Reversible C-H Bond Activation Reactions of the N-Heterocyclic Carbene Ligands in Ru(Ph_2PCHH_2CH_2CH_2PPh_2)(IMes)(CO)H_2 and Ru(Ph_2AsCH_2CH_2PPh_2)(IMes)(CO)H_2 (IMes = 1,3-Dimesityl-1,3-dihydro-2H-imidazol-2-ylidene)

摘要

Thermolysis of Ru(IMes)(dppp(CO)H_2 (1, IMes = 1,3-dimesity-1,3-dihydro-2H-imidazol-2-ylidene; dppp = Ph_2PCH_2CH_2CH_2PPh_2) in the presence of trimethylvinylsilane yields Ru(I-Mes')(dppp)(CO)H (2) resulting from intramolecular ArCH_2-H C-H bond activation of the N-heterocyclic carbene ligand. The structures of 1 and 2 have been established by X-ray crystallography. Treatment of Ru(IMes)(arphos)(CO)H_2 (3, arphos = Ph_2AsCH_2CH_2PPh_2) with CH_2 = CHSiMe_3 at 85 ℃ produces a mixture of three C-H activated products 4a-c. The C-H activated complexes 2 and 4a-c reform their dihydride precursors upon heating under hydrogen.