Combined Solid-State NMR and Computational Approach for Probing the CO2 Binding Sites in a Porous-Organic Polymer

We report on utilization of 1D and 2D C-13 cross polarization magic angle spinning (CPMAS) and MAS solid-state NMR spectroscopy in probing the binding sites and dynamical processes of C-13-enriched CO, inside the pores of a pyridine containing porous organic polymer (POP). Our findings from the spectroscopic measurements conducted on the evacuated sample and on the sample dosed with 800 mbar (CO2)-C-13 indicated preferential adsorption of the CO, molecules at the vicinity of the basic binding sites within the POP, the pyridine rings. We further demonstrate the results of a computational study for probing the most favorable binding sites of CO, inside a geometrically optimized model of the polymer in an attempt to better rationalize the experimental findings from C-13 solid-state NMR. investigations. Because of the amorphous nature of the studied POP, also being observed for a large number of emerging microporous solids, this combined approach can prove useful and versatile toward drawing a detailed picture of the gas solid interactions, aiming for enhanced designs for futuristic materials toward CO, capture and sequestration.