Trimethylsilyl Chloride Aids in Solubilization of Oxidative Addition Intermediates from Zinc Metal

Trimethylsilyl chloride (TMSCl) is commonly used to activate metal(0) powders toward oxidative addition of organohalides, but knowledge of its mechanism remains limited by the inability to characterize chemical intermediates under reaction conditions. Here, fluorescence lifetime imaging microscopy (FLIM) overcomes these prior limitations and shows that TMSCl aids in solubilization of the organozinc intermediate from zinc(0) metal after oxidative addition, a previously unknown mechanistic role. This mechanistic role is in contrast to previously known roles for TMSCl before the oxidative addition step. To achieve this understanding, FLIM, a tool traditionally used in biology, is developed to characterize intermediates during a chemical reaction-thus revealing mechanistic steps that are unobservable without fluorescence lifetime data. These findings impact organometallic reagent synthesis and catalysis by providing a previously uncharacterized mechanistic role for a widely used activating agent, an understanding of which is suitable for revising activation models and for developing strategies to activate currently unreactive metals. A widely used activating agent for metal powders, trimethylsilyl chloride, creates an efficient synthesis of organometallic reagents by increasing their solubility. Fluorescence lifetime imaging microscopy (FLIM) is developed to provide molecular fingerprints that characterize intermediates and products, enabling mechanistic determination.image

Automated summary

This study utilizes fluorescence lifetime imaging microscopy (FLIM) to reveal a novel mechanistic role of trimethylsilyl chloride (TMSCl) in metal-catalyzed reactions, which aids in solubilizing organozinc intermediates after oxidative addition, providing a previously uncharacterized mechanistic role for the activating agent.