Base-Stabilized Phosphinidene Boranes by Silylium-Ion Abstraction

Area of Science:

• Inorganic Chemistry
• Organophosphorus Chemistry
• Organoboron Chemistry

Background:

• Phosphorus-boron compounds are of significant interest due to their unique bonding and reactivity.
• Stabilization of low-coordinate phosphorus species remains a synthetic challenge.

Purpose of the Study:

• To synthesize and characterize novel N-heterocyclic carbene (NHC)-stabilized compounds with P=B double bonds.
• To investigate the reaction mechanism for the formation of these unique species.

Main Methods:

• Reaction of a highly functionalized phosphinoborane (Mes*(SiMe3)P-B(Cl)Cp*) with Lewis bases (DMAP, NHC).
• Characterization of the resulting base-stabilized phosphinidene boranes (Mes*P=B(L)Cp*).

Main Results:

• Successful preparation of NHC-stabilized compounds containing P=B double bonds.
• Demonstration of Me3SiCl elimination as a key step in the formation pathway.
• Identification of transient borylphosphide anions as intermediates generated by Me3Si abstraction.

Conclusions:

• The study reports a new method for accessing base-stabilized phosphinidene boranes.
• The findings expand the scope of known P=B compounds and their synthetic routes.
• This work offers insights into the fundamental reactivity of phosphorus-boron systems.