Heterogeneous catalyst precursors

Heterogeneous tandem catalysis involving at least one of the components being supported has also been reported [178, 179]. For example, calcosilicate has recently been used as an effective carrier for simultaneous immobilisation of a dual-functional system based on a bis(imino)pyridine iron compound and a zirconocene to form a heterogeneous catalyst precursor. On activation with triethylaluminium, ethylene was converted to LLDPE the layered structure of the calcosilicate was used to account for the improved thermal stability and higher molecular weights of the LLDPE formed [179],... 

The addition of dopants is found to have beneficial effects. However, they are not restricted only to transition metals. The hydrogenation of acrylic acid can be promoted significantly by the addition of neodymium ions onto the palladium particles [142], The selective transformation of 3,4-dichloronitrobenzene to the corresponding aniline has been selected to test pre-prepared Pt hydrosols as heterogeneous catalyst precursors (see Figure 3.9) [143],... 

Colloidal nanoparticles can be employed as heterogeneous catalyst precursors in the same fashion as molecular clusters. In many respects, colloidal nanoparticles offer opportunities to combine the best features of the traditional and cluster catalyst preparation routes to prepare uniform bimetallic catalysts with controlled particle properties. In general, colloidal metal ratios are reasonably variable and controllable. Further, the application of solution and surface characterization techniques may ultimately help correlate solution synthetic schemes to catalytic activity. 

Davies IW, Matty L, Hughes DL, Reider PJ. Are heterogeneous catalysts precursors to homogeneous catalysts J Am Chem Soc 2001 123 10139-10140. 

Cobaltocenium calix[4]arene receptors, characteristics, 12,475 Cobaltocenium-metallacarborane salts, preparation, 3, 23 Cobaltocenium receptors, characteristics, 12, 474 Cobalt phosphines, as supports, 12, 683 Cobalt-platinum nanoparticles, preparation, 12, 74 Cobalt-ruthenium clusters, as heterogeneous catalyst precursors, 12, 768... 

Gold nanoclusters, luminescent properties, 12, 775 Gold nanoparticles, characteristics, 12, 495 -96 Gold-platinum clusters, as heterogeneous catalyst precursors,... 

Gold-ruthenium nanoparticles, as heterogeneous catalyst precursors, 12, 768 Gold salts... 

Heterometal alkoxide precursors, for ceramics, 12, 60-61 Heterometal chalcogenides, synthesis, 12, 62 Heterometal cubanes, as metal-organic precursor, 12, 39 Heterometallic alkenes, with platinum, 8, 639 Heterometallic alkynes, with platinum, models, 8, 650 Heterometallic clusters as heterogeneous catalyst precursors, 12, 767 in homogeneous catalysis, 12, 761 with Ni—M and Ni-C cr-bonded complexes, 8, 115 Heterometallic complexes with arene chromium carbonyls, 5, 259 bridged chromium isonitriles, 5, 274 with cyclopentadienyl hydride niobium moieties, 5, 72 with ruthenium—osmium, overview, 6, 1045—1116 with tungsten carbonyls, 5, 702 Heterometallic dimers, palladium complexes, 8, 210 Heterometallic iron-containing compounds cluster compounds, 6, 331 dinuclear compounds, 6, 319 overview, 6, 319-352... 

Colloidal nanoparticles can be employed as heterogeneous catalyst precursors in the same way as molecular clusters. The recent explosion of interest in nanoparticles for nanotechnology applications has fueled the development of several new nanoparticle preparative techniques [14—16]. In some cases, careful syntheses allow control over nanoparticle size, composition, and even morphology [14-16]. Several synthetic routes to colloidal nanoparticles in the 1-5 nm range are now... 

Unprotected, that is to say electrostatically stabilized, colloids of the precious metals can be attached to supports, presumably through electrostatic interactions, and there are numerous examples of heterogeneous catalysts prepared in this manner. Although the use of colloids as heterogeneous catalyst precursors will not be covered in detail here, some results should be mentioned. 

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