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Université de Fribourg

Amide neighbouring-group effects in peptides: phenylalanine as relay amino acid in long-distance electron transfer

Nathanael, Joses G. ; Gamon, Luke F. ; Cordes, Meike ; Rablen, Paul R. ; Bally, Thomas ; Fromm, Katharina M. ; Giese, Bernd ; Wille, Uta

In: ChemBioChem, 2018, vol. 19, no. 9, p. 922–926

In nature, proteins serve as media for long‐distance electron transfer (ET) to carry out redox reactions in distant compartments. This ET occurs either by a single‐step superexchange or through a multi‐step charge hopping process, which uses side chains of amino acids as stepping stones. In this study we demonstrate that Phe can act as a relay amino acid for long‐distance electron...

Université de Fribourg

The bisketene radical cation and its formation by oxidative ring-Opening of cyclobutenedione

Piech, Krzysztof ; Bally, Thomas ; Allen, Annette D. ; Tidwell, Thomas T.

In: The Journal of Organic Chemistry, 2013, vol. 78, no. 7, p. 2908–2913

Parent cyclobutenedione 1 was photolyzed and ionized in an Ar matrix at 10K. The bisketene 2 that results in both cases (in the form of its radical cation after ionization) was characterized by its IR spectrum and by high-level quantum chemical calculations. Experiment and theory show that the neutral bisketene has only a single conformation where the two ketene moieties are nearly perpendicular,...

Université de Fribourg

Calculating accurate proton chemical shifts of organic molecules with density functional methods and modest basis sets

Jain, Rupal ; Bally, Thomas ; Rablen, Paul R.

In: The Journal of Organic Chemistry, 2009, vol. 74, no. 11, p. 4017–4023

The purpose of this paper is to convince practitioners of ¹H NMR spectroscopy to consider simple quantum chemical calculations as a viable option to aid them in the assignment of their spectra. To this end, it is demonstrated, on a test set of 80 conformationally stable molecules of various kinds carrying different functional groups, that, in contrast to what is claimed in the literature, large...

Université de Fribourg

Calculations of the optical spectra of hydrocarbon radical cations based on Koopmans' theorem

Nelsen, Stephen F. ; Weaver, Michael N. ; Yamazaki, Daisuke ; Komatsu, Koichi ; Rathore, Rajendra ; Bally, Thomas

In: The Journal of Physical Chemistry A, 2007, vol. 111, no. 9, p. 1667 -1676

The first few bands in the optical spectra of radical cations can often be interpreted in terms of A-type transitions that involve electron promotions from doubly occupied to the singly occupied molecular orbital (SOMO) and/or B-type transition which involve electron promotion from the SOMO to virtual molecular orbitals. We had previously demonstrated that, by making use of Koopmans' theorem, the...

Université de Fribourg

Carbocations generated under stable conditions by ionization of matrix-Isolated radicals: the allyl and benzyl cations

Mišić, Vladimir ; Piech, Krzysztof ; Bally, Thomas

In: Journal of the American Chemical Society, 2013, vol. 135, no. 23, p. 8625–8631

Carbocations are crucial intermediates in many chemical reactions; hence, considerable effort has gone into investigating their structures and properties, for example, in superacids, in salts, or in the gas phase. However, studies of the vibrational structure of carbocations are not abundant, because their infrared spectra are difficult to obtain in superacids or salts (where furthermore the...

Université de Fribourg

Cyclobutadiene : the antiaromatic paradigm ?

Bally, Thomas

In: Angewandte Chemie International Edition, 2006, vol. 45, no. 40, p. 6616 - 6619

Université de Fribourg

The Dewar benzene radical cation and tts ring-opening reaction

Bally, Thomas ; Matzinger, Stephan ; Bednarek, Pawel

In: Journal of the American Chemical Society, 2006, vol. 128, no. 24, p. 7828 -7834

Université de Fribourg

Dimer radical cations of indole and indole-3-carbinol: localized and delocalized radical cations of diindolylmethane

Błoch-Mechkour, Anna ; Bally, Thomas ; Marcinek, Andrzej

In: The Journal of Physical Chemistry A, 2011, vol. 115, no. 26, p. 7700–7708

Extending our previous study on the title species (J. Phys. Chem. A2010, 114, 6787), we investigated the dimer cations that are formed on oxidation of the glucobrassin derivatives indole-3-carbinol (I3C) and diindolylmethane (DIM) and of parent indole (I). Radiolysis in ionic liquid and Ar matrices shows that, at sufficiently high concentrations and/or on...

Université de Fribourg

Effect of substituents on the stabilities of multiply-substituted carbon-centered radicals

Menon, Ambili S. ; Henry, David J. ; Bally, Thomas ; Radom, Leo

In: Organic & Biomolecular Chemistry, 2011, vol. 9, p. 3636-3657

The bond dissociation energies (BDEs) and radical stabilization energies (RSEs) which result from 166 reactions that lead to carbon-centered radicals of the type ˙CH₂X, ˙CHXY and ˙CXYZ, where X, Y and Z are any of the fourteen substituents H, F, Cl, NH₂, OH, SH, CH=CH₂, C≡CH, BH₂, CHO, COOH, CN, CH₃, and CF₃, were calculated using spin-restricted and -unrestricted variants of the...