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 (Fe 3 O 4 @SiO 2 -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 Fe 3 O 4 @SiO 2 -Cl to form a quaternary ammonium salt as an ionic Scheme 1. Various pathways for the synthesis of propargylamines.[a]