Synthesis and Characterization of Silylated Phosphonium [P(OSiMe3)4]+ and Phosphate [O2P(OSiMe3)2]- Salts.

Starting from an optimized synthesis of silylated phosphoric acid, OP(OSiMe3)3, a borate salt bearing the [P(OSiMe3)4]+ cation was generated in the reaction of OP(OSiMe3)3 with [Me3Si-H-SiMe3][B(C6F5)4], isolated, and fully characterized. Analogously to the protonated species, phosphoric acid (H3PO4) reaction of OP(OSiMe3)3 with a base led to the formation of the unknown [O2P(OSiMe3)2]- anion, which could be crystallized as potassium salt and structurally characterized, too. Both [P(OSiMe3)4]+ and [O2P(OSiMe3)2]- can be regarded as the formal autoprotolysis products of OP(OSiMe3)3.