Functionalized Fluorophosphonium Ions

Abstract

Efforts to prepare an elusive donor-free phosphenium ion, [R₂ P]⁺ , led us to synthesize functionalized fluorophosphonium cations of the type [R₂ P(F)X]⁺ (X=SiEt₃ , H, F), which were obtained from the related neutral fluorophosphines R₂ PF and R₂ PF₃ upon protonation and reaction with solvated [Et₃ Si]⁺ ions (R=2,6-Mes₂ C₆ H₃ ). The hypothetical reductive elimination of [R₂ P(F)SiEt₃ ]⁺ and [R₂ P(F)H]⁺ affording [R₂ P]⁺ , Et₃ SiF and HF, respectively, was calculated to be endothermic by 40.1 and 190.6 kJ mol^-1 .