Self-Assembly and X-Ray Crystal Structures of New Copper Complexes With Similar O,N-Donor Schiff Base Ligands and Ammonium Thiocyanate

Abstract

The self-assembly of one equivalent each of copper bromide and ammonium thiocyanate with O,N-donor Schiff base ligands 2-bromo-6-[(2-dimethylaminoethylimino)methyl]phenol (L¹) and 2-bromo-6-[(2-ethylaminoethylimino)methyl]phenol (L²) in methanol under aerobic conditions provide two mononuclear copper(II) complexes [CuL¹(NCS))] (1) and [Cu(L²)₂]·2Br (2). The complexes have been characterized by analytical and spectroscopic measurements. The crystal structures of the complexes have been determined by X-ray crystallography. In both complexes, the metal centers are in square planar coordination geometries. The L¹ ligand coordinates the metal ion through the three N,N,O donor atoms, while the L² ligand coordinates the metal ion merely through the imine-N and the phenolate-O atoms. Slight change in the terminal groups of the Schiff base ligands as well as the formation of hydrogen bonds can lead to totally different structures during the self-assembly processes.

Keywords:

• copper complexes
• crystal structures
• hydrogen bond
• mononuclear complexes
• self-assembly