- Settore: Chemistry
- Number of terms: 1965
- Number of blossaries: 0
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The International Union of Pure and Applied Chemistry (IUPAC) serves to advance the worldwide aspects of the chemical sciences and to contribute to the application of chemistry in the service of people and the environment. As a scientific, international, non-governmental and objective body, IUPAC ...
The product formed by the attachment of an electrophilic or nucleophilic entering group or of a radical to a ring carbon of an aromatic species so that a new sigma bond is formed and the original conjugation is disrupted. (This has generally been called a "σ-complex", but adduct is more appropriate than complex according to the definitions given.) The term may also be used for analogous adducts to unsaturated (and conjugated) systems in general.
Industry:Chemistry
The product formed by the attachment of an electrophilic or nucleophilic entering group or of a radical to a ring carbon of an aromatic species so that a new sigma bond is formed and the original conjugation is disrupted. (This has generally been called a "σ-complex", but adduct is more appropriate than complex according to the definitions given.) The term may also be used for analogous adducts to unsaturated (and conjugated) systems in general.
Industry:Chemistry
Term used mainly in the German literature for starting material (reactant). It should be avoided in English, because there it means "something that comes out" and not "something that goes in". The German use of the term is in fact also incorrect.
Industry:Chemistry
A term sometimes employed instead of charge-transfer complex or Lewis adduct.
Industry:Chemistry
A synonym for pericyclic reaction. The number of "centers" is the number of atoms not bonded initially, between which single bonds are breaking or new bonds are formed in the transition state. This number does not necessarily correspond to the ring size of the transition state for the pericyclic reaction. Thus, a Diels-Alder reaction is a "four-center reaction". This terminology has largely been superseded by the more detailed one developed for the various pericyclic reactions.
Industry:Chemistry
A chemical reaction that can be described as the conversion of a reactant into its mirror image, without rotation or translation of the product, so that the product enantiomer actually coincides with the mirror image of the reactant molecule. Examples of such reactions are cited under the entries fluxional and degenerate rearrangement.
Industry:Chemistry
This term has been used synonymously with proton (hydron)-transfer reaction. Because of its misleading similarity to hydrolysis, photolysis, etc., its use is discouraged.
Industry:Chemistry
The use of this awkwardly formed term is discouraged. It is synonymous with "intermolecular rearrangement".
Industry:Chemistry
A term sometimes used as synonymous with pseudo-first order, but is inherently meaningless.
Industry:Chemistry
The conformational preference of an equatorial compared to an axial substituent in a monosubstituted cyclohexane. This steric substituent parameter equals Δ<sub>r</sub>G<sup>o</sup> in kcal/mol for the equatorial to axial equilibration on cyclohexane. The values are also known as "Winstein-Holness" A values.
Industry:Chemistry
