A magnetically separable MgFe2O4/Cu nanocomposite was prepared and used as a novel heterogeneous catalyst for the synthesis of new β-thiol-1,4-disubstituted-1,2,3-triazoles from thiiranes.

The magnetic nanoparticles of Fe3O4 were synthesized through a solid-state reaction of hydrated iron (III) chloride, hydrated iron (II) chloride and NaOH, and then purified by calcination at high temperature. In order to protect ferrite nanoparticles from oxidation and agglomeration, and to manufacture a novel catalytic system of anchored copper on the magnetic substrate, the Fe3O4 was core-shelled by adding tetraethyl orthosilicate. Next, the prepared Fe3O4@SiO2 was supported by phosphomolybdic acid (PMA) as the second layer of nanocomposite at 80 °C in 30 h. Eventually, the new nanocomposite of Fe3O4@SiO2-PMA-Cu was successfully synthesized by adding copper (II) chloride solution and solid potassium borohydride. The structure of magnetic nanocatalyst was acknowledged through different techniques such as EDS, VSM, XRD, TEM, FT-IR, XPS, TGA, BET and FESEM. The synthesis of β-thiolo/benzyl-1,2,3-triazoles from various thiiranes, terminal alkynes and sodium azide was catalyzed by Fe3O4@SiO2-PMA-Cu nanocomposite in aqueous medium. In order to obtain the optimum condition, the effects of reaction time, temperature, catalyst amount and solvent were gauged. The recycled catalyst was used for several consecutive runs without any loss of activity.

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Magnetically separable CoFe2O4/Cu(OH)2 nanocomposite was prepared and used as a novel heterogeneous catalyst for synthesis of β-hydroxy-1,4-disubstituted-1,2,3-triazoles from epoxides.

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Magnetically separable MgFe 2 O 4 /Mg(OH) 2 nanoparticles were fabricated and characterized using various techniques. These nanoparticles were used as a new catalyst for regioselective one-pot synthesis of β-chloroacetates from epoxides in the presence of NiCl 2 ⋅6H 2 O and acetic anhydride. All reactions were carried out in ethanol at room temperature within 22-80 min giving the β-chloroacetates in high to excellent yields. The nanocatalyst was easily separated using an external magnet and reused several times without any significant loss of efficiency or magnetic property.

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