Fabrication of magnetic amino-functionalized nanoparticles for S-arylation of heterocyclic thiols

Abstract

A series of uniformed mono-disperse magnetic nanoligands (MNLs) (CoFe₂O₄–NH₂ (MNL A), Fe₃O₄@Si(CH₂)₃NH₂ (MNL B), Fe₃O₄@Si(CH₂)₃NHC(O) (CH₂)₂PEI (MNL C) and Fe₃O₄@Si(CH₂)₃NHC(O)PEI (MNL D)) were obtained by loading two ligands, an aminosilane coupling agent and PEI-600, onto magnetic nanoparticles prepared using a solvothermal method. The catalytic applications of the synthesized MNLs were explored for the cross-coupling reaction of heterocyclic thiols with aromatic iodides. The reactions were carried out in the presence of CuI (5 mol%), MNL (10 mol% N) and K₂CO₃ (1.3 eq.) in DMF at 120 °C. A variety of heterocyclic sulfides were afforded in good to excellent yields (up to 98%) when MNL B was used. The magnetic, crystal, organic matter structure and morphology of MNL B exhibited no obvious changes after five consecutive cycles. XPS characterization of MNL B revealed the combination of a small amount of Cu⁰ nanoparticles, but this had no significant effect on catalytic performance.