Effect of chalcogen bonding on the packing and coordination geometry in hybrid organic-inorganic Cu(ii) networks

The effect of chalcogen bonding interaction led to the interesting crystal packing and coordination geometry of copper(ii) in novel organic-inorganic hybrids. The reactions of organic bridging ligands 1,2,5-benzothiadiazole (btd) and 1,2,5-benzoselenazadiazole (bsed) with CuCl2 and CuBr2 by slow diffusion of two miscible solvents afforded three isomorphic 2D-network polymers, [CuCl2(btd)]n (1), [CuBr2(btd)]n (2), and [CuCl2(bsed)]n (3), and one molecular hybrid, CuBr2(bsed)2 (4). The crystal structures of these novel hybrids were determined by single X-ray crystallography. The three isomorphic hybrids consist of 2-D sheets in which [Cu(μ-X)2]n infinite linear chains running along the a axis are linked through N-coordinated molecules of btd and bsed along the b axis. On the other hand, the crystal packing of 4 is strongly influenced by the presence of the [Se⋯N]2 supramolecular synthon and Se⋯Br short interactions, all based on chalcogen bonding, that link the dimeric complex molecules into two-dimensional arrays parallel to the ac plane.