find stronger support through background experiments involving both cations at varying water levels. The results from DiPh and MM show that when the cation is acting as a co-catalyst the overpotential is not only dependent on the intrinsic kinetics of the co-catalyzed reaction but also on the stability of the cation and possible side reactions involving residual water. This will bring this notion that to gain a full picture of the performance, transient experiments (for example: LSVs) should always be complemented by steady-state experiments. It's noteworthy to acknowledge that while we have put forth the potential influence of residual water on the observed behavior of the MM and DiPh cations, an alternative explanation might also be considered. This alternative explanation suggests the potential for a mechanistic alteration in the reaction during steady-state experiments, specifically involving the DiPh cation. Notably, in the steady-state scenario, the DiPh cation demonstrates an improved performance compared to the MM cation, aligning with the expectations from our theory of C2-H acidity. However, at the moment, we lack any viable hypothesis that could be proposed for such a scenario. The last experiment was aimed at the comparison between MM and DiCl cations. Figure 4.9 shows the LSVs results under CO2 atmosphere and the electron density map for both cations. Clearly, DiCl is an electron poor cation, and we would expect a higher activity compared with that for MM. This is confirmed by the LSV results and the electrolysis results for which a more positive overpotential up to +200 mVs is obtained by DiCl (Figure 4.10). However, electrolysis results did not show the expected amount of CO. Thus, we suspect the formation of other products or the degradation of the cation. Yet, 13C NMR and 1H NMR analysis after few hours of electrolysis did show neither any liquid product nor any evidence of the degradation of the cation (Supporting Information, Figures S4.4-S4.6).
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