Hexaphenyl carbodiphosphorane adducts of heavier group 15 element trichlorides: syntheses, properties and reactivities

Abstract

Herein, we present a series of hexaphenyl carbodiphosphorane (CDP^Ph) adducts of heavier group 15 trichlorides ECl₃ (E = P-Bi). The reaction with PCl₃ yields the known salt [CDP^Ph–PCl₂][Cl] ([1][Cl]), the heavier element trichlorides ECl₃ (E = Sb (4), Bi (5)) give the neutral adducts CDP^Ph–ECl₃ which were characterised crystallographically and spectroscopically. The reaction of CDP^Ph with AsCl₃ does not yield CDP^Ph–AsCl₃ (2), but in the presence of GaCl₃ the corresponding salt [CDP^Ph–AsCl₂][GaCl₄] ([3][GaCl₄]) is formed. DFT (density functional theory) calculations were carried out to examine the molecular frontier orbitals in 1⁺–5. Additional reactivity studies revealed an intramolecular electrophilic aromatic substitution (S_EAr) in 1⁺, which represents an excellent starting point for further selective C–P bond formation reactions.