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Effect of buffer gas on the fluorescence yield of trapped gas-phase ions

Dashtiev, Maxim ; Zenobi, Renato

In: Journal of the American Society for Mass Spectrometry, 2006, vol. 17, no. 6, p. 855-858

Université de Fribourg

Variations in rotational barriers of allyl and benzyl cations, anions, and radicals

Li, Zhe ; Bally, Thomas ; Houk, Kendall N. ; Borden, and Weston Thatcher

In: The Journal of Organic Chemistry, 2016, vol. 81, no. 20, p. 9576–9584

High accuracy quantum chemical calculations show that the barriers to rotation of a CH2 group in the allyl cation, radical, and anion are 33, 14, and 21 kcal/mol, respectively. The benzyl cation, radical, and anion have barriers of 45, 11, and 24 kcal/mol, respectively. These barrier heights are related to the magnitude of the delocalization stabilization of each fully conjugated system. This...

Université de Fribourg

Unusual Rearrangements of Radical Cations: The Role of Vibronic Coupling

Bally, Thomas

In: CHIMIA International Journal for Chemistry, 2016, vol. 70, no. 3, p. 164–171

Radicalcations often undergo very unexpected rearrangements. Three examples of such rearrangements are given, and it is shown how vibronic coupling between the ground and low-lying excited states may cause certain bonds that are quite solid in the neutral molecules to become so weak that they break spontaneously, even though the bond order does not change (or changes very little) on...

Université de Fribourg

Electronic structure of hole-conducting states in polyprolines

Monney, Nicolas P.-A. ; Bally, Thomas ; Giese, Bernd

In: The Journal of Physical Chemistry B, 2015, vol. 119, no. 22, p. 6584–6590

Electron transfer over long distances in proteins by a hopping process requires transient relay stations that can harbor charge and spin for a short time span. Certain easily oxidizable or reducible side chains may assume that role, but it has been shown that charge transport in peptides can also take place in the absence of such groups which implies that the peptide backbone provides for hopping...

Université de Fribourg

Proline as a charge stabilizing amino acid in peptide radical cations

Monney, Nicolas P.-A. ; Bally, Thomas ; Giese, Bernd

In: Journal of Physical Organic Chemistry, 2015, vol. 28, no. 5, p. 347–353

Long distance electron transfer in proteins requires relay stations that can be transitorily oxidized or reduced. Although individual prolines cannot assume this function, because of their high ionization energy, it has been shown that polyprolines have the ability to transfer charges. In order to determine the role of the proline in the hole distribution and transport within a PheProPhe...