Novel Al-based FLP systems.

Area of Science:

• Organometallic Chemistry
• Catalysis
• Supramolecular Chemistry

Background:

• Frustrated Lewis pairs (FLPs) are key to activating small molecules.
• Developing stable and reactive FLPs is crucial for catalysis.

Purpose of the Study:

• To synthesize novel Al/P-based FLPs.
• To investigate their reactivity with small molecules and ionic hydrides.
• To explore their catalytic applications.

Main Methods:

• Hydroalumination of alkynylphosphines to generate multigram quantities of Al/P FLPs.
• Reactions with terminal alkynes, carbon dioxide, and alkali metal hydrides.
• Synthesis of Al/N Lewis pairs via hydroalumination of ynamines.

Main Results:

• Sterically shielded Al/P FLPs activate terminal alkynes via C-H cleavage or C≡C bond activation, forming heterocycles.
• FLPs act as ion pair receptors for alkali metal hydrides, enabling phase transfer catalysis.
• Less shielded analogues form dimers or methylene-bridged compounds, retaining masked FLP activity.
• Al/N Lewis pairs reversibly activate phenylethyne and react with carbodiimide.

Conclusions:

• Novel Al/P and Al/N Lewis pairs were successfully synthesized and characterized.
• These compounds exhibit diverse reactivity, including small molecule activation and catalysis.
• The findings open new avenues for designing advanced Lewis pair systems.