As nanoreactors

These P-CD/adamantyl pseudorotaxane-terminated dendrimers can be used as nanoreactors in the preparation of gold and platinum nanoparticles in water... 

The most intensive development of the nanoparticle area concerns the synthesis of metal particles for applications in physics or in micro/nano-electronics generally. Besides the use of physical techniques such as atom evaporation, synthetic techniques based on salt reduction or compound precipitation (oxides, sulfides, selenides, etc.) have been developed, and associated, in general, to a kinetic control of the reaction using high temperatures, slow addition of reactants, or use of micelles as nanoreactors [15-20]. Organometallic compounds have also previously been used as material precursors in high temperature decomposition processes, for example in chemical vapor deposition [21]. Metal carbonyls have been widely used as precursors of metals either in the gas phase (OMCVD for the deposition of films or nanoparticles) or in solution for the synthesis after thermal treatment [22], UV irradiation or sonolysis [23,24] of fine powders or metal nanoparticles. 

Kim D, Oh S, Lee J (1999) Preparation of ultrafine monodispersed Indium-Tin Oxide particles in AOT-Based reverse microemulsions as nanoreactors. Langmuir 15(5) 1599-1603... 

Lee, Y Lee, J., Bae, C.J., Park, J.G., Noh, H.J., Park, J.H. and Hyeon, T. (2005) Large-scale synthesis of uniform and crystalline magnetite nanoparticles using reverse micelles as nanoreactors under reflux conditions. Advanced Functional Materials, 15 (3), 503-509. 

Rhee and coworkers published the synthesis of bimetallic Pt-Pd nanoparticles [57] or Pd-Rh nanoparticles [58] within dendrimers as nanoreactors. These nanocatalysts showed a promising catalytic activity in the partial hydrogenation of 1,3-cyclooctadiene. The reaction was carried out in an ethanol/water mixture at 20 °C under dihydrogen at atmospheric pressure. The dendrimer-encapsulated nanoclusters could be reused, without significant loss of activity. 

Kaneda et al. reported substrate-specific hydrogenation of olefins using the tri-ethoxybenzamide-terminated polypropylene imine) dendrimers (PPI) as nanoreactors encapsulating Pd nanoparticles (mean diameter 2-3 nm) [59]. The catalytic tests were performed in toluene at 30 °C under dihydrogen at atmospheric pressure (Table 9.3). The hydrogenation rates were seen to decrease with increasing generation of dendrimers, from G3 to G5. 

PS-PEO reverse spherical micelles have been used as nanoreactors for the synthesis of metallic nanoparticles, as shown by the works of Moller and coworkers [102] and Bronstein et al. [103]. 

As a last example on the fabrication of silver clusters, it is worth mentioning that they can also be prepared in microemulsions, where the small droplets of water act as nanoreactors. The surfactant used was AOT and the reducing agent was a very mild one, i.e. sodium hypophosphite. In this manner, fluorescent silver clusters with less than ten atoms are formed and showed planar shape when deposited onto gold substrates, as determined by scanning tunneling microscopy [67, 68]. 

Out of these assemblies, microemulsion droplets and swollen micelles have been widely used as nanoreactors for inorganic nanoparticie synthesis [20-23]. These self-assembled nanosized beakers/droplets provide a robust and tunable environment that permits size-controlled encapsulation of... 

Unilamellar vesicles prepared from mixtures of cetyl trimethylammonium tosylate and sodium dodecyl benzene sulfonate 8-Al203 prepared in vesicles Morphologies and sizes of 8-Al203 formed in vesicles were investigated by TEM and X-ray diffraction measurements use of vesicles as nanoreactors for the precipitation of ceramic particles was examined 129... 

Functionalised dendrimers permit exploitation of the advantages of homogeneous and heterogeneous catalysis. Their spheroid architecture facilitates better recovery than comparable catalysts on polymer supports. They are distinctly easier to separate from the reaction mixture because the catalytic dendrimer molecules are larger than those of the resulting product. This attribute makes the dendrimers attractive as nanoreactors . 

In a sense, PAMAM dendrimers can be thought of as nanoreactors for preparing bimetallic nanoparticles. Several synthetic methodologies are now available for preparing a wide variety of bimetallic nanoparticles on the order of 1-3 nm. Beyond well-mixed nanoparticles, it is also possible to selectively... 

Larger capsules prepared by the same group have been used extensively as nanoreactors in which exotic chemical species can be formed. The group has also used a molecular panel approach as shown in Fig. 3.8. These compounds are, however, too small for any biomimetic activity. 

Bruns N, Tiller JC (2005) Amphiphilic network as nanoreactor for enzymes in organic solvents. Nano Lett 5 45—48... 

Baier G, Musyanovych A, Dass M, Theisinger S, Landfester K (2010) Crosslinked starch capsules prepared in inverse miniemulsion as nanoreactors for dsDNA and polymerase chain reaction. Biomacromolecules 11 960-968... 

Armes et al. [49] have reported the use of pH-responsive microgels based solely on 2-(diethylamino)ethyl methacrylate (DEA) as colloidal templates for the in situ synthesis of Pt nanoparticles (PtNPs). The swollen microgels can be used as nanoreactors efficient impregnation with PtNPs can be achieved by incorporating precursor platinum compounds, followed by metal reduction. Addition of platinic acid, H2PtCl6, to the latex particles causes the protonation of the tertiary amine... 

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