Small molecule activation by frustrated Lewis pairs.

Area of Science:

• Organometallic Chemistry
• Catalysis
• Sustainable Chemistry

Background:

• Frustrated Lewis pairs (FLPs) are key to activating small molecules.
• Developing efficient catalysts for CO2 utilization is crucial for sustainability.

Purpose of the Study:

• To synthesize and characterize novel FLPs based on tris(perchloroaryl)borane (BAr(Cl)) and tris(2,2',2''-perfluorobiphenyl)borane (PBB) with trialkylphosphines.
• To investigate the catalytic activity of these FLPs in dihydrogen heterolytic cleavage, CO2 insertion, and methanol synthesis.
• To explore the potential of FLPs in homogeneous catalytic preparation of carbonates via CO2 insertion into B-OH bonds.

Main Methods:

• Synthesis of FLPs incorporating BAr(Cl) and PBB Lewis acids with trialkylphosphines.
• Spectroscopic and crystallographic characterization of FLP complexes, including single crystal X-ray diffraction for [PBB-OH][H-P((t)Bu)(3)].
• In situ studies of FLP reactivity towards dihydrogen and carbon dioxide.

Main Results:

• Successful preparation of FLPs based on BAr(Cl) and PBB.
• Demonstrated heterolytic cleavage of dihydrogen by the FLPs.
• Observed insertion of CO2 into borohydride intermediates, leading to formatoborate species.
• Catalytic reduction of formatoborate to methanol.
• Exploration of CO2 insertion into a B-OH bond for carbonate synthesis.

Conclusions:

• The novel FLPs exhibit significant reactivity towards dihydrogen and carbon dioxide activation.
• These FLPs show promise for the catalytic conversion of CO2 into valuable chemicals like methanol and carbonates.
• The study contributes to the development of homogeneous catalytic systems for sustainable chemical transformations.