| Autor: |
Donkers, R. L., Workentin, M. S. |
| Zdroj: |
The Journal of Physical Chemistry - Part B; May 21, 1998, Vol. 102 Issue: 21 p4061-4063, 3p |
| Abstrakt: |
The reduction of the known antimalarial agent Artemisinin (ART) has been studied in N,N-dimethylformamide (DMF) by cyclic voltammetry and other electrochemical techniques. ART undergoes an irreversible, dissociative reduction with an anodic peak potential (Ep) that varies with scan rate and is −1.68 V vs SCE at 1 V/s. Direct electrochemical reduction of ART is subject to a large activation overpotential, and thus the Ep's do not provide an accurate value of the standard reduction potential (E°diss(ART)) required for the determination of the free energy of electron transfer from possible biological electron donors (ΔG°ET = F(E°D•+/D − E°diss(ART))). Using careful heterogeneous electrochemical methods with convolution analysis, the standard potential of the dissociative reduction of ART (E°diss(ART)) has been determined for the first time to be −0.89 V versus SCE in DMF. This value is ca. 0.8 V more positive than the irreversible direct reduction observed using cyclic voltammetric measurements. In addition, the value E°diss(ART) allows the estimation of the O−O bond dissociation energy. The thermochemical values determined are important to understanding ART's biological activity and investigating its potential for undergoing electron-transfer-initiated processes with biological donors. |
| Databáze: |
Supplemental Index |
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