Solvothermal synthesis and crystal structures of two new cadmium coordination polymers containing polynitrile ligands

Two new coordination polymers of cadmium-containing polynitrile ligands have been synthesized using sovothermal methods. In both poly[ trans , trans , trans -bis(μ-dicyanamido-κ 2 N 1 : N 3 )bis(2-methylbenzimidazole-κ N )cadmium(II)], [Cd(C 2 N 3 ) 2 (C 8 H 8 N 2 ) 2 ] n , (I), and poly[ trans , trans , trans -bis(2-methylbenzimidazole-κ N )bis(μ-tricyanomethanido-κ 2 N : N ′)cadmium(II)], [Cd(C 4 N 3 ) 2 (C 8 H 8 N 2 ) 2 ] n , (II), the Cd atom lies on a centre of inversion, in space groups P 2 1 / n and P 2 1 / c , respectively. In each polymer, each anionic ligand acts as a bridge between two metal centres, forming sheets of 24-membered rings, and in each structure a single N—H...N hydrogen bond links the polymer sheets to form a three-dimensional framework structure. Comparisons are made with the structures of some related complexes.