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

ABSTRACT

Two new mononuclear nickel(II) complexes, [NiL¹(NCS)] (1) and [Ni(L²)₂]·2NO₃ (2), 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 1 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 2 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.

KEYWORDS:

• Nickel complex
• Schiff base
• crystal structure
• X-ray diffraction
• antibacterial activity

Funding

This work was financially supported by the Open Laboratory Program of Liaoning Province (Project No. cx20160102).