Hydrothermal synthesis of a new layered inorganic–organic hybrid cobalt(II) phosphite: (C2H10N2)[Co3(HPO3)4]

The (C2H10N2)[Co3(HPO3)4] phosphite templated by ethylenediamine has been prepared by hydrothermal synthesis. It crystallizes in the triclinic space group P-1 with the parameters: a=5.351(2), b=5.347(4), c=14.010(6) Å, α=80.98(5), β=85.66(4), γ=60.04(4)°, V=343.0(3) Å3 and Z=1. The compound shows a layered structure stacked along the c-axis. The ethylenediammonium cations are placed between the sheets. Ionic interactions and hydrogen bonds are present between the ethylenediammonium cations and the inorganic layers. The layers are formed by Co3O12 trimeric entities which contain face-sharing CoO6 octahedra interconnected by (HPO3)2− tetrahedral phosphite anions. The spectroscopic study by diffuse reflectance allowed us to obtain the Dq=725 cm−1 and the Racah parameters, B=880 and C=3950 cm−1 for the high spin octahedral Co(II) ions. Magnetic measurements reveal the presence of antiferromagnetic exchange interactions in the trimeric units of (C2H10N2)[Co3(HPO3)4].