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Towards a general approach to the deprotonation of carbon acids, including nitroalkanes
Author(s) -
Arnaut Luís G.
Publication year - 1991
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610041205
Subject(s) - deprotonation , chemistry , nitro , protonation , carbon fibers , photochemistry , transition state , base (topology) , computational chemistry , resonance (particle physics) , medicinal chemistry , stereochemistry , organic chemistry , catalysis , atomic physics , physics , composite number , composite material , ion , mathematical analysis , alkyl , materials science , mathematics
The deprotonation of nitroalkanes and ketones was studied through the intersecting state model of Formosinho. The anomalous Brønsted coefficients observed when substituted nitroalkanes react with a common base are explained in terms of variable transition‐state electronic structures. These are very sensitive to substitution in the nitroalkane, owing to the high electron affinity of the nitro group. In ketones, such electronic effects are much attenuated. The transition states are characterized by the bond order, n ,*, which is quantitatively correlated to the field/inductive and resonance effects of the substituents. The deprotonation of fluorence and other carbon acids was also studied. The theoretical model applied shows that all these reactions follow a mechanistic continuum, dictated by the extent into which the group directly bonded to the acidic carbon is mixed in the reaction coordinate.