| Abstract
| - Platinum and palladium dendrimer-encapsulated nanoparticles (DENs) were prepared within commercially available, fourth-generation, amine-terminated, poly(amidoamine) dendrimers (G4-NH2). Thesynthesis is carried out by selectively encapsulating metal complexes within the dendrimer and thenreducing the resulting composite. Intradendrimer complexation requires control over the solution pH toprevent attachment of the metal complexes to primary amine groups on the dendrimer periphery. Thatis, the surface primary amines of the dendrimer must be selectively protonated in the presence of theinterior tertiary amines. The metal-ion encapsulation and reduction processes were characterized by UV−vis spectroscopy. Forty-atom Pt and Pd DENs were examined by high-resolution transmission electronmicroscopy, which showed that the mean particle sizes were 1.4 and 1.5 nm, respectively, and that bothwere nearly monodisperse (standard deviation = 0.3 nm). The free amine groups on the dendrimer surfacewere used to link Pd DENs to monolithic Au surfaces via an intermediate self-assembled monolayeradhesion layer.
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