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Apperloo JJ, Streefland L, Engberts JB, et al. Pairwise gibbs energies of interaction involving N-alkyl-2-pyrrolidinones and related compounds in aqueous solution obtained from kinetic medium effects. J Org Chem. 2000;65(2):411-8doi: 10.1021/jo991262q.
Apperloo, J. J., Streefland, L., Engberts, J. B., & Blandamer, M. J. (2000). Pairwise gibbs energies of interaction involving N-alkyl-2-pyrrolidinones and related compounds in aqueous solution obtained from kinetic medium effects. The Journal of organic chemistry, 65(2), 411-8. https://doi.org/10.1021/jo991262q
Apperloo, et al. "Pairwise gibbs energies of interaction involving N-alkyl-2-pyrrolidinones and related compounds in aqueous solution obtained from kinetic medium effects." The Journal of organic chemistry vol. 65,2 (2000): 411-8. doi: https://doi.org/10.1021/jo991262q
Apperloo JJ, Streefland L, Engberts JB, Blandamer MJ. Pairwise gibbs energies of interaction involving N-alkyl-2-pyrrolidinones and related compounds in aqueous solution obtained from kinetic medium effects. J Org Chem. 2000 Jan 28;65(2):411-8. doi: 10.1021/jo991262q. PMID: 10813949.
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J Org Chem. 2000 Jan 28;65(2):411-8. doi: 10.1021/jo991262q.

Pairwise gibbs energies of interaction involving N-alkyl-2-pyrrolidinones and related compounds in aqueous solution obtained from kinetic medium effects.

The Journal of organic chemistry

Apperloo, Streefland, Engberts, Blandamer

Affiliations

  1. Department of Organic and Molecular Inorganic Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and the Department of Chemistry, University of Leicester, Leicester LE1 7RH, England.

PMID: 10813949 DOI: 10.1021/jo991262q

Abstract

Kinetic solvent effects of N-alkyl-2-pyrrolidinones and structurally related compounds on the water-catalyzed hydrolysis reactions of p-methoxyphenyl dichloroacetate (MPDA), 1-benzoyl-3-phenyl-1,2, 4-triazole (BPhT), and 1-benzoyl-1,2,4-triazole (BT) in highly dilute aqueous solutions at pH 4 and 298.15 K have been determined by UV/vis spectroscopy. Using a thermodynamic description of solute-solute interactions in aqueous solutions, the kinetic results have been analyzed in terms of pairwise Gibbs energy interaction parameters: G(c) values. These are negative, indicating that hydrophobic interactions in the initial state dominate the medium effects. The interaction parameters increase in the order MPDABT>BPhT. However, when differences in reactivity and transition state effects are taken into account, it appears that BPhT is more successful in establishing hydrophobic interactions with the cosolutes than are MPDA and BT. Using the SWAG-approach for additivity of group interactions, additivity is observed for the first three consecutive CH(2) groups in the cosolute in all three hydrolysis reactions. Larger alkyl substituents cause larger retardations than anticipated on basis of this additivity. The results are explained by intramolecular destructive overlap of the polar hydration shell of the amide functionality and the apolar (hydrophobic) hydration shell of the alkyl group, which extends to the third CH(2) group in the N-alkyl group of the cosolute molecule. The inner apolar groups, therefore, have a reduced apparent hydrophobicity. More remote CH(2) groups develop independent hydrophobic hydration shells. The effect of the position of a CH(2) group in the cosolute molecule is also considered. Kinetic solvent effects with structurally related esters show that amide-amide, ester-ester, and amide-ester group interactions affect the transition state in different ways. Finally, the effects of PVP polymers on the three hydrolysis reactions have been examined. The data presented enhance the understanding of pairwise hydrophobic interactions in aqueous solutions. In addition the results provide insights into the interactions between hydrophobic and hydrophilic hydration shells as well as into the energetics of amide hydration and interactions involving amides in aqueous solution, both playing important roles in protein stabilization.

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