“Release and catch” catalytic systems

Abstract

In this perspective article the “release and catch” catalytic system concept is discussed. A “release and\ud catch” catalytic system is prepared by non-covalent immobilization of the catalytic moiety on a suitable support, but differently from the usual non-covalently supported catalyst, the catalytic moiety is released in solution over the course of the reaction and it is recaptured at the end of the reaction. Such a “catalyst-\ud sponge like” or “boomerang” system allows one to combine the benefits of homogeneous and heterogeneous catalysis and can be applied to organometallic-based catalysts, organocatalysts and metal-based catalysts

Design of PNIPAAM covalently grafted on halloysite nanotubes as a support for metal-based catalysts

“…The absence of leaching of palladium has been attributed to a "release and catch" mechanism. 30 It has been proposed that Suzuki cross-coupling can involve the presence of soluble palladium species (leaching) arising from the surface of the catalyst. However, aer completion of the catalytic process, palladium is redeposited onto the support avoiding the leaching in solution.…”

Advances in Organic and Organic-Inorganic Hybrid Polymeric Supports for Catalytic Applications

“…Both catalysts were tested in Suzuki-Miyaura and Mizoroki-Heck reactions and catalyst 144b-Pd showed the best performances. The authors proposed a "release and catch" mechanism [88] for both reactions. During the Suzuki reaction, the re-deposition of soluble Pd-species was highly effective.…”

Definition of green synthetic tools based on safer reaction media, heterogeneous catalysis, and flow technology

“…The use of flow approach has proven that many solid palladium sources operate via a "release and catch" mechanism [80] in which the active Pd species are released from the solid support during the oxidative addition step and then, at the conclusive elimination step when C-C bond is formed, recaptured onto the heterogeneous support. The effectiveness of this mechanism is related to the solvent used as medium, temperature and obviously to the capability of the heterogeneous support to stabilize palladium nanoparticles [81][82][83].…”