Two New Schiff-Base Copper(II) and Nickel(II) Complexes: Synthesis, Structures, and Antimicrobial Activities

Abstract

Schiff base ligands 2-bromo-6-[(2-isopropylaminoethylimino) methyl]phenol (BP) and 2-ethoxy-6-[(2-isopropylaminoethylim ino))methyl]phenol (EP) and their copper(II) and nickel(II) complexes [Cu(BP)₂(μ_1,3-N₃)]_n·nClO₄ (1) and [Ni(EP)₂(dca)₂] (2) (dca = dicyanamide), have been prepared and characterized by elemental analyses, IR, and single-crystal X-ray crystallographic determination. The crystal of (1) is triclinic: space group P , a = 7.666(2), b = 8.319(2), c = 13.395(3) Å, α = 90.023(2), β = 99.742(2), γ = 99.856(2)°, V = 829.1(3) ų, Z = 1. The crystal of (2) is triclinic: space group P , a = 8.987(1), b = 9.480(1), c = 10.522(2) Å, α = 68.237(2), β = 71.906(2), γ = 82.816(2)°, V = 791.3(2) ų, Z = 1. The Schiff bases coordinate to the metal atoms through phenolate O and imine N atoms. The metal atoms in the complexes are in octahedral coordination. The effect of the complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.

Keywords:

• antimicrobial
• copper complex
• crystal structure
• nickel complex
• Schiff base

Acknowledgments

This research was supported by the National Sciences Foundation of China (No. 20676057 and 20877036) and Top-Class Foundation of Pingdingshan University (No. 2008010).