Water-soluble anthraquinones (AQs) hold great promise serving as redox-active species in aqueous organic redox flow batteries. Systematic investigations into how the properties of redox molecules depend on the water-solubilizing groups and the way in which they are bound to the redox core are, however, still lacking. We introduce water-solubilizing groups linked to anthraquinone by C=C bonds via Heck cross-coupling reactions and convert C=C bonds to CC bonds through hydrogenation. The anthraquinone and the ending groups are connected via branched or straight chains with either unsaturated or saturated bonds. We investigate the influence of water-solubilizing chains and ionic ending groups on redox potentials of molecules and identify three important trends. (1): The electron-withdrawing ending groups can affect redox potentials of AQs with two unsaturated hydrocarbons on the chains through π-conjugation. (2): For chains with two saturated or unsaturated straight hydrocarbons, water-solubilizing ending groups increase redox potentials of the AQs in the order of PO32
The supporting information include molecular characterizations, electrochemical studies, and cost analysis of AQDP.