Measuring Gas-Phase Basicities Relative to the Lithium Cation by Mass Spectrometry: A Physical Chemistry Experiment
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Jean-François Gal [1] ; Charly Mayeux [2] ; Lionel Massi [1] ; Mohamed Major [3] ; Laurence Charles [3] ; Tõiv Haljasorg [2]
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[1] Nice Sophia Antipolis University
Nice Sophia Antipolis University
Arrondissement de Nice, Francia
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[2] University of Tartu
University of Tartu
Tartu linn, Estonia
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[3] Aix-Marseille University
Aix-Marseille University
Arrondissement de Marseille, Francia
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- Localización: Journal of chemical education, ISSN 0021-9584, Vol. 89, Nº 11, 2012, págs. 1476-1478
- Idioma: inglés
- Texto completo no disponible (Saber más ...)
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Resumen
The determination of the gas-phase basicity of organic bases (ligands) toward the lithium cation may be achieved by mass spectrometry, as described for protonic gas-phase basicity by Sunderlin et al. (J. Chem. Educ.2005, 82, 1071–1073). The lithium cation-bound dimers, generated by electrospray ionization, are dissociated by collision-induced dissociation in a tandem mass spectrometer such as triple quadrupole or quadrupole–time-of-flight instruments. An ion trap instrument is not recommended because of solvent adduct formation from Li+ containing fragments. The relative intensities of the ionic fragments are treated along the kinetic method. This experiment is another illustration of the possibilities offered by mass spectrometry for the determination of thermochemical data on gas-phase species. In this experiment, students have the opportunity to identify and manipulate metal–cation adducts which are frequently observed in mass spectrometry. Additional pedagogical interest may arise from discussion of the bonding with Li+, the structural effects on Li+ basicity, and the specific applications of the lithium ion, in particular its role in energy storage.
