PCl3–C6H6 heterodimers: evidence for P⋯π phosphorus bonding at low temperatures

Abstract

A phosphorous trichloride (PCl₃)–benzene (C₆H₆) heterodimer was generated in a low temperature N₂ matrix and was characterized using infrared spectroscopy. The structure of the heterodimer produced in the matrix isolation experiment was discerned through ab initio computations. Computations disclosed that the experimentally detected dimer is stabilized through strong non-covalent phosphorus bonded P⋯π interaction, considered as a class of pnicogen bonding. This experimentally unmapped P⋯π interaction so far has been reconnoitered using atoms in molecules and natural bond orbital and energy decomposition analyses. The influence of substitutions on both the PCl₃ and C₆H₆ monomeric units of the heterodimer was subsequently examined to understand the strength of P⋯π interaction as a result of these substitutions.