Dendrimer Templates for the Formation of Gold Nanoclusters

Abstract

Charged poly(amidoamine) (PAMAM) dendrimers are used to create organic-inorganic hybrid colloids in aqueous solution. The formation of gold colloids upon reduction of a gold salt precursor serves as a model reaction to study the influence of reaction conditions and dendrimer generation on the resulting nanostructures. Characterization by transmission electron microscopy (TEM), small-angle neutron scattering (SANS), and small-angle X-ray scattering (SAXS) show that the gold particles are formed inside the dendrimer and located offset from the center. Although lower generation dendrimers aggregate when stabilizing the metal particles formed, dendrimers of generation 6-9 can template one gold colloid per dendrimer molecule, the size of which is well-controlled by the number of gold atoms added per dendrimer. For generation 10, multiple smaller gold particles per dendrimer are observed. The effectiveness of PAMAM dendrimers as templates in the host-guest nanoscale synthesis is confirmed for different chemical reactions.

Dendrimer-Encapsulated Metal Nanoparticles: Synthesis, Characterization, and Applications to Catalysis

“…53 More recently, Amis and co-workers, 35 Esumi et al, 36 and Goodson 54 have provided remarkably detailed microscopy, scattering, and photophysical data that have yielded additional insight into dendrimer encapsulation of metal nanoparticles. New results from our laboratory indicate that even semiconductor quantum dots (CdS) are accessible by this synthetic route, 55 and Amis et al have further expanded the scope of dendrimer-encapsulated nanoparticles by preparing them within monolithic dendrimer-containing polymer composites.…”

A combined small-angle scattering study of a chemical reaction at specific sites and reaction-induced self-assembly as a problem in open non-equilibrium phenomena

“…Since the first successful report by Crooks and his coworkers in 1998 (Zhao et al, 1998), quite a few studies have been reported, focusing on synthesis, structure and also catalytic activity of metal nanoparticles stabilized by dendrimers (Balogh & Tomalia, 1998;Grö hn et al, 2000). Most of the studies in this field deal with the reduction in the solution where dendrimers are molecularly dissolved and metal ions are encapsulated in an interior space of single dendrimers.…”

Dendrimer-based bionanomaterials produced by surface modification, assembly and hybrid formation

“…84 Considering their applications to bionanomaterials, PEG-modified PAMAM dendrimers have been used for complex formation with Au NPs. [85][86][87] As is the case of unmodified PAMAM dendrimers, PEG-modified PAMAM dendrimers are useful as a template for the formation of Au NPs.…”