Metals particle formation

For the amino-borane dehydrocoupling using [Rh(l,5-cod)(p-Cl)]2 as starting catalyst, an induction period and a sigmoid-shaped kinetic curve (plot of substrate conversion versus time) were also observed, consistent with metal-particle formation. But, for Ph2PH BH3... 

Force C., Belzunegui, J. P., Samz J., Martlnez-Arias A. and Soria J., Influence of precursor salt on metal particle formation in Rh/CeOj catalysts. J. Catal. 197 (2000) pp. 192-199. 

The environmentally benign, nontoxic and nonflammable fluids water and carbon dioxide (CO2) are the two most abundant and inexpensive solvents on earth. Vater-in-CO2 (W/C) or C02-in-water (C/W) dispersions in the form of microemulsions and emulsions offer new possibilities in waste minimization for the replacement of organic solvents in fields including chemical processing, pharmaceuticals, and microlectronics for solubilization and separations (e.g., proteins, ions, heavy metals), particle formation, enzymatic catalysis, organometallic catalysis, and synthesis of polymer colloids and inorganic nanoparticles (2,13,11). 

Overall, this study and the others mentioned in Sections C and D illustrate that ionomers provide supports for a variety of interesting chemical reactions, including metal particle formation, which can be either quite different from those in other media or they can be sufficiently similar to carry out known reactions in a useful type of polymeric material. 

Scheme 3.2 Schematic image of PAHAPS colloid metallation. Step I is incorporation of metal compounds inside the PAHAPS colloids due to interaction with amino groups. Step II Is metal particle formation due to reduction of metal species. Reprinted with permission from Ref [86]. Copyright (2003) American Chemical Society.

Fig. 3.10 TEM image of the cross-section of the PAHAPS-H4 sample obtained after incorporation of K2PdCl4 and metal particle formation using N2H4-xH20.

Noble Metal Particle Formation at Redox-Active Frameworks... 

The model of Natarajan et al, [ 160] introduced a parameter , defined as the critical nucleation number for metal particle formation. It has been shown that with an increase in n, particles of a particular size should grow in number, and the polydispersity in size should also increase. The reason behind this is that with higher values of n, more free metal atoms will be available for growth. 

Unlike PAN, this polymer remains unchanged for thermal treatments below 420°C. The use of two types of polymeric matrices permits the study of the influence of the polymer nature on metal particle formation. Co octacarbonyl was chosen for incorporation into polymeric matrices because it can give ferromagnetic cobalt particles in mild thermal conditions however, previously we have found that Co2(CO)g is not compatible with polybutadiene, polystyrene and a pdly(styrene-butadiene) block copolymer. 

Natarajan, U., Handique, K., Mehra, A., Bellare, J.R., and Khilar, K.C. 1996. Ultra-fine metal particle formation in reverse micellar systems Effects of intermicellar exchange on the formation of particles. Langmuir, 12, 2670-2678. 

Surface-adsorbed polystyrene spheres as a template for nano-sized metal particle formation. Optical properties of nano-sized Au particle, H. Takei, J. Vac. Sci. Technol. B, 1999,17, 1906. 

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