Substituent Engineering in Pore-Space-Partitioned Metal-Organic Frameworks for CO2 Selective Adsorption and Fixation.

Comprehensive understanding of substituent groups located on the pore surface of metal-organic frameworks (which we call substituent engineering herein) can help to promote gas adsorption and catalytic performance through ligand functionalization. In this work, pore-space-partitioned metal-organic frameworks (PSP MOFs) were selected as a platform to evaluate the effect of organic functional groups on CO2 adsorption, separation, and catalytic conversion. Twelve partitioned acs metal-organic frameworks (pacs-MOFs, named SNNU-25-Rn here) containing different functional groups were synthesized, which can be classified into electron-donor groups (-OH, -NH2, -CH3, and -OCH3) and electron-acceptor groups (-NO2, -F, -Cl, and -Br). The experimental results showed that SNNU-25-Rn with electron donors usually perform better than those with electron acceptors for the comprehensive utilization of CO2. The CO2 uptake of the 12 SNNU-25-Rn MOFs ranged from 30.9 to 183.6 cm3 g-1 at 273 K and 1 bar, depending on the organic functional groups. In particular, SNNU-25-OH showed the highest CO2 adsorption, SNNU-25-CH3 had the highest IAST of CO2/CH4 (36.1), and SNNU-25-(OH)2 showed the best catalytic activity for the CO2 cycloaddition reaction. The -OH functionalized MOFs with excellent performance may be attributed to the Lewis acid-base and hydrogen-bonding interactions between -OH groups and the CO2 molecules. This work modulated the effect of the microenvironment of MOFs on CO2 adsorption, separation, and catalysis in terms of substituents, providing valuable information for the precise design of porous MOFs with a comprehensive utilization of CO2.

Development of a Mixed Multinuclear Cluster Strategy in Metal-Organic Frameworks for Methane Purification and Storage.

Metal-organic frameworks (MOFs) have attracted extensive attention in methane (CH4) purification and storage. Specially, multinuclear cluster-based MOFs usually have prominent performance because of large cluster size and abundant open metal sites. However, compared to diverse combinations of organic linkers, one MOF with two or more multinuclear clusters is difficult to achieve. In this paper, we demonstrate a mixed multinuclear cluster strategy, which successfully led to three new heterometallic MOFs (SNNU-328-330) with the same common H3TATB [2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine] tritopic linker and six types of multinuclear clusters ([YCd(COO)4(µ2-H2O)], [YCd2(COO)8], [In3(COO)6(µ3-OH)], [In3Eu2(COO)9(µ3-OH)3(µ4-O)], [Y9(COO)12(µ3-OH)14] and [Y2Cd8(COO)16(µ2-H2O)4(µ3-OH)8]). Three MOF adsorbents all show great potentials to remove the impurities (CO2 and C2-hydrocarbons) in natural gas and show prominent high-pressure methane storage capacity. Among them, the ideal adsorbed solution theory separation ratios of equimolar C2H2/CH4, C2H4/CH4, C2H6/CH4, and CO2/CH4 at 298 K for SNNU-328 reach to 29.7-16.0, 19.1-8.2, 33.2-10.3, and 74.3-8.5, which have surpassed many famous MOF adsorbents. Dynamic breakthrough experiments conducted at 273 and 298 K showed that SNNU-330 can separate CH4 from C2H2/CH4, C2H4/CH4, C2H6/CH4, and CO2/CH4 mixtures with the breakthrough interval times of about 48.2, 17.9, 37.2, and 17.1 min g-1 (273 K, 1 bar, v/v = 50/50, 2 mL min-1), respectively. Remarkably, SNNU-329 exhibits extremely high methane storage performance at 298 K with the total uptake and working capacity of 192 cm3 cm-3 (95 bar) and 171 cm3 cm-3 (65 bar) due to the synergistic effects of high surface area, suitable pore sizes, and multiple open metal sites.

AaSEPALLATA1 integrates jasmonate and light-regulated glandular secretory trichome initiation in Artemisia annua.

Glandular secretory trichomes (GSTs) can secrete and store a variety of specific metabolites. By increasing GST density, valuable metabolites can be enhanced in terms of productivity. However, the comprehensive and detailed regulatory network of GST initiation still needs further investigation. By screening a complementary DNA library derived from young leaves of Artemisia annua, we identified a MADS-box transcription factor, AaSEPALLATA1 (AaSEP1), that positively regulates GST initiation. Overexpression of AaSEP1 in A. annua substantially increased GST density and artemisinin content. The HOMEODOMAIN PROTEIN 1 (AaHD1)-AaMYB16 regulatory network regulates GST initiation via the jasmonate (JA) signaling pathway. In this study, AaSEP1 enhanced the function of AaHD1 activation on downstream GST initiation gene GLANDULAR TRICHOME-SPECIFIC WRKY 2 (AaGSW2) through interaction with AaMYB16. Moreover, AaSEP1 interacted with the JA ZIM-domain 8 (AaJAZ8) and served as an important factor in JA-mediated GST initiation. We also found that AaSEP1 interacted with CONSTITUTIVE PHOTOMORPHOGENIC 1 (AaCOP1), a major repressor of light signaling. In this study, we identified a MADS-box transcription factor that is induced by JA and light signaling and that promotes the initiation of GST in A. annua.

The use of vestibular evoked myogenic potentials (VEMP) in the diagnosis of otolithic dysfunction of patients with obstructive sleep apnea: a survey of awareness and recognition of otorhinolaryngology medical staffs.

PURPOSE: To assess awareness and recognition of vestibular function tests in otorhinolaryngology medical staffs, especially the vestibular evoked myogenic potentials (VEMP) testing in patients with obstructive sleep apnea (OSA). METHODS: A survey was delivered via either email or a social media app. The medical staffs of the Chinese Medical Association of Otolaryngology Head and Neck Surgery from various branches were enrolled. Study data were collected and managed with an online data collection tool. RESULTS: A total of 1781 emails and 623 social media messages were sent to 2404 otorhinolaryngology medical staffs. One hundred and fifty-seven of them participated in the survey, including 24 via emails and 133 via the social media app. Regarding the knowledge of VEMP, only 59 (37.6%) of them agreed that OSA could be related to vertigo/dizziness/imbalance and 28 (17.8%) believed that OSA could result in VEMP abnormalities and would factor this in diagnosing the impairment of the vestibular function of OSA patients. A total of 7.6% of the respondents had never heard of the VEMP tests. Responses regarding the minimum age at which VEMP are possible ranged from younger than 6 months to greater than 18 years of age. Beliefs regarding the utility and reliability of VEMP varied, with 'unsure' being the most frequent response. In addition, only 17.8% of otolaryngologists indicated some access to the VEMP test. CONCLUSIONS: Knowledge and beliefs about the role of VEMP in diagnosing otolithic organ dysfunction caused by OSA in otorhinolaryngology vary widely. It is important for otorhinolaryngology medical staffs to learn the latest literatures and updated knowledge through continuing education.

MADS-box gene AaSEP4 promotes artemisinin biosynthesis in Artemisia annua.

The plant Artemisia annua is well known for its production of artemisinin, a sesquiterpene lactone that is an effective antimalarial compound. Although remarkable progress has been made toward understanding artemisinin biosynthesis, the effect of MADS-box family transcription factors on artemisinin biosynthesis is still poorly understood. In this study, we identified a MADS transcription factor, AaSEP4, that was predominantly expressed in trichome. AaSEP4 acts as a nuclear-localized transcriptional activator activating the expression of AaGSW1 (GLANDULAR TRICHOME-SPECIFIC WRKY1). Dual-luciferase and Yeast one-hybrid assays revealed that AaSEP4 directly bound to the CArG motif in the promoter region of AaGSW1. Overexpression of AaSEP4 in A. annua significantly induced the expression of AaGSW1 and four artemisinin biosynthesis genes, including amorpha-4,11-diene synthase (ADS), cytochrome P450 monooxygenase (CYP71AV1), double-bond reductase 2 (DBR2) and aldehyde dehydrogenase 1 (ALDH1). Furthermore, the results of high-performance liquid chromatography (HPLC) showed that the artemisinin content was significantly increased in the AaSEP4-overexpressed plants. In addition, RT-qPCR results showed that AaSEP4 was induced by methyl jasmonic acid (MeJA) treatment. Taken together, these results explicitly demonstrate that AaSEP4 is a positive regulator of artemisinin biosynthesis, which can be used in the development of high-artemisinin yielding A. annua varieties.

Precise Introduction of Single Vanadium Site into Indium-Organic Framework for CO2 Capture and Photocatalytic Fixation.

The capture and fixation of CO2 under mild conditions is a cost-effective route to reduce greenhouse gases, but it is challenging because of the low conversion and selectivity issues. Metal-organic frameworks (MOFs) are promising in the fields of adsorption and catalysis because of their structural tunability and variability. However, the precise structural design of MOFs is always pursued and elusive. In this work, a metal-mixed MOF (SNNU-97-InV) was designed by precisely introducing single vanadium site into the isostructural In-MOF (SNNU-97-In). The single V sites clearly change the interactions between the MOF framework and CO2 molecules, leading to a 71.3% improvement in the CO2 adsorption capacity. At the same time, the enhanced light absorption enables SNNU-97-InV to efficiently convert CO2 into cyclic carbonates (CCs) with epoxides under illumination. Controlled experiments showed that the promoted performance of SNNU-97-InV may be that the V═O site can more easily combine with CO2 and convert them into an intermediate state under illumination, and the possible mechanism was thus speculated.

Pore-Window Partitions in Metal-Organic Frameworks for Highly Efficient Reversed Ethylene/Ethane Separations.

The development of paraffin-selective adsorbents is desirable but extremely challenging because adsorbents usually prefer olefin over paraffin. Herein, a new pore-window-partition strategy is proposed for the rational design of highly efficient paraffin-preferred metal-organic framework (MOF) adsorbents. The power of this strategy is demonstrated by stepwise installations of linear bidentate N-donor linkers into a prototype MOF (SNNU-201) to produce a series of partitional MOF adsorbents (SNNU-202-204). With continuous pore-window partitions from SNNU-201 to SNNU-204, the isosteric heat of adsorption can be tuned from -34.4 to -19.4 kJ mol-1 for ethylene and from -25.5 to -20.7 kJ mol-1 for ethane. Accordingly, partitional MOFs exhibit much higher ethane adsorption capacities, especially for SNNU-204 (104.6 cm3 g-1), representing nearly 4 times as much ethane as the prototypical counterpart (SNNU-201; 27.5 cm3 g-1) under ambient conditions. The C2H6/C2H4 ideal adsorbed solution theory selectivity, dynamic breakthrough experiments, and theoretical simulations further indicate that pore-window partition is a promising and universal strategy for the exploration of highly efficient paraffin-selective MOF adsorbents.

Near-Infrared Responsive Membrane Nanovesicles Amplify Homologous Targeting Delivery of Anti-PD Immunotherapy against Metastatic Tumors.

The major obstacles of anti-PD therapy in metastatic tumors are limited drug delivery in primary tumors and metastatic foci, and the lack of tumor-infiltrating lymphocytes (TILs). Here, the authors constructed a novel cellular membrane nanovesicles platform (M/IR NPs) based on homologous targeting and near-infrared (NIR) responsive release strategy to potentiate PD-1/PD-L1 blockade therapy against metastatic tumors. In tumor-bearing mice, biomimetic M/IR NPs targeted both primary tumors and their lung metastases. Upon laser irradiation, M/IR NPs reduced cancer-associated fibroblasts (CAFs) in tumor microenvironment, thus increasing the penetration of TILs. When shed from homologous tumor cell membranes, positively charged nanoparticles (IR NPs) core can capture released tumor-associated antigens, thereby enhancing the antigen-presenting ability of DCs to activate cytotoxic T lymphocytes. When the photothermal conversion temperature under NIR-laser is higher than 42 °C, M/IR NPs initiated the rupture of cell membranes and the responsive release of PD-1/PD-L1 inhibitor BMS, which significantly attenuated tumor-associated immunosuppression and synergistically induced T cellular immunity to inhibit the tumor growth and metastasis. Overall, biomimetic M/IR NPs can improve the targeting and therapeutic efficacy of anti-PD therapy in primary tumors and metastases, opening up a new avenue for the diagnosis and treatment of metastatic tumors in the future.

Thermal-sensitive lipid nanoparticles potentiate anti-PD therapy through enhancing drug penetration and T lymphocytes infiltration in metastatic tumor.

The response rate of anti-PD therapy in most cancer patients remains low. Therapeutic drug and tumor-infiltrating lymphocytes (TILs) are usually obstructed by the stromal region within tumor microenvironment (TME) rather than distributed around tumor cells, thus unable to induce the immune response of cytotoxic T cells. Here, we constructed the cationic thermosensitive lipid nanoparticles IR780/DPPC/BMS by introducing cationic NIR photosensitizer IR-780 iodide (IR780) modified lipid components, thermosensitive lipid DPPC and PD-1/PD-L1 inhibitor BMS202 (BMS). Upon laser irradiation, IR780/DPPC/BMS penetrated into deep tumor, and reduced cancer-associated fibroblasts (CAFs) around tumor cells to remodel the spatial distribution of TILs in TME. Interestingly, the cationic IR780/DPPC/BMS could capture released tumor-associated antigens (TAAs), thereby enhancing the antigen-presenting ability of DCs to activate cytotoxic T lymphocytes. Moreover, IR780/DPPC/BMS initiated gel-liquid crystal phase transition under laser irradiation, accelerating the disintegration of lipid bilayer structure and leading to the responsive release of BMS, which would reverse the tumor immunosuppression state by blocking PD-1/PD-L1 pathway for a long term. This combination treatment can synergistically exert the antitumor immune response and inhibit the tumor growth and metastasis.

Ultrahigh-Uptake Capacity-Enabled Gas Separation and Fruit Preservation by a New Single-Walled Nickel-Organic Framework.

High gas-uptake capacity is desirable for many reasons such as gas storage and sequestration. Moreover, ultrahigh capacity can enable a practical separation process by mitigating the selectivity factor that sometimes compromises separation efficiency. Herein, a single-walled nickel-organic framework with an exceptionally high gas capture capability is reported. For example, C2H4 and C2H6 uptake capacities are at record-setting levels of 224 and 289 cm3 g-1 at 273 K and 1 bar (169 and 110 cm3 g-1 at 298 K and 1 bar), respectively. Such ultrahigh capacities for both gases give rise to an excellent separation performance, as shown for C2H6/C2H4 with breakthrough times of 100, 60 and 30 min at 273, 283 and 298 K and under 1 atm. This new material is also shown to readily remove ethylene released from fruits, and once again, its ultrahigh capacity plays a key role in the extraordinary length of time achieved in the preservation of the fruit freshness.

A New Molecular Recognition Concept: Multiple Hydrogen Bonds and Their Optically Triggered Proton Transfer in Confined Metal-Organic Frameworks for Superior Sensing Element.

We report a new sensing mechanism based on an indium-dihydroxyterephthalic acid metal-organic framework (MOF, SNNU-153), in which the spatially fitted analyte-MOF hydrogen-bond (H-bond) formation provides selective recognition while the analyte-H-bond assisted excited-state intramolecular proton transfer (ESIPT) and the resulting ratiometric emission act as a superior signal transducer with ultrafast response. The synergy of ESIPT signal transduction and confined MOF pore enables the SNNU-153 sensor selectively sensing hydrazine even among nitrogen-containing hydride analogs such as NH3, NH2OH, and (Me)2NNH2. The key of H-bond and associated ESIPT was further counter evidenced by an indium-2,5-dimethoxyterephthalic acid MOF (SNNU-152), where the hydroxyl protons were removed by methylation, showing near inertness to N2H4. The new molecular recognition concept thus makes SNNU-153 a powerful N2H4 sensor, which should be far-reaching to other sensing elements.

Tuning the Pore Surface of an Ultramicroporous Framework for Enhanced Methane and Acetylene Purification Performance.

Both methane (CH4) and acetylene (C2H2) are important energy source and raw chemicals in many industrial processes. The development of an energy-efficient and environmentally friendly separation and purification strategy for CH4 and C2H2 is necessary. Ultramicroporous metal-organic framework (MOF) materials have shown great success in the separation and purification of small-molecule gases. Herein, the synergy effect of tritopic polytetrazolate and ditopic terephthalate ligands successfully generates a series of isoreticular ultramicroporous cadmium tetrazolate-carboxylate MOF materials (SNNU-13-16) with excellent CH4 and C2H2 purification performance. Except for the uncoordinated tetrazolate N atoms serving as Lewis base sites, the pore size and pore surface of MOFs are systematically engineered by regulating dicarboxylic acid ligands varying from OH-BDC (SNNU-13) to Br-BDC (SNNU-14) to NH2-BDC (SNNU-15) to 1,4-NDC (SNNU-16). Benefiting from the ultramicroporous character (3.8-5.9 Å), rich Lewis base N sites, and tunable pore environments, all of these ultramicroporous MOFs exhibit a prominent separation capacity for carbon dioxide (CO2) or C2 hydrocarbons from CH4 and C2H2. Remarkably, SNNU-16 built by 1,4-NDC shows the highest ideal adsorbed solution theory CO2/CH4, ethylene (C2H4)/CH4, and C2H2/CH4 separation selectivity values, which are higher than those of most famous MOFs with or without open metal sites. Dynamic breakthrough experiments show that SNNU-16 can also efficiently separate the C2H2/CO2 mixtures with a gas flow rate of 4 mL min-1 under 1 bar and 298 K. The breakthrough time (18 min g-1) surpasses most best-gas-separation MOFs and nearly all other metal azolate-carboxylate MOF materials under the same conditions. The above prominently CH4 and C2H2 purification abilities of SNNU-13-16 materials were further confirmed by the Grand Canonical Monte Carlo (GCMC) simulations.

Multimetal Incorporation into 2D Conductive Metal-Organic Framework Nanowires Enabling Excellent Electrocatalytic Oxidation of Benzylamine to Benzonitrile.

As an important organic intermediate, benzonitrile (BN) is widely involved in organic synthetic chemistry and pharmaceutical and dyestuff industries. However, the exploration of a more efficient and controllable synthesis technique and the corresponding greener catalysts for the synthesis of BN still poses a great challenge. Herein, with multimetallic two-dimensional conductive metal-organic frameworks (2D cMOF) as anodic electrocatalysts, we develop a green, convenient, and highly efficient electrochemical synthesis strategy for BN. Thanks to the intrinsic 2D electrically conductive structure and the optimized the multimetallic coupling catalytic effect, the resulting multimetallic 2D cMOFs exhibit excellent benzylamine (BA) electrooxidation performance. Especially, the trimetallic 2D cMOF (NiCoFe-CAT) requires an ultralow potential of 1.29 V vs reversible hydrogen electrode (RHE) to achieve a 10 mA·cm-2 current density, which indicates the fastest reaction and the most favorable thermodynamic condition. A very high yield (0.058 mmol·mg-1·h-1) and faradic efficiency (∼87%) of benzonitrile are both achieved during the BA electrooxidation reaction at 1.45 V. The reaction mechanism investigations indicated that the various redox mediators of MII/MIII (Ni, Co, Fe) may be regarded as multimetal active species to promote BA conversion. Also, the excellent cycling durability of multimetallic 2D cMOFs further promotes their potential practical applications. These electrocatalytic performances are considered excellent and nearly surpass all other reported Ni-based inorganics or MOF-based electrocatalysts for the electrocatalytic oxidation of benzylamine.

Systematic Regulation of C2H2/CO2 Separation by 3p-Block Open Metal Sites in a Robust Metal-Organic Framework Platform.

The separation of a mixture of C2H2 and CO2 is a great challenge due to their similar molecular sizes and shapes. Al-based metal-organic frameworks (Al-MOFs) have great promise for gas separation applications due to their light weight, high stability, and low cost. However, the cultivation of suitable Al-MOF single crystals is extremely difficult and has limited their explorations up to now. Since In, Ga, and Al are all 3p-block metal elements, a systematic application of the periodic law to investigate 3p-MOFs will undoubtedly help in the understanding and development of worthy Al-MOF materials. Herein, we report the design of a robust 3p metal-organic framework platform (SNNU-150) and the systematic regulation of C2H2/CO2 separation by open 3p-block metal sites. X-ray single-crystal diffraction analysis reveals that SNNU-150 is a 3,6-connected 3D framework consisting of [M3O(COO)6] trinuclear secondary building units (SBUs) and tritopic nitrilotribenzoate (NTB) linkers. Small {[M3O(COO)6]4(NTB)6} tetrahedral cages and extra-large {[M3O(COO)6]10(NTB)14} polyhedral cages connect with each other to generate a hierarchically porous architecture. These 3p-MOFs present very high water, thermal, and chemical stability, especially for SNNU-150-Al, which can maintain its framework at 85 °C in water for 24 h and in a room-temperature environment for more than 30 days. IAST calculations, breakthrough experiments, and GCMC simulations all show that SNNU-150 MOFs have top-level C2H2/CO2 separation performance and follow the order Al-MOF > Ga-MOF > In-MOF.

Mimic of Ferroalloy To Develop a Bifunctional Fe-Organic Framework Platform for Enhanced Gas Sorption and Efficient Oxygen Evolution Electrocatalysis.

It is well-known that the formation of ferroalloy with the addition of the second or third metal during the steel-making process usually can improve the performance of the iron. Inspired by ferroalloy materials, it is speculated that the pore environment, framework charge, and catalytic properties of metal-organic frameworks (MOFs) could be optimized dramatically via the introduction of ferroalloy-like inorganic building blocks. However, different to ferroalloy, the accurate integration of different metals into one MOF platform is still challenging. Herein, taking advantages of the good compatibility for metals in trigonal prismatic trinuclear cluster, a series of Fe-based alloy-like [M3O(O2C)6] motifs (M3 = Fe3, Fe1.5Ni1.5, Fe1.5Co1.5, Fe1.5Ti1.5, FeCoNi, and FeTiCo) are successfully generated, which further lead to a robust Fe-MOF material family (SNNU-5s). These multicomponent MOFs not only provide a good chance to explore the impact of pore environment on gas adsorption/separation but also offer an opportunity to the efficient electrocatalytic reaction directly. Accordingly, compared with the SNNU-5-Fe parent structure, the pore characters of heterometallic SNNU-5 MOFs are clearly regulated by the type of alloy-like building blocks. SNNU-5-FeTi displays more superior gas separation performance for CO2/CH4, C2H2/CH4, C2H4/CH4, and C2H2/CO2 gas mixtures. What is more, benefited from the multimetallic active sites and their catalytic synergy, FeCoNi-ternary alloy-like cluster-based SNNU-5 MOF material exhibits an exceptional oxygen evolution reaction activity in aqueous solution at pH = 13, which delivers a low overpotential (ηj=10 = 317 mV), a fast reaction kinetics (Tafel slope = 37 mV dec-1), and excellent catalytic stability. This facile multialloy-like building block strategy holds promise to accurately design and improve the performance of MOFs, as well as open an avenue to understand the related mechanisms.

Ultramicroporous Building Units as a Path to Bi-microporous Metal-Organic Frameworks with High Acetylene Storage and Separation Performance.

A strategy called ultramicroporous building unit (UBU) is introduced. It allows the creation of hierarchical bi-porous features that work in tandem to enhance gas uptake capacity and separation. Smaller pores from UBUs promote selectivity, while larger inter-UBU packing pores increase uptake capacity. The effectiveness of this UBU strategy is shown with a cobalt MOF (denoted SNNU-45) in which octahedral cages with 4.5 Špore size serve as UBUs. The C2 H2 uptake capacity at 1 atm reaches 193.0 cm3 g-1 (8.6 mmol g-1 ) at 273 K and 134.0 cm3 g-1 (6.0 mmol g-1 ) at 298 K. Such high uptake capacity is accompanied by a high C2 H2 /CO2 selectivity of up to 8.5 at 298 K. Dynamic breakthrough studies at room temperature and 1 atm show a C2 H2 /CO2 breakthrough time up to 79 min g-1 , among top-performing MOFs. Grand canonical Monte Carlo simulations agree that ultrahigh C2 H2 /CO2 selectivity is mainly from UBU ultramicropores, while packing pores promote C2 H2 uptake capacity.

Highly Selective and Sensitive Turn-Off-On Fluorescent Probes for Sensing Al3+ Ions Designed by Regulating the Excited-State Intramolecular Proton Transfer Process in Metal-Organic Frameworks.

The concept of high-performance excited-state intramolecular proton transfer (ESIPT)-based fluorescent metal-organic framework (MOF) probes for Al3+ is proposed in this work. By regulating the hydroxyl groups on the organic linker step by step, new fluorescent magnesium-organic framework (Mg-MOF) probes for Al3+ ions were established based on the ESIPT fluorescence mechanism. It is observed for the first time that the number of intramolecular hydrogen bonds between adjacent hydroxyl and carboxyl groups can effectively adjust the ESIPT process and lead to tunable fluorescence sensing performance. Together with the well-designed porous and anionic framework, the Mg-TPP-DHBDC probe decorating with a pair of intramolecular hydrogen bonds exhibits extra-high quantitative fluorescence response to Al3+ through an unusual turn-off (0-1.2 µM) and turn-on (4.2-15 µM) luminescence sensing mechanism. Notably, the 28 nM limit of detection value represents the lowest record among all reported MOF-based Al3+ fluorescent sensors up to now. Benefited from the unique turn-off-on ESIPT fluorescence detection process, the Mg-TPP-DHBDC MOF sensor exhibits single Al3+ detection compared with other 16 common metal ions including Ga3+, In3+, Fe3+, Cr3+, Ca2+, and Mg2+. Impressively, such an Al3+ selective sensing process can even be fulfilled by the reusable MOF test paper detected by naked eyes. Overall, the quantitative Al3+ detection, together with the extraordinary sensitivity, selectivity, fast response, and good reusability, strongly supports our concept of ESIPT-based fluorescent MOF Al3+ probes and makes Mg-TPP-DHBDC one of the most powerful Al3+ fluorescent sensors.

Enhanced electrochemical performance of Li-Co-BTC ternary metal-organic frameworks as cathode materials for lithium-ion batteries.

Metal-organic frameworks (MOFs) with diverse structures have been projected as futuristic electrode materials for lithium-ion batteries (LIBs). In this work, two ternary Li-Co-MOFs of three-dimensional (3D) porous structures were synthesized, inspired by LiCoO2 inorganic metal salts, through a simple solvothermal method and further applied as active cathode materials for the first time in lithium-ion batteries. In these MOF structures, the lithium atoms are located at the same (SNNU-73) or different (SNNU-76) sites as cobalt atoms, and the four-coordinated tetrahedron mode is used to coordinate with the oxygen atoms. The 3D porous frameworks provide a good channel for the embedding and de-embedding of lithium ions. The experimental results suggest that porous Li-Co-MOF ternary composites show excellent cycling stability. Particularly, the discharge capacity and average coulombic efficiency of SNNU-73 reach 155.6 mA h g-1 and nearly 100% for 50 cycles at a rate of 50 mA g-1. This synergistic effect of mixed Li and Co sites demonstrates great potential of MOFs as advanced electrode materials, and provides a promising route to designing porous materials for lithium-ion batteries in the future.

A semiconductor and fluorescence dual-mode room-temperature ammonia sensor achieved by decorating hydroquinone into a metal-organic framework.

Presented herein is a magnesium-organic framework (SNNU-88) incorporated with active hydroquinone groups, which exhibits not only remarkable semiconductor sensing for traces of ammonia vapor (5-100 ppm), but also extra-high fluorescence response to liquid NH3·H2O through an unusual turn-off (0-1.5 ppm) and turn-on (3.0-100 ppm) luminescence sensing mechanism at room temperature. Such bifunctional quantitative ammonia detection together with the extraordinary sensitivity and selectivity, fast response, and good reusability makes SNNU-88 one of the most powerful ammonia sensors.