Related Experiment Video
Updated: Feb 16, 2026

Hydrogen Charging of Aluminum using Friction in Water
Published on: January 28, 2020
Size-Dependent Hydrogen Atom Attachment to Gas-Phase Hydrogen-Deficient Polypeptide Radical Cations
Luciano H Di Stefano1, Dimitris Papanastasiou2, Roman A Zubarev1
1Division of Physiological Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institutet , Scheelesväg 2, S-171 77 Stockholm, Sweden.
Abstract:
Despite significant affinity to carbonyl oxygens, thermal hydrogen atoms attach to unmodified polypeptides at a very low rate, while the hydrogen-hydrogen exchange rate is high. Here, using the novel omnitrap setup, we found that attachment to polypeptides is much more facile when radical site is already present, but the rate decreases for larger radical ions. The likely explanation is the intramolecular hydrogen atom rearrangement in hydrogen-deficient radicals to a more stable or less accessible site.
Related Concept Videos
Hydrogen Bonds
Hydrogen Bonds Control the World!
Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are unequally shared....
Hydrogen Bonds
Reduction of Alkenes: Catalytic Hydrogenation
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation
IR Spectrum Peak Broadening: Hydrogen Bonding
However, the extent of hydrogen bonding influences the observed stretching frequency and band broadening. Intermolecular or intramolecular...
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...

