Copper, zinc, and nickel complexes derived from 3-methyl-2-((pyridin-2-ylmethylene)amino)phenol: syntheses, characterization, crystal structures, and urease inhibitory activity

Five copper(II), zinc(II) and nickel(II) complexes, [Cu₂L₂(μ _1,1-N₃)₂] (1), [Zn₂L₂(μ ₂-η ¹:η ¹-CH₃COO)(NCS)]EtOH (2), [Zn₂L₂(μ ₂-η ¹:η ¹-CH₃COO)(N₃)]MeOH (3), [Zn₂Cl₂L₂] (4) and [NiL(HL)]ClO₄ (5), were prepared from the Schiff base 3-methyl-2-((pyridin-2-ylmethylene)amino)phenol (HL). The compounds have been characterized by physico-chemical methods including elemental analysis, IR, and UV–Vis spectra. Structures of the five new complexes were determined by single crystal X-ray diffraction. The copper ions in 1 are in square pyramidal, while zinc ions in 2, 3, and 4 are distorted square pyramidal, and the nickel ions in 5 are octahedral. The biological assay indicated that zinc complex 2 has the most effective activity on Jack bean urease with IC₅₀ = 1.7 ± 0.8 μmol·L⁻¹. Molecular docking was performed to study the interaction between the active center of the urease with molecules of the complexes.