Water-soluble and durable Au nanoclusters, smaller than 4 nm with a narrow size distribution, weresupported on a pH- and solvent-responsive water-soluble polyampholyte (SPES). Such synthesizedAu@SPES hybrids possessed clear pH- and solvent-sensitive properties, and exhibited precipitationbehaviors in response to pH and solvent changes in aqueous solution. Furthermore, the recycledcatalyst could be redissolved in water for reuseviasimple procedures based on the pH-sensitivity of thepolyampholyte. By employing such catalysts, aerobic oxidation of alcohols should be able to be carriedout in a homogeneous manner and may thus give rise to similar catalytic activities and selectivities asthe homogeneous parent system. The phase separation and sensitivity of the SPES-stabilizing Aunanoclusters permitted a facile separation of the clusters from the reaction mixture without anynegative aggregation.
