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

Abstract

The structure of the title compounds 3-bromo-2-(phenylsulfanyl)benzo[b]thiophene (C14H9BrS2; 1), 3-iodo-2-(phenylsulfanyl)benzo[b]thiophene (C14H9IS2; 2), 3-bromo-2-(phenylselanyl)benzo[b]selenophene (C14H9BrSe2; 3), and 3-iodo-2-(phenylselanyl)benzo[b]selenophene (C14H9ISe2; 4) were determined by single-crystal X-ray diffraction; all structures presented monoclinic (P21/c) symmetry. The phenyl group is distant from the halogen atom to minimize the steric hindrance repulsion for all structures. Moreover, the structures of 3 and 4 show an almost linear alignment of halogen–selenium–carbon atoms arising from the intramolecular orbital interaction between a lone pair of electrons on the halogen atom and the antibonding σ*Se–C orbital (nhalogen→σ*Se–C). This interaction leads to significant differences in the three-dimensional packing of the molecules, which are assembled through π–π and C—H...π interactions. These data provide a better comprehension of the intermolecular packing in benzo[b]chalcogenophenes, which is relevant for optoelectronic applications.

Keywords

• crystal structure
• benzo[b]chalcogenophenes
• intramolecular orbital interaction