Pd immobilized on modified magnetic Fe3O4 nanoparticles: Magnetically recoverable and reusable Pd nanocatalyst for Suzuki-Miyaura coupling reactions and Ullmann-type N-arylation of indoles

The Pd supported on amidoxime (AO)-functionalized Fe3O4 (Fe3O4/AO/Pd) hybrid material was used as an effective and recyclable nanocatalyst in Suzuki-Miyaura coupling reactions. The catalyst was very effective for the Suzuki-Miyaura reaction of aryl halides (Ar–I, Ar–Br, Ar–Cl) with phenylboronic acid and conversion was excellent in most cases. The yields of the products were in the range from 7–98%. The catalyst showed good stability and could be recovered and reused for six reaction cycles without a significant loss in its catalytic activity. Also, a wide range of N-arylated indoles are selectively synthesized through intermolecular C(aryl)–N bond formation from the corresponding aryl iodides and indoles through Ullmann-type coupling reactions in the presence of the prepared catalyst.