Fabrication of Pd@gelatin/agarose nanoparticles: a new heterogeneous catalyst for heck reaction

In last years, stabilized metallic nanoparticles have probably been the most frequently employed in organic synthesis.[1] Heterogeneous catalysis, and supported metal catalysts in particular, play important roles in both industry and academia.It is well known that transition metal nanoparticles (MNPs) such as palladium, are utilized to carry out coupling reactions due to their superiority over traditional metal catalytic systems with respect to controllable size, more degrees of freedom and small surface with active sites accessible to reactants. Also, immobilization of metal NPs in solid supports such as bioorganic beds allowed obtaining recoverable catalysts for crosscoupling reactions. Among the most fundamental reactions in organic chemistry,Mizoroki-Heck cross coupling as a powerful synthetic tool and a major area in multiple organic transformations has received great attention. [2] In the past 5 years, we have developed an easy synthetic route to preparation palladium nanoparticles by using mixture of natural bioorganic carbohydrate as bed. [3] Based on this former work, we describe here the synthesis of Pd nanoparticles stabilized by mixture of gelatin and agarose, and the use of this system as catalyst in the Mizoroki-Heck reaction, along with its recycling (Figure 1).The in situ generation of nanoparticles without addition of any external reducing agents, stability toward air and humidity, easy handling and recycle ability are some unique features of the Pdnp@gelatin/agarose catalytic system.Also the nanocatalyst has been recovered for five runs with some decrease in the catalytic activity of the catalyst.