Synthesis, structure and magnetic properties of {Mn5(OC(O)CH3)6(OC(O)C6H5)4}∞

The ligand exchange reaction between Mn(OC(O)CH3)2 and benzoic acid under solvothermal conditions in toluene at 110 °C yields colorless crystals of {Mn5(OC(O)CH3)6(OC(O)C6H5)4}∞ (1). The asymmetric unit of this complex is Mn2.5(OC(O)CH3)3(OC(O)C6H5)2 with each of the three different Mn(II) atoms in 6-fold coordination and one of the benzoate ligands exhibiting the rare μ3-symmetric bridging mode (O–Mn–O angle = 57°). The structure consists of edge-shared Mn12 loops arranged in a honeycomb-like 2D sheet with the acetate ligands displaced slightly out of the plane. The sheets are spaced at 12 Å and linked into a 3D network via weak intersheet interactions. Magnetic susceptibility characterization of 1 indicates antiferromagnetic exchange with a Weiss constant of −165 K and a transition toward ferromagnetic exchange below 10 K corroborated with a finite imaginary component in the variable temperature susceptibility data.

Graphical abstractA new layered manganese (II) mixed-carboxylate complex is reported. The structure of {Mn5(OC(O)CH3)6(OC(O)C6H5)4}∞ is described as edge-shared Mn12 loops arranged in a honeycomb-like 2D sheet. A sideview of the sheets shows the acetate ligands slightly displaced out of the plane and an intersheet spacing of 12 Å is reported.Figure optionsDownload full-size imageDownload as PowerPoint slide