The situation is somehow different at higher pH. The first oxidation act from 1 to 1ox1 seems to be single-electron in nature with Eox = 0.91 V w.r.t. SHE. While oxidation of 1ox1 can proceed further similarly to the low-pH process to form nitrenium cations 1ox2, it may compete with isomerization that is not possible for protonated species, i.e., formation of radicals 3ox1. The process seems feasible at room temperature (rt=25 Celsius) with an activation barrier of only 11.2 kcal/mol. Although it is thermodynamically uphill by 7.2 kcal/mol, it will be immediately compensated with -14.7 kcal/mol by the formation of dimeric species 4ox1, in which two N-centred radicals recombine to form an N-N bond well known in the organic chemistry of dyes. 4ox1 has distinct electrochemical properties, e.g. its oxidation may involve two electrons and two protons to form 4ox2. In total, more side reactions are possible at higher pH, which is manifested experimentally at a slope of 44 meV that suggests the reaction involves competitive reactions to a major 2-electron/1-proton process. Since the nitrenium cation belongs to a highly reactive electrophilic species, it can react further e.g. with unoxidized 8AQ and create electroactive products. Most probably formation of dimers or polymers occurs, which undergo redox reactions at less positive potentials compared to the monomers. Therefore, we have registered cyclic voltammograms in more negative potentials (from 0.2 to -0.8 up to 0.9 V, Figure ) for each pH value. Here we show the results for pH 7.4 (physiological). (The rest of the results are provided in the RepOD database (.) The first scan (as previously) presents two anodic peaks at Eox1 =+0.46 V and at Eox2 =+0.65 V. In the successive scans, new anodic peaks at Eoxc2p3 ~+0.34 V and Eoxc2p4 ~+0.05 V as well as cathodic peaks at Eredc2p3 ~-0.39 V and Eredc2p4 ~-0.16 V appear. The obtained curves confirmed the formation of redox active species from 8AQ oxidation in the first cycle at the GC surface.