Syntheses, crystal structures, and antimicrobial activities of tetranuclear Ni₄ and Ni₂Zn₂ complexes derived from tetradentate Schiff bases

Abstract

Two new homo-tetranuclear nickel(II) complexes, [Ni4(L¹)₄(CH3OH)4] (1) and [Ni4(L²)₄(CH3OH)4] (2), and two new hetero-tetranuclear nickel(II)-zinc(II) complexes, [Ni₂Zn₂I₂(L¹)₂(μ_1,1-N₃)₂]CH₃OH (3) and [Ni₂Zn₂Cl₂(L²)₂(μ_1,1-N₃)₂]H₂O (4), where L¹is the deprotonated form of 4-tert-butyl-2-(3-ethoxy-2-hydroxybenzylideneamino)phenol (HL¹) and L² is the deprotonated form of 4-tert-butyl-2-(2-hydroxy-3-methoxybenzylideneamino)phenol (HL²), have been synthesized. Structures of the complexes were characterized by elemental analysis, IR and UV-Vis spectroscopy, and single crystal X-ray diffraction. The Ni ions in the complexes are in octahedral coordination, and the Zn ions are in distorted square pyramidal coordination. The compounds were evaluated for their antibacterial (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas fluorescens) and antifungal (Candida albicans and Aspergillus niger) activities by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method.

KEYWORDS:

• Schiff base
• nickel complex
• zinc complex
• crystal structure
• antimicrobial activity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the high level cultivation project of Liaoning Normal University (grant number GD19L005).