Electrochemical reduction, radical anions and solvation energies of 1,2,3,4-tetrafluoro-9,10-anthraquinone and its N-piperidyl derivatives in DMF and DMF–water mixtures

The electrochemical reduction of 1,2,3,4-tetrafluoro-9,10-anthraquinone and its 2-(N-piperidyl) derivative in DMF and DMF–H2O mixtures represents an EE-process, whereas that for 1-(N-piperidyl) and 1,4-di(N-piperidyl) derivatives occurs as an EEC-process. Based on the linear dependences of the first reversible one-electron reductive half-wave potentials of these compounds on the water content of DMF–H2O mixtures, the corresponding changes in the free energies of solvation under electron transfer have been calculated. Radical anions of the above compounds were obtained in DMF and characterized by EPR spectroscopy and DFT calculations at the (U)B3LYP/6-31+G* level of theory.