Acetate bridged zinc(II) complexes with 5-bromo-2-[(2-ethylaminoethylimino)methyl]phenol: Syntheses, X-ray crystal structures and antibacterial potential

Three new acetate bridged polynuclear zinc(II) complexes [ZnL( μ 2 - η 1 : η 1 -OAc)] n ( 1 ), [Zn 3 L 2 ( μ 2 - η 1 : η 1 -OAc) 2 ( μ 2 - η 2 : η 0 -OAc) 2 ] ( 2 ) and [Zn 2 L( μ 2 - η 1 : η 1 -OAc) 2 (NCS)] ( 3 ), were first synthesized from 5-bromo-2-[(2-ethylaminoethylimino)methyl]phenol (HL) with different molar ratio of zinc acetate dihydrate and/or ammonium thiocyanate. The products were studied by IR and UV-Vis spectra. Structures of the complexes were confirmed by single crystal X-ray diffraction. The Schiff base ligand in its tridentate form is coordinated to zinc(II) centers via one phenolate oxygen atom, one imine nitrogen atom and one amine nitrogen atom. The zinc(II) atom in 1 is in a coordination between trigonal bipyramidal and square pyramidal. The zinc(II) atoms in 2 are in square pyramidal and octahedral geometries. The zinc(II) atoms in 3 are in trigonal bipyramidal and tetrahedral geometries. The antibacterial activity of all synthesized complexes was assayed against Gram-positive bacterial strains Bacillus subtilis , Staphylococcus aureus and Streptococcus faecalis , and Gram-negative bacterial strains Escherichia coli , Pseudomonas aeruginosa and Enterobacter cloacae , and show good activity against Bacillus subtilis , Staphylococcus aureus and Escherichia coli .