Immobilization of an Aminobisphosphine-Pd-II Complex over Graphene Oxide: An Efficient and Reusable Catalyst for Suzuki-Miyaura, Ullmann Coupling and Cyanation Reactions

The grafting of an aminobis(phosphine)-Pd-II complex (PNP-Pd-II) [PdCl2{(Ph2P)(2)N(CH2)(3)Si(OMe)(3)}] (2) on graphene oxide (GO) has been carried out by a condensation reaction between methoxysilane groups of 2 and hydroxyl groups of GO. The composite material was characterized by FTIR spectroscopy , solid-state P-31 NMR spectroscopy, SEM, TEM, XPS and ICP-AES techniques. All these tools support the clean immobilization of compound 2 on GO. The composite material showed high catalytic activity in Suzuki-Miyaura, Ullmann coupling and cyanation reactions. The heterogeneity of the composite was confirmed by a hot filtration test. The immobilized PNP-Pd-II shows comparable activity to its homogeneous analogue 2. The recycling ability of the catalyst was examined for five consecutive runs, which showed little or no reduction in its catalytic efficiency.