A two-dimensional anionic CdII polymer constructed through dicyanamide coordination bridges

In the search for potential ferroelectric materials, molecular-based one-, two- and three-dimensional cadmium(II) organic-inorganic compounds have been of interest as they often display solid-solid phase transitions induced by a variation in temperature. A new cadmium dicyanamide complex, poly[4-dimethylamino-1-ethylpyridin-1-ium [tri-μ-dicyanamido-κ(6)N(1):N(5)-cadmium(II)]], {(C9H15N2)[Cd(C2N3)3]}n, was synthesized by the reaction of 4-dimethylamino-1-ethylpyridin-1-ium bromide, cadmium nitrate tetrahydrate and sodium dicyanamide in aqueous solution. In the crystal structure, each Cd(II) cation is octahedrally coordinated by six terminal N atoms from six anionic dicyanamide (dca) ligands. Neighbouring Cd(II) cations are linked together by dicyanamide bridges to form a two-dimensional coordination polymer. The organic cations are not involved in the formation of the supramolecular network.