摘要：SummaryThis work maps the thermodynamics of electrochemically generated C-nucleophiles for reactive capture of CO2. We identify a linear relationship between the pKa, the reduction potential of a protonated nucleophile (Ered), and the nucleophile’s free energy of CO2binding (ΔGbind). Through synergistic experiments and computations, this study establishes a three-parameter correlation described by the equationΔGbind=−0.78pKa+4.28Ered+20.95for a series of twelve imidazol(in)ium/N-heterocyclic carbene pairs with anR2of 0.92. The correlation allows us to predict theΔGbindof C-nucleophiles to CO2using reduction potentials or pKas of imidazol(in)ium cations. The carbenes in this study were found to exhibit a wide range CO2binding strengths, from strongly CO2binding to nonspontaneous. This observation suggests that theΔGbindof imidazol(in)ium-based carbenes is tunable to a desired strength by appropriate structural changes. This work sets the stage for systematic energetic tuning of electrochemically enabled reactive separations.Graphical abstractDisplay OmittedHighlights•CO2binding energy was calculated for a set of N-heterocyclic carbenes (NHCs)•CO2binding energy of NHCs is widely synthetically tunable•pKa, reduction potential, and CO2binding energy correlate linearly for NHCs•3D correlation enables easy prediction of CO2binding strength for novel NHCsChemistry; Theoretical chemistry; Electrochemistry; Computational chemistry; Applied chemistry
