Water-soluble, 1,3,5-Triaza-7-phosphaadamantane-stabilized palladium nanoparticles and their application in biphasic catalytic hydrogenations at room temperature

Water-dispersible Pd nanoparticles stabilized by the hydrophilic cage-like aminophosphine ligand 1,3,5-triaza-7-phosphaadamantane and its N-methyl derivative were synthesized and fully characterized in the colloidal state by TEM, and NMR and UV spectroscopy and in the solid state by X-ray photoelectron spectroscopy and powder XRD. The three different nanoparticles obtained showed a narrow distribution range with average core sizes of 2.8, 3.2, and 3.5 nm. The activity of some of these Pd nanoparticles as catalysts in the biphasic hydrogenation of organic substrates under mild conditions has been tested, and good results and excellent reusability (up to nine catalytic runs) were obtained.