Figure shows CVs for the oxidation of 6.0 mM C2O4 2-where CO2 is initially absent (black) or initially present at its saturation concentration, 0.23 M at 1 atm in DMF (red). Voltammograms identical to those shown in Figure , first reported by Maran and co-workers, were used to establish C2O4 2-•CO2 oxidation as the origin of the CV wave observed near 0.15 V vs Fc/Fc + . Finite-difference simulations and ab initio molecular dynamics simulations from our lab demonstrate that, in the presence of 0.23 M CO2, all C2O4 2-(initially present at 6.0 mM) is bound to CO2 to form the C2O4 2-•CO2 adduct. As such, CV experiments analogous to those presented in Figure were repeated in CO2saturated DMF solutions, Figure . The black curve in Figure , corresponding to a CV of 1.2 mM DiMeFc in the presence of 0.23 M CO2, is unchanged with respect to the CV of DiMeFc in the absence of CO2 (Figure ), demonstrating, as expected, that CO2 does not chemically interact with DiMeFc or DiMeFc + . Addition of 6.0 mM C2O4 2-(Figure , blue) results in an increase in ipa for DiMeFc oxidation and the absence of a cathodic wave for DiMeFc + reduction. Because C2O4 2-•CO2, and not C2O4 2-, exists in the CO2-saturated solution, the results shown in Figure indicate that DiMeFc + mediates the oxidation of C2O4 2-•CO2, eq 14. Simulations presented in the Mechanistic Analysis Section demonstrate that eq 14 is explicitly required to successfully model experimental CV responses. DiMeFc + -mediated C2O4 2-•CO2 oxidation therefore generates CO2 •-in solution (eq 14 followed by eqs 6 and 10), which enables the rapid and irreversible reduction of 4-BrBN.