Platinum level scheme

In determining the diversity of reactions which may be catalysed by polyleucine, it has been shown that the oxidation of sulfides to sulfoxides can be performed, achieving excellent levels of asymmetric induction. Thus, when polyleucine is coated onto a platinum electrode, oxidation of sulfides to optically active sulfoxides has been achieved in 77% e.e. and 56% yield, (Scheme 11) [22]... 

System II assnmes that the pore is filled with water vapor as shown. Given the details of the operating conditions and the water management scheme used, it is possible that some pores would be filled with liquid water, a case which is under study but not included in this report. Graphite is used as the carbon support in system III. System IV uses platinum ([100] Pt) as the catalyst. Constant density and constant temperature (NVT) MD simulations were used to study the systems as a function of humidity level. 

This reaction scheme is similar to the one observed with the platinum anode (Fig. 15A). The main difference between room temperature Fenton s reagent and electrochemical oxidation with platinum anode is that the level of TOC elimination is higher for the electrochemical oxidation with platinum (60 % of TOC elimination) than the chemical oxidation at room temperature with Fenton s reagent (30% of TOC elimination) (10). 

Platinum supported on zeolites such as mordenite is also active and the isomerisation of longer-chain alkanes is achieved with such catalysts, under mild conditions. The essential details of the process are illustrated in Scheme 8.19, with the metal function being to establish equilibrium between alkanes, hydrogen and a low level of olefins. The olefin content must be sufficient to allow isomerisation but sufficiently diluted by alkanes to prevent rapid oligomerisation and coking of the catalyst. The performance of the bifunctional catalyst is improved by the introduction of secondary mesoporosity in the mordenite catalyst, to enhance molecular transport between active site and gas stream, and by the generation of extra-framework aluminium sites that promote Lewis acid catalysed reactions. 

Asymmetric Hydrosilylation of C=C Bond. Successful asymmetric hy-drosilylation of terminal olefins requires the catalyst ensuring both Markovnikov selectivity (unusual for platinum and rhodium) and satisfactory level of asymmetric induction. Asymmetric hydrosilylation followed by Tamao-Fleming oxidation (known to proceed with retention of configuration at the stereogenic carbon) has become one of the most useful, general methods for the preparation of optically active alcohols from alkenes (Scheme 27). 

All these results obtained with palladium samples confirm the stoichiometries already found with platinum with alkaline iodides salts. When charge processes are completed in the presence of TAAX salts, some important discrepancies are noted for stoichiometries derived from the measurement performed at saturation (masses relative to plateau level in EQCM). Table 2.8 exhibits the phase formulas with a large number of tetraalkylammonium salts (Scheme 2.10), and it appears that the nature of the anion of the salt can modify the charge process the harder the anion (strong donor effeet), the weaker the energy storage inside palladium. 

Figure 4.25. Proposed excited state scheme for tetraphosphite platinum dimers showing the emission from the lowest excited state level.

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