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The separation of C2 H2 from C2 H4 is one of the most challenging tasks due to the similarity of their physical properties. In addition, green synthetic protocol and adsorbent's stability are also the major concerns during the separation. Herein, under hydrothermal green synthesis conditions, an ultrastable ultramicroporous Zn-MOF was designed and synthesized with a high yield. The pore diameter of the Zn-MOF is 3.6 A, which lies in between the diameters of C2 H2 (3.3 A) and C2 H4 (4.2 A) molecules, leading to an efficient separation of the C2 H2 /C2 H4 mixtures by the sieving effect. The practical separation performance of C2 H2 /C2 H4 was confirmed by the dynamic breakthrough experiments. Moreover, the high stability enables the adsorption capacity of the Zn-MOF to C2 H2 , which can be maintained under a wide range of pH (1-13). Molecular simulations were also performed to identify the different C2 H2 - and C2 H4 -binding sites in Zn-MOF.

With the aid of a pyridyl tetracarboxylate ligand, 2,5-bis(2',5'-dicarboxylphenyl)pyridine (H4L), two indium-organic frameworks, [In2(L)(OH)2]·2DMF·2H2O (1) and [Me2NH2][In(L)]·2.5NMF·4H2O (2), with (6,8)- and (4,4)-connected nets have been constructed in different solvent systems. Both 1 and 2 exhibit high thermal and chemical stability. Gas sorption behavior of 1 and 2 for N2, C2H2, C2H4, CO2, and CH4 indicate excellent separation selectivities of C2Hx/CH4 and CO2/CH4. Furthermore, 1 possesses a high density of Bronsted sites and shows efficient catalytic conversion for CO2 cycloaddition with epoxides. Meanwhile, luminescence investigations reveal that 2 can detect nitrofurazone efficiently.

By employing a tripod rigid ligand with six coordination sites, 4,4’,4”-(pyridine-2,4,6-triyl)tribenzoic acid (H6PTA), a microporous terbium(III)-organic framework, [(Me)2NH2]1.5[Tb1.5(PTA)]·9H2O (1) has been synthesized under the solvothermal condition. Structural analysis demonstrates that 1 is a 3D anionic framework based on two kinds of Tb(III) units, which presents a rare framework constructed from ternary secondary building units (SBUs) and shows a new (4,5,6)-connected topology. Gas adsorption measurements reveal that 1 exhibits the significant C2H2 and C2H4 adsorption capacity but negligible uptake of CH4, which makes 1 as a promising adsorbent for C2H2/CH4 and C2H4/CH4 separation.