Structural and Magnetization Studies of a New (Mu-Oxo)bis(Mu-Carboxylato)Dimanganese(III) Complex with a Terminal Hydroxo Ligand

The dinuclear MnIII complex [Mn2O(PhCOO)2(bpy)2(OH)(NO3)]·H2O was prepared by controlled oxidation of manganous nitrate with n-tetrabutylammonium permanganate in the presence of benzoic acid (PhCOOH) and 2,2‘-bipyridine (bpy). Its structure was determined in a single-crystal X-ray diffraction experiment, and consists of a triply-bridged [Mn2(μ-O)(μ-PhCOO)2]2+ dinuclear core. Each manganese(III) ion bears a chelating bpy and a terminal X anion (X = OH- or NO3-) completing a distorded octahedral coordination geometry. Although the terminal anions are located in disordered positions, the analysis of bond lengths and steric considerations led us to assign to the complex an asymmetric structure [(bpy)(OH)MnIII(μ-O)(μ-PhCOO)2MnIII(bpy)(ONO2)]. The product, with a chemical formula C34H29Mn2N5O10, crystallizes in the monoclinic system, space group C2/c, with a = 16.607(4) A, b = 25.619(6) A, c = 9.796(3) A, β = 100.15(3)°, and Z = 4. Magnetic studies performed on a series of related compounds have revealed a mode...