Pd-PVP-Fe (palladium-poly(N-vinylpyrrolidone)-iron) catalyzed S-arylation of thiols with aryl halides in aqueous media

•The Pd-PVP-Fe bimetallic catalyst is highly active and selective for coupling of aryl halides with thiols.•The catalyst was characterized by XPS, SEM, EBSD, EDX, TGA, AAS, and UV–vis spectrum.•The yield and selectivity can be controlled by adjusting the order of addition of substrates and catalyst.•The catalyst could be reused for the six times without significant degradation in activity sites.•Natural of bimetallic catalyst after reusing cycles was investigated by SEM, EBSD, EDX, AAS, and UV–vis.

Pd-PVP-Fe (palladium-poly(N-vinylpyrrolidone)-iron) nano catalyst catalyzes selective C–S cross-coupling (S-arylation) reactions of thiols with aryl halides and avoids the formation of S–S (disulfide) homocoupling byproducts. The reactions were carried out in aqueous media using only 0.23 mol% palladium with high selectivity and short reaction time. The effects of the Pd0 and Fe0 moieties on the C–S cross-coupling reaction mechanism, yield, and selectivity were investigated. The yield and selectivity can be controlled by adjusting the order of adding the reactants and catalyst into the reaction medium. The X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) microscopy, energy dispersive X-ray (EDX) spectroscopy, and thermal gravimetric analysis (TGA) tools were used to characterize the catalyst. The C–S cross-coupling reaction process could be repeated up to six times without losing effectiveness. The metals leaching of Pd-PVP-Fe nanocatalyst after reusing cycles were investigated by atomic absorption spectroscopic (AAS) and EDX spectroscopy. The nature of Pd metal after the first run of the C–S cross-coupling reaction was studied by UV–vis spectrophotometry. The morphology of bimetallic nanocatalyst after the first run of the C–S cross-coupling reaction was investigated by SEM, EBSD, and EDX microscopy.

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