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Metalloenzymes are powerful biocatalysts that can catalyze particular chemical reactions with high activity, selectivity, and specificity under mild conditions. Metal-organic frameworks (MOFs) composed of metal ions or metal clusters and organic ligands with defined cavities have the potential to impart enzyme-like catalytic activity and mimic metalloenzymes. Here, a new metal-organic framework implanted with hydroxo iron(III) sites with the structural and reactivity characteristics of iron-containing lipoxygenases is reported. Similar to lipoxygenases, the hydrogen atoms and electrons of the substrate can transfer to the hydroxo iron(III) sites, showing typical proton-coupled electron transfer behavior. In the reactivity mimicking biology system, similar to alcohol oxidase, the material also catalyses the oxidation of alcohol into aldehyde by using O 2 with a high yield and 100% selectivity under mild conditions, without the use of a radical cocatalyst or photoexcitation. These results provide strong evidence for the high structural fidelity of enzymatically active sites in MOF materials, verifying that MOFs provide an ideal platform for designing biomimetic heterogeneous catalysts with high conversion efficiency and product selectivity.

Metal-organic cages are potential artificial models for mimicking biological functions due to their capability of selective encapsulation for certain guest molecules. In this work, we designed and synthesized a series of rhombic dodecahedral Ni-imidazolate cages (Ni 14 L 24 ) with precisely controlled aperture for CO 2 encapsulation. The aperture of the cages can be tuned by the strategies of ligand decoration and metal-ion hybridization. Similar to the breathing function of alveoli, CO 2 passes through the dynamic aperture into the cages under a pressure of 2.0-3.0 bar in methanol solution, and slowly move out of the cages when the pressure goes down. In the solid state, CO 2 is encapsulated and prisoned in the cages under a high pressure of 15.0-30.0 bar or supercritical conditions. By replacing the square-coordinated Ni 2+ with Cu 2+ , the resulting Ni-Cu heteronuclear cage lost the capability of physically encapsulating CO 2 even though the aperture's size is only slightly changed.

A strategy to improve the framework porosity and hydrophobicity of the pore surface by doping metal ions (Cu(2+), Cd(2+), or Fe(2+)) into a gyroidal MOF STU-1 has been developed. It is found that the obtained heterometallic MOFs are exceptionally water stable.

Hollow nanoporous carbon architectures (HNCs) present significant utilitarian value for a wide variety of applications. Facile and efficient preparation of HNCs has long been pursued but still remains challenging. Herein, we for the first time demonstrate that single‐component metal–organic frameworks (MOFs) crystals, rather than the widely reported hybrid ones which necessitate tedious operations for preparation, could enable the facile and versatile syntheses of functional HNCs. By controlling the growth kinetics, the MOFs crystals (STU‐1) are readily engineered into different shapes with designated styles of crystalline inhomogeneity. A subsequent one‐step pyrolysis of these MOFs with intraparticle difference can induce a simultaneous self‐hollowing and carbonization process, thereby producing various functional HNCs including yolk‐shell polyhedrons, hollow microspheres, mesoporous architectures, and superstructures. Superior to the existing methods, this synthetic strategy relies only on the complex nature of single‐component MOFs crystals without involving tedious operations like coating, etching, or ligand exchange, making it convenient, efficient, and easy to scale up. An ultra‐stable Na‐ion battery anode is demonstrated by the HNCs with extraordinary cyclability (93 % capacity retention over 8000 cycles), highlighting a high level of functionality of the HNCs. [ABSTRACT FROM AUTHOR]

To develop a simple and general method for improving the circularly polarized luminescence (CPL) performances of materials is of great significance. In this work, two pairs of CPL‐active homochiral metal–organic frameworks (MOFs) P/M‐Et and P/M‐Et(Cd) with eta topology are reported. In comparison to the reported isomorphic Zn‐imidazolate MOFs P‐Me and M‐Me, both luminescence dissymmetry factor (glum) and photoluminescence quantum yields (ΦPL) of P‐Et and M‐Et are largely improved by simply changing the methyl group to an ethyl group of ligands in P‐Et and M‐Et. Furthermore, the |glum| values are significantly amplified up to 0.015 from 0.0057 by introducing the non‐luminescent halogenated aromatics, while an enhanced fluorescence efficiency is observed simultaneously (from 27.2% to 47.3%). The figure of merit value is about 40 times larger than that of P‐Me and M‐Me. Similarly, the CPL performances of P/M‐Et(Cd) are improved by about five times after encapsulating fluorobenzene molecules. This work represents a new and simple method for developing CPL‐active MOF materials. [ABSTRACT FROM AUTHOR]

A pair of chiral metal–organic frameworks based on enantiomers of chiral Zn(salen) ligands has been successfully obtained by solvothermal subcomponent self-assembly. Both chiral MOFs were characterized by infrared spectroscopy, UV-vis absorption spectroscopy, thermogravimetric analysis, and single-crystal/powder X-ray diffraction. They crystallize in the chiral space group I222 and possess an extended 2D network with a sql topology. Moreover, these MOFs exhibit circularly polarized luminescence (CPL) with a dissymmetry factor of about 3.7 × 10−3. This work provides a simple strategy to make CPL-active MOF materials based on salen ligands. [ABSTRACT FROM AUTHOR]

A two-dimensional (2D) chiral heterometallic Zn(II)-Cd(II) metal-organic framework (MOF), {[(CdI2(ZnL)2·DMF}n (1, H2L = (R,R)-N,N'-bis(3-(4-pyridyl)salicylidene)-1,2-cyclohexanediamine, DMF = N,N-dimethylformamide), was synthesized with predesigned chiral metallosalen ZnL and CdI2 via solvothermal reaction. MOF 1 crystallizes in the orthorhombic chiral space group P21212 and exhibits a 2D chiral framework consisting of right (P) handed 21 helices. Topological analysis indicates that the 2D structure of 1 could be simplified as a uninodal sql topology. The luminescence experiment revealed that MOF 1 showed intense circularly polarized luminescence (CPL), suggesting that it can be a potential CPL material. [ABSTRACT FROM AUTHOR]

The fabrication of circularly polarized luminescence (CPL) active materials by self‐assembly is still in its challenge. In this work, a family of homochiral metal–organic frameworks (MOFs) and metal–organic cages (MOCs) are constructed by solvothermal subcomponent self‐assembly. These MOFs feature an eta topology with trifold helical chains, while the MOCs adopt a cubic cage structure. The chiral ligands show two distinct types of conformations: "opened" and "closed" in MOFs and MOCs, respectively. Although homochiral MOFs and MOCs show similar spectra of circular dichroism and photoluminescence with similar quantum yields and lifetimes, the MOFs yield clear CPL signals and the CPL of MOCs are silent. The turn‐on CPL in MOFs achieved by tuning the conformation of ligands and controlling self‐assembly provides a new approach for development of CPL‐active MOF materials. [ABSTRACT FROM AUTHOR]

Gyroid materials have received considerable attention from scientists due to their beautiful structures and advanced functions. On the other side, metal–organic frameworks are inorganic–organic hybrid crystalline porous materials with atomic precision, and can provide good structural models and rich topologies for gyroid materials. In this review, we will briefly introduce the structures of gyroid metal–organic frameworks and their topologies. In addition, their applications in gas adsorption, catalysis, sensors, and luminescent materials are also discussed in detail. [ABSTRACT FROM AUTHOR]

A family of gyroidal metal–organic frameworks (STUs) composited with transition metal ions and bi‐imidazolate ligands (BIm) were prepared and applied as both Lewis base and acid catalysts. Benefiting from the intrinsic basicity of the ligands and the Lewis acidic sites of the open metal centres, the STUs materials show excellent catalytic activities as Lewis base for the Knoevenagel condensation reaction between various aldehydes and malononitrile, and as Lewis acid for cyanosilylation reactions. Among these STUs, STU‐4 (Ni(BIm)) shows the best catalytic efficiency (conversions >99 %) in both Knoevenagel condensation and cyanosilylation reactions under mild conditions, providing thus an advanced material for both Lewis base and Lewis acid catalysis. [ABSTRACT FROM AUTHOR]

A variety of planar organic fluorophores (R=phenyl, naphthalenyl, pyrenyl) and luminescence promotors (X=Cl, Br, I) were equipped, respectively, on the alternatively arranged vertices of cubic ZnII‐imidazolate cages through orthogonal subcomponent self‐assembly. It was found that supramolecular interactions, especially weak C−H⋅⋅⋅X interactions, play a key role in activating an efficient radiative pathway, coupled with reduced nonradiative decay rate through metal coordination, therefore significantly boosting the emission quantum yields of the system. This finding provides a strategy that utilizes molecular geometry and supramolecular interactions to modulate the emission efficiency of luminescent cage‐based materials. [ABSTRACT FROM AUTHOR]

A Mn-based rod metal–organic framework (MOF), ROD-6, with a new lrk net is synthesized. It represents an unusual type of MOF topology containing both a 1-periodic secondary building unit (rod SBU) and a polytopic linker (here 1,3,6,8-tetrakis(p-benzoic acid)pyrene), and also exhibits high stability (up to 485 °C) and unusual CO2 uptake behaviour and selectivity despite the lack of strong interacting sites, demonstrated by the low and increasing heat of adsorption. [ABSTRACT FROM AUTHOR]

Front Cover: Bifunctional Gyroidal MOFs: Highly Efficient Lewis Base and Lewis Acid Catalysts (Chem. Keywords: Catalysis; Knoevenagel condensation reaction; Lewis acid; Lewis base; Metal-organic frameworks Catalysis, Knoevenagel condensation reaction, Lewis acid, Lewis base, Metal-organic frameworks. [Extracted from the article]

Chiral coordination cages feature both chirality and defined inner space, providing advanced molecular materials. A series of chiral 20-nucleus cobalt- imidazolate cages were synthesized by self-assembly of 72 subcomponents, featuring a novel tetartoid (tetragonal pentagonal dodecahedron) structure. Spontaneous resolution of racemic tetartoidal cages (Δ and Λ) into a conglomerate of homochiral crystals are observed, while both homochiral Δ and Λ tetartoidal cages can be obtained through chiral induction of (D)- and (L)- enantiomers of menthol, respectively. The 2-methyl substituent on imidazolyl is critical to the formation of a tetartoidal cage, and the absence of such steric effect will switch the final structure to a cubic cage. [ABSTRACT FROM AUTHOR]