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As a new class of porous crystalline materials, hydrogen‐bonded organic frameworks (HOFs) assembled from building blocks by hydrogen bonds have gained increasing attention. HOFs benefit from advantages including mild synthesis, easy purification, and good recyclability. However, some HOFs transform into unstable frameworks after desolvation, which hinders their further applications. Nowadays, the main challenges of developing HOFs lie in stability improvement, porosity establishment, and functionalization. Recently, more and more stable and permanently porous HOFs have been reported. Of all these design strategies, stronger charge‐assisted hydrogen bonds and coordination bonds have been proven to be effective for developing stable, porous, and functional solids called hybrid HOFs, including ionic and metallized HOFs. This Review discusses the rational design synthesis principles of hybrid HOFs and their cutting‐edge applications in selective inclusion, proton conduction, gas separation, catalysis and so forth. [ABSTRACT FROM AUTHOR]

Adsorptive separation of xenon (Xe) and krypton (Kr) is a promising technique but remains a daunting challenge since they are atomic gases without dipole or quadruple moments. Herein we report a strategy for fabricating angular anion‐pillared materials featuring shell‐like Xe nano‐traps, which provide a cooperative effect conferred by the pore confinement and multiple specific interactions. The perfect permanent pore channel (4–5 Å) of Ni(4‐DPDS)2MO4 (M=Cr, Mo, W) can host Xe atoms efficiently even at ultra‐low concentration (400 ppm Xe), showing the second‐highest selectivity of 30.2 in Ni(4‐DPDS)2WO4 and excellent Xe adsorption capacity in Ni(4‐DPDS)2CrO4 (15.0 mmol kg−1). Crystallography studies and DFT‐D calculations revealed the energy favorable binding sites and angular anions enable the synergism between optimal pore size and polar porosity for boosting Xe affinity. Dynamic breakthrough experiments demonstrated three MOFs as efficient adsorbents for Xe/Kr separation. [ABSTRACT FROM AUTHOR]

Hydrogen‐bonded organic frameworks (HOFs) have emerged as rapidly growing porous materials while established permanent porosities are very fragile and difficult to stabilize due to weak hydrogen‐bonding interactions among building units. Herein, we report a stable hydrogen‐bonded metallotecton framework (termed as HOF‐ZJU‐102) that was constructed through hydrogen‐bonding networks between cationic metal‐organic complexes [Cu2(Hade)4(H2O)2]4+ (Hade=adenine) and GeF62− anions. The framework not only shows permanent porosity, but also exhibits efficient separation performance of C2H2/C2H4 at room temperature. More interestingly, its crystal structure could be irreversibly transformed into isostructural counterpart HOF‐ZJU‐101 by ion exchange in the SiF62− containing solution, evidenced by multiple characterization techniques including gas sorption measurements, 19F NMR spectra, FTIR and EDS. Utilizing such an ion exchange mechanism, the collapsed HOF‐ZJU‐102 could be restored into HOF‐ZJU‐101 by simply soaking in the salt solution. [ABSTRACT FROM AUTHOR]

The separation of xenon/krypton (Xe/Kr) mixture is of great importance to industry, but the available porous materials allow the adsorption of both, Xe and Kr only with limited selectivity. Herein we report an anion‐pillared ultramicroporous material NbOFFIVE‐2‐Cu‐i (ZU‐62) with finely tuned pore aperture size and structure flexibility, which for the first time enables an inverse size‐sieving effect in separation along with record Xe/Kr selectivity and ultrahigh Xe capacity. Evidenced by single‐crystal X‐ray diffraction, the rotation of anions and pyridine rings upon contact of larger‐size Xe atoms adapts cavities to the shape/size of Xe and allows strong host‐Xe interaction, while the smaller‐size Kr is excluded. Breakthrough experiments confirmed that ZU‐62 has a real practical potential for producing high‐purity Kr and Xe from air‐separation byproducts, showing record Kr productivity (206 mL g−1) and Xe productivity (42 mL g−1, in desorption) as well as good recyclability. [ABSTRACT FROM AUTHOR]

The separation of acetylene from ethylene is of paramount importance in the purification of chemical feedstocks for industrial manufacturing. Herein, an isostructural series of gallate‐based metal–organic frameworks (MOFs), M‐gallate (M=Ni, Mg, Co), featuring three‐dimensionally interconnected zigzag channels, the aperture size of which can be finely tuned within 0.3 Å by metal replacement. Controlling the aperture size of M‐gallate materials slightly from 3.69 down to 3.47 Å could result in a dramatic enhancement of C2H2/C2H4 separation performance. As the smallest radius among the studied metal ions, Ni‐gallate exhibits the best C2H2/C2H4 adsorption separation performance owing to the strongest confinement effect, ranking after the state‐of‐the‐art UTSA‐200a with a C2H4 productivity of 85.6 mol L−1 from 1:99 C2H2/C2H4 mixture. The isostructural gallate‐based MOFs, readily synthesized from inexpensive gallic acid, are demonstrated to be a new top‐performing porous material for highly efficient adsorption of C2H2 from C2H4. [ABSTRACT FROM AUTHOR]

Abstract: The one‐step removal of multi‐component gases based on a single material will significantly improve the efficiency of separation processes but it is challenging, owing to the difficulty to precisely fabricate porous materials with multiple binding sites tailored for different guest molecules. Now a niobium oxide–fluoride anion‐pillared interpenetrated material ZU‐62 (NbOFFIVE‐2‐Cu‐i, NbOFFIVE=NbOF52−) is presented. It features asymmetric O/F node coordination for the simultaneous removal of trace propyne and propadiene from propylene. The narrow distribution nanospace (aperture of Site I 6.75 Å, Site II 6.94 Å, Site III 7.20 Å) derived from the special coordination geometry within ZU‐62 customized the corresponding energy‐favorable binding sites for the propyne and propadiene that enable propadiene uptake (1.74 mmol g−1) as well as excellent propyne uptake (1.87 mmol g−1) under ultra‐low pressure (5000 ppm). The multisite capture mechanism was revealed by modeling studies. [ABSTRACT FROM AUTHOR]

Hybrid HOFs with high stability, permanent porosity, and efficient functionalization designed by charged or metal-containing building blocks have been highlighted. Charge-assisted hydrogen bonds, hydrogen-bonded organic frameworks, metal-nucleobase complexes, metal-organic frameworks, porous materials Keywords: charge-assisted hydrogen bonds; hydrogen-bonded organic frameworks; metal-nucleobase complexes; metal-organic frameworks; porous materials EN charge-assisted hydrogen bonds hydrogen-bonded organic frameworks metal-nucleobase complexes metal-organic frameworks porous materials 1 1 1 03/15/23 20230307 NES 230307 This Review discusses a new class of functional crystalline materials, the hybrid hydrogen-bonded organic frameworks (HOFs) including ionic HOFs and metallized HOFs. [Extracted from the article]

A novel NbO-type metal–organic framework UTSA-88a with polarized trifluoromethyl groups exhibits a notably high methane storage capacity of 248 cm3 (STP) cm−3 (at room temperature and 65 bar) and a working capacity of 185 cm3 (STP) cm−3. [ABSTRACT FROM AUTHOR]

The sorting of C4 olefins is possible with a combination of molecular recognition and size‐sieving effects. In their Communication on page 16282 ff. H. B. Xing and co‐workers report anion‐pillared hybrid interpenetrated porous materials with finely tuned cavities (the bridge tunnel) and functional sites (flowers) arranged at 0.2 Å increments. These materials exhibit outstanding performance for the separation of C4 olefins. [ABSTRACT FROM AUTHOR]

[Display omitted] Porous materials have shown great promise in the development of cost- and energy-efficient separation processes, particularly for the challenging industrial purification of ethylene from an ethylene/ethane mixture. This review has summarized the latest development in metal–organic frameworks (MOFs) and hydrogen-bonded organic frameworks (HOFs) for C 2 H 4 /C 2 H 6 separation, including the strategies to improve adsorption capacity and separation selectivity, as well as their efficient separation of gas mixtures in various practical environments. The separation mechanism of C 2 H 4 /C 2 H 6 in different adsorbents has also been highlighted, along with the discussion on various adsorbents' challenges and future developments. [ABSTRACT FROM AUTHOR]

• Efficient separation of acetylene/carbon dioxide mixture by T-shaped adsorption sites. • FJU-83 showed extremely high stability up to 470 °C and can retain intact in aqueous solutions with the pH value ranging from 1 to 12 without phase change. • The guest of acetylene was determined using single-crystal X-ray technology revealing that C 2 H 2 molecules are found to preferentially bind the organic moieties by C-H∙∙∙π and π∙∙∙π multiple intermolecular interactions in a T-type aromatic space. It is challenging to achieve high-purity acetylene (C 2 H 2) from the methylene (CH 4) and carbon dioxide (CO 2), due to their similar molecular structure and physical properties. Adsorption utilized porous materials, such as metal–organic frameworks (MOFs), has been considered as cost- and energy-efficient technology to separate acetylene mixtures. Herein, we reported a highly stable MOF, [Zn 6 L 4 (Me 2 NH 2 +) 4 ‧3H 2 O] (named FJU-83), featuring T-shaped functional capture sites explored for acetylene capture and separation. In addition, FJU-83a exhibits not only a high C 2 H 2 uptake capacity of 122.9 cm3/g at 273 K, 1 bar, but also good C 2 H 2 /CH 4 and C 2 H 2 /CO 2 selectivity of 24 and 2.9 under moderate temperature and 1 bar, respectively. The high separation efficiency of the C 2 H 2 /CH 4 and C 2 H 2 /CO 2 are validated by dynamic fixed bed breakthrough experiments. The single crystal X-ray diffraction studies and Hirshfeld surface analysis revealed that T-type aromatic sites of FJU-83a can separate C 2 H 2 from CH 4 and CO 2 through multiple C-H∙∙∙π and π∙∙∙π interactions. [ABSTRACT FROM AUTHOR]

A novel porous organic cage exhibits moderately high permanent porosity, preferred adsorption of CO 2 over CH 4 and N 2 , and highest capacity of 3.21 g g−1 for iodine vapour capture. [Display omitted] • A novel bithiophene-based organic cage (BTPOC) was synthesized and its structure was clarified by single crystal X-ray diffraction. • High CO 2 uptake adsorption of 265 cm3 g−1 at 760 mmHg and 196 K. • The permanent microporosities of this cage are able to selectively adsorb CO 2 over CH 4 and N 2. • BTPOC is able to accommodate a large amount of I 2 with a high uptake value of 3.21 g g−1 and excellent recyclability. The enantiomeric porous organic cages, (R)/(S)-BTPOC, have been devised and prepared by means of dynamic covalent chemistry, using imine bond formation between bithiophene-based tetraaldehyde and cyclohexanediamine building blocks. These two cage molecules with porous interiors, stable aromatic backbones, and multiple electron-rich building units have been fully characterized by spectroscopy and single crystal X-ray diffraction studies. Self-assembly of BTPOC molecules provided porous crystalline materials with high CO 2 adsorption of 265 cm3 g−1 under 760 mmHg and 196 K according to the physical gas sorption analysis. The guest-free cage shows distinct CO 2 , CH 4 , and N 2 adsorption behaviors. Moreover, BTPOC is able to accommodate a large amount of I 2 with a high uptake value of 3.21 g g−1, superior to almost all the porous molecular crystals reported thus far. This stable material has also excellent recyclability, keeping above 85% capacity when being activated for the fourth cycles. Mechanism investigations reveal the close association of the good adsorption ability with the abundant porosity, π-conjugated network structure, and high imine bonds content. The present work shows the great application potentialities of these microporous POCs. [ABSTRACT FROM AUTHOR]