Easy Access to Amides through Aldehydic C–H Bond Functionalization Catalyzed by Heterogeneous Co-Based Catalysts

• Published in: ACS catalysis Vol. 5; no. 2; pp. 884 - 891
• Main Authors: Bai, Cuihua, Yao, Xianfang, Li, Yingwei
• Format: Journal Article
• Language: English
• Published: American Chemical Society 06.02.2015
• Subjects: amides; aldehydes; cobalt; nanoparticles; heterogeneous catalysis; metal−organic frameworks
• ISSN: 2155-5435; 2155-5435
• DOI: 10.1021/cs501822r

A novel synthesis strategy for amides by oxidative amidation of aldehydes is developed using a heterogeneous Co-based catalyst. The Co composite was prepared by simple pyrolysis of a Co-containing MOF, to obtain well-dispersed Co nanoparticles enclosed by carbonized organic ligands. The catalysts were characterized by powder X-ray diffraction (PXRD), N2 physical adsorption, atomic absorption spectroscopy (AAS), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The small Co nanoparticles embedded in the N-doped carbons were highly dispersed with an average size of ca. 7 nm. The Co@C-N materials exhibited significantly enhanced catalytic activity in the oxidative amidation of aldehydes in comparison to those of commercial sources. A series of amides can be easily obtained in good to excellent yields. It was found that the reaction proceeded via radicals under mild conditions, and the carbonyl group in the amide product was from the aldehyde. Moreover, the catalyst could be easily separated by using an external magnetic field and reused several times without significant loss in catalytic efficiency under the investigated conditions.