Protonation of an ylide leads to a unique C–H ⋯ O hydrogen-bonded dimer: the first synthesis, isolation and X-ray structural characterisation of a phosphonium aryloxide

Abstract

The phosphonium ylide triphenylphosphonium methylide Ph₃PCH₂ reacts with 2,4,6-trimethyiphenol to give the phosphonium aryloxide dimer [(Ph₃PMe)⁺(OC₆H₂Me₃-2,4,6)^–]₂1, in the solid state, in which aggregation is solely through C–H ⋯ O hydrogen bonding from both alkyl and aryl donors within the phosphonium cation, resulting in each phenoxide oxygen acceptor being five-coordinate (tetrafurcated).