L1 hydrolysis. The Schiff base HL was then prepared by direct reaction of 2-hydroxy-5-nitrobenzaldehyde and benzylamine. Complexes 1–3 were also directly synthesized and their crystal and molecular structures determined by X-ray crystallography. The ligand and its metal complexes were also screened for in vitro antibacterial activity.