Conceptual and Practical Aspects of Metal–Organic Frameworks for Solid–Gas Reactions Chemical Reviews, Pub Date : 2023-02-17 , DOI: 10.1021/acs.chemrev.2c00537 Andrei Iliescu, Julius J Oppenheim , Chenyue Sun , Mircea Dincǎ The presence of site-isolated and well-defined metal sites has enabled the use of metal–organic frameworks (MOFs) as catalysts that can be rationally modulated. Because MOFs can be addressed and manipulated through molecular synthetic pathways, they are chemically similar to molecular catalysts. They are, nevertheless, solid-state materials and therefore can be thought of as privileged solid molecular catalysts that excel in applications involving gas-phase reactions. This contrasts with homogeneous catalysts, which are overwhelmingly used in the solution phase. Herein, we review theories dictating gas phase reactivity within porous solids and discuss key catalytic gas–solid reactions. We further treat theoretical aspects of diffusion within confined pores, the enrichment of adsorbates, the types of solvation spheres that a MOF might impart on adsorbates, definitions of acidity/basicity in the absence of solvent, the stabilization of reactive intermediates, and the generation and characterization of defect sites. The key catalytic reactions we discuss broadly include reductive reactions (olefin hydrogenation, semihydrogenation, and selective catalytic reduction), oxidative reactions (oxygenation of hydrocarbons, oxidative dehydrogenation, and carbon monoxide oxidation), and C–C bond forming reactions (olefin dimerization/polymerization, isomerization, and carbonylation reactions). https://pubs.acs.org/doi/abs/10.1021/acs.chemrev.2c00537 A Tailored COF for Visible-Light Photosynthesis of 2,3-DihydrobenzofuransJournal of the American Chemical Society， Pub Date : 2023-02-24 , DOI: 10.1021/jacs.2c10471 Prakash T. Parvatkar, Sharath Kandambeth, Aslam C. Shaikh, Issatay Nadinov, Jun Yin, Vinayak S. Kale, George Healing, Abdul-Hamid Emwas, Osama Shekhah, Husam N. Alshareef, Omar F. Mohammed, Mohamed EddaoudiHeterogeneous photocatalysis is considered as an ecofriendly and sustainable approach for addressing energy and environmental persisting issues. Recently, heterogeneous photocatalysts based on covalent organic frameworks (COFs) have gained considerable attention due to their remarkable performance and recyclability in photocatalytic organic transformations, offering a prospective alternative to homogeneous photocatalysts based on precious metal/organic dyes. Herein, we report Hex-Aza-COF-3 as a metal-free, visible-light-activated, and reusable heterogeneous photocatalyst for the synthesis of 2,3-dihydrobenzofurans, as a pharmaceutically relevant structural motif, via the selective oxidative [3+2] cycloaddition of phenols with olefins. Moreover, we demonstrate the synthesis of natural products (±)-conocarpan and (±)-pterocarpin via the [3+2] cycloaddition reaction as an important step using Hex-Aza-COF-3 as a heterogeneous photocatalyst. Interestingly, the presence of phenazine and hexaazatriphenylene as rigid heterocyclic units in Hex-Aza-COF-3 strengthens the covalent linkages, enhances the absorption in the visible region, and narrows the energy band, leading to excellent activity, charge transport, stability, and recyclability in photocatalytic reactions, as evident from theoretical calculations and real-time information on ultrafast spectroscopic measurements.https://pubs.acs.org/doi/full/10.1021/jacs.2c10471 Bioorthogonal-Activated In Situ Vaccine Mediated by a COF-Based Catalytic Platform for Potent Cancer ImmunotherapyJournal of the American Chemical Society, Pub Date : 2023-02-23 , DOI: 10.1021/jacs.2c13010 Mengyu Sun, Zhengwei Liu, Li Wu*, Jie Yang, Jinsong Ren*, and Xiaogang Qu*Personalized tumor vaccines have become a promising modality for cancer immunotherapy. However, in situ personalized tumor vaccines generated from immunogenic cancer cell death (ICD) and adjuvants are mired by toxic side effects and unsatisfactory efficiency. Herein, by functionalizing the reticular structure to optimize the catalytic activity of the materials, a series of biocompatible covalent organic framework (COF)-based catalysts have been designed and screened for establishing a bioorthogonal-activated in situ cancer vaccine in an efficient and safe way. Especially, pro-doxorubicin (pro-DOX) could be bioorthogonally activated in situ by the COF-based Fe(II) catalysts, which elicited ICD and released tumor-associated antigens (TAAs). This in situ prodrug activation strategy could minimize drug side effects and maximize treatment effects. More importantly, the system could also catalytically activate pro-imiquimod (pro-IMQ, a TLR7/8 immune agonist), which served as an adjuvant to amplify the antitumor immunity. Notably, this bioorthogonal-activated in situ cancer vaccine not only facilitated a strong antitumor immune response but also prevented the dose-dependent side effects of chemotherapeutic drugs, including systemic inflammation caused by the random distribution of adjuvants. To the best of our knowledge, it is the first time to devise an efficient catalytic platform for generating an in situ bioorthogonal-activated cancer vaccine, which would provide a paradigm for achieving secure and robust immunotherapy. https://pubs.acs.org/doi/abs/10.1021/jacs.2c13010 Zeolites as a Class of Semiconductors for High-Performance Electrically Transduced Sensing Journal of the American Chemical Society, Pub Date : 2023-02-22 , DOI: 10.1021/jacs.2c13160 Tianshuang Wang, Yueying Chu, Xiao Li, Yinghao Liu, Hao Luo, Donglei Zhou, Feng Deng*, Xiaowei Song*, Geyu Lu, and Jihong Yu*Zeolites are widely used as catalysts and adsorbents in the chemical industry, but their potential for electronic devices has been stunted to date, as they are commonly recognized as electronic insulators. Here, we have for the first time demonstrated that Na-type ZSM-5 zeolites are ultrawide-direct-band-gap semiconductors based on optical spectroscopy, variable-temperature current–voltage characteristics, and photoelectric effect as well as electronic structure theoretical calculations and further unraveled the band-like charge transport mechanism in electrically conductive zeolites. The increase in charge-compensating Na+ cations in Na-ZSM-5 decreases the band gap and affects its density of states, shifting the Fermi level close to the conduction band. Remarkably, the semiconducting Na-ZSM-5 zeolites have been first applied for constructing electrically transduced sensors that can sense trace-level (77 ppb) ammonia with unprecedentedly high sensitivity, negligible cross-sensitivity, and high stability under moisture ambient conditions compared with conventional semiconducting materials and conductive metal–organic frameworks (MOFs). The charge density difference shows that the massive electron transfer between NH3 molecules and Na+ cations ascribed to Lewis acid sites enables electrically transduced chemical sensing. This work opens a new era of zeolites in applications of sensing, optics, and electronics. Orthogonal luminescence lifetime encoding by intermetallic energy transfer in heterometallic rare-earth MOFsNature Communications， Pub Date : 2023-02-22 , DOI: 10.1038/s41467-023-36576-zJacob I. Deneff, Lauren E. S. Rohwer, Kimberly S. Butler, Bryan Kaehr, Dayton J. Vogel, Ting S. Luk, Raphael A. Reyes, Alvaro A. Cruz-Cabrera, James E. Martin & Dorina F. Sava GallisLifetime-encoded materials are particularly attractive as optical tags, however examples are rare and hindered in practical application by complex interrogation methods. Here, we demonstrate a design strategy towards multiplexed, lifetime-encoded tags via engineering intermetallic energy transfer in a family of heterometallic rare-earth metal-organic frameworks (MOFs). The MOFs are derived from a combination of a high-energy donor (Eu), a low-energy acceptor (Yb) and an optically inactive ion (Gd) with the 1,2,4,5 tetrakis(4-carboxyphenyl) benzene (TCPB) organic linker. Precise manipulation of the luminescence decay dynamics over a wide microsecond regime is achieved via control over metal distribution in these systems. Demonstration of this platform’s relevance as a tag is attained via a dynamic double encoding method that uses the braille alphabet, and by incorporation into photocurable inks patterned on glass and interrogated via digital high-speed imaging. This study reveals true orthogonality in encoding using independently variable lifetime and composition, and highlights the utility of this design strategy, combining facile synthesis and interrogation with complex optical properties.https://www.nature.com/articles/s41598-023-30267-x Spatially confined protein assembly in hierarchical mesoporous metal-organic frameworkNature Communications, Pub Date : 2023-02-21 , DOI: 10.1038/s41467-023-36533-w Xiaoliang Wang, Lilin He, Jacob Sumner, Shuo Qian, Qiu Zhang, Hugh O’Neill, Yimin Mao, Chengxia Chen, Abdullah M. Al-Enizi, Ayman Nafady & Shengqian MaImmobilization of biomolecules into porous materials could lead to significantly enhanced performance in terms of stability towards harsh reaction conditions and easier separation for their reuse. Metal-Organic Frameworks (MOFs), offering unique structural features, have emerged as a promising platform for immobilizing large biomolecules. Although many indirect methods have been used to investigate the immobilized biomolecules for diverse applications, understanding their spatial arrangement in the pores of MOFs is still preliminary due to the difficulties in directly monitoring their conformations. To gain insights into the spatial arrangement of biomolecules within the nanopores. We used in situ small-angle neutron scattering (SANS) to probe deuterated green fluorescent protein (d-GFP) entrapped in a mesoporous MOF. Our work revealed that GFP molecules are spatially arranged in adjacent nanosized cavities of MOF-919 to form “assembly” through adsorbate-adsorbate interactions across pore apertures. Our findings, therefore, lay a crucial foundation for the identification of proteins structural basics under confinement environment of MOFs.https://www.nature.com/articles/s41467-023-36533-w Insertion of CO 2 in metal ion-doped two-dimensional covalent organic frameworksProceedings of the National Academy of Sciences of the United States of America, Pub Date : 2023-02-22 , DOI: 10.1073/pnas.2217081120Carbon capture is one of the essential low-carbon technologies required to achieve societal climate goals at the lowest cost. Covalent organic frameworks (COFs) are promising adsorbents for CO 2 capture because of their well-defined porosity, large surface area, and high stability. Current COF-based CO 2 capture is mainly based on a physisorption mechanism, exhibiting smooth and reversible sorption isotherms. In the present study, we report unusual CO 2 sorption isotherms featuring one or more tunable hysteresis steps with metal ion (Fe 3+ , Cr 3+ , or In 3+ )-doped Schiff-base two-dimensional (2D) COFs (Py-1P, Py-TT, and Py-Py) as adsorbents. Synchrotron X-ray diffraction, spectroscopic and computational studies indicate that the sharp adsorption steps in the isotherm originate from the insertion of CO 2 between the metal ion and the N atom of the imine bond on the inner pore surface of the COFs as the CO 2 pressure reaches threshold values. As a result, the CO 2 adsorption capacity of the ion-doped Py-1P COF is increased by 89.5% compared with that of the undoped Py-1P COF. This CO 2 sorption mechanism provides an efficient and straightforward approach to enhancing the CO 2 capture capacity of COF–based adsorbents, yielding insights into developing chemistry for CO 2 capture and conversion. https://www.pnas.org/doi/epdf/10.1073/pnas.2217081120 Emerging tetrapyrrole porous organic polymers for chemosensing applicationsCoordination Chemistry Reviews, Pub Date : 2023-02-21 , DOI: 10.1016/j.ccr.2023.215078 Qi Liu, Qiqi Sun, Jingshun Shen, Hao Li, Yuming Zhang, Wenmiao Chen, Sirong Yu, Xiyou Li, Yanli Chen Chemosensors are of great significance for medical detection, food safety, and environmental monitoring, and have received more and more attention. Tetrapyrrole porous organic polymers (POPs), as promising materials, were concerned widely due to their adjustable pore sizes, structures, and functions. Furthermore, the permanent porous nature of tetrapyrrole POPs can provide abundant adsorption sites to pre-enrich the guest molecules and facilitate the interaction between tetrapyrrole POPs and guest molecules, making tetrapyrrole POPs attractive for chemosensing applications. Here, we provide a comprehensive overview of tetrapyrrole POPs as chemosensing platforms. The chemosensors based on tetrapyrrole POPs fall into six main categories: electrochemical sensors, photoelectrochemical sensors, colorimetric sensors, fluorescence sensors, chemiresistive sensors, and quartz crystal microbalance sensors. And the various sensing applications of these six types of chemosensors in the detection of small molecules, biological molecules, heavy metal cations, anions, and toxic gas are summarized. The synthetic strategies of tetrapyrrole POPs with different structures and the related sensing mechanisms are also discussed. Finally, a brief exposition of the future perspectives is concluded.https://www.sciencedirect.com/science/article/abs/pii/S001085452300067X Prussian blue and its analogues: Reborn as emerging catalysts for a Fenton-like process in water purificationCoordination Chemistry Reviews, Pub Date : 2023-02-21 , DOI: 10.1016/j.ccr.2023.215067 Xiaqing Dong, Xuanming Liu, Min Cheng, Danlian Huang, Gaoxia Zhang, Wenjun Wang, Li Du, Guangfu Wang, Hongda LiuPrussian blue (PB) and its analogues (PBAs) are among the oldest Metal-organic frameworks (MOFs) and have been widely studied for their larger surface area, ultra-high porosity, and plentiful active sites. More importantly, its ease of preparation makes it more suitable for practical application than other types of MOFs. The aim of this article is to provide an in-depth overview of the environmental remediation of PB/PBAs in Fenton-like advanced oxidation process (AOPs) (activation of hydrogen peroxide (H2O2) and persulfate (PS, e.g., S2O82−/HSO5−)). First, common synthetic strategies for PB/PBAs-based materials are summarized. Then, the applications of PB/PBAs-based materials in the removal of organic matter and purification of wastewater by Fenton-like oxidation are discussed, with particular attention to their catalytic mechanisms and the identification of reactive oxygen species (ROS). Finally, unresolved challenges and perspectives of the future are proposed. This review provides guidance for the future application and development of PB/PBA in advanced oxidation.https://www.sciencedirect.com/science/article/abs/pii/S0010854523000565 Synergistic Steric and Electronic Effects on the Photoredox Catalysis by a Multivariate Library of Titania Metal–Organic FrameworksJournal of the American Chemical Society ,Pub Date : 2023-02-16 , DOI: 10.1021/jacs.2c12147 Jacob T. Bryant, Matthew W. Logan, Zhihengyu Chen, Marcus Djokic, Daniel R. Cairnie, Demetrius A. Vazquez-Molina, A. Nijamudheen, Kyle R. Langlois, Michael J. Markley, Gisselle Pombar, Ashley A. Holland, Jonathan D. Caranto, James K. Harper, Amanda J. Morris, Jose L. Mendoza-Cortes, Titel Jurca, Karena W. Chapman, Fernando J. Uribe-RomoMetal–organic frameworks (MOFs) that display photoredox activity are attractive materials for sustainable photocatalysis. The ability to tune both their pore sizes and electronic structures based solely on the choice of the building blocks makes them amenable for systematic studies based on physical organic and reticular chemistry principles with high degrees of synthetic control. Here, we present a library of eleven isoreticular and multivariate (MTV) photoredox-active MOFs, UCFMOF-n, and UCFMTV-n-x% with a formula Ti6O9[links]3, where the links are linear oligo-p-arylene dicarboxylates with n number of p-arylene rings and x mol% of multivariate links containing electron-donating groups (EDGs). The average and local structures of UCFMOFs were elucidated from advanced powder X-ray diffraction (XRD) and total scattering tools, consisting of parallel arrangements of one-dimensional (1D) [Ti6O9(CO2)6]∞ nanowires connected through the oligo-arylene links with the topology of the edge-2-transitive rod-packed hex net. Preparation of an MTV library of UCFMOFs with varying link sizes and amine EDG functionalization enabled us to study both their steric (pore size) and electronic (highest occupied molecular orbital–lowest unoccupied molecular orbital, HOMO–LUMO, gap) effects on the substrate adsorption and photoredox transformation of benzyl alcohol. The observed relationship between the substrate uptake and reaction kinetics with the molecular traits of the links indicates that longer links, as well as increased EDG functionalization, exhibit impressive photocatalytic rates, outperforming MIL-125 by almost 20-fold. Our studies relating photocatalytic activity with pore size and electronic functionalization demonstrate how these are important parameters to consider when designing new MOF photocatalysts.https://pubs.acs.org/doi/abs/10.1021/jacs.2c12147
Conceptual and Practical Aspects of Metal–Organic Frameworks for Solid–Gas ReactionsChemical Reviews, Pub Date : 2023-02-17 , DOI: 10.1021/acs.chemrev.2c00537
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By Kate Blackwood College of Arts and SciencesFebruary 22, 2023To develop more efficient next-generation materials for solar energy harvesting, researchers must