The computational expense of DFT training and extensive DFT NMR calculations on the CD-MOF system (> 1000 atom unit cell) meant a combination of additional NMR experiments (Fig. ), direct inference from the quantitative modelling of KHCO 3 and K 2 CO 3 (Tables ), and qualitative MD simulations (Fig. ) were utilised for mechanistic conclusions to be achieved. Experimentally, insight into the constituent environments of the chemisorbed CO 2 peak was resolved via an MQMAS spectrum, supported by multi-field fitting of O NMR spectra obtained at 20.0 and 23.5 T (see SI section 5.2 and Figs. S29-S33 for further details). This identified three environments (Fig. ) assigned as carbonyls and hydroxyls all with a large degree of broadening, symptomatic of dynamics being at play.