Palladium Nanoparticles Bonded to Two‐Dimensional Iron Oxide Graphene Nanosheets: A Synergistic and Highly Reusable Catalyst for the Tsuji–Trost Reaction in Water and Air

Abstract

Low cost, high activity and selectivity, convenient separation, and increased reusability are the main requirements for noble-metal-nanocatalyst-catalyzed reactions. Despite tremendous efforts, developing noble-metal nanocatalysts to meet the above requirements remains a significant challenge. Here we present a general strategy for the preparation of strongly coupled Fe(3)O(4) and palladium nanoparticles (PdNPs) to graphene sheets by employing polyethyleneimine as the coupling linker. Transmission electron microscopic images show that Pd and Fe(3)O(4) nanoparticles are highly dispersed on the graphene surface, and the mean particle size of Pd is around 3 nm. This nanocatalyst exhibits synergistic catalysis by Pd nanoparticles supported on reduced graphene oxide (rGO) and a tertiary amine of polyethyleneimine (Pd/Fe(3)O(4)/PEI/rGO) for the Tsuji-Trost reaction in water and air. For example, the reaction of ethyl acetoacetate with allyl ethyl carbonate afforded the allylated product in more than 99 % isolated yield, and the turnover frequency reached 2200 h(-1). The yield of allylated products was 66 % for Pd/rGO without polyethyleneimine. The catalyst could be readily recycled by a magnet and reused more than 30 times without appreciable loss of activity. In addition, only about 7.5 % of Pd species leached off after 20 cycles, thus rendering this catalyst safer for the environment.

Facile Fabrication of Highly Active Magnetic Aminoclay Supported Palladium Nanoparticles for the Room Temperature Catalytic Reduction of Nitrophenol and Nitroanilines

“…Besides the k value, the TOF was also calculated and the value was about 0.928 s −1 . Compared with recent studies with catalysts based on Pd nanoparticles, the TOF value of AC@Fe 3 O 4 @Pd nanocatalyst was also higher than others [ 36 , 41 , 42 ].…”

Modified Nanocarbons for Catalysis

“…In 2014, Wang et al . immobilized Fe 3 O 4 and Pd NPs onto rGO functionalized with polyetheylenimine (PEI) endcapped with 3,4‐dihydroxybenzaldehyde to obtain material 118 (Scheme ) . Both Fe 3 O 4 and Pd NPs resulted well dispersed onto the surface of material 118 as evidenced by TEM analysis.…”

“…Su et al . used a similar approach to the one used by Wang et al . to obtain a heterogeneous catalyst resembling material 118 and active in the reduction of 4‐nitrophenol…”

Concerted Catalysis in Tight Spaces: Palladium‐Catalyzed Allylation Reactions Accelerated by Accumulated Active Sites in Mesoporous Silica

“…Concerted catalysis between metal complexes and organic functional groups is a notable strategy to create novel heterogeneous catalysis and a highly efficient technique for molecular transformations . Several research groups have reported Pd, Rh, and Cu complexes immobilized on solid surfaces with organic functionalities for the efficient transformation of organic molecules. In the case of concerted catalysis with Pd complexes, the allylation of nucleophiles was shown to be effectively accelerated by the assistance of a basic amine group: both allylic substrates and nucleophiles were activated by Pd complexes and bases, respectively …”