Electrochemical analysis in charge-transfer science: The devil in the details

Revisiting the non-fluorescence of nitroaromatics: presumption versus reality

“…For non-charged donors and acceptors (eqn (5)). 134,135 The estimated change that PCT induces in the Gibbs free energy of the optically excited systems (Δ G (0) PCT ) comprising non-charged donor and acceptor amounts to: 136,137 where and are the single-electron reduction potentials of the acceptor and the oxidized donor obtained for solution media with static dielectric constants ε A and ε D , respectively; is the zero-to-zero energy for the optical excitation to the S 1 LE state obtained for medium with a dielectric constant ε and a refractive index n ; Δ G S ( ε , ε D , ε A ) is the Born solvation term accounting for the interaction between the donor and the acceptor with the surrounding media and correcting the reduction potentials from values for ε D and ε A to values for ε : 136 W ( ε ) is the Coulombic work term accounting for the electrostatic interactions between the oxidized donor and the reduced acceptor, which strongly depends on the distance between them; and F is the Faraday constant relating the potentials to the energy values.…”

“…The thermodynamic driving force of PCT, which is quantified by the negative values of Δ G (0) PCT , illustrates how low under the LE state is the energy level of the CT states. Eqn (5) shows that all the terms defining the PCT driving force depend on the polarity of the solvating media, 137 as implemented by the Born solvation model 138 for the reduction potentials and Δ G S , by the Coulombic model 139–141 for W , and by the Onsager solvation model 142 (accounting for the solvatochromism of the LE state) for . Permanent electric dipoles of moieties attached to donor–acceptor conjugates further modulate Δ G (0) PCT .…”

Photophysics and Electrochemistry of Biomimetic Pyranoflavyliums: What Can Bioinspiration from Red Wines Offer

“…Employing Koopmans’ theorem for interpretation of electrochemical results warrants a great deal of caution. The experimental measurements yield energies of transitions between states and not energy levels of molecular orbitals [ 41 ]. Optical transitions between the ground and excited states with the same multiplicity provide estimates for .…”

“…The relatively high stability of its singly oxidized form, along with its solubility in lipophilic solvents, makes ferrocene an excellent choice for testing the performance of the reference electrodes in organic electrochemistry. Nevertheless, reporting measured potentials versus the ferrocene redox couple as a reference is fundamentally wrong and may lead to misinterpretation of results [ 41 ]. The reference should be as invariant as possible to the medium conditions in the electrochemical cells, and the reduction potential of Fc + strongly depends not only on the solvent polarity, but also on the electrolyte concentration [ 38 ].…”

“…The liquid-junction potentials ( E LJ ) in electrochemical cells [ 41 , 54 ], indeed, contribute to the solvent-induced changes in . Ensuring that the liquid junctions of the salt bridges are between miscible electrolytes tend to minimize the contributions from E LJ to the recorded voltammograms [ 54 ].…”