Difunctional phosphorus dendrimer complexes as catalysts in supercritical CO2

Dendrimers offer a rare opportunity to tune catalysis through molecular architecture. Poly(phosphorhydrazone) (PPH) dendrimers, functionalized with perfluoroalkyl chains and palladium imino‑phosphine complexes, were designed to test this principle under the demanding conditions of supercritical CO₂ (scCO₂). Three generations incorporating 6 to 24 Pd centers, alongside their monomeric precursor, were evaluated as catalysts for Stille cross‑coupling. Despite their lack of solubility, the dendrimers remained well dispersed in the medium. Remarkably, catalytic performance increased systematically with dendrimer generation, revealing for the first time a positive dendritic effect in scCO₂.