Synthesis, structure and properties of a dicopper(II) complex

A dinuclear copper(II) complex, [Cu-2(bhsNO(2))(2)(H2O)(2)] was isolated by reacting Cu(O2CCH3)(2). H2O and 2-hydroxy-5-nitrobenzaldehyde benzoylhydrazone (H(2)bhsNO(2)) in methanol, The X-ray structure of the complex has been determined. The dinegative ligands bind the Cu(II) ions through the deprotonated amide-O, imine-N and phenolate-O atoms. The pair of Cu(II) ions are linked by the two phenolate-O atoms. The coordination geometry around each Cu(II) is square pyramidal. The imine-N, amide-O and the bridging phenolate-O atoms form the square plane and the oxygen atom of a water molecule occupies the axial coordination site. The complex is redox active. Variable temperature (25-300 K) magnetic susceptibility measurements in the solid state are consistent with an antiferromagnetic interaction between the two metal centres. The coupling constant J is found to be -186(5) cm(-1) by least-squares fitting of the magnetic susceptibility data using an expression derived from the isotropic spin Hamiltonian, H = -2JS(1). S-2 (S-1 = S-2 = 1/2). (C) 1999 Elsevier Science Ltd. All rights reserved.