2-羟基-1,4-萘醌的电化学氧化还原机理研究

利用现场红外光谱电化学方法、 红外光谱循环伏吸法(CVA)和导数循环伏吸法(DCVA)研究了2-羟基-1,4-萘醌(2-HNQ)在乙腈溶剂中的电子转移机理. 在扫描范围为0.2~-1.8 V时, 2-HNQ的循环伏安(CV)图中有2对氧化还原峰. 在扫描范围为1.0~-2.0 V时, CV图在更正的电位下会出现1个氧化峰. 通过分析循环伏安扫描过程中1656, 1495, 1549和1325 cm^-1等峰的变化, 观察到整个电化学过程中存在2种中间状态, 去质子化醌(Q-O^-)还原生成的自由基二价阴离子会继续发生电化学反应, 即Q-O^-的还原遵循电化学-电化学反应机理(EE机理). 红外分析结果表明, 2-HNQ的电化学过程中存在较强的氢键作用.

Study on the Electrochemical Redox Mechanism of 2-Hydroxy-1,4-naphthoquinone

In situ IR spectroelectrochemistry, cyclic voltabsorptometry(CVA) and derivative cyclic voltabsorptometry(DCVA) techniques were used to study the electron transfer mechanism of 2-hydroxy-1,4-naphthoquinone(2-HNQ) in acetonitrile. When the scan range is from 0.2 V to -1.8 V, the voltammogram of 2-HNQ in acetonitrile shows two couples of anodic and cathodic peaks. When the scan range is from 1.0 V to -2.0 V, there is another anodic peak in cyclic voltammetry(CV) at more positive potential. Tracing the change of some IR absorption peaks during CV scan, there are two kinds of intermediates in the electrochemical process. Radical dianion formed by the reduction process of deprotonated quinine(Q-O^-) continues to reduce, i. e., Q-O^- reduces by an electrochemical reaction-electrochemical reaction mechanism(EE pathway). In addition, it involves the formation of strong hydrogen bonding.