Structure and stability of thiophene–hydrogen halide complexes: An ab initio molecular orbital study

The structures of thiophene–hydrogen halide (HX) complexes are examined at the second-order Møller-Plesset (MP2) level to understand hydrogen bonding and intermolecular interactions of a heteroaromatic ring as the hydrogen bond acceptor. In contrast with the previous results on similar furan complexes, only the face-on geometry type is observed for the thiophene complexes. Variations in complex geometry can be accounted for by the differences in the electrostatic potential on the aromatic ring. A decomposition of interaction energy reveals that thiophene–hydrogen halide is bounded largely by orbital and electrostatic energy contributions.