Bis-coenzyme q(0) : synthesis, characteristics, and application

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.