Electrophiles nucleophiles

It should be pointed out the H ion alone is insufficiently powerful to affect disruption of the siloxane bond without the simultaneous action of the F" ion. Consequently sulphuric and nitric acid do not initiate attack, even at temperatures up to 1 000°C. Exceptions to the principle are hydrochloric and hydroiodic acid, which, although satisfying the requirements of simultaneous nucleophilic-electrophilic attack, exert a negligible degrading effect on silica. 

Nucleophiles Electrophiles Physical stimuli Microbes (dead or alive)... 

Electron donors (D) and electron acceptors (A) constitute reactant pairs that are traditionally considered with more specific connotations in mind - such as nucleophile/electrophile in bond formation, reductant/oxidant in electron transfer, base/acid in adduct production, and so on. In each case, the chemical transformation is preceded by a rapid (diffusion-controlled) association to form the 1 1 intermolecular complex9 (equation 2). 

The electron-transfer paradigm for chemical reactivity in Scheme 1 (equation 8) provides a unifying mechanistic basis for various bimolecular reactions via the identification of nucleophiles as electron donors and electrophiles as electron acceptors according to Chart 1. Such a reclassification of either a nucleophile/ electrophile, an anion/cation, a base/acid, or a reductant/oxidant pair under a single donor/acceptor rubric offers a number of advantages previously unavailable, foremost of which is the quantitative prediction of reaction rates by invoking the FERET in equation (104). 

To conclude, silylation of AN and their derivatives made it possible to substantially extend the reactivity of AN. The reactions of AN with nucleophilic, electrophilic, and radical reagents at both the a- and 3-carbon atoms are summarized in Chart 3.24. 

Other nucleophile-electrophile pairs for which the pm-disubstituted naphthalene system has been used to monitor potential bonding interactions are illustrated in [35] and [36], The methoxynitrile [35], for example, shows the same sort of evidence for a bonding interaction, marked by a 7° distortion from linearity at the nitrile carbon, in plane, and exactly away from the methoxyl oxygen (Procter et al., 1981) so also does the bipyridyl dinitrile [37] (Baxter et al., 1991). In the unique case of the 8-diazonium quinoline-N-oxide [36] the proximity of a formally negatively charged oxygen induces a distortion from linearity of 10.4° in the diazonium group (Wallis and Dunitz, 1984). 

But using Ingold s nucleophilic-electrophilic nomenclature, all "basic" reagents, organic or inorganic, are nucleophilic and "basicity" ("affinity" for... 

Weak nucleophile-electrophile interactions (and the donor-acceptor complexes) are considered precursors in aromatic electrophilic substitutions133 and in additions of electrophiles to C=C double bond of olefins the first step (the addition of the electrophile to an electron-rich substrate) is probably the same for both reactions. 

Cyclative-cleavage strategy is a process in which activation promotes the cleavage, while an intramolecularly located nucleophile, electrophile, radical or another group attacks, so that the product is released from the sohd support (Scheme 3.4). 

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