Naslov
Kinetic isotope effects and hydrogen tunnelling in PCET oxidations of ascorbate: new insights into aqueous chemistry?

Autori
Karković Marković, Ana ; Jakobušić Brala, Cvijeta ; Pilepić, Viktor ; Uršić, Stanko

Izvornik
Molecules (1420-3049) 25 (2020), 6; 1443, 16

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, pregledni rad, znanstveni

Ključne riječi
kinetic isotope effects ; ascorbate PCET reactions ; hydrogen tunnelling ; water vibrational dynamics ; activation processes

Sažetak
Recent experimental studies of kinetic isotope e ects (KIE-s) and hydrogen tunnelling comprising three proton-coupled electron transfer (PCET) oxidations of ascorbate monoanion, (a) in aqueous reaction solutions, (b) in the mixed water-organic cosolvent systems, (c) in aqueous solutions of various salts and (d) in fairly diluted aqueous solutions of the various partial hydrophobes are reviewed. A number of new insights into the wealth of the kinetic isotope phenomena in the PCET reactions have been obtained. The modulation of KIE-s and hydrogen tunnelling observed when partially hydrophobic solutes are added into water reaction solution, in the case of fairly diluted solutions is revealed as the strong linear correlation of the isotopic ratios of the Arrhenius prefactors Ah/Ad and the isotopic di erences in activation energies DEa (D, H). The observation has been proposed to be a signature of the involvement of the collective intermolecular excitonic vibrational dynamics of water in activation processes and aqueous chemistry.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA