Syntheses and crystal structures of cadmium(II) coordination polymers with end-to-end dicyanamide bridges

Two new derivatives of cadmium(II) dicyanamide (dicyanamide = [N(CN)(2)](-), dca), [Cd(N(CN)(2))(2)(phen)](n) (1) and [Cd(N(CN)(2))(2)(2,2'-bipy)](n) (2), have been synthesized and structurally characterized. The cadmium(II) centers in 1 are connected through single or double end-to-end dca bridging ligand to form a 2-D layer structure, which furthermore condense into a 3-D structure through the pi-pi interaction between aromatic rings of adjacent layers. In 2, the cadmium(II) coordination sphere is a distorted octahedron, bound to four dca ligands and one chelate 2,2'-bipy ligand, and the adjacent cadmium(II) centers are bridged by the double end-to-end mu(1.5)-N = C-N-C = N to form an extended structure with a zigzag 1-D chain, and a 2-D layer structure results from the pi-pi interactions of the adjacent chains. Crown Copyright (C) 2002 Published by Elsevier Science Ltd. All rights reserved.