Taming a silyldiium cation and its reactivity towards sodium phosphaethynolate

Area of Science:

• Organosilicon Chemistry
• Main Group Chemistry
• Coordination Chemistry

Background:

• N-heterocyclic carbenes (NHCs) are versatile ligands in coordination chemistry.
• Dicationic silicon complexes are less explored compared to their monocationic counterparts.
• Stabilization of low-valent main group elements by NHC ligands is an active area of research.

Purpose of the Study:

• To synthesize and characterize a novel dicationic bis(NHC)-stabilized silyldiium complex.
• To investigate the reactivity of this silyldiium complex with phosphorus-containing reagents.
• To explore the formation of novel silicon-phosphorus heterocycles.

Main Methods:

• Synthesis of the dicationic bis(NHC)-stabilized silyldiium complex using established synthetic routes.
• Reaction of the silyldiium complex with sodium phosphaethynolate (NaOCP) to achieve P-insertion.
• Subsequent reactions of the P-insertion product with dichlorophosphanes to yield diphosphanide cations.

Main Results:

• Successful synthesis and characterization of the first dicationic bis(NHC)-stabilized silyldiium complex, [bis(NHC)-SiPh2]2+.
• Formation of a P-insertion product, [bis(NHC)-PSiPh2]+, featuring a seven-membered heterocycle with a Si-P moiety.
• Demonstration of facile desilylation and subsequent synthesis of diphosphanide cations, [bis(NHC)-PPCy]+ and [bis(NHC)-PPPh]+, using dichlorophosphanes.

Conclusions:

• The novel dicationic silyldiium complex serves as a valuable precursor for silicon-phosphorus chemistry.
• The P-insertion reaction provides a facile route to unique heterocyclic structures.
• The developed methodology allows for the synthesis of diverse diphosphanide cations.