Taming a silyldiium cation and its reactivity towards sodium phosphaethynolate

Abstract

A dicationic bis(NHC)-stabilised silyldiium complex, [bis(NHC)-SiPh₂]²⁺ (7²⁺) (bis(NHC) = [CH₂(NC₃H₂NDipp)₂], Dipp = 2,6-ⁱPr₂C₆H₃), was synthesised for the first time. It reacts with sodium phosphaethynolate (NaOCP) as a source of monoanionic phosphorus to give the P-insertion product [bis(NHC)-PSiPh₂]⁺ (8⁺). The latter comprises a seven-membered heterocycle containing a Si–P moiety which can easily be desilylated when exposed to dichlorophosphanes as exemplified by the synthesis of the diphosphanide cations [bis(NHC)-PPCy]⁺ (9⁺) and [bis(NHC)-PPPh]⁺ (10⁺).