| Summary: | A cycloaurated phosphinothioic amide gold(III) complex was supported on amorphous silica with the aid of an imidazolium ionic liquid (IL) physisorbed in the SiO<sub>2</sub> pores (SiO<sub>2</sub>⁻IL) and covalently bonded to the SiO<sub>2</sub> (SiO<sub>2</sub>@IL). Gold(0) nanoparticles (AuNPs) were formed in situ and subsequently immobilized on the SiO<sub>2</sub>⁻IL/SiO<sub>2</sub>@IL phase. The resulting catalytic systems Au⁻SiO<sub>2</sub>⁻IL and Au⁻SiO<sub>2</sub>@IL promoted the solvent-free A<sup>3</sup> coupling reaction of alkynes, aldehydes, and amines in high yields under solvent-free conditions with very low catalyst loading and without the use of additives. The Au⁻SiO<sub>2</sub>@IL catalyst showed good recyclability and could be reused at least five times with yields of propargylamines of ≥80%. This synthetic method provides a green and low cost way to effectively prepare propargylamines. Additionally, <sup>31</sup>P high resolution magic angle spinning (HRMAS) NMR spectroscopy is introduced as a simple technique to establish the Au loading of the catalyst.
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