Synthesis, Magnetic Property, and Crystal Structure of Imidazolate-Bridged Manganese(III)–Copper(II) Dinuclear Complex

The synthesis, crystal structure, and magnetic property of an imidazolate-bridged manganese(III)–copper(II) dinuclear complex [Mn(salen)Cu(A)]BPh4 are described, where [H2salen]=N,N′-disalicylideneethylenediamine, [H2A]=4-(6-methyl-8-oxo-2,5-diazanonane-1,5,7-trienyl)imidazole, and BPh4=tetraphenylborate. The X-ray analysis confirmed an imidazolate-bridged manganese(III)–copper(II) dinuclear structure, in which the coordination geometries of the manganese(III) and copper(II) ions are square pyramid and square planar, respectively. The apical position of the manganese(III) ion is occupied by an imidazolate nitrogen N(3) of the [Cu(A)] moiety with the bond distance of Mn–N(3) 2.165(5) Å. As the temperature is lowered, the effective magnetic moment per molecule decreases gradually from 5.17 B.M. at 300.2 K, reaches the minimum value 4.44 B.M. at 24.9 K, and then increases to 4.73 B.M. at 4.2 K, indicating that antiferro- and ferro-magnetic interactions are co-operative in the complex.