Copper nanoparticles supported on graphene as an efficient catalyst for A3 coupling of benzaldehydes

Cu nanoparticles (NPs) supported on graphene (G) obtained by pyrolysis of alginate is a highly active catalyst for the A(3) coupling of aldehydes, secondary amines and terminal acetylenes. Adsorption of Cu NPs previously formed by the polyol method onto dispersed G in ethylene glycol was found a suitable procedure for the preparation of a highly active catalyst. Cu/G undergoes gradual deactivation upon use due to Cu NP agglomeration and loss of 2D morphology of G. The occurrence of a small percentage of Cu leaching was also measured. Cu/G is more active than analogous catalysts in which Cu NPs have been supported on other carbon supports or metal oxides. Moreover, the performance of Cu/G ranks this material at the top of the reported catalysts for this type of coupling.