Zucker–Hammett hypothesis

https://doi.org/10.1351/goldbook.Z06751
This hypothesis states that, if in an acid catalysed reaction, log10⁡k1 (first-order rate constant of the reaction) is linear in H0 (Hammett acidity function), water is not involved in the transition state of the rate-controlling step. However, if log10⁡k1 is linear in log10⁡[H+] then water is involved. This has been shown to be incorrect by Hammett himself.
Source:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1176 [Terms] [Paper]
Citation: 'Zucker–Hammett hypothesis' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.Z06751 RIS BibTex EndNote
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Last revised: February 24, 2014