With Phosphinophosphonic Acids to Nanostructured, Water-Soluble, and Catalytically Active Rhodium Clusters



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Pressure-sized clusters: Aqueous solutions of rhodium complexes stabilized by phosphinophosphonic acid ligands turn ink-black under a hydrogen atmosphere. Depending on the hydrogen pressure applied, rhodium clusters of 2–6 nm can be isolated (see scheme). These clusters are catalysts for the biphasic hydrogenation of olefins, arenes, and nitro compounds.