Threshold Collision-Induced Dissociation of Hydrogen-Bonded Dimers of Carboxylic Acids
Energy-resolved competitive collision-induced dissociation is used to investigate the proton-bound heterodimer anions of a series of carboxylic acids (formic, acetic, and benzoic acid) and nitrous acid with their conjugate bases. The dissociation reactions of the complexes [CH3COO·H·OOCH]-, [CH3COO·...
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Published in | The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 112; no. 8; pp. 1773 - 1782 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
28.02.2008
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Online Access | Get full text |
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Summary: | Energy-resolved competitive collision-induced dissociation is used to investigate the proton-bound heterodimer anions of a series of carboxylic acids (formic, acetic, and benzoic acid) and nitrous acid with their conjugate bases. The dissociation reactions of the complexes [CH3COO·H·OOCH]-, [CH3COO·H·ONO]-, [HCOO·H· ONO]-, [C6H5COO·H·OOCH]-, and [C6H5COO·H·ONO]- are investigated using a guided ion beam tandem mass spectrometer. Cross sections of the two dissociation channels are measured as a function of the collision energy between the complex ions and xenon target gas. Apparent relative gas-phase acidities are found by modeling the cross sections near the dissociation thresholds using statistical rate theory. Internal inconsistencies are found in the resulting relative acidities. These deviations apparently result from the formation of higher-energy conformers of the acids within the complex ions induced by double hydrogen bonding, which impedes the kinetics of dissociation to ground-state product acid conformations. |
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Bibliography: | istex:662E6CDB8A156B96E1373F7C3299D0B867FD2BF0 ark:/67375/TPS-R3KCW9XQ-6 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1089-5639 1520-5215 |
DOI: | 10.1021/jp7114093 |