Synthesis, Characterization, Crystal Structures, and Antibacterial Activity of Polynuclear Nickel(II) and Copper(II) Complexes with Similar Tridentate Schiff Bases

Abstract

An end-on azido-bridged dinuclear nickel(II) complex [Ni₂(L¹)₂(μ_1,1-N₃)₂] · CH₃COOH (I) and an end-on azido-bridged polynuclear copper(II) complex [CuL²(μ_1,1-N₃)]_n, where L¹ is the deprotonated form of 2-[(2-ethylaminoethylimino)methyl]-4-fluorophenol and L2 is the deprotonated form of 2-[(2- dimethylaminoethylimino)methyl]-4-fluorophenol, were prepared and characterized by elemental analysis and FT-IR spectra. Crystal and molecular structures of the complexes were determined by single crystal X-ray diffraction method (CIF files CCDC nos. 942641 (I) and 942642 (II)). Single crystal X-ray structural studies indicate that the Schiff base ligands coordinate to the metal atoms through phenolate oxygen, imine nitrogen, and amine nitrogen. The Ni atoms in the nickel complex are in octahedral coordination, and the Cu atoms in the copper complex are in square pyramidal coordination. Crystals of the complexes are stabilized by hydrogen bonds. The Schiff bases and the complexes showed potent antibacterial activities.