Tetranuclear manganese(III) clusters containing both carboxylate and phosphonate bridging ligands

This paper reports two tetranuclear manganese clusters, namely, [Mn4O2(O2CCH3)4(O3PC6H11)2(phen)2] (1) and [Mn4O2(O2CPh)4 (O3PC6H11)2(bpy)2] (2). Both contain a butterfly-like [Mn4(μ3-O)2]8+ core. The neighboring Mn atoms within the core are bridged by the carboxylate groups, forming approximately a plane. The phosphonate ligands locate above and below the plane, and cap on top of the Mn3O triangles by using its three phosphonate oxygen atoms. The magnetic measurements of complexes 1 and 2 reveal that dominant antiferromagnetic interactions are propagated between the magnetic centers.