Ferromagnetic exchange in μ-alkoxo-μ-dicarboxylato double bridged tetranuclear copper(II) complexes: [Cu4(L-X)2(μ-C4H4O4)(dmf)2] (L = 1,3-bis(5-X-salicylideneamino)-2-propanol, X = Br, Cl)

Two new μ-alkoxo-μ-dicarboxylato double bridged tetranuclear copper(II) complexes [Cu4(L-Br)2(μ-C4H4O4)(dmf)2] (1) and [Cu4(L-Cl)2(μ-C4H4O4)(dmf)2] (2) (H3L-Br = 1,3-bis(5-bromo-salicylideneamino)-2-propanol; H3L-Cl = 1,3-bis(5-chloro-salicylideneamino)-2-propanol; dmf = N,N-dimethylformamide) have been prepared and structurally characterized. Temperature dependence of magnetic susceptibility measurements show a ferromagnetic coupling between two copper(II) ions in complex 1 with J = 54 cm−1, and in 2 with J = 56 cm−1.