Endeavors on the development of efficient and sustainable supported metal catalysts for chemical synthesis on solid-liquid interfaces

Supported metal catalysts, particularly for precious metals, have gained increasing attention in green synthetic chemistry. They can make metal-catalyzed organic synthesis more sustainable and economical due to easy separation of product with less metal residue, as well as reusability of the high-cost catalysts. Although great effort has been spent, the precise catalytic mechanism of supported metal-catalyzed reactions has not been clearly elucidated and the development of efficient and stable recyclable catalysts remains challenging. This highlight reveals a “molecular fence” metal stabilization strategy and discloses the metal evolution in Pd-catalyzed C-C bond formation reactions using N-heterocyclic carbene (NHC)-functionalized hypercrosslinked polymer support, wherein the polymeric skeleton isolates or confines the metal species involved in the catalytic reactions, and NHC captures free low-valent metal species in solution and stabilizes them on the support via strong metal-support coordination interaction. This strategy creates a novel route for the development of supported metal catalysts with high stability and provides insights into the reaction mechanism of heterogeneous catalysis.