Syntheses, Crystal Structures, and Antibacterial Activity of New Tetranuclear Zinc(II) Complexes with Schiff Base Ligands

Abstract

Two new tetranuclear zinc(II) complexes, [Zn₄(L¹)₂(μ₂-η¹:η¹-CH₃COO)₄(μ_1,1-N₃)₂] (1) and [Zn₄(L²)₄(CH₃CH₂OH)(H₂O)] (2), where L¹ and L² are the deprotonated forms of 4-fluoro-2-((pyridin-2-ylmethylimino)methyl)phenol (HL¹) and 4-fluoro-2-((2-(hydroxymethyl)phenylimino)methyl)phenol (H₂L²), have been synthesized and characterized by elemental analysis, IR and UV-vis spectroscopy, and single crystal X-ray diffraction. X-ray crystal structural study indicated that the distances between the adjacent Zn atoms are 3.160(1)–3.353(1) Å in 1 and 3.005(1)–3.168(1) Å in 2. All zinc atoms in 1 are pentacoordinated in trigonal bipyramidal geometry, and those in 2 are in square pyramidal and octahedral geometry. The complexes and the Schiff bases were assayed for antibacterial activities against three Gram-positive bacterial strains (B. subtilis, S. aureus, and St. faecalis) and three Gram-negative bacterial strains (E. coli, P. aeruginosa, and E. cloacae) by MTT method.