STRUCTURE, SPECTRAL AND MAGNETIC BEHAVIORS OF COPPER(NIFLUMATO)(2)(N,N-DIETHYLNICOTINAMIDE)(2)

The green Cu(nif)(2)(denc)(2) (nif = niflumate, denc = diethylnicotina mide) crystallizes in the triclinic system, space group P-l with unit cell parameters: a = 7.984(2)Angstrom, b = 12.270(2)Angstrom, c = 12.9 04(3)Angstrom, alpha = 75.23(3)degrees, beta = 71.22(3)degrees, gamma = 72.04(3)degrees and Z = 2. The final R valuer far 5325 independent r eflections is equal to 0.0455. The structure is centrosymmetric. The C u(II) atom is pseudo-octahedrally trans-coordinated by four carboxylic O atoms of two niflumate anions, Cu-O bond distances being 1.955(2) ( 2x) and 2.643(2)Angstrom (2x), and by two N atoms from two N,N-diethyl -nicotinamide ligands, Cu - N bond distance is 2.007(3)Angstrom (2x). An EPR spectrum of the complex is of the axial type with g(II) > g(per pendicular to) and S = 1/2. Magnetic data of the complex obey the Curi e-Weiss law with a small positive value of the Weiss constant (6.6K) i ndicating a weak ferromagnetic interaction.