Modeled Single-Atomic-Site Pt Catalyst with Well-Defined Coordination Structure for Hydrosilylation Reaction

Area of Science:

• Heterogeneous catalysis
• Single-atom site (SAS) catalysts
• Organometallic chemistry

Background:

• Single-atom-site (SAS) catalysts offer high activity and are ideal for mechanistic studies.
• Controlling the coordination environment and distribution of SAS catalysts synthesized via pyrolysis is challenging.
• Developing model catalysts with well-defined coordination structures is crucial but difficult.

Purpose of the Study:

• To synthesize a platinum single-atom-site (SAS) catalyst with a precisely defined coordination structure.
• To utilize this model catalyst for mechanistic investigations of anti-Markovnikov alkene hydrosilylation.
• To establish a structure-activity relationship for SAS catalysts.

Main Methods:

• In situ reduction-assembly strategy for SAS catalyst synthesis.
• Single-crystal X-ray diffraction and X-ray absorption spectroscopy for structural confirmation.
• Density functional theory (DFT) calculations to investigate reaction mechanisms.

Main Results:

• A Pt₁C₄₈H₆₁P₂Cl SAS catalyst with a confirmed Pt-P₂C₁Cl₁ coordination structure was synthesized.
• The catalyst achieved 98% conversion and >99% selectivity in anti-Markovnikov alkene hydrosilylation under solvent-free conditions within 1 hour.
• DFT calculations showed a reduced energy barrier for hydrosilylation on the SAS catalyst compared to Pt (111).

Conclusions:

• The synthesized Pt-SAS catalyst serves as an effective model for studying SAS catalysts.
• The precisely defined coordination environment enhances catalytic activity and selectivity.
• The catalyst's performance is attributed to weaker interactions during the oxidative addition step, facilitating product desorption.