This work presents an ab initio study on chalcogen–hydride interactions in several binary com- plexes of chalcogen-containing molecules with HXeH. The geometries, H–Xe stretching frequencies and interaction energies of XCYHXeH binary complexes are investi- gated at MP2/aug-cc-pVTZ and CCSD(T)/aug-cc-pVTZ levels of theory, where X = O, S, Se, Te and Y = S, Se, Te. For each XCYHXeH complex, a chalcogen–hydride bond is formed between the negatively charged hydrogen atom of the HXeH molecule and the most positive elec- trostatic potential region (r-hole) on the surface of the interacting atom Y. Upon complex formation, a notable blue shift is found for the H–Xe stretch vibration. This result reveals that there is a stronger H - (XeH) ? ion-pair character in XCYHXeH complexes than in free HXeH molecule. In order to shed light on the origin of the chalcogen–hydride interactions, molecular electrostatic potential, quantum theory of atoms in molecules and interaction energy decomposition analyses are performed. Cooperative effects between a conventional chalcogen bond and the chalcogen–hydride interaction in OCYOCYHXeH complexes are also investigated.
