Mass spectrometric study of negative ions from unsaturated carbonyls

1989-01-01
Negative ion formation from some unsaturated carbonyl derivatives is investigated as a function of electron energy by using a monochromatic (0.2 eV) and low-energy (0-10 eV) electron beam and a mass spectrometer. Negative ions at low energies are formed via a dissociative attachment process. Appearance potentials of certain negative ions can be correlated with the electron-releasing or -withdrawing power of the substituents and/or with bond strengths. For example, the appearance potentials of C6H5CO" and C2H3CO" both shift to higher energies as the C-X bond is weakened through the electron-withdrawing power of X in the order X = Cl > OH > H > CH3. The appearance potentials are also used to estimate the bond dissociation energies not available in the literature. Accordingly, C6H5-COX bond energies can be calculated as 3.9, 3.7, and 3.0 eV for X = H, OH, and Cl, respectively, by using the measured appearance potentials of C6H5" ion from these molecules and the published bond energy of 4.033 eV for acetophenone (X = CH3).
Journal of Physical Chemistry

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Citation Formats
J. Hacaloğlu, A. Gökmen, and H. Baumgartel, “Mass spectrometric study of negative ions from unsaturated carbonyls,” Journal of Physical Chemistry, pp. 7095–7098, 1989, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/32080.