Efficient Reduction of C–N Multiple Bonds Catalyzed by Magnetically Retrievable Magnetite Nanoparticles with Sodium Borohydride

Nanoparticles and single atoms of cobalt synergistically enabled low-temperature reductive amination of carbonyl compounds

Low-temperature and selective reductive amination of carbonyl compounds is a highly promising approach to access primary amines. However, it remains a great challenge to conduct this attractive route efficiently over earth-abundant metal-based catalysts. Herein, we designed several Co-based catalysts (denoted as Co@C–N(x), where x represents the pyrolysis temperature) by the pyrolysis of the metal–organic framework ZIF-67 at different temperatures. Very interestingly, the prepared Co@C–N(800) could efficiently catalyze the reductive amination of various aldehydes/ketones to synthesize the corresponding primary amines with high yields at 35 °C. Besides non-noble metal and mild temperature, the other unique advantage of the catalyst was that the substrates with different reduction-sensitive groups could be converted into primary amines selectively because the Co-based catalyst was not active for these groups at low temperature. Systematic analysis revealed that the catalyst was composed of graphene encapsulated Co nanoparticles and atomically dispersed Co–N_x sites. The Co particles promoted the hydrogenation step, while the Co–N_x sites acted as acidic sites to activate the intermediate (Schiff base). The synergistic effect of metallic Co particles and Co–N_x sites is crucial for the excellent performance of the catalyst Co@C–N(800). To the best of our knowledge, this is the first study on efficient synthesis of primary amines via reductive amination of carbonyl compounds over earth-abundant metal-based catalysts at low temperature (35 °C).

An earth-abundant Co-based catalyst, Co@C–N(800), could efficiently catalyze the reductive amination of carbonyl compounds into primary amines at 35 °C owing to the synergistic effect of Co nanoparticles and atomically dispersed Co–N_x sites.

Gold-carbonaceous materials based heterostructures for gas sensing applications

The carbon nanostructures such as carbon nanotubes and graphene decorated with gold nanoparticles exhibit promising gas sensing applications with enhanced sensitivity.

Heterogeneous palladium-based catalyst promoted reduction of oximes to amines: using H2 at 1 atm in H2O under mild conditions

A highly active palladium-based heterogeneous catalyst with excellent activity for the hydrogenation of oximes to form amines was prepared.