Hydrogen-bonding in the self-organising system 3,5-dimethylpyrazole

John A. Stride, Upali A. Jayasooriya, Njagi Mbogo, Ross P. White, Béatrice Nicolaï, Gordon J. Kearley

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4 Citations (Scopus)


The family of pyrazoles containing only H and CH3 substituents displays a wide variation in physical properties which can be directly related to the manner in which the molecules self-organise in the solid state. Hydrogen-bonded multimeric motifs of the substituted pyrazoles are a recurring feature of this family. The quasielastic neutron scattering data for 3,5-dimethylpyrazole presented here indicate that the hydrogen-bonded amide protons within trimer units undergo a short-range hopping motion between two equivalent sites, straddling the direct N . . .H hydrogen-bond axis. This motion is in addition to the larger tautomeric hop previously observed using NMR. The activation energy of the short-range motion has been determined herein as 1.7(1) kJ mol(-1), ca. 1/30th of that of the tautomeric proton hopping motion.
Original languageEnglish
Pages (from-to)1069-1072
Number of pages4
JournalNew Journal of Chemistry
Issue number8
Publication statusPublished - 2001

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