Diamine-functionalised Mg 2 (dobpdc) materials were synthesised according to a procedure previously reported in literature. Methanol-solvated Mg 2 (dobpdc) was filtered and washed with toluene (50 mL). The filtered MOF (ca 0.1 -0.4 g) was then added to a toluene (4 mL) and diamine (1 mL) solution and left to soak for at least 12 h. The solid was then collected via vacuum filtration and washed with toluene (50 mL). e-2, dmpn, ee-2, i-2 and ii-2, functionalised Mg 2 (dobpdc) materials were activated by heating in an aluminium bead bath under N 2 to 125 °C for 1 h, 150 °C for 1 h, 125 °C for 1 h, 130 ºC for 1 h, and for 130 ºC for 1.5 h, respectively. A portion (10-20 mg) was taken for powder X-ray diffraction analysis (Figure ). To determine sample stoichiometries by 1 H NMR (Figure , Table ), ~ 5 mg of the activated amine-functionalised MOFs was digested in a mixture of dimethyl sulfoxide (DMSO-d 6 ) (1 mL) and two Pasteur pipette drops of deuterated hydrochloric acid (DCl) (35 wt% in D 2 O, ≥99 atom % D).