“water soluble” palladium nanoparticles engineering for C-C coupling, reduction and cyclization catalysis
The use of Pd nanoparticles (Pd-NPs) to realize several important organic reaction can permit to achieve efficient catalysis with low metal loading of metal (<1000 ppm), hence providing greener catalytic system. However, to be truly green Pd-NPs need to be synthesized in a sustainable manner and be able to react in aqueous media in order to avoid the use of organic solvent. Here we described an original and eco-friendly synthesis of Pd-NPs (using benign reactants and simple conditions) perfectly stable in water. Remarkably, this synthesis allow for control over their size and morphology by simply tuning the stabilizer pH. We then evaluated the catalytic efficiency of these Pd-NPs on six different model reactions (Suzuki Myaura, Sonogashira, Heck, nitrophenol reduction and pentynoic cycloizomerization) in aqueous media. We show that the stabilizer structure influence the activity owing to its ability to promote mass transfer of the organic substrates towards the NP surface in the aqueous environment. Finally, catalytic evaluations shows that our nano-catalyst prepared in eco-friendly manner are among the best catalysts described so far in the literature in each cases, with high Turn Over Frequencies reached with low loading of Palladium.
- This article is part of the themed collection: International Symposium on Green Chemistry 2019