Abstract

MPUNGOSE, P.P. et al. : a copper- and ligand-free quasi-heterogeneous catalyst for aquacatalytic Sonogashira cross-coupling reaction. J. S. Afr. Inst. Min. Metall. [online]. 2017, vol.117, n.10, pp.955-962. ISSN 2411-9717.  https://doi.org/10.17159/2411-9717/2017/v117n10a5.

A Pdo.o2Ceo.98O2-e solid solution oxide was synthesised in one step using a urea-assisted solution combustion method. XRD, ICP-OES, BET, XPS, SEM, EDX, TEM, TGA and Raman spectroscopy were used to study the structural and electronic properties of the as-prepared Pd₀₀₂Ce₀₉₈O_2-6 catalyst. The catalyst testing results revealed that the Pd₀₀₂Ce₀₉₈O_2-6 system performs as an efficient precatalyst for the Sonogashira cross-coupling reactions under copper- and ligand-free conditions. A wide range of iodoarenes were efficiently coupled to phenylacetylene with good to excellent isolated yields. A thorough investigation through a series of suitable experiments explicitly showed that the Sonogashira cross-coupling reaction is accomplished via a quasi-heterogeneous mechanism by the leached Pd(0) species. As a result, the Pd₀₀₂Ce₀₉₈O_2-6 lost some activity upon recycling.

Keywords : Pd²⁺ substituted ceria; solution combustion; nanoparticles and Sonogashira coupling reactions.

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