Cationic Platinum(II) σ-SiH Complexes in Carbon Dioxide Hydrosilation

Area of Science:

• Organometallic Chemistry
• Catalysis
• Silane Chemistry

Background:

• Low-electron-count cationic platinum complexes offer unique reactivity.
• Understanding silane interactions with metal centers is crucial for catalytic applications.

Purpose of the Study:

• To investigate the interaction of a specific cationic platinum complex with primary and secondary silanes.
• To characterize the resulting sigma-SiH complexes and their coordination modes.
• To evaluate the catalytic activity of these complexes in the hydrosilation of carbon dioxide.

Main Methods:

• Synthesis and characterization of platinum-silane complexes.
• Density Functional Theory (DFT) calculations to determine stable coordination modes.
• X-ray crystallography for structural elucidation of key intermediates.
• Catalytic testing for CO2 hydrosilation.

Main Results:

• The cationic platinum complex [Pt(ItBu')(ItBu)][BArF] (1) forms sigma-SiH complexes with silanes.
• DFT calculations predict an uncommon eta(1)-SiH coordination as the most stable mode.
• A 14-electron Pt(II) species, [Pt(SiEt2H)(ItBu)2][BArF] (2), stabilized by an agostic interaction, was structurally characterized.
• Complexes 1, 2, and the related hydride complex 3 catalyze the room-temperature hydrosilation of CO2.

Conclusions:

• The cationic platinum complex enables the formation of stable platinum-silane complexes.
• The characterized platinum-silane species and related hydride are active catalysts for CO2 hydrosilation.
• The exclusive formation of silyl formates demonstrates high selectivity in CO2 conversion.