We investigated the entropy of the electrical double layer (EDL) formation at a (111)-textured Au film in the ionic liquid 1-butyl-1methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide by electrochemical microcalorimetry. We found reversible heat exchange upon EDL charging in the potential range of −0.6 to 1 V versus Fc/Fc + . Dependent on the potential, the heat evolution continued for 10 to 200 ms after the current flow, indicating slow reorganization of the EDL on this time scale. The partial molar entropy of the formation of the EDL Δ R S form was derived from the reversibly exchanged heat upon EDL charging. It varied about linearly with the potential from 27 J K −1 mol −1 at −0.6 V to −79 J K −1 mol −1 at 1 V versus Fc/Fc + . Δ R S form crosses zero close to the potential of zero charge of the system. The entropy values are much higher than those arising from purely configurational entropy of a 2D lattice gas, thus pointing to strong, potentialdependent immobilization of the constituents of the EDL, where the immobilization is correlated with the strength of the electric field in the EDL. In addition, from our entropy values, we derive an apparent contradiction with experimentally determined temperature coefficients of the EDL capacitance, which implies a strongly varying activity of the ions participating in charging of the EDL with temperature.

The regioselectivity of the intramolecular cyclization of bifunctional α-phenyl alkenes can be controlled simply by the choice of the organic chromophore as the photocatalyst. The central photoredox catalytic reaction in both cases is a nucleophilic addition of the hydroxy function to the olefin function of the substrates. N,N-(4-Diisobutylaminophenyl)phenothiazine catalyzes exo-trig cyclizations, whereas 1,7-dicyanoperylene-3,4,9,10-tetracarboxylic acid bisimides catalyze endo-trig additions to products with anti-Markovnikov regioselectivity. We preliminarily report the photoredox catalytic conversions of 11 representative substrates into 20 oxaheterocycles in order to demonstrate the similarity, but also the complementarity, of these two variants in this photoredox catalytic toolbox.