One-Electron Reduction of 8-Bromoisoguanosine and 8-Bromoxanthosine in the Aqueous Phase: Sequential versus Concerted Proton-Coupled Electron Routes

The reactions of hydrated electrons (eaq −) with 8-bromoisoguanosine and 8-bromoxanthosine were studied by pulse radiolysis techniques and addressed computationally by means of hybrid meta DFT calculations at the B1B95/6-31+G** level. The one-electron oxidized purine derivative is formed either by o...

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Published in:The journal of physical chemistry letters 2010-01, Vol.1 (1), p.174-177
Main Authors: Chatgilialoglu, Chryssostomos, D’Angelantonio, Mila, Kaloudis, Panagiotis, Mulazzani, Quinto G, Guerra, Maurizio
Format: Article
Language:English
Subjects:
Biophysical Chemistry
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Summary:The reactions of hydrated electrons (eaq −) with 8-bromoisoguanosine and 8-bromoxanthosine were studied by pulse radiolysis techniques and addressed computationally by means of hybrid meta DFT calculations at the B1B95/6-31+G** level. The one-electron oxidized purine derivative is formed either by oxidation of the corresponding purine with SO4 •− or by reduction of the corresponding 8-bromopurine with eaq − at pH 7. The reactivity of 8-bromoxanthosine depends on its protonation state. In agreement with the experimental findings, DFT calculations suggest that the reaction of the eaq −/H+ couple with 8-bromoisoguanosine and 8-bromoxanthosine (monoanion) involves sequential electron-transfer−proton-transfer (ET−PT) and concerted electron−proton-transfer (EPT) pathways, respectively.
ISSN:1948-7185
1948-7185
DOI:10.1021/jz9001532