Water dynamics and hydrogen tunnelling in proton-coupled electron transfer reaction

Karković Marković, Ana (2016) Water dynamics and hydrogen tunnelling in proton-coupled electron transfer reaction. Doctoral thesis, Faculty of Science > Department of Chemistry.

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Abstract

The influences of molecular hydrophobic interfaces, involving organic solvents and quarternary ammonium ions, on the proton-coupled electron transfer (PCET) reaction of ascorbate monoanion with hexacyanoferrate(III) ion in water has been investigated. The kinetic isotope effect (KIE) in the reaction and the isotopic differences in Arrhenius activation energies increased and the isotopic ratios of the corresponding pre-factors AH/AD decreased significantly, suggesting a change from the apparent over-the-barrier process in neat water to a tunnelling regime on involving hydrophobic interfaces in the water solvent system. The observed phenomena are ascribed, invoking a Marcus-like tunnelling model that includes dynamical aspects of system and surroundings, to hydrogen tunnelling in reaction dynamically connected with femtosecond motions of water OH, where presence of hydrophobic interfaces causes changes in water dynamics coupled with reaction coordinate of the PCET process through intermolecular vibrational coupling mechanism of water.

Item Type: Thesis (Doctoral thesis)
Keywords: hydrogen tunnelling, hydrophobicity, promoting vibration, proton-coupled electron transfer, water dynamics
Supervisor: Uršić, Stanko
Date: 2016
Number of Pages: 149
Subjects: NATURAL SCIENCES > Chemistry
Divisions: Faculty of Science > Department of Chemistry
Depositing User: Branka Maravic
Date Deposited: 03 Nov 2016 11:52
Last Modified: 03 Nov 2016 11:52
URI: http://digre.pmf.unizg.hr/id/eprint/5257

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