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Coordination chemistry, supported metal

Coordination Chemistry Supported Organotransition Metal Compounds Titanium Organometallic Chemistry Vanadium Organometallic Chemistry Zirconium Hafnium Organometallic Chemistry. [Pg.3215]

In the sixties of past century, a few patents issued to Bergbau Chemie [5,48,49] and to Mobil Oil [50-52], respectively described the use of CFPs as supports for catalytically active metal nanoclusters and as carriers for heterogenized metal complexes of catalytic relevance. For the latter catalysts the term hybrid phase catalysts later came into use [53,54], At that time coordination chemistry and organo-transition metal chemistry were in full development. Homogeneous transition metal catalysis was expected to grow in industrial relevance [54], but catalyst separation was generally a major problem for continuous processing. That is why the concept of hybrid catalysis became very popular in a short time [55]. [Pg.208]

The smaller p -tert-butyl-calix [4] arenes have a rich coordination chemistry as well (65). Of these, however, only the upper-rim modified calixarenes seem to support metal complexes with confined binding sites (66), except in those cases where the lower-rim substituents form an appended cavity. Thus, Matt and coworkers have reported (67) a pocket-shaped calix[4]arene ligand L2 bearing two lower-rim [([Pg.410]

The development, synthesis, and the coordination chemistry of novel metal complexes with deep binding cavities have been described. It was demonstrated that the doubly deprotona-ted forms of the macrocycles (LR)2 support the formation of... [Pg.457]

It is evident from the preceding discussion that the field of C02 coordination chemistry is still a new area, but enough work has been reported to allow the several different modes of C02 coordination to be identified. These include (1) binding to the metal center as a Lewis acid through carbon alone, (2) n-complexation involving one of the C=0 units, and (3) supported coordination in which an additional weak interaction stabilizes the bound C02. In all cases except for the irreversible reactions of C02 leading to bound carbonate, carboxylate, etc., the metal-C02 interaction is relatively weak and the C02 is easily liberated. [Pg.128]

Although the above catalytic processes involve different metals, different ligands and very different reaction conditions, the cycles which support their catalytic mechanism can be based on a series of few but similar fundamental steps. This supports the view that a unified approach based on (he relevant aspects of organometallic and coordination chemistry can produce a framework for understanding this area of carbon monoxide catalytic chemistry, at least in a qualitative way. In fact, to a first approximation, any particular mechanistic... [Pg.150]

The same coordination geometry was also inferred from the analysis of the lowest energy LMCT bands (see Ligand-to-Metal Charge Transfer) in the far-UV absorption spectra of Zu7- and Cd7-MT, and those of corresponding tetrahedral halide complexes (see Cadmium Inorganic Coordination Chemistry see Zinc Inorganic Coordination Chemistry) Further support came from... [Pg.2671]

Linear systems with an NO3 donor set are exemplified by simple saturated molecules, which show preferences toward lighter, higher charged metal ions, such as linear (90). Branched systems include tripodal ligands having different central atoms and 0-donors terminating the chains, for example, (91) and (92). Their coordination chemistry is partly directed by their shape, which tends to support trigonal... [Pg.2700]

Properties of supported catalysts by bimetallic substrates depend on the changes in geometry of the catalyst material by the strain of the substrate. Using a bimetallic substrate multiphes the possibilities to tune the catalyst to specific requirements. The chemistry of the nanosized overlayer is affected by the different orbital overlaps of atoms from the catalyst cluster and those from the substrate. Additionally, small supported metallic islands show low coordination and reduced near-neighbor distances thus their chemical properties are different with respect to those of flat surfaces. " Reactivity of several bimetallics were also studied by Balbuena et al., including bimetallics systems . Norskov et al. found several relations for the bimetallic systems considering local and nonlocal effects have also been reported. ... [Pg.205]


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