Fig. 3: Analysis of time-resolved NMR spectra series.

Concentration of (A) protonated and (B) deprotonated carboxyl group in terephthalic acid obtained from ¹³C MAS NMR spectra; temporal evolution of ¹H-¹³C CP-MAS signals of (C) terephthalate and (D) formate species in solid nuclei of MIL-53 together with the ¹³C DMF signal intensity; (E) concentration of aluminum species in solution versus synthesis time; (F) time-resolved response of the integral intensity of the MIL-53 spinning side band centered at −150 ppm; (G) integral intensity and (H) position of ¹H signal due to the formate species in solution. Colured circled encode reaction temperature except in (D).