Direct electrochemical synthesis of copper(II) and zinc(II) complexes of the tetradentate ligand N,N′-bis(2-pyridinecarboxamide)-2-aminobenzylamine (H2bpabza). The crystal structures of the ligand and its Cu(II) complex

Abstract

The direct electrosynthesis of neutral copper(II) and zinc(II) complexes of a new unsymmetrical carboxamide ligand, N,N′-bis(2-pyridinecarboxamide)-2-aminobenzylamine (H2bpabza) derived from 2-pyridinecarboxylic acid and 2-aminobenzylamine, was accomplished by electrochemical oxidation of anodic metals (copper and zinc) in an acetonitrile solution of the ligand. These compounds were characterized by elemental analyses and different spectroscopic methods. The crystal and molecular structures of the ligand, H2bpabza, and its copper complex, Cu(bpabza), were determined by X-ray diffraction. The copper atom adopts a distorted square-pyramidal (4+1) CuN2N′N″O coordination geometry with bpabza2− acting as a dianionic tetradentate ligand furnishing four N atoms in the base, with the O atom of a carbonyl group from an adjacent molecule in the apical position of the coordination environment.