Catalytic Dinitrogen Reduction to Silylamines by Molybdenum Nitride Complexes Bearing a Diphenolate N-Heterocyclic Carbene Ligand

Despite substantial strides in the catalytic silylation of N2 employing phosphine-ligated transition metal complexes, further development has been impeded by the low reaction yields (based on reducing or silylating reagents). Here we present a series of Mo(VI) nitride complexes featuring a robust tridentate diphenolate N-heterocyclic carbene (OCO) ligand that serves as efficient catalysts for the reduction of N2 to silylamines, producing 57.3 equiv of tris(trimethylsilyl)amine with a yield of as high as 86%. Reductive silylation of Mo nitride complexes resulted in the isolation of a molybdenum silylimide intermediate. Our findings showed that the enhanced efficiency of the system could be ascribed to the high activity of catalysts and the suppression of side reactions, indicating that the OCO ligand plays a crucial role in stabilizing the Mo center across in high- and low-oxidation states in catalysis.