Dendrimers cluster polymers

In general, silver clusters in solution are prepared by reduction of silver ions. Proper scaffolds, e.g., DNA, proteins, dendrimers and polymers, are essential to prevent the aggregation of clusters to larger nanoparticles. Although it is clear that the emission originates from few-atom silver clusters, many aspects of this exciting class of nanoscopic metals are not yet fully understood. 

Studies of nanochemical systems span many areas, from the study of the interactions of individual atoms and how to manipulate them, how to control chemical reactions at an atomic level, to the study of larger molecular assembhes, such as dendrimers, clusters, and polymers. From studies of assemblies, significant new structures—such as nanotubes, nanowires, three-dimensional molecular assembhes, and lab-on-a-chip devices for separations and biological research—have been developed. 

A. Kimoto, J. Cho, M. Higuchi, and K. Yamamoto, Novel carbazole dendrimers having a metal coordination site as a unique hole-transport material, Macromolecular Symposia 209 (Organo-metallic and Coordination Clusters and Polymers) pp. 51-65 (2004). 

Bielinska et al. define DNCs as hybrid nanoparticles formed by the dispersion and immobilization of guest atoms or small clusters in dendritic polymer matrices. These authors describe the synthesis of 5-25 nm DNCs of Au NPs and G5-PAMAM dendrimers through UV decomposition of the PAMAM-HAuCf precursor. These nanoparticles have been imaged by in both in vitro and in vivo conditions [135]. 

O. Katzenelson, H. Z. Hel-Or, D. Avnir, Chem. Eur. J. 1996, 2, 174-181] and serve for definition of the chirality of large su-pramolecular and macromolecular systems (e.g. chiral clusters, aggregates, polymers, or dendrimers). 

Advances in techniques include sophisticated NMR methods, both in solution and the solid-state, and computational methods, and these, coupled with X-ray diffraction and other established methods, have been applied to the study of a wide variety of structures. Topics covered in the book include Sn(II) clusters, tin Zintl ions, Sn(II) heterobimetallic compounds, RsSn+ cations, stannylenes (R2Sn ), stannenes (R2Sn=SnR2 and R2Sn=CR2), stannynes (RSn=SnR), organotin oxide, carboxylate and sulfonate clusters, dendrimers and macrocycles, organotin polymers, Sh-tt interactions, unusual bondings and structures, and compounds with non-linear optical properties. 

It is noted that a growing number of dendrimers and hyperbranched polymers have been synthesized that have metal-metal bonded dimers or metal clusters attached to the surface of the dendrimer. These materials are analogous to polymers that have metal-metal units appended to the polymer backbone rather than incorporated into the backbone chain, and as such they are not covered in this chapter. The field was recently reviewed by Rossell and co-workers.54 The interest in these materials stems from the catalytic properties of the metal complexes attached to the dendrimer surface. In particular, these dendrimer species offer the opportunity to combine the advantages of homogeneous and heterogeneous catalysis, because the materials can be recycled by nanofiltration. 

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