A Series of new Urea‐MOFs Obtained via Post‐synthetic Modification of NH 2 ‐MIL‐101(Cr): SO 2 , CO 2 and H 2 O Sorption

The amino group in the MOF NH 2 ‐MIL‐101(Cr) was post‐synthetically converted into urea‐groups partially using either ethyl isocyanatoacetate, furfuryl isocyanate, p ‐toluenesulfonyl isocyanate or 3‐(triethoxysilyl)propyl isocyanate in acetonitrile. The derived four novel urea‐MOFs exhibit the expected lower BET surface areas and pore volumes than MIL‐101(Cr) and NH 2 ‐MIL‐101(Cr) MOFs but the partially p ‐toluenesulfonyl‐urea‐modified MOF exhibits an outstanding SO 2 adsorption capacity of 823 cm 3  g −1 (corresponding to 36.7 mmol g −1 or 70 wt.% at T=0 °C and 0.9 bar), which is the second highest SO 2 uptake of any known material today – surprisingly even better than for highly porous MIL‐101(Cr) with an uptake of 645 cm 3  g −1 SO 2 under the same conditions. The high uptake is linked to the favorable dipole interactions of SO 2 with the sulfonyl group of the p ‐toluenesulfonyl‐modified MOF.