An Enthalpic Scale of Hydrogen-Bond Basicity. 4. Carbon pi Bases, Oxygen Bases, and Miscellaneous Second-Row, Third-Row, and Fourth-Row Bases and a Survey of the 4-Fluorophenol Affinity Scale - UMR 3495 MAP Accéder directement au contenu
Article Dans Une Revue Journal of Organic Chemistry Année : 2010

An Enthalpic Scale of Hydrogen-Bond Basicity. 4. Carbon pi Bases, Oxygen Bases, and Miscellaneous Second-Row, Third-Row, and Fourth-Row Bases and a Survey of the 4-Fluorophenol Affinity Scale

Résumé

The thermodynamics of the O-H center dot center dot center dot B hydrogen bond (FIB) has been determined in CCl(4) by FTIR spectrometry for a wide variety of carbon pi bases, oxygen bases, and miscellaneous first- to fourth-row bases, using 4-fluorophenol as a reference hydrogen-bond donor (H BD). After inclusion of previously studied nitrogen, sulfur, and halogen bases, this 4-fluorophenol affinity scale contains 314 varied organic bases and ranges over 40 kJ mol(-1). The 4-fluorophenol affinity scale in CCl(4) is shown to be applicable to most HBDs in most media, provided a small family dependence is taken into account. The HB affinity orders are quantitatively established according to the atomic acceptor site or to its bearing functional group. A comprehensive survey of the influence of substituents on these affinity orders is then achieved, considering electronic and steric effects, as well as effects of vinylogy or iminology. Iminology is found to be more efficient than vinylogy for transmitting resonance effects. Steric effects are shown to be less important in B affinity than in HB basicity since they mainly act on the HB entropy. The spatial proximity of two acceptor sites can favor complexation through three-center hydrogen bonds, leading to superhydrogen-bond bases on the affinity scale.

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Chimie
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Dates et versions

hal-02143496 , version 1 (29-05-2019)

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Christian Laurence, Jérôme Graton, Michel Berthelot, Francois Besseau, Jean-Yves Le Questel, et al.. An Enthalpic Scale of Hydrogen-Bond Basicity. 4. Carbon pi Bases, Oxygen Bases, and Miscellaneous Second-Row, Third-Row, and Fourth-Row Bases and a Survey of the 4-Fluorophenol Affinity Scale. Journal of Organic Chemistry, 2010, 75 (12), pp.4105-4123. ⟨10.1021/jo100461z⟩. ⟨hal-02143496⟩
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