Crystal structures of 3-halo-2-organochalcogenylbenzo[ b ]chalcogenophenes

The structure of the title compounds 3-bromo-2-(phenyl-sulfan-yl)benzo[ ]thiophene (C H BrS ; ), 3-iodo-2-(phenyl-sulfan-yl)benzo[ ]thio-phene (C H IS ; ), 3-bromo-2-(phenyl-selan-yl)benzo[ ]seleno-phene (C H BrSe ; ), and 3-iodo-2-(phenyl-selan-yl)benzo[ ]seleno-phene (C H ISe ; ) were determined by single-crystal X-ray diffraction; all structures presented monoclinic ( 2 / ) symmetry. The phenyl group is distant from the halogen atom to minimize the steric hindrance repulsion for all structures. Moreover, the structures of and show an almost linear alignment of halogen-selenium-carbon atoms arising from the intra-molecular orbital inter-action between a lone pair of electrons on the halogen atom and the anti-bonding σ* orbital ( →σ* ). This inter-action leads to significant differences in the three-dimensional packing of the mol-ecules, which are assembled through π-π and C-H⋯π inter-actions. These data provide a better comprehension of the inter-molecular packing in benzo[ ]chalcogenophenes, which is relevant for optoelectronic applications.