When EDGs are substituted, as in the case of -OMe, the reduction potentials become more negative for both CV and DFT results as the reduced forms become disfavoured. In the case of -OH, however, intramolecular hydrogen-bonding stabilises the Q 2-form so an overall increase in E • EE is observed. This increase is supported by the change in DFT geometry: the hydroxyl proton in Q transfers to quinone O following electrochemical reduction (Figure ).