In comparison with the fast development of binary mixture separations, ternary mixture separations are significantly more difficult and have rarely been realized by a single material. Herein, a new strategy of tuning the gate‐opening pressure of flexible MOFs is developed to tackle such a challenge. As demonstrated by a flexible framework NTU‐65, the gate‐opening pressure of ethylene (C2H4), acetylene (C2H2), and carbon dioxide (CO2) can be regulated by temperature. Therefore, efficient sieving separation of this ternary mixture was realized. Under optimized temperature, NTU‐65 adsorbed a large amount of C2H2 and CO2 through gate‐opening and only negligible amount of C2H4. Breakthrough experiments demonstrated that this material can simultaneously capture C2H2 and CO2, yielding polymer‐grade (>99.99 %) C2H4 from single breakthrough separation.

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Two series of lanthanide metal–organic frameworks (Ln-MOFs) from two structurally related flexible carboxylate-based ligands were solvothermally synthesized. H3L2 with additional −CH2− group provides more flexibility and different coordination modes and conformations compared with H3L1. As a result, 2-Ln MOFs are modulated from two-dimensional kgd of 1-Ln to three-dimensional rtl topological frameworks and further achieve enhanced chemical stability. The Eu- and Tb-MOFs exhibit strong fluorescent emission at the solid state because of the antenna effect of the ligands. Interestingly, the emissions can be tuned by simply doping Eu3+ and Tb3+ of different concentrations within the Eu x Tb 1–x MOFs. Notably, 2-Ln MOFs realize nearly white light emission by means of a trichromatic approach (red of Eu­(III), green of Tb­(III), and blue of the H3L2 ligand). Furthermore, 2-Ln MOFs also exhibit water stability and demonstrate high selective and sensitive sensing activities toward Fe­(III) and Cr­(VI) in aqueous solutions. The results further highlight the importance of the ligand flexibility on tuning MOF structures with improved structural stability and ion-sensing properties.

A new approach of finely tuning multinuclear clusters of MOFs through symmetry-upgradingly isoreticular transformation was firstly presented and a bcu-type MOF, {[Cu4(μ4-O)Cl2(IN)8]•CuCl2}∞ (NJU-Bai35; NJU-Bai for Nanjing University Bai group), with cluster [Cu4(μ4-O)(COO)4N4Cl2] of higher symmetry com-pared to the pristine MOF, was successfully synthesized. The symmetry upgrading implemented on the inorganic part triggers the adjustment of channels in NJU-Bai35 to fit CO2 molecules, leading to a high CO2 adsorption capacity (7.20 wt% at ~ 0.15 bar and 298 K) and high selectivity of CO2 over N2 and CH4 (275.8 for CO2/N2 and 11.6 for CO2/CH4) in NJU-Bai35. Breakthrough experiments further confirmed that NJU-Bai35 might be an excel-lent candidate for CO2 capture and natural gas purification.

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