Sulfonium cation [SF3]+ complexes with noble gases

Abstract

Chalconium cations are powerful Lewis acids containing a hypervalent chalcogen atom. They are utilized in the field of organocatalysis and crystal engineering. In the current work, the electrophilic force of these species has been examined. The [SF₃]⁺ chalconium cation was selected for the current study, and its complexes with noble gas atoms were modeled. In this manner, a set of three [SF₃(NCCH₃)₂Ng]⁺ and [SF₃(Ng)₂][SbF₆] complexes (Ng = Ar, Kr, Xe) were computed. The Ng atom was substituted in place of the anion (in [SF₃(NCCH₃)₂Ng]⁺) or neutral ligands (in [SF₃(Ng)₂][SbF₆]). The computations were performed using a polarizable continuum model. The obtained tetramers were stable, true minima, characterized by weak interaction energies between −2 and −1 kcal mol⁻¹. When the [SbF₄]⁻ anion was substituted by a noble gas atom, the interaction energy was significantly weakened compared to the full [SF₃(NCCH₃)₂][SbF₆] system, and its nature changed from electrostatic to dispersive. A comparable scenario was observed when the NCCH₃ ligands were replaced with two noble gas atoms.