Copper supported silica-based nanocatalysts for CuAAC and cross-coupling reactions

Copper nanoparticles supported on silica (CuNPs–SiO2) have been explored as sustainable catalysts for various catalytic reactions such as Huisgen 1,3-dipolar cycloaddition (click reaction), carbon-sulfur (C–S), carbon-nitrogen (C–N), and carbon–oxygen (C–O) coupling reactions. The Cu-catalyzed azide–alkyne cycloaddition (CuAAC) protocol that belongs to the family of click chemistry is one of the most reliable and widespread synthetic transformations in organic chemistry, with multidisciplinary applications. The Cu-based SiO2 nanocomposites exhibit superior catalytic activity, stability, and recyclability compared to their unsupported counterparts. Thus, it reveals the advantages and importance of designing Cu nanocomposites with desirable catalytic properties. This review discusses a better understanding of the catalytic behavior of CuNPs–SiO2 nanocatalysts than that of some commercial Cu catalysts with regard to the metal loadings, reaction time, yield of products, recycle tests, and other protocols. Furthermore, recent signs of progress in the synthesis, characterization, and industrial applications of CuNPs–SiO2 nanocatalysts are summarized and discussed along with the prospective outlook of the relevant research fields.