SYNTHESIS AND CHARACTERIZATION OF NEW SYMMETRICAL BINUCLEATING LIGANDS AND THEIR MU-PHENOXO-BRIDGED BICOPPER(II) COMPLEXES - STRUCTURAL, ELECTROCHEMICAL, AND MAGNETIC STUDIES

The new pentadentate binucleating ligands -dimethyl-2-hydroxybenzyl)-N -methylaminomethyl]-4- chlorophenol, H3L1, and xybenzyl)-N-cyclohexyla minomethyl]-4-methylphenol, H3L2, and their binuclear copper(II) compl exes of the general formulas [Cu2L1(X)] (X = OMe, OH, Br (1-3)) and [C u2L2(X)] (X = OMe, OH, Br (4-6)) have been prepared. The molecular str ucture of the complex [Cu2L1(OMe)]. MeOH was studied by X-ray crystall ography. It exists as a discrete binuclear species in which the copper atoms are in a distorted square planar environment with two oxygen br idges provided by the phenolate of the ligand and methoxy exogenous do nor and the Cu ... Cu distance is 3.030 Angstrom. A cyclic voltammetri c study of the complexes shows two quasireversible reduction waves at negative potentials. A cryomagnetic investigation on powdered samples of the complexes (1-6) shows moderately strong antiferromagnetic coupl ing (-2J in the range 120-300 cm(-1)). A comparison of the electrochem ical and magnetic properties of the complexes prepared from both ligan ds is discussed. Crystal data for the complex [Cu2L1(OMe)]. MeOH: mole cular formula C30H39ClCu2N2O5, monoclinic, space group P2(1)/c with p = 13.222(1) Angstrom, b = 15.912(1) Angstrom, c = 14.149(1) Angstrom, beta = 91.64(1)degrees, and Z = 4.