Fig. 5: In-situ ¹H NMR investigation during TpPa-COF-10% membrane synthesis.

a In-situ ¹H NMR spectra of the reactions between TP and PPG-NH2 monitored over the 4-hour heating period. b In-situ ¹H NMR spectra of the reactions between TP, PDA, and PPG-NH2 monitored over the 6-hour heating period. c DFT-calculated reaction energies of forming the possible products and reaction routes during the sol-gel solution formation using 1-methoxy-2-propylamine as the alternative of PPG-NH2.