A Diphenoxo-bridged Ferromagnetic Copper(II) Dimer Based on N-(2-Hydroxybenzyl)salicylaldimine

A new dinuclear copper(II) complex, [Cu(L)(py)](2) 1 (H2L = N-(2-hydroxybenzyl)-salicylaldimine, py = pyridine), has been synthesized and characterized by elemental analysis, IR and UV spectra. I crystallizes in space group P2(1)/n with a = 8.2106, b = 10.715, c = 17.864 angstrom, beta = 99.365 degrees, V = 1550.7 angstrom(3), Z = 4, C19H16CuN2O2, M-r = 367.88, D-c = 1.576 g/cm(3), mu(MoK alpha) = 1.422 mm(-1), F(000) = 756, the final R = 0.0280 and wR = 0.0746. Complex I is a centrosymmetric dimer with two copper(II) centers, two py ligands and two L2- ligands. Each L2- ligand donates its azomethine nitrogen and one of the phenolate groups to one copper(II) ion and shares the other phenolate group between the two copper(II) ions, affording a Cu2O2 plane. Each copper(II) center has a slightly distorted square pyramidal geometry with a bridging phenolate group at the apex. Magnetic studies suggest the presence of a weak ferromagnetic interaction via two phenoxo bridges. The magnetic susceptibility data (2 similar to 300 K) of complex 1 were analyzed by means of (H) over cap = -2J (S) over cap (1)(S) over cap (2) - D (S) over cap (z). The least-squares fitting of the data to the theoretical equation leads to J = 10.3 cm(-1), g = 2.03, D = 0.67 cm(-1) and R = Sigma-(chi(obsd) - chi(calcd))(2)/Sigma chi(2)(obsd) = 2.76 x 10(-3).