Efficient one-pot synthesis of propargylamines catalysed by gold nanocrystals stabilized on montmorilloniteElectronic supplementary information (ESI) available. See DOI: 10.1039/c4cy00666f

• Main Authors: Borah, Bibek Jyoti, Borah, Subrat Jyoti, Saikia, Kokil, Dutta, Dipak Kumar
• Format: Article
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/c4cy00666f

Size selective Au 0 -nanoparticles were generated in situ in the nanopores of modified montmorillonite. The modification of montmorillonite was carried out with HCl under controlled conditions for generating nanopores (less than 8 nm) in the matrix and these nanopores acted as "hosts" for the in situ generation of Au 0 -nanoparticles. The synthesis consisted of impregnation of the acid-activated montmorillonite with HAuCl 4 aqueous solution followed by reduction with NaBH 4 . The synthesised Au 0 -nanoparticles crystallized in the face centred cubic lattice were single crystals with a preferential growth direction along the (111) plane. A N 2 adsorption-desorption study revealed specific surface areas of 327-579 m 2 g −1 , large specific pore volumes ~0.7 cm 3 g −1 , and pore diameters of 0-10 nm of the support. TEM, FESEM and X-ray studies indicate that Au 0 -nanoparticles of 0-10 nm were evenly distributed on the support which then serves as an efficient green catalyst for the one-pot, three-component coupling of an aldehyde, an amine and an alkyne via C-H alkyne-activation to synthesize propargylamines with 82-94% yield and 100% selectivity under mild reaction conditions. The nanocatalysts can be recycled and reused several times without significant loss of their catalytic activity. Size selective Au 0 -nanoparticles were generated in situ in the nanopores of montmorillonite and applied in the one-pot, three-component coupling of an aldehyde, an amine and an alkyne to synthesize propargylamines.