Highly Efficient Aqueous Synthesis of Propargylamines through C–H Activation Catalyzed by Magnetic Organosilica-Supported Gold Nanoparticles as an Artificial Metalloenzyme

چکیده مقاله

Highly efficient magnetic organosilica-supported gold nanoparticles were developed as an artificial metalloenzyme for the synthesis of propargylamines through C–H activation in water under an ambient atmosphere. Herein, we present a very simple and efficient method for the deposition of Au nanoparticles on porous magnetic organosilica (Fe₃O₄@SiO₂-Cl) through the thermal reduction of an organometallic Au^III complex. As a nucleophile, a Au^III polypyridyl coordination complex could react with alkyl halides from the Fe₃O₄@SiO₂-Cl to form a quaternary ammonium salt as an ionic liquid; subsequently, the ligand was oxidized and the Au nanoparticles were embedded into the porous organosilica shell. The synergic effect of the gold nanoparticles as catalytically active sites, pyridinium chloride as a phase-transfer agent, and the magnetite nanoparticle core, which could function as a protein mimic, endow the material with high efficiency, stability, recoverability, reusability, and good turnover frequency, all of which are necessary characteristic for an artificial enzyme. A reliable catalytic procedure for the synthesis of propargylamines was identified. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim