Synthesis, crystal structures and antibacterial activities of a pair of isostructural dinuclear Schiff base nickel(II) and copper(II) complexes

Two novel dinuclear Schiff base complexes, [Ni2L2(NCS)(2)] (1) and [CU2L2(NCS)(2)] (2), where L = 2-[(2-dimethylaminoethylimino)methyl]phenolate, have been synthesized and characterized by elemental analyses, IR, and single crystal X-ray diffraction. They are structurally similar. Each of the two metal ions of the complex is coordinated by two nitrogen and two oxygen atoms in the basal plane of a distorted square pyramid and by one nitrogen atom in its apex. The oxygen atoms belong to two Schiff base ligands and form bridges between two metal ions, while the nitrogen atoms of the basal plane belong to one ligand coordinated to a given metal atom. The apex nitrogen is that of the thiocyanate anion. The Schiff base and the two complexes showed effective antibacterial activities. It is noteworthy that the two complexes have stronger antibacterial activities than that of the corresponding Schiff base ligand.