Water-Accelerated Decomposition of Olefin Metathesis Catalysts

Area of Science:

• Organometallic Chemistry
• Catalysis
• Green Chemistry

Background:

• Olefin metathesis is a vital synthetic tool, but its application is limited by water presence.
• Water can cause decomposition of ruthenium catalysts, leading to undesired side reactions like DNA degradation.
• Current understanding of water-induced catalyst decomposition is limited to the initial aquation step.

Purpose of the Study:

• To elucidate the mechanisms by which water promotes ruthenium catalyst decomposition in olefin metathesis.
• To identify strategies for inhibiting water-promoted decomposition pathways.

Main Methods:

• Investigated the decomposition cascade of ruthenium catalysts in the presence of water.
• Characterized the role of aqua species in accelerating key decomposition steps.
• Explored methods to block catalyst aquation and β-elimination.

Main Results:

• Demonstrated that aqua species significantly accelerate β-elimination and bimolecular decomposition pathways.
• Identified specific ruthenium aqua species involved in the decomposition cascade.
• Showed that blocking aquation and β-elimination inhibits catalyst decomposition.

Conclusions:

• Water plays a critical role in accelerating ruthenium catalyst decomposition beyond initial aquation.
• Understanding and inhibiting these pathways is crucial for enabling olefin metathesis in aqueous media.
• Strategies targeting aquation and β-elimination offer a route to more robust catalysts for water-rich applications.