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1. Rapid design of top-performing metal-organic frameworks with qualitative representations of building blocks

   https://doi.org/10.1038/s41524-023-01125-1  

   Comlek, Yigitcan; Pham, Thang Duc; Snurr, Randall Q.; Chen, Wei (September 2023, npj Computational Materials)

   Abstract Data-driven materials design often encounters challenges where systems possess qualitative (categorical) information. Specifically, representing Metal-organic frameworks (MOFs) through different building blocks poses a challenge for designers to incorporate qualitative information into design optimization, and leads to a combinatorial challenge, with large number of MOFs that could be explored. In this work, we integrated Latent Variable Gaussian Process (LVGP) and Multi-Objective Batch-Bayesian Optimization (MOBBO) to identify top-performing MOFs adaptively, autonomously, and efficiently. We showcased that our method (i) requires no specific physical descriptors and only uses building blocks that construct the MOFs for global optimization through qualitative representations, (ii) is application and property independent, and (iii) provides an interpretable model of building blocks with physical justification. By searching only ~1% of the design space, LVGP-MOBBO identified all MOFs on the Pareto front and 97% of the 50 top-performing designs for the CO₂working capacity and CO₂/N₂selectivity properties. 

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2. Spectroscopic Evidence of Hyponitrite Radical Intermediate in NO Disproportionation at a MOF‐Supported Mononuclear Copper Site

   https://doi.org/10.1002/anie.202015359  

   Sun, Chenyue; Yang, Luming; Ortuño, Manuel A.; Wright, Ashley M.; Chen, Tianyang; Head, Ashley R.; López, Núria; Dincă, Mircea (March 2021, Angewandte Chemie International Edition)

   Abstract Dianionic hyponitrite (N₂O₂²⁻) is often proposed, based on model complexes, as the key intermediate in reductive coupling of nitric oxide to nitrous oxide at the bimetallic active sites of heme‐copper oxidases and nitric oxide reductases. In this work, we examine the gas‐solid reaction of nitric oxide with the metal–organic framework Cu^I‐ZrTpmC* with a suite of in situ spectroscopies and density functional theory simulations, and identify an unusual chelating N₂O₂^.−intermediate. These results highlight the advantage provided by site‐isolation in metal–organic frameworks (MOFs) for studying important reaction intermediates, and provide a mechanistic scenario compatible with the proposed one‐electron couple in these enzymes. 

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3. Elucidation of the role of metals in the adsorption and photodegradation of herbicides by metal-organic frameworks

   https://doi.org/10.1038/s41467-024-45546-y  

   Chiu, Nan Chieh; Lessard, Jacob M.; Musa, Emmanuel Nyela; Lancaster, Logan S.; Wheeler, Clara; Krueger, Taylor D.; Chen, Cheng; Gallagher, Trenton C.; Nord, Makenzie T.; Huang, Hongliang; et al (December 2024, Nature Communications)

   Abstract Here, four MOFs, namely Sc-TBAPy, Al-TBAPy, Y-TBAPy, and Fe-TBAPy (TBAPy: 1,3,6,8-tetrakis(p-benzoic acid)pyrene), were characterized and evaluated for their ability to remediate glyphosate (GP) from water. Among these materials, Sc-TBAPy demonstrates superior performance in both the adsorption and degradation of GP. Upon light irradiation for 5 min, Sc-TBAPy completely degrades 100% of GP in a 1.5 mM aqueous solution. Femtosecond transient absorption spectroscopy reveals that Sc-TBAPy exhibits enhanced charge transfer character compared to the other MOFs, as well as suppressed formation of emissive excimers that could impede photocatalysis. This finding was further supported by hydrogen evolution half-reaction (HER) experiments, which demonstrated Sc-TBAPy’s superior catalytic activity for water splitting. In addition to its faster adsorption and more efficient photodegradation of GP, Sc-TBAPy also followed a selective pathway towards the oxidation of GP, avoiding the formation of toxic aminomethylphosphonic acid observed with the other M³⁺-TBAPy MOFs. To investigate the selectivity observed with Sc-TBAPy, electron spin resonance, depleted oxygen conditions, and solvent exchange with D₂O were employed to elucidate the role of different reactive oxygen species on GP photodegradation. The findings indicate that singlet oxygen (¹O₂) plays a critical role in the selective photodegradation pathway achieved by Sc-TBAPy. 

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4. Water-enhanced CO2 capture in metal–organic frameworks

   https://doi.org/10.3389/fchem.2025.1634637  

   Cammarere, Celine; Cortés, Jaeden; Glover, T Grant; Snurr, Randall Q; Hupp, Joseph T; Liu, Jian (July 2025, Frontiers in Chemistry)

   CO₂capture from post-combustion flue gas originating from coal or natural gas power plants, or even from the ambient atmosphere, is a promising strategy to reduce the atmospheric CO₂concentration and achieve global decarbonization goals. However, the co-existence of water vapor in these sources presents a significant challenge, as water often competes with CO₂for adsorption sites, thereby diminishing the performance of adsorbent materials. Selectively capturing CO₂in the presence of moisture is a key goal, as there is a growing demand for materials capable of selectively adsorbing CO₂under humid conditions. Among these, metal–organic frameworks (MOFs), a class of porous, highly tunable materials, have attracted extensive interest for gas capture, storage, and separation applications. The numerous combinations of secondary building units and organic linkers offer abundant opportunities for designing systems with enhanced CO₂selectivity. Interestingly, some recent studies have demonstrated that interactions between water and CO₂within the confined pore space of MOFs can enhance CO₂uptake, flipping the traditionally detrimental role of moisture into a beneficial one. These findings introduce a new paradigm: water-enhanced CO₂capture in MOFs. In this review, we summarize these recent discoveries, highlighting examples of MOFs that exhibit enhanced CO₂adsorption under humid conditions compared to dry conditions. We discuss the underlying mechanisms, design strategies, and structural features that enable this behavior. Finally, we offer a brief perspective on future directions for MOF development in the context of water-enhanced CO₂capture. 

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5. Charge‐Separated and Lewis Paired Metal–Organic Framework for Anion Exchange and CO ₂ Chemical Fixation

   https://doi.org/10.1002/chem.202002823  

   Thapa, Sheela; Meng, Lingyao; Hettiarachchi, Eshani; Bader, Yousef_K; Dickie, Diane_A; Rubasinghege, Gayan; Ivanov, Sergei_A; Vreeland, Erika_C; Qin, Yang (October 2020, Chemistry – A European Journal)

   Abstract Charge‐separated metal–organic frameworks (MOFs) are a unique class of MOFs that can possess added properties originating from the exposed ionic species. A new charge‐separated MOF, namely, UNM‐6 synthesized from a tetrahedral borate ligand and Co²⁺cation is reported herein. UNM‐6 crystalizes into the highly symmetricP43nspace group with fourfold interpenetration, despite the stoichiometric imbalance between the B and Co atoms, which also leads to loosely bound NO₃⁻anions within the crystal structure. These NO₃⁻ions can be quantitatively exchanged with various other anions, leading to Lewis acid (Co²⁺) and Lewis base (anions) pairs within the pores and potentially cooperative catalytic activities. For example, UNM‐6‐Br, the MOF after anion exchange with Br⁻anions, displays high catalytic activity and stability in reactions of CO₂chemical fixation into cyclic carbonates. 

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