Fig. 3: Redox reaction pathways and pKa estimation of 1.
From: Electrifying amine carbon capture with robust redox-tunable acids
a PCET pathways under conditions without amine (i), with MEA and N2 (ii), and with MEA and CO2 (iii). The potentials (vs. Fc+/0) for the electron transfer steps (E), the changes in Gibbs free energy for the proton transfer steps (∆G), and the pKa values of each state are calculated by DFT and compared with experimental results if available. The most favourable pathway in the presence of proton donors with varying pKa is shaded in pink (1), blue (2), green (3), and yellow (4), corresponding to the four different regions in the pKa-potential diagram in (b). b Reduction potentials of 1-ox in the presence of proton donors with varying pKa (−14.9 to 32 in DMSO). The data was obtained by the average of three independent CV measurements in the presence of proton donors under N2. The diagram is divided into four regions, which undergo different reaction pathways highlighted in (a). Source data for Fig. 3 are provided as a Source Data file.
