A Boron-Transfer Mechanism Mediating the Thermally Induced Revival of Frustrated Carbene−Borane Pairs from their Shelf-Stable Adducts

Combined experimental and theoretical studies allowed clarifying the reaction mechanism for the revival of frustrated carbene−borane pairs from external-stimuli-responsive classical Lewis adducts comprised of N-phosphine oxide-substituted imidazolylidenes and triarylboranes. A borane-transfer process from the carbene carbon atom to the N-phosphinoyl oxygen atom was identified as the rate-determining event for the regeneration of the FLP species, eventually enabling the heterolytic cleavage of H2.