Exchange controlled triplet fusion in metal–organic frameworksNature Materials，Pub Date:2022-10-06,DOI:10.1038/s41563-022-01368-1Dong-Gwang Ha, Ruomeng Wan, Changhae Andrew Kim, Ting-An Lin, Luming Yang, Troy Van Voorhis, Marc A. Baldo, Mircea DincăTriplet-fusion-based photon upconversion holds promise for a wide range of applications, from photovoltaics to bioimaging. The efficiency of triplet fusion, however, is fundamentally limited in conventional molecular and polymeric systems by its spin dependence. Here, we show that the inherent tailorability of metal–organic frameworks (MOFs), combined with their highly porous but ordered structure, minimizes intertriplet exchange coupling and engineers effective spin mixing between singlet and quintet triplet–triplet pair states. We demonstrate singlet–quintet coupling in a pyrene-based MOF, NU-1000. An anomalous magnetic field effect is observed from NU-1000 corresponding to an induced resonance between singlet and quintet states that yields an increased fusion rate at room temperature under a relatively low applied magnetic field of 0.14 T. Our results suggest that MOFs offer particular promise for engineering the spin dynamics of multiexcitonic processes and improving their upconversion performance.https://www.nature.com/articles/s41563-022-01368-1
Soft 2D Covalent Organic Framework with Compacted Honeycomb TopologyJournal of the American Chemical Society，Pub Date:2022-10-06, DOI:10.1021/jacs.2c08468Chenglong Liu, Zhenzhu Wang, Lei Zhang, Zeyuan DongIn this contribution, we report the synthesis of an imine-based soft 2D covalent organic framework (S-COF) with compacted honeycomb topology via inveterately selecting a helically folded ditopic flexible linker and a trigonal building block. In contrast to various topological structures of rigid monomer-based COFs (R-COFs) reported so far, owing to the presence of flexible skeleton S-COF can spontaneously form a compacted and nonporous topological structure via intramolecular π stacking of presupposed honeycomb-like topology. Such S-COFs with a compacted honeycomb topology have neither been proposed theoretically nor been achieved experimentally. The compacted topological structure of 2D S-COF was clearly characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), and circular dichroism (CD) measurements. This study opens a new window to the development of S-COFs and will significantly expand the scope of COF materials.https://pubs.acs.org/doi/abs/10.1021/jacs.2c08468Room-Temperature Quantitative Quantum Sensing of Lithium Ions with a Radical-Embedded Metal–Organic FrameworkJournal of the American Chemical Society，Pub Date:2022-10-06, DOI:10.1021/jacs.2c07692Lei Sun, Luming Yang, Jin-Hu Dou, Jian Li, Grigorii Skorupskii, Michael Mardini, Kong Ooi Tan, Tianyang Chen, Chenyue Sun, Julius J. Oppenheim, Robert G. Griffin, Mircea Dincă, Tijana RajhRecent advancements in quantum sensing have sparked transformative detection technologies with high sensitivity, precision, and spatial resolution. Owing to their atomic-level tunability, molecular qubits and ensembles thereof are promising candidates for sensing chemical analytes. Here, we show quantum sensing of lithium ions in solution at room temperature with an ensemble of organic radicals integrated in a microporous metal–organic framework (MOF). The organic radicals exhibit electron spin coherence and microwave addressability at room temperature, thus behaving as qubits. The high surface area of the MOF promotes accessibility of the guest analytes to the organic qubits, enabling unambiguous identification of lithium ions and quantitative measurement of their concentration through relaxometric and hyperfine spectroscopic methods based on electron paramagnetic resonance (EPR) spectroscopy. The sensing principle presented in this work is applicable to other metal ions with nonzero nuclear spin.https://pubs.acs.org/doi/abs/10.1021/jacs.2c07692
Metal-organic frameworks as platforms for the removal of per- and polyfluoroalkyl substances from contaminated watersMatter，Pub Date:2022-10-05,DOI:10.1016/j.matt.2022.07.028Rui Li, Nayarassery N. Adarsh, Hui Lu, Mario WriedtPoly- and perfluoroalkyl substances (PFAS) have received considerable attention due to their toxicity, ubiquitous presence, and recalcitrance in the environment. The manufacturing and disposal of PFAS-containing products has resulted in PFAS contamination of groundwater and drinking water supplies. Substantial interest and efforts in developing PFAS treatment technologies has been triggered since PFAS are associated with numerous adverse health effects. Physical separation using activated carbon and ion exchange is the most widely adopted technique for PFAS removal from contaminated water. However, both adsorbents generally exhibit low PFAS adsorption capacities and/or slow adsorption kinetics. The development of efficient adsorbents is of urgent need. Metal-organic frameworks (MOFs) are an emerging class of hybrid crystalline nanoporous materials, which are composed of inorganic and organic building blocks to form multidimensional networks. Key features—tunable structures and high internal surface areas—render MOFs as ideal platforms for PFAS removal from aqueous environments. This review critically examines the application of MOFs for PFAS removal and highlights the structural features of MOFs in context of their PFAS removal performances. Factors affecting the adsorption efficiency, regeneration, and application for PFAS detection are extensively discussed while also providing important insights on design strategies for next-generation MOF materials with improved PFAS removal performancesNanostructural engineering of metal-organic frameworks: Construction strategies and catalytic applicationsMatter，Pub Date:2022-10-05,DOI:10.1016/j.matt.2022.07.014Yutian Qin, Zhixi Li, Yulong Duan, Jun Guo, Meiting Zhao, Zhiyong TangFamous as emerging inorganic-organic hybrid materials, metal-organic frameworks (MOFs) and MOF-based composites have been displaying bright prospects in catalysis fields. It is desirable to develop highly efficient MOF-based catalysts with excellent activity, selectivity, and stability. The nanostructure of MOFs can bring dramatic effects on their inherent physical/chemical properties and the interaction with reaction substrates/intermediates. Therefore, it is applicable to promote the performance of MOF-based catalysts via nanostructure engineering. In this review, we focus on four classes of nanostructures, i.e., ultrathin nanostructure, hierarchically porous nanostructure, defective nanostructure, and MOF-shelled nanostructure (composite with MOF shell). Strategies for nanostructure engineering of MOF-based catalysts are summarized, their applications in thermo-catalysis, electrocatalysis, and photocatalysis are overviewed, and the effects of nanostructure engineering on catalytic performance are discussed. We hope this review will be instructive for researchers in the rational and controllable construction of MOF nanostructures for catalytic performance promotions.
Molecular engineering of interplanar spacing via π-conjugated phenothiazine linkages for high-power 2D covalent organic framework batteriesChem,Pub Date:2022-10-04,DOI:10.1016/j.chempr.2022.09.015Weiping Li, Wen Xie, Fei Shao, Ju Qian, Shantao Han, Peng Wen, Jun Lin, Mao Chen, Xinrong LinTwo-dimensional covalent organic frameworks (2D-COFs) represent an attractive platform for organic electrodes, yet they suffer from inferior power capability caused by poor Li+intercalation in densely π-π stacked interlayers. Herein, featuring nonplanar π-conjugated heteroaromatic linkages, phenothiazine with 「butterfly」 conformation is integrated as a structural scaffold to instantly tune packing topology and interplanar distance. Corrugated 2D-COF maintaining aromaticityand crystallinity is formed with good electroactivity, enlarged d-spacing, and accessibility to interior Li+-interactive sites, which results in remarkable capacity of 220–773 mAh g−1at high rates ranging from 100 to 3,200 mA g−1with a good cycle life, bridging the performance gap between power and energy. Mechanistic studies reveal a dual storage mechanism with dominating capacitive storage promoted by π-Li+interactions, as well as enhanced redox activity of carbonyls for better chemical accessibility. These findings elucidate inherent effects of molecular-level d-spacing regulation enabled by heteroaromatics, presenting a new design concept of interlayer engineering for organic porous energy storage materials.https://www.sciencedirect.com/science/article/pii/S2451929422004880
Progress in metal-organic-framework-based single-atom catalysts for environmental remediationCoordination Chemistry Reviews,Pub Date:2022-10-04, DOI:10.1016/j.ccr.2022.214855Wei Qu, Cheng Chen, Zhuoyun Tang, Hailin Wen, Lingling Hu, Dehua Xia, Shuanghong Tian, Huinan Zhao, Chun He, Dong ShuIn 2011, Zhang’s research team discovered the first atomically dispersed Pt1/FeOxcatalysts worldwide and proposed the concept of 「single-atom catalysis」. The excellent atomic utilization rate of single-atom catalysts (SACs) in combination with their high specific catalytic activity makes them extremely appealing for environmental remediation. As research in this field has progressed, many methods of preparing SACs have emerged. However, strategies for the construction of high stability SACs with reasonable generality are still urgently needed to be developed. As metal-organic frameworks (MOFs) possess a well-defined structure and a high specific surface area, they can be considered viable and promising materials for the manufacture of SACs. MOF-based SACs can combine the advantages of SACs and MOFs, showing conspicuous performance in environment-related catalysis. In this review, we summarize the reported synthesis methods and explain how MOF-based SACs can be constructed according to their structural characteristics. We briefly examine accessibility characterization techniques for SACs. Additionally, several representative reports are presented on the successful preparation of MOF-based SACs for environmental remediation (mainly advanced oxidation processes (AOPs)). Finally, we conclude by suggesting several future development directions for MOF-based SACs.https://www.sciencedirect.com/science/article/pii/S0010854522004507
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