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

Abstract

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.