Hydrogen bond strength and acidity. Structural and energetic correlations for acetylides and alcohols

TitleHydrogen bond strength and acidity. Structural and energetic correlations for acetylides and alcohols
Publication TypeJournal Article
Year of Publication1999
AuthorsM.L. Chabinyc, and J.I. Brauman
JournalJOURNAL OF PHYSICAL CHEMISTRY A
Volume103
Pagination9163-9166
Date PublishedNOV 18
ISSN1089-5639
AbstractIon-molecule complexes of acetylide anions, RCC- (R = tert-butyl, H, phenyl, p-tolyl), and methanol have been studied using Fourier transform ion cyclotron resonance mass spectrometry. The RCC- complexation energies with HOCH3 were measured relative to CH3O-. H2O and CH3O-. HOCH3. These complexes, RCC-. HOCH3, all have complexation energies of -21 kcal/mol and are, therefore, hydrogen-bonded. The acetylides vary in basicity over an 8 kcal/mol range, but all have the same complexation energy with methanol. These results show that the frequently observed relationship between acid-base energetics and complexation energy is a property of the specific system and not:a general one. Thus, the existence, and magnitude, of these correlations cannot be used to infer structural information about the complexes. The stability of hydrogen-bonded complexes appears to be related to the charge distributions of the separated ion and neutral.
DOI10.1021/jp992852v