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Hydrogen‐bonded organic frameworks (HOFs) are porous crystalline materials. The pores in HOFs are usually non‐covalent extrinsic pores constructed through the formation of the framework. Supramolecular macrocycles with intrinsic pores in their structures are good candidates for constructing HOFs with intrinsic pores from the macrocycles themselves, thus leading to hierarchically porous structures. Combining the macrocycle and HOFs will endow these hierarchically porous materials with enhanced properties and special functionalities. This review summarizes recent advances in macrocycle‐based HOFs, including the macrocycles used for constructing HOFs, the hierarchically porous structures of the HOFs, and the applications induced by the hierarchically HOFs porous structures. This review provides insights for future research on macrocycle‐based hierarchically porous HOFs and the appropriate applications of the unique structures. [ABSTRACT FROM AUTHOR]

Due to the high surface area and uniform porosity of covalent organic frameworks (COFs), they exhibit superior properties in capturing and detecting even trace amounts of gases in the air. However, the COFs materials that possess dual detected functionality are still less reported. Here, an imine‐based COF containing thiophene as a donor and triazine as an acceptor to form spatial‐distribution‐defined D‐A structures was prepared. D‐A system between thiophene and triazine facilitates the charge transfer process during the protonation process of the imine and the triazine units. The obtained COF exhibits simultaneous sensing ability toward both acidic and alkaline vapors with obvious colorimetric sensing functionality. [ABSTRACT FROM AUTHOR]

Utilizing weak interactions to effectively recover and separate precious metals in solution is of great importance but the practice remains a challenge. Herein, we report a novel strategy to achieve precise recognition and separation of gold by regulating the hydrogen‐bond (H‐bond) nanotrap within the pore of covalent organic frameworks (COFs). It is found that both COF‐HNU25 and COF‐HNU26 can efficiently capture AuIII with fast kinetics, high selectivity, and uptake capacity. In particular, the COF‐HNU25 with the high density of H‐bond nanotraps exhibits an excellent gold uptake capacity of 1725 mg g−1, which is significantly higher than that (219 mg g−1) of its isostructural COF (COF‐42) without H‐bond nanostrap in the pores. Importantly, the uptake capacity is strongly correlated to the number of H‐bonds between phenolic OH in the COF and [AuCl4]− in water, and multiple H‐bond interactions are the key driving force for the excellent gold recovery and reusability of the adsorbent. [ABSTRACT FROM AUTHOR]

A weak CH/O hydrogen‐bonded organic framework (HOF) with both rigidity and flexibility that could easily and reversibly switch from a non‐crystalline to a crystalline phase was constructed. The specific solvent molecule acts as a "key" to control the crystallinity, while the highly rigid triangle macrocycle as the building block is the "lock". The introduction and removal of the "key" could influence the local flexibility of the whole framework and lead to switchable crystallinity. Furthermore, the obtained HOF exhibits excellent separation efficiency for benzene and cyclohexane (94.4 %). [ABSTRACT FROM AUTHOR]

Crystalline Porous Materials, Hydrogen-Bonded Organic Framework, Local Flexibility, Porous Molecular Crystals, Switchable Crystallinity Inside Back Cover: Rigid-Flexible Hybrid Porous Molecular Crystals with Guest-Induced Reversible Crystallinity (Angew. Keywords: Crystalline Porous Materials; Hydrogen-Bonded Organic Framework; Local Flexibility; Porous Molecular Crystals; Switchable Crystallinity EN Crystalline Porous Materials Hydrogen-Bonded Organic Framework Local Flexibility Porous Molecular Crystals Switchable Crystallinity 1 1 1 03/15/23 20230320 NES 230320 B A rigid-flexible b hybrid hydrogen-bonded organic framework (HOF) with guest-induced reversible crystallinity was designed by Yingjie Zhao and Danbo Wang in their Research Article (e202217903). [Extracted from the article]

Keywords: Crystalline Porous Materials; Hydrogen-Bonded Organic Framework; Local Flexibility; Porous Molecular Crystals; Switchable Crystallinity EN Crystalline Porous Materials Hydrogen-Bonded Organic Framework Local Flexibility Porous Molecular Crystals Switchable Crystallinity 1 1 1 03/15/23 20230320 NES 230320 B A rigid-flexible b hybrid hydrogen-bonded organic framework (HOF) with guest-induced reversible crystallinity was designed by Yingjie Zhao and Danbo Wang in their Research Article (e202217903). A specific compound, such as hexane, acts as a "key" to control the crystallinity, while the triangle macrocycle as the building module is the "lock". Crystalline Porous Materials, Hydrogen-Bonded Organic Framework, Local Flexibility, Porous Molecular Crystals, Switchable Crystallinity. [Extracted from the article]

Identifying relatively low permeability areas (RLPA) is significant for site selection and parameter design for implementing enhanced gas mining measures (e.g. hydraulic fracturing, hydraulic perforation, etc.) in coal and gas outburst seams. The P-wave velocity of coal is sensitive to the variation of porosity. This paper researched the P-wave velocity change of coal with respect to confining pressure and gas pressure, the mathematical relationship model between P-wave velocity with porosity and permeability, and the relative permeability identification index. The research found that the P-wave velocity response to gas pressure varies non-monotonically. When the gas pressure is <2 MPa, the confining pressure is the main control factor leading to P-wave velocity variation. The mathematical model of P-wave velocity versus porosity and permeability was derived based on the linear relationship between wave velocity and porosity in dense rocks and the Seidle permeability model for porous media. Then the wave velocity anomaly coefficient (A n) is used as the identification index for the relative permeability of the coal seam. That is, when the anomaly coefficient of coal seam wave velocity A n < -8%, the coal seam is a relatively high permeability area (RHPA); when −8% < A n < 8%, the coal seam is relatively normal permeability area (RNPA); when A n > 8%, the coal seam is (RLPA). Based on the identification indexes studied, two RHPA (H1 and H2) and two RLPA (L1 and L2) were identified in the field engineering application. Comparing the drainage parameters in different relative permeability areas, the gas drainage volume fraction and flow in the RLPA are 56% and 90% lower than RHPA, respectively, validating the accuracy of identifying RLPA in the coal seam. • Relationship model between P-wave velocity and coal permeability was developed. • Established an identification index for the relative permeability of coal seams. • Proposed a method to identify the relative permeability of coal seams. [ABSTRACT FROM AUTHOR]

• A ring-open reaction introduces a alkyl chain and anionic -SO 3 H in MIL-125-NH 2. • The modified material shows a high adsorption capacity of 164 mg•g−1 for Met•HCl. • Boosted hydrophobicity and H-bonds/electrostatic interactions contributes to the excellent adsorption. Removal of metformin hydrochloride (Met•HCl) is necessary but still faces challenges. Our work reported a new adsorbent (MIL-125-NH-RSO 3 H, R = CH 2 CH 2 CH 2), constructed via the post-synthesis covalent reaction between MIL-125-NH 2 and 1,3-propanesultone. Compared with the pristine MIL-125-NH 2 , the newly obtained material shows improved negative surface property and enhanced hydrophobicity, ascribed to the contributions from -SO 3 H and the alkyl groups respectively. As a result, the adsorption capacity of MIL-125-NH-RSO 3 H can reach 164 mg•g−1, superior to the unmodified sample and other reported porous materials. The adsorption behavior follows the Langmuir model and pseudo-second-order model. The adsorbent possesses excellent anti-interference ability from co-existing salts and can be well regenerated through a simple elution method. Therefore, our work provides a new sight to construct high-efficiency adsorbents by simultaneously improving various host-guest interactions. [Display omitted] [ABSTRACT FROM AUTHOR]