摘要
采用线性扫描示波极谱法、循环伏安法、紫外光谱法及恒电位电解法等方法分别在水和 N,N-二甲基甲酰胺 ( DMF)两种介质中研究了抗癌药物马蔺子素的伏安行为及其极谱平行催化波产生机理 .结果表明 ,在 Na2 B4 O7-KH2 PO4 ( p H=7.7)缓冲溶液中 ,马蔺子素的醌基首先发生 1 e- 和 1 H+ 还原 ,产生中间体半醌自由基 ,该自由基再以同样方式进一步还原生成相应氢醌 ,并伴随有化学反应 ;在 DMF-四乙基溴化铵( TEAB)质子惰性介质中 ,马蔺子素连续两步单电子还原生成相应氢醌阴离子 ,无中间体半醌自由基的化学反应发生 .上述过程产生马蔺子素可逆还原波 .当氧化剂 K2 S2 O8存在时 ,马蔺子素醌基还原中间体半醌自由基被氧化 ,使原醌基再生 ,产生了马蔺子素的极谱平行催化波 .测得 S2 O2 - 8氧化马蔺子素半醌自由基的表观一级速率常数 kf=3 .3× 1 0 6 L· mol- 1 · s- 1 .
The voltammetric behavior and the production mechanism of polarographic catalytic wave of irisquinone were studied by linear potential scan polarography, cyclic voltammetry, UV spectroscopy and constant potential electrolysis in both aqueous and N,N dimethyl formamide(DMF) media. In Na 2B 4O 7 KH 2PO 4(pH=7.7) buffer, the quinonyl group of irisquinone was first reduced in a 1e -, 1H + process to produce an intermediate free radical semiquinone, and the further reduction of the free radical semiquinone to the corresponding hydroquinone anion in the same way was accompanied by its chemical reaction. In DMF tetraethyl ammonium bromide(TEAB) media, the reduction of irisquinone was two successive single electron processes without the chemical reaction of the free radical semiquinone. All these processes yield the reversible reduction wave of irisquinone. When S 2O 2- 8 was present, the free radical semiquinone of irisquinone was oxidized to regenerate the original quinonyl group, which resulted in the production of a polarographic catalytic wave. The apparent first order rate constant k f of the oxidation reaction of the free radical semiquinone of irisquinone with S 2O 2- 8 was 3.3×10 6 L·mol -1 ·s -1 .
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2003年第4期599-604,共6页
Chemical Journal of Chinese Universities
基金
国家自然科学基金 (批准号 :2 9875 0 17)
