Crystal Structure and Magnetic Properties of a (/z-Hydroxo)(/x-acetato) Dicopper(II) Complex

[Cu2(L)(02CMe)] H20 (L = l,3-Bis(2-Hydroxy-l-napthylideneamino)propan-2-ol) was synthesized and its crystal structure determined. (C27Hi3N->0 5 Cu2).H->0 , monoclinic, space group P2i/c, a = 11.795(3), b = 17.988(5), c = 12.005(6) A, 0 = 109.99(3)°, V = 2393(2) A3, Z = 4. Two copper(II) ions in a square-planar coordination are bridged by alkoxide and acetate oxygen atoms to form a dinuclear unit. The metal coordination sphere is four-coordinate, planar with an NO3 donor set. The dihedral angle between the two coordination planes is 6.34(9)°. The copper(II) centers are separated by 3.492(2) A and weakly antiferromagnetically cou­ pled (-27 = 163.6 cm-1 ), which follows from temperature-dependent magnetic susceptibility measurements in the temperature range 4.6 to 310 K. The Cu-O-Cu angle is 133.5(1)° in the super-exchange pathway. The weak antiferromagnetic coupling of the complex is interpreted in terms of countercomplementary 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 140 K and decreases rapidly as the temperature is lowered to liquid helium temperature.