ABSTRACT
A simple and efficient protocol for the synthesis of diaryl thioethers from the reaction of thiourea with a wide variety of aryl halides, including aryl iodides, aryl bromides and aryl chlorides in the presence of 3D hierarchical core-shell Fe3O4@NiO/Co3O4 microspheres has been described. This reaction enables the one-pot synthesis of diaryl thioethers in good to high yields using a non-toxic and magnetically separable catalyst in PEG-400 as an eco-friendly, safe, inexpensive and thermally stable solvent. Magnetic separation and reusability of catalyst for eight times without any significant loss of activity, the use of a commercially available, eco-friendly, cheap and chemically stable sulfur transfer agent and solvent, operational simplicity, environmentally benign, easier work-up procedure and cost efficiency make this method a promising candidate for potential applications in some organic reactions.
The catalytic activity of Fe3O4@NiO/Co3O4 as a novel and inexpensive catalyst was investigated in the C-S cross coupling reaction.
GRAPHICAL ABSTRACT
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Acknowledgements
The authors gratefully acknowledge the partial support of this study by Ferdowsi University of Mashhad Research Council (grant number p/3/51304). Furthermore, it should be noted that this manuscript is derived from the thesis entitled ‘Ferromagnetic 3D hierarchical core-shell Fe3O4@NiO/Co3O4 microspheres as an efficient and heterogeneous nanostructured ligand-free catalyst for C–S bond formation in poly (ethylene glycol).'
Disclosure statement
No potential conflict of interest was reported by the author(s).