Solvothermal synthesis and magnetic properties of cobalt(II) phosphite structures of varying dimensionality

Three new organically templated cobalt phosphites, [C4N2H12][Co(HPO3)(2)] (1), [(C4N2H12)(0.5)(C2NH8)][Co-2(HPO3)(3)] (2) and [C2NH8](2)[Co-3(HPO3)(4)] (3) have been synthesized under solvothermal conditions templated by piperazine. Single-crystal structure analysis reveals that compound 1 displays a one-dimensional (1D) chain-like structure, containing corner-shared four-membered rings. In compound 2, the linkages between CoO4 and HPO3 units form an inorganic layer with 4- and 12-membered aperture, while in compound 3, corner-sharing CoO4 and HPO3 units give rise to a three-dimensional structure with 16-membered ring channels, in which organic amine cations reside. The presence of 4-membered rings and one-dimensional chain/ladder structures in all compounds shows that such units are vital for building up of higher dimensionality. The magnetic properties of the three compounds are also discussed.