Synthesis of a monomolecular anionic FLP complex

Area of Science:

• Organometallic chemistry
• Main group chemistry
• Lewis pair chemistry

Background:

• Frustrated Lewis pairs (FLPs) are reactive species formed from Lewis acids and bases that do not associate.
• While FLP chemistry is well-researched, anionic FLPs and their complexes remain unexplored.
• This knowledge gap limits the understanding of FLP reactivity and applications.

Purpose of the Study:

• To synthesize and characterize the first monomolecular anionic FLP complex.
• To investigate the reactivity of this novel anionic FLP complex.
• To expand the scope of FLP chemistry into anionic systems.

Main Methods:

• Synthesis of a tungsten-based precursor complex containing a silylated phosphine ligand.
• Reaction of the precursor with dicyclohexylboron chloride (Cy2BCl).
• Deprotonation using potassium bis(trimethylsilyl)amide (KHMDS) to generate the anionic FLP complex.
• Characterization of the resulting complex.

Main Results:

• Successful synthesis and characterization of the first anionic FLP complex, [(OC)5W{(Me3Si)2HCP(H)OLi(12-crown-4)}].
• The anionic FLP complex was formed via reaction with Cy2BCl and deprotonation with KHMDS.
• The obtained anionic FLP complex demonstrated reactivity towards carbon dioxide (CO2).
• CO2 activation occurred in a concerted manner with the anionic FLP complex.

Conclusions:

• The first anionic FLP complex has been synthesized and characterized.
• This discovery opens new avenues in FLP chemistry by introducing anionic systems.
• The reactivity of the anionic FLP complex with CO2 suggests potential applications in small molecule activation and catalysis.