Isotopic probes for ruthenium-catalyzed olefin metathesis
Routes are described to previously unreported first- and second-generation Grubbs metathesis catalysts bearing a 13C label at the key benzylidene or methylidene site. Improved syntheses of the 2H-labelled isotopologues are also presented. Labelling at the alkylidene position is important because it provides unique, direct information about changes at the active site of the catalyst, and the fate of the [Ru]CHR ligand during catalyst deactivation. A case study demonstrates the power of 13C-labelling in tracking the methylidene moiety in amine-induced decomposition of the second-generation complex RuCl2(PCy3)(H2IMes)(13CH2). Also reported is the solubility of ethylene in C6D6 and CD2Cl2, measured at 296 ± 1.5 K and 101.0 ± 0.8 kPa.
- This article is part of the themed collection: Mechanistic Studies in Catalysis