Modulation of the CO₂ fixation in dinickel azacryptands

While bimetallic azacryptands are known to selectively coordinate CO₂, there is little knowledge on how different substitution patterns of the azacryptand cage structure influence CO₂ coordination. Stopped-flow UV-vis spectroscopy, electrochemical analysis and DFT calculations were performed on a series of dinickel azacryptands and showed different rates of CO₂ coordination to the complexes. We herein present data showing that the different flexibility of the azacryptands is directly responsible for the difference in the CO₂ uptake capability of dinickel azacryptand complexes.