Crystal structure and magnetic properties of a (mu-hydroxo)(mu-acetato) dicopper(II) complex

[Cu-2(L)(O2CMe)]. H2O (L = 1,3-Bis(2-Hydroxy-1-napthylideneamino)propan-2-o l) was synthesized and its crystal structure determined. (C27H23N2O5Cu2). H 2O, monoclinic, space group P2(1)/c, a = 11.795(3), b = 17.988(5), c = 12.0 05(6) Angstrom, beta = 109.99(3)degrees, V = 2393(2) Angstrom(3), Z = 4. Tw o copper(II) ions in a square-planar coordination are bridged by alkoxide a nd acetate oxygen atoms to form a dinuclear unit. The metal coordination sp here is four-coordinate, planar with an NO3 donor set. The dihedral angle b etween the two coordination planes is 6.34(9)degrees. The copper(II) center s are separated by 3.492(2) Angstrom and weakly antiferromagnetically coupl ed (-2J = 163.6 cm(-1)), which follows from temperature-dependent magnetic susceptibility measurements in the temperature range 3.6 to 310 K. The Cu-O -Cu angle is 133.5(1)degrees in the super-exchange pathway. The weak antife rromagnetic coupling of the complex is interpreted in terms of countercompl ementary effects of the different bridging ligands which participate in the super-exchange interaction. The magnetic moment at 310 K is ca. 2.7 B.M., but 0.2 B. M. at 4.6 K. The magnetic susceptibility is at a maximum near 14 0 K and decreases rapidly as the temperature is lowered to liquid helium te mperature.