植物黄酮的阴极还原及自由基检测

Electro-Reduction Behaviour of Flavone and Measurement of Free Radicals

用循环伏安法研究典型植物黄酮化合物在乙醇-水体系中汞膜电极上的阴极还原过程及在非水体系DMF中铂电极上的阴极还原行为.在乙醇-水体系中只出现1个还原峰,在DMF体系中出现2个还原峰,分别对应于第1个电子和第2个电子的还原.电子自旋共振波谱仪(ESR)与电化学装置联用进行就地检测,首次得到了还原过程中产生的单电子还原中间体——自由基的ESR信号及精细波谱.通过测定和计算得到了有关自由基的ESR参数.g因子为2.006;超精细耦合常数分别为2.78,1.61和0.60Gs.

Electroreduction of 3,3′,4′, 5,7pentahydroxyl flavone was studied using cyclic voltammetry. In ethanolwater solution only one peak was observed while in DMF two peaks were found, each peak corresponding to a oneelectron reduction. ESR spectroscopy technique was applied in situ to the study of the flavone jointly with the electrolysis. Hyperfine structures of ESR spectrum of the electrochemically generated free radical of flavone in DMF were observed for the first time. Relative parameters of the ESR signals were obtained through calculation. The gfactor was found to be 2006, different hyperfine coupling constants were 278, 161 and 060Gs.