Temperature-Dependent Acid Dissociation Constants (Ka, ΔHa, ΔSa) for a Series of Nitrogen-Substituted Hydroxamic Acids in Aqueous Solution

Journal Article (Journal Article)

The acid dissociation constants (K ) of a series of eight substituted N-phenylacetohydroxamic acids, CH C—(O)N(OH)C H X (X = H, 4-CH , 4-Cl, 4-I, 3-I, 3-CN, 4-CN, 4-C(O)CH ), have been determined in aqueous solution (I = 2.0) for a range of temperatures. The pK data at 25 °C exhibit a small variation with the substituent X in the direction expected according to their Hammett substituent constants (ρ ≈ 0.1). These small variations in pK values are due to compensating trends in ΔH and ΔS , which show significant variation with substituent. These results are discussed in terms of the substituent's influence on hydroxamate anion-solvent interactions and the relative influence on pK of a substituted phenyl group attached to the C or N end of the hydroxamate moiety. © 1982, American Chemical Society. All rights reserved. a 3 6 4 3 3 a a a a a

Full Text

Duke Authors

Cited Authors

  • Brink, CP; Crumbliss, AL

Published Date

  • January 1, 1982

Published In

Volume / Issue

  • 47 / 7

Start / End Page

  • 1171 - 1176

Electronic International Standard Serial Number (EISSN)

  • 1520-6904

International Standard Serial Number (ISSN)

  • 0022-3263

Digital Object Identifier (DOI)

  • 10.1021/jo00346a005

Citation Source

  • Scopus