Tetragonal phosphorus(v) cations as tunable and robust catalytic Lewis acids

Area of Science:

• Organometallic Chemistry
• Catalysis
• Materials Science

Background:

• Lewis acids are crucial catalysts in organic synthesis.
• Traditional Lewis acids often suffer from instability in the presence of water or protic solvents.
• Developing robust and water-tolerant Lewis acids is essential for broader catalytic applications.

Purpose of the Study:

• To synthesize and characterize novel water-tolerant cationic phosphorus-based Lewis acids.
• To investigate the catalytic activity and stability of these new compounds.
• To understand the electronic structure influencing their reactivity and stability.

Main Methods:

• Synthesis of corrole-based phosphorus(v) cations.
• Characterization using Nuclear Magnetic Resonance (NMR) and X-ray diffraction.
• Quantification of Lewis acidity via spectrophotometric titrations.
• Density Functional Theory (DFT) analyses of electronic structure.

Main Results:

• Successfully synthesized and characterized novel cationic phosphacorroles.
• Demonstrated unprecedented stability towards water and alcohols.
• Exhibited high catalytic activity and robustness in carbonyl hydrosilylation, C-H bond functionalization, and carbohydrate deoxygenation.
• DFT studies revealed P-N antibonding interactions in the P-acceptor orbital.

Conclusions:

• The synthesized cationic phosphacorroles are highly stable and active Lewis acid catalysts.
• Their unique electronic structure contributes to water tolerance and catalytic efficiency.
• These compounds represent a significant advancement in the development of robust Lewis acid catalysts for organic synthesis.