Syntheses, Crystal Structures and Antimicrobial Activity of Zinc(II) Complexes Derived from 5-Bromo-2- (((2-piperazin-1-yl)ethyl)imino)methyl)phenol

Three new zinc(II) complexes, [ZnCl2L]·CH3OH (1), [ZnClL(NCS)]·2CH3OH·0.5H2O (2), and [ZnL(NCS)2]·CH3OH·H2O (3), where L is the zwitterionic form of 5-bromo-2-(((2-piperazin-1-yl)ethyl)imino)methyl)phenol, NCS is thiocyanate anion, were facile prepared by reaction of different molar ratio of L, zinc chloride and ammonium thiocyanate in methanol. The complexes were characterized by IR and UV-Vis spectroscopy. Detailed structures of the three complexes were confirmed by single crystal X-ray determination. The Zn atoms in the complexes are in tetrahedral coordination. The Schiff base ligand coordinates to Zn atom through phenolate oxygen and imino nitrogen. The remaining two sites are occupied by two Cl for 1, one Cl and one NCS for 2, and two NCS for 3. The compounds show significant antimicrobial activities.