Kinetics Measurements. Adsorption and desorption kinetics are also critical factors to consider when assessing the utility of a candidate adsorbent. We investigated the kinetics of O2 and N2 adsorption and desorption in Cu2.7-MFU-4l at temperatures of 288, 298, and 308 K after dosing with initial quantities of each adsorbate (0.5, 1.0, 5.0, or 10.0 mmol/g) corresponding to equilibrated pressures ranging from approximately 3 to 330 mbar (see Table ; these pressures reflecting the steep region of the single-component isotherms for each gas). Adsorption of O2 and N2 occurred rapidly in Cu2.7-MFU-4l, with pressure equilibration occurring within approximately 50 s or less in both cases and for all temperatures and dosing conditions (Figure ). For both gases, the rate of adsorption increased with increasing temperature, although this effect is more pronounced for N2 (Figure ). At the lowest two dosing concentrations and all three temperatures, N2 uptake in Cu2.7-MFU-4l equilibrated more rapidly than O2 (~20 s versus 50 s). This difference was minimized at the highest two dosing concentrations of 10 mmol/g (Figures , and S21), and the saturation times for both gases appeared to approach the diffusion-controlled timescales measured for Ar adsorption kinetics (~20 s, see Figure ).