Fig. 3. CPOS-5 loaded with ¹³C-enriched CO₂ (0.75 bar at RT): (A) ¹³C MAS NMR spectrum; (B) 2D ¹H–¹³C HETCOR MAS NMR spectra collected at room temperature and at two distinct contact times (ct). The host–CO₂ cross peaks are highlighted in red. Chemical structures of TBS and DAB with labels (below). (C) Electrostatic potential projected on CO₂ molecules by the DAB and TBS host moieties. The CO₂ molecules were localized by DFT calculations.