Metal-Core-Organic Shell Dendrimers as Unimolecular Micelles.

The synthesis and characterization of nanoparticle-cored dendrimers (NCDs), consisting of a metal core capped by arylpolyethers terminated with ester or carboxylate groups, are reported. These NCDs, comprising nanometer-sized gold clusters at the core and organic dendrons radially connected to the gold core by gold-sulfur bonds, were analyzed by TEM, TGA, UV, IR, and NMR spectroscopies. The density of the branching units connected to the core decreased from 1.90/nm[SUP2] for a first-generation NCD (Au-G1 (CO[SUB2]Me)) to 0.80/nm[SUB2] for a fourth-generation NCD (Au-G4(CO[SUB2]Me)). Although the ester-terminated NCDs were stable and resisted aggregation, they were easily hydrolyzed to the corresponding watersoluble sodium salts. Aqueous solutions of (Au-Gn(CO[SUB2]Na)) exhibited micellar properties. Since these NCDs possess a relatively unpassivated metal core and an organic aryl ether shell with micellar and dendritic properties, they are expected to have important potential applications in catalysis. [ABSTRACT FROM AUTHOR]