Inorganic-organic hybrid materials with methylviologen dication confined in magnetic hosts: Synthesis, crystal structures and magnetic properties

Abstract

Two novel coordination polymers {(MV)[M3(dca)8]}n (MV2+ = methylviologen dication, dca = dicyanamide anion, M = Co (1) and Ni (2)) have been synthesized by the reactions of methylviologen dichloride andsodium dicyanamidewith cobalt(II) or nickel(II) ions. Their structures have been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, infrared spectra, and thermogravimetric analytical techniques. Compounds 1 and 2 are isomers, and crystallize in a centrosymmetric P21/n space group. In the structures of 1 and 2, the metal ions are attached through the µ1,3,5- dicyanamide groups generating a 2D sheet in bc plane. Furthermore, the neighbouring sheets are supported by the strut µ1,5-dca ligands into a 3D framework with open channels occupied by MV2+ cations. Magnetic studies indicate that, compound 1 exhibits antiferrimagnetic coupling between cobalt(II) ions, whereas ferromagnetic interaction was occurred between nickel(II) ions in compound 2.