Towards rational design of supramolecular helices using linear pseudohalides in Cd(II)-2,2 '-biimidazole system

Three cadmium complexes, [Cd(H(2)biim)(2)(SCN)(2)] ( 1), [Cd(H(2)biim)(2)(SeCN)(2)] (2) and [Cd(H(2)biim)(2)( dca)(2)] ( 3) [H(2)biim = 2,2'-biimidazole; dca = dicyanamide] have been synthesized and characterized by X-ray single crystal structure analysis. In complexes 1 and 2 monomeric units assemble into supramolecular helix whereas in 3 monomeric units assemble into supramolecular 2-Dgrid with ( 4,4) net topology. The appearance of helical topology in complexes 1 and 2 is due to the linear nature of SCN-/SeCN- whereas (4,4) net topology in complex 3 is due to the bent nature of dca(-). In each case R-2(1)( 7) hydrogen bonding synthon is attained facilitating the helical and ( 4,4) net topology.