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.