Coordination chemistry of copper(II) with oxaaza macrocyclic ligands. Crystal structure of a dinuclear tetramer copper(II) complex

Abstract

A new series of copper(II) nitrate and perchlorate complexes with eight different oxaaza macrocyclic ligands (L 1–L 8) have been prepared and characterised. Complexes with the diiminic ligands L 1–L 6 have been obtained by template condensation of the appropriate dialdehyde and diamine precursors; the reduced L 7 and L 8 macrocycles have been synthesised using a direct route. The overall geometry and bonding mode have been deduced on the basis of elemental analysis data, IR, FAB, UV–Vis spectroscopy, cyclic voltammetry, and conductivity and magnetic susceptibility measurements. After treatment of an acetonitrile solution of the complex [L 6Cu](ClO 4) 2·5H 2O with acetic acid 15%, dark blue single crystals, the result of a secondary reaction, were isolated and characterised as a new binuclear tetramer copper(II) complex, with formula C 13H 28ClCu 2N 3O 10.