Mesoporous CMK-3 (50 mg, 1 equiv.) and 2-AAQ (0.28 g, 3 equiv.) were stirred in degassed acetonitrile for 16 hours under N2. Tert-butyl nitrite (0.13 g, 1 equiv. compared to 2-AAQ) was added and the mixture was stirred for 30 min, and then another 1 equiv. of tert-butyl nitrite was added to the organic suspension. This process was repeated until a total of 3 equiv. of tert-butyl nitrite were added. The suspension was kept at ambient temperature while stirring under N2. After 4 h, the reaction mixture was vacuum filtered on a nylon filtration membrane and the f-CMK-3 powder was washed with successive aliquots of acetonitrile (500 mL), DMF (500 mL), acetone (100 mL) and methanol (100 mL) and dried in a vacuum oven at 100 °C for 12 h. The final weight percentage increase after functionalisation was 22 ± 7 wt. %.