• Difunctional poly(phosphorhydrazone) PPH dendritic catalysts have been synthesized. • PPH dendrimers bear both a perfluoroalkyl polymer and a ligand complexing Pd or Cu. • Difunctional PPH dendrimers catalyze Stille, Suzuki, and Heck C–C couplings • The influence of solvent, temperature, base, catalyst and generation is studied. • The easy difunctionalization on the surface is a unique property of PPH dendrimers. Dendrimers are a special type of hyperbranched polymers constituted of branched monomers arranged radially around a central core, and synthesized step-by-step. Phosphorus-containing dendrimers of type poly(phosphorhydrazone), PPH, possess phosphorus atoms at each branching point, and P(S)Cl 2 terminal functions every two steps. That offers an exceptional platform for surface engineering. Such terminal functions enable the sequential grafting of one function, then of a second function, to get precisely difunctionalized dendrimers. This strategy is exploited here to introduce, in a strictly programmed manner, both a fluoroalkyl chain and a ligand for complexing a metal (Pd or Cu), thus generating a new family of fluorous, difunctional dendritic catalysts. The dendritic Pd complexes were used as soluble catalysts in Stille, Suzuki and Heck C–C cross-couplings, whereas the Cu complexes were used in C-N couplings. The influence of the length of the fluoroalkyl chain, the generation of the dendrimers, the base, the solvent, and the possible recovery and re-use of the catalyst on the outcome of the catalytic reactions are described, highlighting how dendrimer architecture can be combined to tune activity and recyclability in a uniquely systematic way.
Petriccone et al. (Sun,) studied this question.
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