Bond activation by d0 metal carbene complexes in the gas phase



The formation and bond activation reactions of the d0 carbene complexes MCHCN+ (M = Sc, Y) are presented. Sc+ and Y+ dehydrogenate acetonitrile to produce the metallocarbenes. The carbene complexes are less reactive towards hydrocarbons than their bare metal ion counterparts, but will activate C[BOND]H, O[BOND]H, and N[BOND]H bonds through a four-centered intermediate. Labeling studies indicate that reactions with olefins proceed by migratory insertion after initial C[BOND]H activation, and that subsequent ligand coupling produces metal-bound nitrite products. Oletin metathesis reactions are not observed due to the electron-withdrawing characteristics of the CN substituent and the electrophilicity of the metal centers.