Key Laboratory for Advanced Materials, Department of Chemistry, East China University of Science and Technology, Shanghai, PR China.
Chem Asian J. 2011 Apr 4;6(4):1064-73. doi: 10.1002/asia.201000477. Epub 2010 Nov 16.
A methylene-bridged bis-coenzyme Q(0), bis(2,3-dimethoxy-5-methyl-l,4-benzoquinone)methane (Bis-CoQ(0)), that shows intramolecular electronic communications has been synthesized for the first time. By employing electrochemical, in situ UV/Vis, and electron paramagnetic resonance (EPR) spectroelectrochemical techniques, the unstable reduced intermediate species-monoradicals, diamagnetic dianions and tetraanions of Bis-CoQ(0)-have been observed. The electron-transfer process can be defined as a three-step reduction process with a total of four electrons in solution in CH(3) CN. The chemical reaction in the third redox step process was confirmed by variable temperature cyclic voltammetry. In an aprotic CH(3) CN solution, the peak potential separation between electron-transfer steps diminished sequentially with increasing concentration of water. The hydrogen-bonding interactions between water and the electrochemically reduced intermediates of Bis-CoQ(0) can be estimated by peak potential shifts. The electronic communications of Bis-CoQ(0) may have been blocked when one reduction peak was observed with proper quantities of water in CH(3) CN solution. The antioxidant defense capacity of Bis-CoQ(0)-protected cells has also been assessed.
一种亚甲基桥联的双辅酶 Q(0)，双(2,3-二甲氧基-5-甲基-1,4-苯醌)甲烷(Bis-CoQ(0))，首次被合成，其显示出分子内电子通讯。通过使用电化学、原位紫外/可见光谱和电子顺磁共振（EPR）光谱电化学技术，观察到不稳定的还原中间物种-单自由基、双自由基和 Bis-CoQ(0)的四自由基。电子转移过程可以定义为在 CH(3) CN 溶液中总共四个电子的三步还原过程。通过变温循环伏安法证实了第三个氧化还原步骤中的化学反应。在非质子 CH(3) CN 溶液中，随着水浓度的增加，电子转移步骤之间的峰电位分离依次减小。通过峰电位位移可以估计水与 Bis-CoQ(0)电化学还原中间体之间的氢键相互作用。当在 CH(3) CN 溶液中加入适量的水时，观察到一个还原峰，可能会阻断 Bis-CoQ(0)的电子通讯。Bis-CoQ(0)保护细胞的抗氧化防御能力也得到了评估。
