A novel Mn(II) oxalato-bridged 2D coordination polymer: synthesis, crystal structure, spectroscopic, thermal and magnetic properties

Besides the fact that direct synthesis of oxalate-based Mn(II) complexes did not succeed a lot due to the high insolubility of manganese oxalate (Mn-II(C2O4)center dot 2H(2)O), a new 2D polymeric Mn(II) salt has been synthesized by slow evaporation at room temperature and its structure has been determined by single-crystal X-ray diffraction. The structure was solved by direct methods and refined to conventional agreement indices. The crystal structure is built from anionic, two-dimensional, honeycomb networks formed by the oxalate-bridged Mn(II) ions, interleaved by 2,6-diaminopyridinium cations that are entrapped between the layers. The interactions between adjacent layers result from the extended network of intermolecular hydrogen bonds created by the mentioned cations and water molecules. The complex has been fully characterized by single crystal X-ray diffraction, FT-IR and UV-Vis spectroscopy, Rietveld refinement, TGA-DSC analysis and magnetic susceptibility. The title compound exhibits antiferromagnetic coupling between Mn(II) centres.