A new two-dimensional anionic cadmium(II) polymer constructed through thiocyanate coordination bridges.

A new cadmium-thiocyanate complex, poly[4-(dimethylamino)pyridin-1-ium [di-μ-thiocyanato-κ(2)N:S;κ(2)S:N-thiocyanato-κN-cadmium(II)]], {(C7H11N2)[Cd(NCS)3]}n, was synthesized by the reaction of cadmium thiocyanate and 4-(dimethylamino)pyridine hydrochloride in aqueous solution. In the crystal structure, each Cd(II) ion is square-pyramidally coordinated by three N and two S atoms from five different thiocyanate ligands, four of which are bridging. The thiocyanate ligands play different roles in the build up of the structure; one role results in the formation of [Cd2(NCS)2] building blocks, while the other links the building blocks and cations via N-H···S hydrogen bonds. The N-H···S hydrogen bonds and weak π-π stacking interactions are involved in the formation of both a two-dimensional network structure and the supramolecular network.