| Abstract: | Electrochemical studies on metronidazole using mixed aqueous/dimethylformamide (DMF) solvents have allowed us to generate the one-electron addition product, the nitro radical anion, RNO?2. Cyclic volt-ammetric techniques have been employed to study the tendency of RNO?2 to undergo further chemical reaction. The return-to-forward peak current ratio. ip/ipf. was found to increase towards unity with increasing DMF content of the medium, indicating the extended lifetime of RNO?2. Second order kinetics for the decay of RNO?2 were established at all DMF concentrations examined. Extrapolation has allowed the rate constant and a first half-life of 8.4 × 104dm2/mol-sec and 0.059 seconds respectively, to be determined for the decay of RNO?2 in a purely aqueous media. This is impossible by direct electrochemical measurement in water. due to a different reduction mechanism, giving the hydroxylamine derivative in a single 4-electron step. The application of the technique to other nitro-aromatic compounds is discussed. |
