Gold Nanoparticles Supported on Imidazole‐Modified Bentonite: Environmentally Benign Heterogeneous Catalyst for the Three‐Component Synthesis of Propargylamines in Water

Abstract

Gold nanoparticles supported on imidazole‐modified bentonite, Bent@Im@Au NPs, has been developed for the first time as an effective heterogeneous catalyst for the synthesis of propargylamines under mild reaction conditions in water at a loading of 0.07 mol % of Au. Various techniques such as X‐ray diffraction, high‐resolution transmission electron microscopy, Fourier transform infrared spectroscopy, and element mapping by scanning electron microscopy were used to determine the physicochemical properties of the catalysts. The new gold catalyst was found to be highly active providing high to excellent yields of A3 coupling products via the reactions of various aldehydes, having electron‐withdrawing as well as electron‐donating substituents, with different amines and alkynes. The catalysts can be easily recovered and reused without significant loss of activity and the recycled catalyst was characterized.We are grateful to the Institute for Advanced Studies in Basic Sciences (IASBS) Research Council and Iran National Science Foundation (INSF-Grant number of 95844587) for support of this study. C.N. is also thankful for financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) (projects CTQ2013-43446-P and CTQ2014-51912-REDC), the Spanish Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación (AEI), the Fondo Europeo de Desarrollo Regional (FEDER, EU) (projects CTQ2016-76782-P and CTQ2016-81797-REDC), the Generalitat Valenciana (PROMETEOII/2014/017), and the University of Alicante