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Metal carbon cleavage

Metal alkyl reagents react with the acidic OH groups of silica, probably by the electrophilic cleavage of the metal-carbon bond. For example, the electrophilic cleavage of the metal-carbon bond occurs when organometallic reagents react with the electrophilic OH groups of the silica surface (Scheme... [Pg.267]

Daub, G. William, Oxidatively Induced Cleavage of Transition Metal-Carbon... [Pg.628]

In some cases pulse-radiolysis techniques were employed to study the effect of pressure on inorganic reactions. For instance the oxidation of [CuI(phen)2] by dioxygen via the formation of a C -C transient species was studied using this technique (see Section III,A). Other examples include the formation and cleavage of metal-carbon (7-bonds, which formally involve a change in the oxidation state of the metal. A typical example of a volume profile for the formation and cleavage of a Co-CH3 bond is reported in Fig. 21 for the reaction (162)... [Pg.47]

The nucleation of these decomposition processes was studied by means of thermomicroscopy on single crystal cleavage plates of calcite, magnesite, dolomite and smithsonite (Fig. 59). The shape of the nuclei was found to be different for these carbonates, which might be also of importance for the decomposition mechanism. The partial pressure of water vapor has a pronounced effect on the decomposition of transition metal carbonates such as ZnC03 and CdC03. The evolution of C02 is probably catalyzed in the presence of water vapor and shifted to considerably... [Pg.130]

Most of the studies on organo-gallium, indium, and thallium porphyrin complexes have focused on synthesis and properties of the complexes, and rather little attention has been devoted to reaction chemistry. Two areas which have received some attention are the insertion of small molecules (SO2 or CO2) into the metal—carbon bonds and photochemical metal—carbon bond cleavage. The... [Pg.306]

Equation 6.36) on the catalyst surface. These adsorbed intermediates can be formed on the metal surface by the formation of either metal-carbon bonds and/or metal-oxygen bonds. The dehydrogenation step must be followed by rapid and irreversible cleavage of the C-G bond (Equation 6.37) to avoid parallel undesired reactions which lower the selectivity towards H2. [Pg.215]

Part IV of this article outlines a description of the processes involved in cleavage of a single metal-carbon bond, and puts forward a theory of the influences of electron count, and of configuration interaction, on metal-carbon bond stability. Finally, in Part V, I attempt a critical appraisal of the method adopted and the results obtained. [Pg.150]

IV The Cleavage of Individual Metal-Carbon Bonds A. General Theory... [Pg.165]

The hydrocarboxylation can take place by insertion of the alkene into a metal-hydride bond followed by CO insertion and finally reaction of the acyl complex with solvent as illustrated in equation (36). Alternatively, a transition metal-carboxylate complex can be generated initially. Insertion of the alkene into the metal-carbon bond of this carboxylate complex followed by cleavage of the metal-carbon bond by solvent completes the addition, as shown in equation (37). Both sequences provide the same product. [Pg.936]

Both mechanisms are predicted to show syn addition of hydride and caiboxylate to the alkene. In the metal hydride mechanism (equation 36) alkene insertion is syn and CO insertion proceeds with retention of configuration at carbon. In the metal carboxylate mechanisms (equation 37) alkene insertion is syn and cleavage of the metal-carbon bond can take place with retention at carbon. The palladium-catalyzed hydroesterification reaction produces the erythro ester from (Z)-3-methyl-2-pentene (equation 38) and the threo ester from ( )-3-methyl-2-pentene (equation 39).w... [Pg.936]

Of-carbon atom, both retention and inversion have been evoked to account for the cleavage of metal-carbon bonds by halogens20,35,70,74. ... [Pg.88]


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See also in sourсe #XX -- [ Pg.560 ]




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Metal cleavage

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