Supramolecular catalysts by encapsulating palladium complexes within dendrimers

Dendrimers are well-defined and highly branched macromolecules. By utilizing their capsular architectures, dendrimers encapsulating various catalytically active species can be prepared, which often bring about unique catalysis. Treatment of the alkylated PPI dendrimer with 4-diphenylphosphinobenzoic acid and PdCl(C3H5)]2 afforded the dendrimer-encapsulated Pd complex using ionic interactions. The dendrimers encapsulating Pd complexes acted as unique supramolecular catalysts for the Heck reaction and allylic amination. The specific nanoenvironment created by the dense amino groups inside the dendrimers can provide high catalytic activity and stability for the Pd complexes. Facile recovery of the dendritic catalysts could be achieved by thermomorphic systems.