Two mononuclear nickel(II) complexes with Schiff base ligands: Synthesis, crystal structures, and antibacterial activities

Abstract

<p>Two new mononuclear nickel(II) complexes, [NiL¹(NCS)] (<b>1</b>) and [Ni(L²)₂]·2NO₃ (<b>2</b>), where L¹ is the deprotonated form of 1-[(2-ethylaminoethylimino)methyl]-naphthalen-2-ol, and L² is the zwitterionic form of 2,4-dibromo-6-[(2-ethylaminoethylimino)methyl]phenol, have been prepared and characterized by physico-chemical methods and single-crystal X-ray diffraction. The Ni atoms in both complexes are in square planar coordination. The Ni atom in <b>1</b> is coordinated by one phenolate O, one imine N, and one amine N atom of L¹ ligand and one thiocyanate N atom. The Ni atom in <b>2</b> is coordinated by two phenolate O and two imine N atoms of two L² ligands. Crystals of the complexes are stabilized by hydrogen bonds. Thermal stability of the complexes has been studied. The Schiff bases and the complexes showed potent antibacterial activities.</p