Separation of acetylene from carbon dioxide remains a daunting challenge because of their very similar molecular sizes and physical properties. We herein report the first example of using copper(I)‐alkynyl chemistry within an ultra‐microporous MOF (CuI@UiO‐66‐(COOH)2) to achieve ultrahigh C2H2/CO2 separation selectivity. The anchored CuI ions on the pore surfaces can specifically and strongly interact with C2H2 molecule through copper(I)‐alkynyl π‐complexation and thus rapidly adsorb large amount of C2H2 at low‐pressure region, while effectively reduce CO2 uptake due to the small pore sizes. This material thus exhibits the record high C2H2/CO2 selectivity of 185 at ambient conditions, significantly higher than the previous benchmark ZJU‐74a (36.5) and ATC‐Cu (53.6). Theoretical calculations reveal that the unique π‐complexation between CuI and C2H2 mainly contributes to the ultra‐strong C2H2 binding affinity and record selectivity. The exceptional separation performance was evidenced by breakthrough experiments for C2H2/CO2 gas mixtures. This work suggests a new perspective to functionalizing MOFs with copper(I)‐alkynyl chemistry for highly selective separation of C2H2 over CO2.

In this work, we prepared two types of isostructural Ln 3+ -based metal−organic frameworks (LnMOFs) under solvothermal conditions, where two structurally similar pyridine-containing dicarboxylate ligands, 6-(4-carboxyphenyl)nicotinic acid and [2,2′-bipyridine]-5,5′-dicarboxylic acid, were used as the organic linkers. The as-synthesized LnMOF compounds were characterized using single-crystal X-ray diffraction (XRD), powder XRD, and thermogravimetric analysis. With the lanthanide co-doping approach, two mixed LnMOFs, Tb 0.95 Eu 0.05 cpna and Tb 0.95 Eu 0.05 bpydc, were obtained and evaluated for application as potential ratiometric luminescence thermometers. The temperature-dependent luminescence of the two materials was investigated, and their emission intensities, luminescence lifetimes, and thermometric parameters were compared. They exhibit an excellent S-shaped response for temperatures in the range of 25−300 K, with favorable relative sensitivity and temperature uncertainty. Moreover, their color changes from green at 25 K to red at 300 K, so that they are also suitable as colorimetric luminescent probes.

A tetracarboxylic acid ligand containing a highly polarized benzothiadiazole moiety was designed and used to construct the luminescent porous MOFZJU-21, which can efficiently absorb the luminescent dye DMASM into the pores as well as sensitize it, yielding a dual-emitting MOF⊃dye compositeZJU-21⊃DMASM.

separations. [1] Ethylene (C 2 H 4 ), as the most important olefins, is the mainstay of petrochemical industry, with a global annual production of exceeding 170 million tonnes per year. "Polymer-grade" specification of ethylene is required for the manufacture of polyethylene plastic. The industrial separation of ethylene from ethylene/ethane (C 2 H 4 /C 2 H 6 ) mixtures highly relies on the repeated distillation-compression cycling at the temperature as low as −160 °C. [1,2] Such heat-driven separation involving in the phase change of isolated fractions, is highly energy-and capital-intensive. Finding energy-efficient alternatives to distillation would widely lower global energy consumption, carbon emissions, and pollution. It is feasible in principle to separate C 2 H 4 /C 2 H 6 mixtures based on porous solid materials via the energy-efficient and environmentally friendly adsorption technology. In this context, development of suitable porous adsorbents for ethylene/ ethane separation is of highly commercial significance.A number of porous materials including zeolites, [3] carbon molecular sieves, [4] and alumina, [5] have been explored for the separation of ethylene and ethane. However, the limits on deliberately designing the structure of such purely inorganic materials make them hardly meet the requirement of industrial implement. As an emerging class of microporous The development of new materials for separating ethylene (C 2 H 4 ) from ethane (C 2 H 6 ) by adsorption is of great importance in the petrochemical industry, but remains very challenging owing to their close molecular sizes and physical properties. Using isoreticular chemistry in metal-organic frameworks (MOFs) enables the precise design and construction of target materials with suitable aperture sizes and functional sites for gas separations. Herein, it is described that fine-tuning of pore size and π-complexation simultaneously in microporous copper(I)-chelated MOFs can remarkably boost the C 2 H 4 /C 2 H 6 adsorption selectivity. The judicious choice of organic linkers with a different number of carboxyl groups in the UiO-66 framework not only allows the fine tuning of the pore size but also immobilizes copper(I) ions onto the framework. The tailor-made adsorbent, Cu I @UiO-66-(COOH) 2 , thus possesses the optimal pore window size and chelated Cu(I) ions to form π-complexation with C 2 H 4 molecules. It can rapidly adsorb C 2 H 4 driven by the strong π-complexation interactions, while effectively reducing C 2 H 6 uptake due to the selective size-sieving. Therefore, this material exhibits an ultrahigh C 2 H 4 /C 2 H 6 selectivity (80.8), outperforming most previously described benchmark materials. The exceptional separation performance of Cu I @UiO-66-(COOH) 2 is validated by breakthrough experiments for 50/50 v/v C 2 H 4 /C 2 H 6 mixtures under ambient conditions.