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.