Incorporation of Molecular Catalysts in Metal-Organic Frameworks for Highly Efficient Heterogeneous Catalysis

Building Co16-N3-Based UiO-MOF to Expand Design Parameters for MOF Photosensitization

The construction of secondary building units (SBUs) in versatile metal-organic frameworks (MOFs) represents a promising method for developing multi-functional materials, especially for improving their sensitizing ability. Herein, we developed a dual small molecules auxiliary strategy to construct a high-nuclear transition-metal-based UiO-architecture Co16-MOF-BDC with visible-light-absorbing capacity. Remarkably, the N3 - molecule in hexadecameric cobalt azide SBU offers novel modification sites to precise bonding of strong visible-light-absorbing chromophores via click reaction. The resulting Bodipy@Co16-MOF-BDC exhibits extremely high performance for oxidative coupling benzylamine (~100 % yield) via both energy and electron transfer processes, which is much superior to that of Co16-MOF-BDC (31.5 %) and Carboxyl @Co16-MOF-BDC (37.5 %). Systematic investigations reveal that the advantages of Bodipy@Co16-MOF-BDC in dual light-absorbing channels, robust bonding between Bodipy/Co16 clusters and efficient electron-hole separation can greatly boost photosynthesis. This work provides an ideal molecular platform for synergy between photosensitizing MOFs and chromophores by constructing high-nuclear transition-metal-based SBUs with surface-modifiable small molecules.

Bridging molecular photosensitizer and catalyst on carbon nanotubes toward enhanced selectivity and durability for CO2 photoreduction

Homogenous molecular photocatalysts for CO2 reduction, especially metal complex-based photosensitizer‒catalyst assemblages, have been attracting extensive research interests due to their efficiency and customizability. However, their low durability and recyclability limit practical applications. In this work, we immobilized the catalysts of metal terpyridyl complexes and the photosensitizer of [Ru(bpy)3]Cl2 onto the surface of carbon nanotubes through covalent bonds and electrostatic interactions, respectively, transforming the homogeneous system into a heterogeneous one. Our characterizations prove that these metal complexes are well dispersed on CNTs with a high loading (ca. 12 wt.%). Photocatalytic measurements reveal that catalytic activity is remarkably enhanced when the molecular catalysts are anchored, which is three times higher than that of homogeneous molecular catalysts. Moreover, when the photosensitizer of [Ru(bpy)3]Cl2 is immobilized, the side reaction of hydrogen evolution is completely suppressed and the selectivity for CO production reaches 100%, with its durability also significantly improved. This work provides an effective pathway for constructing heterogeneous photocatalysts based on rational assembly of efficient molecular photosensitizers and catalysts.

Synergistic Effects of MOFs and Noble Metals in Photocatalytic Reactions: Mechanisms and Applications

Photocatalytic technology can efficiently convert solar energy to chemical energy and this process is considered as one of the green and sustainable technology for practical implementation. In recent years, metal-organic frameworks (MOFs) have attracted widespread attention due to their unique advantages and have been widely applied in the field of photocatalysis. Among them, noble metals have contributed significant advances to the field as effective catalysts in photocatalytic reactions. Importantly, noble metals can also form a synergistic catalytic effect with MOFs to further improve the efficiency of photocatalytic reactions. However, how to precisely control the synergistic effect between MOFs and noble metals to improve the photocatalytic performance of materials still needs to be further studied. In this review, the synergistic effects of MOFs and noble metal catalysts in photocatalytic reactions are firstly summarized in terms of noble metal nanoparticles, noble metal monoatoms, noble metal compounds, and noble metal complexes, and focus on the mechanisms and advantages of these synergistic effects, so as to provide useful guidance for the further research and application of MOFs and contribute to the development of the field of photocatalysis.

Micropores in Hollow Organic Cage Nanocapsule as a Size Exclusion Gate: Cage Entrapped Pd(II)-Catalyst for Efficient Cross-Coupling Reaction

Hollow porous organic capsules (HPOCs) with an entrapped active catalyst have nanosized cavities, providing the benefits of a nanoreactor, as well as separation of the catalysts from the reaction medium via pores acting as a size-exclusion gate. Such purpose-built HPOCs with desired molecular weight cutoffs offer the advantages of semipermeable membrane separation and a sustainable chemical process that excludes energy-extensive separation. Here, we report a newly synthesized HPOC with an entrapped Pd(PPh3)2Cl2 as the catalyst for demonstrating a Suzuki-Miyaura coupling reaction as a proof of concept.

Construction of Indium(III)-Organic Framework Based on a Flexible Cyclotriphosphazene-Derived Hexacarboxylate as a Reusable Green Catalyst for the Synthesis of Bioactive Aza-Heterocycles

The constant demand for eco-friendly methods of synthesizing complex organic compounds inspired researchers to design and develop modern, highly efficient heterogeneous catalytic systems. Herein, In-HCPCP metal-organic framework (SRMIST-1), a heterogeneous Lewis acid catalyst containing less toxic indium and eco-friendly robust cyclotriphosphazene and exhibiting notable chemical and thermal stability, durable catalytic activity, and exceptional reusability was produced through the reaction between indium(III) nitrate hydrate and hexakis(4-carboxylatophenoxy)-cyclotriphosphazene. In the SRMIST-1 structure, secondary building units {InO7} are assembled by a connection of η2- and η1-carboxylic oxo atoms from different HCPCP ligands, forming a three-dimensional network. The occurrence of regularly distributed In(III) sites in SRMIST-1 confers superior reactivity on the catalyst toward the synthesis of 2,3-dihydroquinazolin-4(1H)-ones and 3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxides by the cyclization reaction of 2-aminobenzamides and 2-aminobenzenesulphonamides with aldehydes under optimized reaction conditions, respectively. The notable features of this method include broad functional group compatibility, low catalyst loading (1-5 mol %), mild reaction conditions, easy workup procedures, good to excellent reaction yields, ethanol as a green solvent, reusability of the catalyst (five cycles), and economic attractiveness, which is mainly due to sustainability of SRMIST-1 as a reusable green catalyst. Our findings demonstrate that the highly reactive and reusable green catalyst finds widespread applications in medicinal chemistry.

Bridging Homogeneous and Heterogeneous Catalysis: Phosphine-Functionalized Metal-Organic Frameworks

Phosphine-functionalized metal-organic frameworks (P-MOFs) as an emerging class of coordination polymers, have provided novel opportunities for the development of heterogeneous catalysts. Yet, compared with the ubiquitous phosphine systems in homogeneous catalysis, heterogenization of phosphines in MOFs is still at its early stage. In this Minireview, we summarize the synthetic strategies, characterization and catalytic reactions based on the P-MOFs reported in literature. In particular, various catalytic reactions are discussed in detail in terms of phosphine ligand structure-function relationship, including the potential obstacles for future development. Finally, we discuss the possible solutions, including new types of reactions and techniques as the perspectives for the development of P-MOF catalysts, highlighting the opportunities and challenges.

Partial-Interpenetration-Controlled UiO-Type Metal-Organic Framework and its Catalytic Activity

An unprecedented correlation between the catalytic activity of a Zr-based UiO-type metal-organic framework (MOF) and its degree of interpenetration (DOI) is reported. The DOI of an MOF is hard to control owing to the high-energy penalty required to construct a partially interpenetrated structure. Surprisingly, strong interactions between building blocks (inter-ligand hydrogen bonding) facilitate the formation of partially interpenetrated structures under carefully regulated synthesis conditions. Moreover, catalytic conversion rates for cyanosilylation and Knoevenagel condensation reactions are found to be proportional to the DOI of the MOF. Among MOFs with DOIs in the 0-100% range, that with a DOI of 87% is the most catalytically active. Framework interpenetration is known to lower catalytic performance by impeding reactant diffusion. A higher effective reactant concentration due to tight inclusion in the interpenetrated region is possibly responsible for this inverted result.

DNA flexible chain modified MOFs as a versatile platform for chemoenzymatic cascade reactions in glucose catalysis

Glucose oxidase (GOD) is widely used in the pharmaceutical industry, fermentation products and glucose biosensors for its essential role in catalyzing the conversion of glucose to gluconic acid and hydrogen peroxide (H2O2). As H2O2 is the by-product and will have a toxic effect on glucose oxidase, so introducing another enzyme that could consume H2O2 to form an enzymatic cascade reaction is a practical solution. However, this decision will lead to extra expenses and complex condition optimization such as the specific mass ratio, temperature and pH to improve the activity, stability and recyclability. Herein, we describe a mild and versatile strategy by anchoring GOD on carboxyl-activated MOF (Cu-TCPP(Fe)) through DNA-directed immobilization (DDI) technology. Robust MOF nanosheets were utilized as not only the carrier for the immobilization of GOD, but also a peroxidase-like catalyst for the decomposition of H2O2 to reduce its harmful impacts. In this work, the immobilized GOD retained 55.78% of its initial activity after being used for 7 times. More than 60% of the immobilized enzyme's catalytic activity was still maintained after 96 h of being stored at 50 ℃. This study provides a new idea for preparing immobilized enzymes with enhanced stability, fast diffusion and high activity, which can be used in fields such as biocatalysis and biotechnology.

An Fe-organic framework/arginine-glycine-aspartate peptide-modified sensor for electrochemically detecting nitric oxide released from living cells

Nitric oxide (NO) is a crucial cell-signaling molecule utilized in numerous physiological and pathological processes. Monitoring cellular levels of NO requires a sensor with sufficient sensitivity, transient recording capability, and biocompatibility. Owing to the large surface area and high catalytic activity of the metal-organic framework, Fe-BTC was used for the modification of screen-printed electrodes (SPEs). This study investigates the electrochemical sensing of NO on modified SPEs. Additionally, the introduction of a cell-adhesive molecule, arginine-glycine-aspartate peptide (RGD), considerably improved the cytocompatibility, resulting in superior cell attachment and growth on the SPE. The Fe-BTC/RGD-modified SPE (Fe-BTC/RGD/SPE) exhibited electrocatalytic NO oxidation at 0.8 V, demonstrating a linear response with a detection limit of 11.88 nM over a wide concentration range (0.17-47.37 μM) and a response time of approximately 0.9 s. Subsequently, the as-obtained Fe-BTC/RGD/SPE was successfully utilized for the real-time detection of NO released from human endothelial cells cultured on the electrode. Therefore, the study undertaken shows remarkable potential of Fe-BTC/RGD/SPE for practical applications in biological processes and clinical diagnostics.

Ultrafast Photocatalytic Detoxification of Mustard Gas Simulants by a Mesoporous Metal-Organic Framework with Dangling Porphyrin Molecules

Developing effective catalysts to degrade chemical warfare agents is of great significance. Herein, a mesoporous MIL-101(Cr) composite material dangled with porphyrin molecules (denote as TCPP@MIL-101(Cr), TCPP = tetra(4-carboxyphenyl)porphyrin) is reported, which can be used as a heterogeneous photocatalyst for detoxification of mustard gas simulants 2-chloroethyl ethyl sulfide (CEES) to 2-chloroethyl ethyl sulfoxide (CEESO) with a half-life of 1 min. The catalytic performance of TCPP@MIL-101(Cr) is comparable to that of homogeneous molecular porphyrin. Mechanistic studies reveal that both 1 O2 and O2 •- are efficiently generated and play vital roles in the oxidation reaction. Gold nanoparticles (AuNPs) are attached to the TCPP@MIL-101(Cr) to further enhance the catalytic activity with a benchmark half-life of 45 s, which is the fastest record so far. A medical mask loaded TCPP@MIL-101(Cr) is fabricated for practical applications, which can selectively photoxidize CEES to CEESO under sunlight and air atmosphere, exhibiting the best degradation performance among the reported fabric-like composite materials.

Generation and Stabilization of a Dinickel Catalyst in a Metal-Organic Framework for Selective Hydrogenation Reactions

Although many monometallic active sites have been installed in metal-organic frameworks (MOFs) for catalytic reactions, there are no effective strategies to generate bimetallic catalysts in MOFs. Here we report the synthesis of a robust, efficient, and reusable MOF catalyst, MOF-NiH, by adaptively generating and stabilizing dinickel active sites using the bipyridine groups in MOF-253 with the formula of Al(OH)(2,2'-bipyridine-5,5'-dicarboxylate) for Z-selective semihydrogenation of alkynes and selective hydrogenation of C=C bonds in α,β-unsaturated aldehydes and ketones. Spectroscopic studies established the dinickel complex (bpy⋅- )NiII (μ2 -H)2 NiII (bpy⋅- ) as the active catalyst. MOF-NiH efficiently catalyzed selective hydrogenation reactions with turnover numbers of up to 192 and could be used in five cycles of hydrogenation reactions without catalyst leaching or significant decrease of catalytic activities. The present work uncovers a synthetic strategy toward solution-inaccessible Earth-abundant bimetallic MOF catalysts for sustainable catalysis.

Interfacial chemistries in metal-organic framework (MOF)/covalent-organic framework (COF) hybrids

Metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) have been attracting tremendous attention in various applications due to their unique structural properties. Recent interest has been focused on their combination as hybrids to enable the engineering of new classes of frameworks with complementary properties. This review gives a comprehensive summary on the interfacial chemistries in MOF/COF hybrids, which play critical roles in their hybridization. The challenges and perspectives in the field of MOF/COF hybrids are also provided to inspire more efforts in diversifying this hybrid family and their cross-disciplinary applications.

Efficacy and prognosis of adjuvant treatment of endometrial cancer with medroxyprogesterone acetate COX regression analysis

BACKGROUND

Endometrial cancer is one of the most commonly diagnosed gynecological cancers worldwide, and early-stage high-risk endometrial cancer has a poor prognosis. Adjuvant treatments after surgery, such as chemotherapy and radiotherapy, have been widely used in clinical practice to improve patient survival. Medroxyprogesterone acetate is a synthetic progestogen that has been reported to have potential anticancer effects in endometrial cancer. However, its efficacy, safety, and long-term prognostic benefits as an adjuvant treatment for endometrial cancer remain controversial. Therefore, this study aimed to observe the efficacy and prognostic impact of adjuvant medroxyprogesterone acetate treatment in patients with early-stage high-risk endometrial cancer and evaluate its safety.

AIM

To observe the efficacy and prognosis of adjuvant treatment of endometrial cancer with medroxyprogesterone acetate and to evaluate its safety.

METHODS

We collected the clinical data of 200 patients with early-stage high-risk endometrial cancer who were admitted to the Department of Obstetrics and Gynecology of our hospital from January 2018 to December 2022. The control group (100 patients) underwent conventional surgical treatment, and the study group (100 patients) was administered adjuvant medroxyprogesterone acetate tablets on top of the control group. The Kaplan-Meier curve analysis and log-rank test were performed to determine the possible factors influencing the 5-year cumulative survival rate in the patients. The Cox regression analysis was performed to identify the factors influencing the survival prognosis of endometrial cancer.

RESULTS

According to the Cox regression analysis, age [hazard ratio (HR) = 4.636, 95% confidence interval (95%CI): 1.411-15.237], pathological type (HR = 6.943, 95%CI: 2.299-20.977), molecular typing (HR = 5.789, 95%CI: 3.305-10.141), and myometrial infiltration (HR = 5.768, 95%CI: 1.898-17.520) were factors influencing the prognosis of patients with early-stage high-risk endometrial cancer.

CONCLUSION

Age, pathological type, molecular typing, and myometrial infiltration were all relevant factors affecting the prognosis of early-stage high-risk endometrial cancer. The potential long-term prognostic benefit of adjuvant postoperative radiotherapy in patients with early-stage high-risk endometrial cancer is worthy of clinical consideration.

Metal-organic frameworks/metal nanoparticles as smart nanosensing interfaces for electrochemical sensors applications: a mini-review

Metal-organic frameworks (MOFs) are porous materials with huge specific surface area and abundant active sites, which are composed of metal ions or clusters and organic ligands in the form of coordination bonds. In recent years, MOFs have been successfully applied in many fields due to their excellent physical, chemical, and biological properties. Electrochemical sensors have advantages such as economy, portability, and sensitivity, making them increasingly valued in the field of sensors. Many studies have shown that the electrode materials will affect the performance of electrochemical sensors. Therefore, the research on electrode materials is still one of the hotspots. MOFs are also commonly used to construct electrochemical sensors. However, electrochemical sensors prepared from single MOFs have shortcomings such as insufficient conductivity, low sensitivity, and poor electrochemical catalytic ability. In order to compensate for these defects, a new type of nanocomposite material with very ideal conductivity was formed by adding metal nanoparticles (MNPs) to MOFs. The combination of the two is expected to be widely applied in the field of sensors. This review summarizes the applications of various MNPs/MOFs composites in the field of electrochemical sensors and provides some references for the development of MNPs/MOFs composites-based electrochemical sensors in the future.

Surface-decorated porphyrinic zirconium-based metal-organic frameworks (MOFs) using post-synthetic self-assembly for photodegradation of methyl orange dye

We report herein the surface decoration of a water-soluble free-base porphyrin, namely, 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin-tetra(p-toluenesulfonate) (H₂TMPyP), over three different zirconium-based metal-organic frameworks of different linker structure and functionality; namely UiO66, UiO66-NH₂, and MIP-202, via self-assembly. The synthesized MOFs along with the resulting complexes have been characterized via spectroscopic and analytical techniques (XRD, FT-IR, TEM, N₂ adsorption/desorption, and laser scanning confocal microscopy). The self-assembly of H₂TMPyP with the examined three MOFs was observed by using the steady-state absorption and fluorescence, as well as the fluorescence lifetime studies. It was evident that the highest complex interaction was recorded between porphyrin and UiO-66-NH₂ compared with the lowest interactions between porphyrin and MIP-202. This is in good agreement with the high surface area and pore volume of UiO-66 (1100 m² g^-1 and 0.68 cm³ g^-1) and compared to that of MIP-202 (94 m² g^-1 and 0.26 cm³ g^-1). The photocatalytic activities of the three porphyrin entities immobilized zirconium-based MOFs were compared toward methyl orange dye degradation from aqueous solution under visible light irradiation (λ_ex = 430 nm). The photocatalytic studies render the fabrication of the self-assembled H₂TMPyP@UiO-66-NH₂ composite as a promising material for dye degradation from polluted wastewater.

MOFganic Chemistry: Challenges and Opportunities for Metal-Organic Frameworks in Synthetic Organic Chemistry

Metal-organic frameworks (MOFs) are porous, crystalline solids constructed from organic linkers and inorganic nodes that have been widely studied for applications in gas storage, chemical separations, and drug delivery. Owing to their highly modular structures and tunable pore environments, we propose that MOFs have significant untapped potential as catalysts and reagents relevant to the synthesis of next-generation therapeutics. Herein, we outline the properties of MOFs that make them promising for applications in synthetic organic chemistry, including new reactivity and selectivity, enhanced robustness, and user-friendly preparation. In addition, we outline the challenges facing the field and propose new directions to maximize the utility of MOFs for drug synthesis. This perspective aims to bring together the organic and MOF communities to develop new heterogeneous platforms capable of achieving synthetic transformations that cannot be replicated by homogeneous systems.

Recent strategies for constructing hierarchical multicomponent nanoparticles/metal-organic framework hybrids and their applications

Hybrid nanoparticles with unique tailored morphologies and compositions can be utilized for numerous applications owing to their combination of inherent properties as well as the structural and supportive functions of each component. Controlled encapsulation of nanoparticles within nanospaces (NPNSs) of metal-organic frameworks (MOFs) (denoted as NPNS@MOF) can generate a large number of hybrid nanomaterials, facilitating superior activity in targeted applications. In this review, recent strategies for the fabrication of NPNS@MOFs with a hierarchical architecture, tailorability, unique intrinsic properties, and superior catalytic performance are summarized. In addition, the latest and most important examples in this sector are emphasized since they are more conducive to the practical applicability of NPNS@MOF nanohybrids.

Stabilization of transition metal heterojunctions inside porous materials for high-performance catalysis

Transition metal-based heterostructural materials are a class of very promising substitutes for noble metal-based catalysts for high-performance catalysis, due to their inherent internal electric field at the interface in the heterojunctions, which could induce electron relocalization and facilitate charge carrier migration between different metal sites at heterostructural boundaries. However, redox-active metal species suffer from reduction, oxidation, migration, aggregation, leaching and poisoning in catalysis, which results in heavy deterioration of the catalytic properties of transition metal-based heterojunctions and frustrates their practical applications. To improve the stability of transition metal-based heterojunctions and sufficiently expose redox-active sites at the heterosurfaces, many kinds of porous materials have been used as porous hosts for the stabilization of non-precious metal heterojunctions. This review article will discuss recently developed strategies for encapsulation and stabilization of transition metal heterojunctions inside porous materials, and highlight their improved stability and catalytic performance through the spatial confinement effect and synergistic interaction between the heterojunctions and the host matrices.

Highly enhanced electrocatalytic OER activity of water-coordinated copper complexes: effect of lattice water and bridging ligand

The use of metal-organic compounds as electrocatalysts for water splitting reactions has gained increased attention; however, a fundamental understanding of the structural requirement for effective catalytic activity is still limited. Herein, we synthesized water-coordinated mono and bimetallic copper complexes (CuPz-H₂O·H₂O, CuPz-H₂O, CuBipy-H₂O·H₂O, and CuMorph-H₂O) with varied intermetallic spacing (pyrazine/4,4'-bipyridine) and explored the structure-dependent oxygen evolution reaction (OER) activity in alkaline medium. Single crystal structural studies revealed water-coordinated monometallic complexes (CuMorph-H₂O) and bimetallic complexes (CuPz-H₂O·H₂O, CuPz-H₂O, CuBipy-H₂O·H₂O). Further, CuPz-H₂O·H₂O and CuBipy-H₂O·H₂O contained lattice water along with coordinated water. Interestingly, the bimetallic copper complex with lattice water and shorter interspacing between the metal centres (CuPz-H₂O·H₂O) showed strong OER activity and required an overpotential of 228 mV to produce a benchmark current density of 10 mA cm^-2. Bimetallic copper complex (CuPz-H₂O) without lattice water but the same intermetallic spacing and bimetallic complex with increased interspacing but with lattice water (CuBipy-H₂O·H₂O) exhibited relatively lower OER activity. CuPz-H₂O and CuBipy-H₂O·H₂O required an overpotential of 236 and 256 mA cm^-2, respectively. Monometallic CuMorph-H₂O showed the lowest OER activity (overpotential 271 mV) compared to bimetallic complexes. The low Tafel slope and charge transfer resistance of CuPz-H₂O·H₂O facilitated faster charge transfer kinetics at the electrode surface and supported the enhanced OER activity. The chronoamperometric studies indicated good stability of the catalyst. Overall, the present structure-electrocatalytic activity studies of copper complexes might provide structural insight for designing new efficient electrocatalysts based on metal coordination compounds.

Solubilizing Metal-Organic Frameworks for an In Situ IR-SEC Study of a CO2 Reduction Catalyst

Metal-organic frameworks (MOFs) are typically assembled by bridging metal centers with organic linkers for various applications, including providing robust support for heterogeneous catalysts for CO2 reduction. In this study, we have demonstrated the solubilization of a MOF tethered to a CO2-reducing electrocatalyst and studied its fundamental electrochemistry in THF solvent using infrared spectroelectrochemistry (IR-SEC). The fundamental electrochemical properties of this immobilized catalyst were compared to that of its homogeneous counterpart. This approach provides a foundation for future experimental studies to bridge the gap between homogeneous and heterogeneous electrocatalysis.

Utilizing Metal-Thiocatecholate Functionalized UiO-66 Framework for Photocatalytic Hydrogen Evolution Reaction

Exploiting clean energy is essential for sustainable development and sunlight-driven photocatalytic water splitting represents one of the most promising approaches toward this goal. Metal-organic frameworks (MOFs) are competent photocatalysts owing to their tailorable functionality, well-defined structure, and high porosity. Yet, the introduction of the unambiguous metal-centered active site into MOFs is still challenging since framework motifs capable of anchoring metal ions firmly are lacking. Herein, the assembly using 1,4-dicarboxylbenzene-2,3-dithiol (H₂ dcbdt) and Zr-Oxo clusters to give a thiol-functionalized UiO-66 type framework, UiO-66-dcbdt, is reported. The thiocatechols on the struts are allowed to capture transition metal (TM) ions to generate UiO-66-dcbdt-M (M  = Fe, Ni, Cu) with unambiguous metal-thiocatecholate moieties for photocatalytic hydrogen evolution reaction (HER). UiO-66-dcbdt-Cu is found the best catalyst exhibiting an HER rate of 4.18 mmol g^-1  h^-1  upon irradiation with photosensitizing Ru-polypyridyl complex. To skip the use of the external sensitizer, UiO-66-dcbdt-Cu is heterojunctioned with titanium dioxide (TiO₂ ) and achieves an HER rate of 12.63 mmol g^-1  h^-1  (32.3 times that of primitive TiO₂ ). This work represents the first example of MOF assembly employing H₂ dcbdt as the mere linker followed by chelation with TM ions and undoubtedly fuels the rational design of MOF photocatalysts bearing well-defined active sites.

Oxidation of N-Alkyl(iso)quinolinium Salts Over TEMPO@Metal-Organic Framework Heterogeneous Photocatalyst†

Quinolones and isoquinolones are of particular importance to pharmaceutical industry due to their diverse biological activities. However, their synthetic protocols were limited by high toxicity, high energy consumption, poor functional group tolerance and noble metal catalyst. This study concerns the development of a series of TEMPO@PCN-222 (TEMPO: 2,2,6,6-tetramethylpiperidinyl-1-oxy; PCN: porous coordination network) composite photocatalysts by coordinating different amount of 4-carboxy-TEMPO with the secondary building units of PCN-222. Upon visible-light irradiation, photogenerated holes in the highest occupied molecular orbital of PCN-222 can smoothly transfer to TEMPO, which can significantly boost the photosynthesis of bioactive (iso)quinolones from readily available N-alkyl(iso)quinolinium salts. TEMPO@PCN-222 exhibits an outstanding catalytic stability and substrate tolerance with a 1-methyl-2-quinolinone yield of 86.7 %, over four times that with PCN-222 (21.4 %). This work provides a new route to construct composite photocatalysts from abundant starting materials for efficient photosynthesis of high value-added chemicals.

Metal organic frameworks derived functional materials for energy and environment related sustainable applications

With the vigorous development of industrial economy, energy and environmental problems have become the most serious issues affecting people's production and life. Therefore, the demand for clean energy production, effective separation and storage is growing. Metal-organic frameworks (MOFs), as a kind of porous crystalline materials with large surface area and porosity, which is self-assembled by metal ions or clusters and organic ligands through coordination bonds. Thanks to a number of unique characteristics such as adjustable pore environment, homogeneous void structure, abundant active sites, unprecedented chemical composition tunability and functional versatility, it has been widely studied, especially for the clean energy conversion in catalysis. In this review, we focus on the research progress of clean energy in catalysis based on MOFs. Emphasis is placed on MOFs with different structures of compositions and their applications in catalytic for clean energy conversion, such as CO oxidation, CO₂ reduction and H₂ evolution. In addition, the situation of MOFs assisting environmental remediation is also briefly described. Finally, the prospects and challenges of MOFs in clean energy and the remaining issues in this field are presented.

Modification of bimetal Zn/ Mg MOF with nanoparticles Fe3O4 and Fe3O4@SiO2, investigation of the peroxidase-like activity of these compounds by calorimetry and fluorimetry methods

In this article; the bimetal metal-organic framework Zn/Mg (Zn/Mg MOF) is synthesized. Then Zn/Mg MOF bimetal was combined with Fe₃O₄ and Fe₃O₄@SiO₂, and composites of Fe₃O₄@ SiO₂/MOF/Dextrin, Fe₃O₄@SiO₂/MOF, Fe₃O₄@MOF/Dextrin and Fe₃O₄@MOF made. The peroxidase-like activity of these compounds was investigated and compared by calorimetric Resazurin (Rz) and O-phenylenediamine (OPD); (Rz-H₂O₂, OPD-H₂O₂) and fluorimetric Rz and terephtalic acid (TA); (Rz-H₂O₂, TA-H₂O₂). The Fe₃O₄@ MOF/Dextrin composite has the highest peroxidase-like activity. The effect factors (amount of pH (6), the values of TA (1.37 mM), H₂O₂ (0.025 mM), reaction time (8.15 min), and amount of Composite (116.67 mg)) to increase the catalytic activity of Fe₃O₄@ MOF/Dextrin measured by chemometrics method. The most suitable linear range of the calibration curve by the TA-H₂O₂ -Composite fluorimetric method is 1-600 μg L^-1, and the detection limit is 2.27 μg L^-1. The relative standard deviation (RSD%) for measuring concentration atropine 1 μg L^-1 (n = 6) is 1.18%. Finally, from this system for measuring atropine extracted by the Liquid-liquid extraction (LLE) method in two types of plants, D. Innoxia north and west and D. stramonium north and west of Iran (118.25 μg L^-1, 79.80 μg L^-1) and (18.477 μg L^-1, 9.27 μg L^-1) used, respectively.

Construction of nano-sized FOX-7/ZIF-8 composites for fast decomposition and reduced sensitivity

Herein, novel nano-sized 1,1-diamino-2,2-dinitroethylene (C₂H₄N₄O₄, FOX-7)/zeolitic imidazolate framework-8 (ZIF-8) composites are constructed by facile liquid-assisted mechanochemical reactions. In contrast to two-step thermal decomposition of raw FOX-7, the prepared FOX-7/ZIF-8 composites demonstrate a single high-intensity exothermal decomposition attributed to the catalysis of ZIF-8. Benefiting from nano-sized energetic materials and the buffering effect of ZIF-8, the mechanical sensitives of FOX-7/ZIF-8 composites are decreased.

Immobilization of a trimeric ruthenium cluster in mesoporous chromium terephthalate and its catalytic application

Molecular trimeric ruthenium carboxylate clusters (Ru₃ clusters) have been introduced into the pore channels of mesoporous metal-organic framework chromium terephthalate [MIL-101(Cr)] by employing a facile two-step post-synthetic strategy in which diamine hooks anchored on the framework metal nodes of the MOF are used to covalently immobilize the Ru₃ clusters. The catalytic activity of the isolated Ru₃ clusters in the pore channels of the MOF was significantly improved compared to the bulk counterpart.

Electrochemical enzyme-based blood uric acid biosensor: new insight into the enzyme immobilization on the surface of electrode via poly-histidine tag

In a new approach, we considered the special affinity between Ni and poly-histidine tags of recombinant urate oxidase to utilize Ni-MOF for immobilizing the enzyme. In this study, a carbon paste electrode (CPE) was modified by histidine-tailed urate oxidase (H-UOX) and nickel-metal-organic framework (Ni-MOF) to construct H-UOX/Ni-MOF/CPE, which is a rapid, sensitive, and simple electrochemical biosensor for UA detection. The use of carboxy-terminal histidine-tailed urate oxidase in the construction of the electrode allows the urate oxidase enzyme to be positioned correctly in the electrode. This, in turn, enhances the efficiency of the biosensor. Characterization was carried out by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and field emission scanning electron microscopy (FE-SEM). At optimum conditions, the biosensor provided a short response time, linear response within 0.3-10 µM and 10-140 µM for UA with a detection limit of 0.084 µM, repeatability of 3.06%, and reproducibility of 4.9%. Furthermore, the biosensor revealed acceptable stability and selectivity of UA detection in the presence of the commonly coexisted ascorbic acid, dopamine, L-cysteine, urea, and glucose. The detection potential was at 0.4 V vs. Ag/AgCl.

Switching Excited State Distribution of Metal-Organic Framework for Dramatically Boosting Photocatalysis

Photosensitization associated with electron/energy transfer represents the central science of natural photosynthesis. Herein, we proposed a protocol to dramatically improve the sensitizing ability of metal-organic frameworks (MOFs) by switching their excited state distribution from ³ MLCT (metal-to-ligand charge transfer) to ³ IL (intraligand). The hierarchical organization of ³ IL MOFs and Co/Cu catalysts facilitates electron transfer for efficient photocatalytic H₂ evolution with a yield of 26 844.6 μmol g^-1 and CO₂ photoreduction with a record HCOOH yield of 4807.6 μmol g^-1 among all the MOF photocatalysts. Systematic investigations demonstrate that strong visible-light-absorption, long-lived excited state and ingenious multi-component synergy in the ³ IL MOFs can facilitate both interface and intra-framework electron transfer to boost photocatalysis. This work opens up an avenue to boost solar-energy conversion by engineering sensitizing centers at a molecular level.

Transformation of metal-organic frameworks with retained networks

Metal-organic frameworks (MOFs) are a class of crystalline porous coordination materials with systematically designable network structures and tunable properties, demonstrating great potential for applications in diverse fields. However, the generally poor stability of dynamic coordination bonds in MOFs hinders their practical applications in harsh environments. Although MOFs have been used as precursors and templates for the production of various derivatives with enhanced stability via thermal treatment, the extreme thermolytic conditions often destroy the network structures, consequently resulting in obvious decreases in porosity and surface areas with undesired characteristics. This feature article discusses the generally used pathways for the transformation of MOFs and the advanced fabrication methods for the production of various MOF-derived materials. We particularly emphasize the recent progress in the designed strategies for customization and derivation tailoring of MOFs, which could produce MOF-derived functional materials with remaining framework skeletons and inherited characteristics (surface area, porosity and properties) of the parent MOFs, exhibiting great promise for practical applications.

Endohedrally Functionalized Metal-Organic Cage-Cross-Linked Polymer Gels as Modular Heterogeneous Catalysts

The immobilization of homogeneous catalysts onto supports to improve recyclability while maintaining catalytic efficiency is often a trial-and-error process limited by poor control of the local catalyst environment and few strategies to append catalysts to support materials. Here, we introduce a modular heterogenous catalysis platform that addresses these challenges. Our approach leverages the well-defined interiors of self-assembled Pd₁₂L₂₄ metal-organic cages/polyhedra (MOCs): simple mixing of a catalyst-ligand of choice with a polymeric ligand, spacer ligands, and a Pd salt induces self-assembly of Pd₁₂L₂₄-cross-linked polymer gels featuring endohedrally catalyst-functionalized junctions. Semi-empirical calculations show that catalyst incorporation into the MOC junctions of these materials has minimal affect on the MOC geometry, giving rise to well-defined nanoconfined catalyst domains as confirmed experimentally using several techniques. Given the unique network topology of these freestanding gels, they are mechanically robust regardless of their endohedral catalyst composition, allowing them to be physically manipulated and transferred from one reaction to another to achieve multiple rounds of catalysis. Moreover, by decoupling the catalyst environment (interior of MOC junctions) from the physical properties of the support (the polymer matrix), this strategy enables catalysis in environments where homogeneous catalyst analogues are not viable, as demonstrated for the Au(I)-catalyzed cyclization of 4-pentynoic acid in aqueous media.

Two Copper-Containing Polyoxometalate-Based Metal-Organic Complexes as Heterogeneous Catalysts for the C-H Bond Oxidation of Benzylic Compounds and Olefin Epoxidation

Using a one-pot assembly method, two novel copper-containing Keggin-type polyoxometalates (POMs)-based metal-organic complexes, that is, [Cu^II₂(pbba)₂NO₃^-(H₂O)₂(PW₁₂O₄₀)]·3H₂O [PW₁₂-Cu-pbba, H₂pbba = 1,1'-(1,4-phenylene-bis(methylene))-bis(pyridine-3-carboxylic acid)] and [Cu^II₂(pbba)₂(H₂O)₂(GeW₁₂O₄₀)]·3H₂O (GeW₁₂-Cu-pbba), were successfully synthesized. These two complexes are isostructural, differing only in their POM components. They are applicable as heterogeneous catalysts for the C-H bond oxidation of benzylic compounds and olefin epoxidation under mild conditions, with oxygen as the oxidant and isobutyraldehyde as the coreductant. The catalytic activity of PW₁₂-Cu-pbba was superior to that of GeW₁₂-Cu-pbba. Under the optimal conditions, PW₁₂-Cu-pbba catalyzed the oxidation of indane into 1-indanone with an 81% yield and >99% selectivity within 48 h. As heterogeneous catalysts, both complexes demonstrated excellent recoverability and high stability and could be stably reused five times without significant activity loss.

Engineering Metal-Organic Framework Hybrid AIEgens with Tumor-Activated Accumulation and Emission for the Image-Guided GSH Depletion ROS Therapy

Aggregation-induced emission (AIE)-active luminogens (AIEgens) have demonstrated exciting potential for the application in cancer phototheranostics. However, simultaneously achieving tumor-activated bright emission, enhanced reactive oxygen species (ROS) generation, high tumor accumulation, and minimized ROS depletion remains challenging. Here, a metal-organic framework (MOF) hybrid AIEgen theranostic platform is designed, termed A-NUiO@DCDA@ZIF-Cu, composed of an AIEgen-loaded hydrophobic UiO-66 (A-NUiO@DCDA) core and a Cu-doped hydrophilic ZIF-8 (ZIF-Cu) shell. The fluorescence emission and therapeutic ROS activity of AIEgens are restrained during delivery. After uptake by tumor tissues, ZIF-Cu decomposition occurs in response to an acidic tumor microenvironment (TME), and the hydrophobic A-NUiO@DCDA cores self-assemble into large particles, extremely increasing the tumor accumulation of AIEgens. This results in enhanced fluorescence imaging (FLI) and highly improved ¹O₂ generation ability during photodynamic therapy (PDT). Meanwhile, the released Cu²⁺ reacts to glutathione (GSH) to generate Cu⁺, which provides an extra chemodynamic therapy (CDT) function through Fenton-like reactions with overexpressed H₂O₂, resulting in the GSH depletion-enhanced ROS therapy. As a result of these characteristics, the MOF hybrid AIEgens can selectively kill tumors with excellent efficacy.

Synthesis of various dimensional metal organic frameworks (MOFs) and their hybrid composites for emerging applications - A review

Metal organic frameworks (MOFs) represent the organic and inorganic hybrid porous materials. MOFs are low dense and highly porous materials which in turn provide large surface area that can accumulate and store numerous molecules within the pores. The pore size may also act as a mesh to separate molecules. The porous nature of MOFs is beneficial for altering the intrinsic properties of the materials. Over the past decade, different types of hybrid MOFs have been reported in combination with polymers, carbon materials, metal nanoparticles, metal oxides, and biomolecules for various applications. MOFs have also been used in the fabrication of electronic devices, sensors, energy storage, gas separation, supercapacitors, drug delivery and environmental clean-up. In this review, the unique structural orientation, exceptional properties and recent applications of MOFs have been discussed in the first section along with their porosity, stability and other influencing factors. In addition, various methods and techniques involved in the synthesis and designing of MOFs such as solvothermal, electrochemical, mechanochemical, ultrasonication and microwave methods are highlighted. In order to understand the scientific feasibility of MOFs in developing new products, various strategies have been applied to obtain different dimensional MOFs (0D, 1D, 2D and 3D) and their composite materials are also been conferred. Finally, the future prospects of MOFs, remaining challenges, research gaps and possible solutions that need to be addressed by advanced experimental design, computational models, simulation techniques and theoretical concepts have been deliberated.

Structure and dynamics of a water/methanol mixture confined in zeolitic imidazolate framework ZIF-8 from atomistic simulations

A classical atomistic simulation study is reported for the microscopic structure and dynamics of a water/methanol mixture confined in flexible nanoporous zeolitic imidazolate framework ZIF-8. Both the radial density distribution and vivid two-dimensional density profile demonstrate that methanol molecules can roughly be viewed as "embedded" between two layers of water molecules to form a "sandwich" structure. The reason for the formation of such a specific structure is explained based on the hydrogen-bonding state and the strength of various hydrogen bonds. The investigation of guest molecular diffusion shows that the self-diffusion coefficient of confined water is generally one to two orders of magnitude smaller than that of bulk water. In addition, the dependence of the self-diffusion coefficient on loading is non-monotonic: the self-diffusion coefficient firstly shows a significant increase and then decreases at higher loading. Moreover, both the structure and dynamics of the hydrogen bond (HB) network of confined water molecules are investigated in a spatially resolved manner. The results indicate that both the HB structure and dynamics of water molecules near the ZIF-8 surface deviate significantly from those of bulk water. However, while water molecules located at the pore center are relatively similar to bulk water molecules with respect to the HB structure, they exhibit strong slowdown in HB dynamics when compared with bulk water. This simulation study elucidates in detail the structural and dynamical properties of a water/methanol mixture in nanoscopic ZIF-8 confinement, which is expected to provide a deep insight into the role of porous fillers, such as ZIF-8, in improving the performance of the dehydration of alcohols via pervaporation and other related processes.

Fe-based MOFs@Pd@COFs with spatial confinement effect and electron transfer synergy of highly dispersed Pd nanoparticles for Suzuki-Miyaura coupling reaction

Controlling the spatial confinement effect and highly dispersed Pd nanoparticles (NPs) can help to improve applicability in catalysis, energy conversion, and separation. However, the nonspatial confinement effect, agglomeration of Pd NPs of catalyst and harsh reaction conditions have become the urgent problems to be solved in Suzuki-Miyaura cross-coupling reaction. Herein, we report the first application of a new MOFs@COFs by using core with metal organic frameworks (MOFs) NH₂-MIL-101(Fe) and shell with covalent organic frameworks (COFs) for loading Pd NPs. The quickly formation of a transition state, the highly dispersed Pd NPs and the advancedly spatial confinement effect were achieved by coupling Fe base synergistic active components, electron-oriented anchoring with controlling pore scale, respectively. Most notably, as a proof-of-concept application, the high catalytic activity of NH₂-MIL-101(Fe)@Pd@COFs(3 + 3) in catalysis is elucidated for Suzuki-Miyaura coupling reaction by the broad scope of the reactants and the preeminent yields of the products, together with excellent stability and recoverability. With this strategy, the mechanism of Suzuki-Miyaura coupling reaction was verified by examining the catalytic activity. We hope that our approach can further facilitate the study of the design and use of functional MOFs@Pd@COFs materials.

MOF-enabled confinement and related effects for chemical catalyst presentation and utilization

A defining characteristic of nearly all catalytically functional MOFs is uniform, molecular-scale porosity. MOF pores, linkers and nodes that define them, help regulate reactant and product transport, catalyst siting, catalyst accessibility, catalyst stability, catalyst activity, co-catalyst proximity, composition of the chemical environment at and beyond the catalytic active site, chemical intermediate and transition-state conformations, thermodynamic affinity of molecular guests for MOF interior sites, framework charge and density of charge-compensating ions, pore hydrophobicity/hydrophilicity, pore and channel rigidity vs. flexibility, and other features and properties. Collectively and individually, these properties help define overall catalyst functional behaviour. This review focuses on how porous, catalyst-containing MOFs capitalize on molecular-scale confinement, containment, isolation, environment modulation, energy delivery, and mobility to accomplish desired chemical transformations with potentially superior selectivity or other efficacy, especially in comparison to catalysts in homogeneous solution environments.

Recent Advances in Metal-Organic Framework-Based Electrochemical Biosensing Applications

In the face of complex environments, considerable effort has been made to accomplish sensitive, accurate and highly-effective detection of target analytes. Given the versatility of metal clusters and ligands, high porosity and large specific surface area, metal–organic framework (MOF) provides researchers with prospective solutions for the construction of biosensing platforms. Combined with the benefits of electrochemistry method such as fast response, low cost and simple operation, the untapped applications of MOF for biosensors are worthy to be exploited. Therefore, this review briefly summarizes the preparation methods of electroactive MOF, including synthesize with electroactive ligands/metal ions, functionalization of MOF with biomolecules and modification for MOF composites. Moreover, recent biosensing applications are highlighted in terms of small biomolecules, biomacromolecules, and pathogenic cells. We conclude with a discussion of future challenges and prospects in the field. It aims to offer researchers inspiration to address the issues appropriately in further investigations.

Metal–organic frameworks incorporating azobenzene-based ligands as a heterogeneous Lewis-acid catalyst for cyanosilylation of imines

Two novel MOFs were synthesized by the reaction of azobenzene-based ligands with Zn(NO3)2/CdCO3 and could both function as heterogeneous Lewis-acid catalysts towards cyanosilylation of imines.

Room-Temperature Mixed-Potential Type ppb-Level NO Sensors Based on K2Fe4O7 Electrolyte and Ni/Fe-MOF Sensing Electrodes

Portable and sensitive mixed-potential type solid-state electrolyte (MPSE) gas sensors can detect exhaled biomarkers in a noninvasive and inexpensive way, which is significant for convenient disease diagnosis and saving medical resources. However, high working temperature is still one of the main bottlenecks for hindering MPSE gas sensors' applications in disease diagnosis. Here, we, for the first time, developed and fabricated new room-temperature MPSE gas sensors utilizing K₂Fe₄O₇ electrolyte and Ni/Fe-MOF (Ni/Fe clusters are coordinated with 1,4-H₂BDC) sensing electrodes (SEs) for the detection of ppb-level NO. Among different MOF SEs, the sensor attached with the Ni-MOF SE presents the highest NO sensitivities. This is attributed to a reducing oxygen reduction reaction activity and enhancing NO electrochemical catalytic reaction activity, verified by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests. In addition, the presented sensor also shows a low detection limit (20 ppb), fast response/recovery characteristic (17 s/6 s to 50 ppb NO), excellent selectivity, acceptable repeatability, and long-term stability of 34 days to NO at 25 °C and 60%RH. Simultaneously, the mechanism of humidity effect on the sensing performance was investigated by EIS and CV tests. Our work provides new insight into the development of room-temperature solid-state electrolyte gas sensors based on the mixed-potential mechanism and enlarges the potential application domain.

Feeding Carbonylation with CO2 via the Synergy of Single-Site/Nanocluster Catalysts in a Photosensitizing MOF

Solar-driven carbonylation with CO₂ replacing toxic CO as a C1 source is of considerable interest; however it remains a great challenge due to the inert CO₂ molecule. Herein, we integrate cobalt single-site and ultrafine CuPd nanocluster catalysts into a porphyrin-based metal-organic framework to construct composite photocatalysts (Cu₁Pd₂)_z@PCN-222(Co) (z = 1.3, 2.0, and 3.0 nm). Upon visible light irradiation, excited porphyrin can concurrently transfer electrons to Co single sites and CuPd nanoclusters, providing the possibility for coupling CO₂ photoreduction and Suzuki/Sonogashira reactions. This multicomponent synergy in (Cu₁Pd₂)_1.3@PCN-222(Co) can not only replace dangerous CO gas but also dramatically promote the photosynthesis of benzophenone in CO₂ with over 90% yield and 97% selectivity under mild condition. Systematic investigations clearly decipher the function and collaboration among different components in these composite catalysts, highlighting a new insight into developing a sustainable protocol for carbonylation reactions by employing greenhouse gas CO₂ as a C1 source.

Green construction of eco-friendly phosphotungstic acid Sr-MOF catalysts for crystal violet removal and synthesis of coumarin and xanthene compounds

There is an urgent need to improve engineering and synthetic chemistry, either through the use of eco-friendly starting materials or the proper design of novel synthesis routes. This reduces the contamination of toxic chemicals and helps the disposal of organic dyes. In the current work, a metal–organic framework-based Sr(ii) was fabricated to achieve the desired goal for dye removal and catalysis. Sr-MOF-based phosphotungstic acid (PWA/Sr-MOF) was hydrothermally synthesized to study its adsorption and catalytic activities. Remarkably, about 99.9% of crystal violet (CV) dye was removed using PWA/Sr-MOF within 90 min at room temperature. Various factors have been studied to investigate the optimum conditions such as pH of solution, initial dye concentration, contact time, and temperature. The maximum adsorption capacity of CV dye was reached after 90 min and well fitted the pseudo-second kinetic order and Langmuir adsorption isotherm. Coumarin and xanthene reactions were chosen to test the catalytic activity of the prepared PWA/Sr-MOF at 373 K. Furthermore, structural and chemical characterization of the fabricated samples was obtained using FT-IR, XRD, TGA, DTA, TEM, EDX, and XPS. PWA/Sr-MOF can be considered as a promising and green framework in the material design used to study catalytic and adsorption performances.

There is an urgent need to improve engineering and synthetic chemistry, either through the use of eco-friendly starting materials or the proper design of novel synthesis routes.

Catalysis in Single Crystalline Materials: From Discrete Molecules to Metal-Organic Frameworks

Catalysis is one of the key techniques for people's modern life. It has created numerous essential chemicals such as biomedicines, agricultural chemicals and unique materials. Heterogeneous catalysis is the new emerging method with reusable catalysts. Among heterogenous catalysis patterns developed so far, single crystalline catalysis has become the promising one owing to its high catalytic density and selectivity resulted by the inherent porosity, orderliness of the lattices and permeability. These crystalline catalysts could be used in various reactions such as photo-dimerization, Diels-Alder reaction, CO₂ transformation and so on. In this review, we highlighted the reported works about the single crystalline catalysts. Both discrete small molecules and metal-organic frameworks (MOFs) have been used to prepare single crystals for catalysis. For discrete molecules based crystalline catalysts, coordinated and covalent molecules have been used. There were more catalytic modes in crystalline MOF catalysts. Three patterns were identified in this review: single crystalline MOFs i) without catalytic sites, ii) with inherent catalytic features and iii) with introducing catalytic units by post synthetic modification. Based on these examples, this review committed to provide the inspirations for the further design and application of single crystalline materials.

Structural Regulation and Light Hydrocarbon Adsorption/Separation of Three Zirconium-Organic Frameworks Based on Different V-Shaped Ligands

On the basis of different V-shaped ligands, three zirconium-organic frameworks (JLU-Liu45, Zr-SDBA, and Zr-OBBA) have been successfully constructed. By regulating spatial configuration and functional groups of organic ligands, these as-synthesized Zr-MOFs (MOF = metal-organic framework) display distinct structures and different light hydrocarbon adsorption/separation capabilities. JLU-Liu45, with a double-walled interpenetrated 3D primitive cubic (pcu) framework, exhibits good gas-adsorption capacity but not prominent selective separation ability. Through regulating sizes and torsion angles of the organic ligands, Zr-SDBA possesses a 2D square lattice (sql) network, while Zr-OBBA displays a non-interpenetrated 3D pcu framework. Furthermore, by regulating functional groups on the ligands, Zr-SDBA shows prominent C₂H₂ uptake (101.2 cm³·g^-1) and the best C₂H₂/CH₄ selectivity (230.5, 1:1) among the three Zr-MOFs, and Zr-OBBA shows a significant C₃H₈/CH₄ selectivity (105.6, 1:1). This work demonstrates the feasibility of structural regulation for MOF materials in the light hydrocarbon adsorption/separation field.