Abstract
A comparison of proton exchange reactions between OH, SH, and CH acids and the NH groups of trialkylammonium ions showed that regardless of the nature of the acid XH, the mechanism of exchange includes transfer of a proton in the ion pair N-H+ ... X− as the slow step. At the fast steps of proton exchange XH- N+H, i.e., molecular exchange with breaking of a hydrogen bond X-H ... N and transfer of a proton along these bonds, differences appear in the properties of XH acids. In the sequence from OH to SH and CH acids, the hydrogen bonds X-H ... N are weakened. As a result of this, in the same sequence the kinetic acidity (k2) decreases but the rate of molecular exchange (kH) increases. The ratio between the values of k2 and kH is inverted when the strong bonds O-H ... N (k2/kH ≫ 1) are replaced by weak bonds C-H ... N (k2/kH ≪ 1). It was also established that the kinetic stability of the anions increases as the oxygen atoms are replaced by sulfur in the series RCOO− < RCOS− < R2PSS− as a result of the more effective delocalization of the negative charge on the diffuse orbitals of sulfur.
This is a preview of subscription content, log in via an institution to check access.
Literature cited
V. K. Pogorelyi and V. V. Turov, “Investigation of rapid proton exchange between SH groups of thiocarboxylic acids and NH of triethylammonium ion,” Teor. Éksp. Khim., 19, No. 6, 698–703 (1983).
V. K. Pogorelyi and V. V. Turov, “Investigation of the equilibrium and kinetics of the transfer of protons from thiocarboxylic acids to collidine,” ibid., 21, No. 2, 187–194 (1985).
V. K. Pogorelyi and V. V. Turov, “Investigation of the kinetics and equilibrium of the transfer of protons from dithiocarboxylic acids to amines,” ibid., 21, No. 6, 676–681 (1985).
V. K. Pogorelyi, T. B. Vishnyakova, and I. P. Gragerov, “PMR investigation of the kinetics and thermodynamics of transfer of a proton from trisubstituted methanes to collidine,” ibid., 18, No. 4, 465–470 (1982).
V. K. Pogorelyi, T. B. Vishnyakova, and I. P. Gragerov, “Investigation of the kinetics of proton exchange in the system trisubstituted methanes-triethylamine,” ibid., 18, No. 5, 590–595 (1982).
E. Grunwald and E. Price, “Ionization and proton exchange of amines in acetic acid,” J. Am. Chem. Soc., 86, No. 15, 2965–2970 (1964).
E. Grunwald and E. Price, “Effect of structure on reactivity and reaction mechanism,” ibid., 86, No. 15, 2970–2977 (1964).
B. Chawla and S. K. Mehta, “Hydrogen-bonded species of pyridinium acetates,” J. Phys. Chem., 88, No. 12, 2650–2655 (1984).
I. P. Gragerov, V. K. Pogorelyi, and I. F. Franchuk, The Hydrogen Bond and Rapid Proton Exchange [in Russian], Naukova Dumka, Kiev (1978).
M. Eigen and L. Maeyer, Investigation of Rates and Mechanism of Reactions, Interscience New York (1963).
V. K. Pogorelyi and V. V. Turov, “NMR investigation of rapid proton exchange with the participation of thiocarboxylic acids,” Teor. Éksp. Khim., 16, No. 5, 643–648 (1980).
V. N. Barvinchenko and V. K. Pogorelyi, “Investigation of the hydrogen bonds of thioacetic and chlorothioacetic acids with various electron donors,” ibid., 17, No. 6, 838–844 (1981).
V. K. Pogorelyi and T. B. Vishnyakova, “The hydrogen bond and CH acidity,” Usp. Khim., 53, No. 12, 1985–2008 (1984).
Author information
Authors and Affiliations
Additional information
Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 4, pp. 471–475, July–August 1987.
Rights and permissions
About this article
Cite this article
Pogorelyi, V.K. Reactions of proton transfer and exchange with the participation of OH, SH, and CH acids and amines. Theor Exp Chem 23, 441–446 (1988). https://doi.org/10.1007/BF00536365
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00536365