Two new end-to-end single dicyanamide bridged Cu(II) complexes with Schiff base ligands: Structural, electrochemical and magnetic properties

The synthesis, crystal structures and magnetic properties of two different copper(II) complexes of formula [Cu(L-1)(dca)](n) center dot nClO(4) (1) and [Cu(L-2)](2)(dca)(ClO4) (2) [L-1 = N,N-dimethylethylene-N'-(pyridine-2-carbaldiiminato), HL2 = N,N-dimethylethylene-N-salicylaldiiminato, dca = dicyanamide anion] are described. Spectroscopic and electrochemical properties have also been discussed. A one-dimensional chain structure with single, symmetrical, mu(1,5)-dca bridges is found in compound 1. The copper atom in 1 has a square pyramidal geometry. A tridentate Schiff base ligand, having NNN donor sites, and one nitrogen atom from dca occupy the basal plane. N(18) of a neighbouring unit occupies the apical site. The Schiff base used in compound 2 is a tridentate anion with NNO donor sites, which changes the structure in a dinuclear unit of copper atoms bridged by single end-to-end dicyanamide ion. The environment around copper in 2 is square planar. Magnetic susceptibility measurements for 1 and 2 reveal the occurrence of weak antiferromagnetic interaction through the dca ligand. (c) 2005 Elsevier B.V. All rights reserved.