J. Mihalick, G. Gatev, J. I. Brauman
Dec 11, 1996
Citations
0
Influential Citations
14
Citations
Journal
Journal of the American Chemical Society
Abstract
Electron photodetachment spectra of three alkoxide ions, 2,2-dimethyl-3-pentoxide, 3,3-dimethyl-2-butoxide, trifluoroethoxide, and two complex ions, 3,3-dimethyl-2-butanol/fluoride, 2,2-dimethyl-3-pentanol/fluoride, have been measured using an ion cyclotron spectrometer to generate, trap, and detect the ions. The electron affinities of trifluoroethoxide, 2,2-dimethyl-3-pentoxide, and 3,3-dimethyl-2-butoxide were measured as 58.9 ± 0.1, 47.8 ± 0.3, and 45.7 ± 0.1 kcal mol-1, respectively. Using known proton affinities of the three alcohols allows us to determine the O−H bond dissociation energies. The threshold detachment energies for 2,2-dimethyl-3-pentanol/fluoride and 3,3-dimethyl-2-butanol/fluoride complex ions are 70.3 ± 0.5, and 70.1 ± 0.5 kcal mol-1, respectively. The fluoride binding energies are thus on the order of 30 kcal mol-1. We show that the observation or non-observation of photodetachment for alcohol/fluoride ions depends only on the alcohol acidity. In complex ions of the form ROHF-, if R...