Structural diversity of four novel cadmium coordination polymers constructed by 1,4-bis(imidazol-1-yl)butane and anion ligands

The reaction of the flexible bis(imidazole) ligand 1,4-bis(imidazol-1-yl)butane (bimb) with corresponding Cd(II) salts (NCS−, dicyanamide (dca), N3-, ClO4-) yields four new coordination polymers, from 1D to 3D networks, namely [Cd(bimb)2(NCS)2]n (1), [Cd(bimb)(dca)2]n (2), [Cd(bimb)(N3)2]n (3) and {[Cd(bimb)3](ClO4)2}n (4). In 1, each Cd(II) atom links two Cd(II) atoms by double bimb ligands and extends to form an one-dimensional chain structure containing the Cd2(bimb)2 22-membered metallocycle. In 2, double μ1,5-dca bridges connect the Cd(II) atoms to form the zigzag [Cd(dca)2]n chains and extend through bimb long bridges in four different directions alternatively to construct a novel three-dimensional network. In 3, double end-to-end (EE) and double end-on (EO) azide short bridges alternatively link Cd(II) atoms to form the [Cd(N3)2]n chains containing both eight- and four-membered metallocycles which further extend via bimb long bridges in four different directions alternatively to result a three-dimensional network. Compound 4 comprises two equivalent, mutually interpenetrating three-dimensional networks.