Université de Fribourg

Kinetics of ion transport through supramolecular channels in single crystals

Assouma, Cyrille D. ; Crochet, Aurélien ; Chérémond, Yvens ; Giese, Bernd ; Fromm, Katharina M.

In: Angewandte Chemie International Edition, 2013, vol. 52, no. 17, p. 4682–4685

Single-crystal to single-crystal transformations are possible by ion-exchange and transport reactions through supramolecular channels that are composed of crown ether molecules and use trihalide ions as scaffolds. Kinetic measurements of ion transport at different temperatures provide activation energy data and show that a very fast.

Université de Fribourg

Radicals and radical ions as intermediates of electron transfer processes through peptides

Giese, Bernd ; Eckhardt, Sonja ; Lauz, Miriam ; Gao, Jian ; Wang, Min

In: Chimia, 2012, vol. 66, no. 6, p. 364-367

Electron transfer (ET) through peptides and proteins is a key biochemical process, which involves radicals and radical ions as reactive intermediates. We have developed an assay that allows us to study this fundamental chemical reaction.

Université de Fribourg

The influence of dipole moments on the mechanism of electron transfer through helical peptides

Lauz, Miriam ; Eckhardt, Sonja ; Fromm, Katharina M. ; Giese, Bernd

In: Physical Chemistry Chemical Physics, 2012, vol. 14, no. 40, p. 13785-13788

The life time of aromatic radical cations is limited by reactions like β-elimination, dimerization, and addition to the solvent. Here we show that the attachment of such a radical cation to the C-terminal end of an α-/3₁₀-helical peptide further reduces its life time by two orders of magnitude. For PPII-helical peptides, such an effect is only observed if the peptide contains an adjacent...

Université de Fribourg

Charge transfer in model peptides: obtaining Marcus parameters from molecular simulation

Heck, Alexander ; Woiczikowski, P. Benjamin ; Kubař, Tomáš ; Giese, Bernd ; Elstner, Marcus ; Steinbrecher, Thomas B.

In: The Journal of Physical Chemistry B, 2012, vol. 116, p. 2284–2293

Charge transfer within and between biomolecules remains a highly active field of biophysics. Due to the complexities of real systems, model compounds are a useful alternative to study the mechanistic fundamentals of charge transfer. In recent years, such model experiments have been underpinned by molecular simulation methods as well. In this work, we study electron hole transfer in helical model...