Document Type

Article

Publication Date

Spring 2-5-2015

Abstract

tHerein, we report a facile and efficient one-step method for the synthesis of highly active, Pd/Fe3O4nanoparticles supported on graphene nanosheets (Pd/Fe3O4/G) that exhibit excellent catalytic activityfor Suzuki and Heck coupling reactions and that can be magnetically separated from the reaction mix-ture and recycled multiple times without loss of catalytic activity. The synthesis approach is based on theMicrowave (MW)-assisted reduction of palladium and ferric nitrates in the presence of graphene oxide(GO) nanosheets using hydrazine hydrate as the reducing agent. The results provide a fundamental under-standing of the system variables by comparing the catalytic activity and recyclability of four differentcatalysts with different properties. The most active and recyclable catalyst contains 7.6 wt% Pd nanopar-ticles with 4-6 nm diameters in Pd(0) oxidation state well-dispersed with 30 wt% Fe3O4nanoparticleswith 12–16 nm diameters on highly reduced GO containing a C/O ratio of 8.1. These combined propertiesproduce remarkable catalytic activity for Suzuki cross coupling reactions under MW reaction conditionswith an extremely high turnover number (TON) of 9250 and turn over frequency (TOF) of 111,000 h−1at 80◦C. The magnetic properties imparted by the Fe3O4component of the catalyst enables the catalystto be easily isolated and recycled, thus greatly simplifying the ability to purify the reaction products andincreasing the economic value of the catalyst. The utility of these magnetic catalysts towards Suzuki andHeck cross coupling reactions with a variety of functionalized substrates was also demonstrated.

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