Fig. 1. (a) Single-component adsorption–desorption isotherms of C₂H₆ and C₂H₄ in Al-MOFM₁₅ measured at 273 and 293 K for pressures 0–690 torr. (b) Isosteric heats of adsorption (Q_st) of C₂H₆ and C₂H₄ at various loading amounts (near-zero coverage Q_st values are provided in the inset). (c) Mixed adsorption isotherms and selectivity calculated using IAST for C₂H₆/C₂H₄ (50 : 50) in Al-MOFM₁₅ at 293 K. (d) C₂H₆/C₂H₄ separation performance in some benchmark porous materials. (e and f) Locations of the highest binding affinity sites determined by DFT optimization for C₂H₆ (−39.9 kJ mol⁻¹) and C₂H₄ (−38.7 kJ mol⁻¹). Insets: Corresponding molecule locations, zoomed out, within the large channel. C₂H₆ participates in two hydrogen-bonding interactions with carboxylate oxygens while C₂H₄ participates in π–π and hydrogen-bonding interactions with the naphthalene ring and carboxylate oxygen, respectively. Binding sites with lower affinities for C₂H₄ and C₂H₆ are shown in Fig. S23 and S24,† respectively.