2.3 Evaluation of SNDESs
The CO2 loading of SNDESs was determined by dual-vessel absorption system as shown in Figure S1 . The enthalpy change of system was estimated according to a previously used method, which is explained in the Supporting Information . Gaussian 09 program was performed to elucidate the molecular interaction between SNDESs and CO2. All the geometries were fully optimized by the B3LYP method based on the density functional theory (DFT) including the dispersion corrections using the Empirical Dispersion=GD3BJ keyword. The influence of the solvent was investigated in the condensed phase using the Polarizable Continuum Model (PCM) with a dielectric constant of 24.55 at the B3LYP/6-311++g(d,p) level39.