Ultrafast Luminescent Light-Up Guest Detection Based on the Lock of the Host Molecular Vibration

Two heterometallic MOFs fluorescence probes: Their syntheses, structures, and sensing properties

Based on a 2-(2,6-bis(pyrazine-2-yl)pyridine-4-yl) benzene-1,3,5-tricarboxylic acid ligand (H3pbta), two isomorphic d-f heterometallic organic frameworks with porous three-dimensional structures were successfully synthesized, namely, {[LnCd2(pbta)2Cl(H2O)4](H2O)4}n(1, Ln = Eu; 2, Ln = Tb). The experimental results indicated that complex 1 and 2 exhibited stable luminescence in a wide range of in aqueous solution. Notably, complex 1 could recognize palmatine (PMT) in simulated human urine and complex 2 was able to distinguish tartrazine (TAR) in some food additives. It was worth pointing out that complex 1 and 2 displayed high selectivity, recoverability, anti-interference, and low detection limits for the identification of PMT and TAR in aqueous solution, respectively. In addition, the fluorescence mechanisms for the detection of PMT and TAR were elucidated in detail by the corresponding experiments and theoretical calculations. Also, the fluorescent sensing films based upon complex 1 and 2 were fabricated to visually discern PMT and TAR for their practical applications, respectively.

Metal-organic frameworks (MOFs): A review of volatile organic compounds (VOCs) detection

This research presents a systematic review of the application of metal-organic frameworks (MOFs) to detect volatile organic compounds (VOCs). VOCs, compounds with high vapor pressure at ambient temperature and normal pressure, are widely present in a variety of industrial and living environments. VOCs are not only hazardous to the environment but also have a severe impact on human health. Therefore, an excellent research interest is developing efficient and sensitive detection technologies for VOCs. In this article, we first introduce the definition and classification of VOCs and their sources and discuss the environmental and health hazards of VOCs. Then, the discussion focuses on various sensors based on MOFs, including electrochemical sensors, fluorescence sensors, colorimetric sensors, and surface-enhanced Raman spectroscopy (SERS) sensors. In electrochemical detection, MOFs, as sensing materials, exhibit good detection performance due to their ultra-large surface area and highly adjustable pore size structure. In fluorescence detection, MOFs achieve high sensitivity and selective detection of VOCs under their unique optical properties. Colorimetric sensors, on the other hand, achieve the detection of VOCs through color change, which has the advantages of low cost and easy operation. In contrast, SERS sensors utilize the high surface area of MOFs and specific Raman enhancement effect to achieve ultra-high sensitivity detection of VOCs, which is especially suitable for trace analysis. Immediately after that, we describe the research progress of various sensors for VOCs detection and analyze their detection mechanisms and application prospects. Finally, the MOFs-based VOCs detection technology is summarized, and the current challenges and future development directions are pointed out.

Mn(II) Coordination Complex Loaded Hydrogel: Synthesis, Characterization, Fluorescence Properties, and Application in Treating Knee Arthritis

Using a mixed-ligand approach, we successfully obtained two Mn(II)-based coordination compounds, namely [Mn2(L1)(TBIP)·H2O]n (1) and [Mn2(L2)(NPTA)·H2O]n (2) (where L1 and L2 are 1,4-bis(thiabenzimidazol-1-ylmethyl)benzene and 1,2-bis(thiabenzimidazol-1-ylmethyl)benzene, H2NPTA is 2-nitroterephthalic acid, and H2TBIP is 5-tert-butylisophthalic acid). Fluorescence performance testing of complexes 1 and 2 showed excellent green and blue fluorescence properties. Based on this, we further prepared HA/CMCS hydrogels using natural polysaccharides hyaluronic acid (HA) and carboxymethyl chitosan (CMCS) as raw materials and studied their internal structural characteristics using scanning electron microscopy. Using "Duhuo Jisheng Decoction" as a drug model, two metal gel scaffolds loaded with "Duhuo Jisheng Decoction" were prepared, and their potential for treating knee osteoarthritis was evaluated.

Synergistic Aggregation-Induced Emissive Linkers in Metal-Organic Frameworks for Ultrasensitive and Quantitative Visual Sensing

Luminescent metal-organic frameworks (MOFs) represent an emerging class of materials for visual analyte detection. In this study, we present a strategy that integrates two synergistic aggregation-induced emissive (AIE) linkers into a MOF, significantly enhancing sensing sensitivity, selectivity, and quantification capabilities for practical applications. The dual AIE linkers simultaneously optimize porosity and amplify emission intensity. The tailored pore structure precisely matches the molecular dimensions of the pesticide 2,6-dichloro-4-nitroaniline (DCN), while Förster resonance energy transfer between the linkers achieves an exceptional fluorescence quantum yield of 92.6%. This design enables ultrasensitive DCN detection in water, with an unprecedented detection limit at the ppb level, along with superior selectivity, rapid response time, high quantification accuracy, recyclability, and strong resistance to interference. A comprehensive investigation using UV-vis, fluorescence, transient absorption, X-ray photoelectron, and Raman spectroscopies, supported by theoretical calculations, attributes the efficient fluorescence quenching to photoinduced energy transfer. Additionally, we demonstrate instant, naked-eye detection of DCN residues on fruit surfaces and contaminated soil by applying MOF solutions and illuminating under UV light. Quantitative analysis of DCN residues on fruits was further achieved using computer vision and a custom script, providing a practical, on-site method for rapid and precise detection of pesticide residues.

CO2-enhanced TADF of an ultra-stable Cu(i) cluster via guest-host π-π interaction

Efficient and reversible luminescence detection for CO2 without solvent assistance is of great significance but remains challenging to achieve, due to the lack of efficient interaction between CO2 molecules and the host emitting center. Benefiting from the abundant host-guest interactions, metal clusters provide a platform for detecting small molecules. However, the insufficient chemical stability of most metal clusters limits their practical applications. Here, we report a hydrophobic Cu(i) cluster (denoted as CuIDPO) with one-dimensional channels. Notably, it displays exceptional chemical stability in both acidic and alkaline aqueous solutions (pH = 1-14). More importantly, CuIDPO shows remarkable CO2-induced luminescence enhancement (up to 385% under 1 bar CO2), which can be applied to analyze CO2 content (LOD = 7.7 mbar). Crystallographic analysis and theoretical calculations suggest the mechanism of CO2-locking rotation of the phenyl groups in the Cu(i) cluster through guest-host π-π interaction, which is quite unique when compared to the known acid-base neutralization and framework flexibility adjustment mechanisms. Such luminescence CO2 sensing shows advantages like ultrafast response and good reversibility. Additionally, CuIDPO-loaded membranes were fabricated for spatially resolved 2D visual detection.

Efficient and Visual Detention of Ammonia and TNP Vapors by a Sustainable Highly Luminescent 1D Zn(II) Coordination Polymer

To realize the aim of easy and accurate detection of ammonia and picric acid (PA) in both aqueous and vapor phases based on function-oriented investigation principles, in the present study, we include a luminescent performance with recognition performance, taking into account the application conditions. Zn(II) ions with luminescence qualities and an amine-substituted imidazole moiety with selective recognition properties towards picric acid and ammonia are coupled to generate a novel 1D luminous Zn(II) coordination polymer, Zn-CP [{Zn(II)( 2-ABZ)2(2-BDC)}].MeOH]∞, where 2-ABZ and 2-BDC stand for terephthalic acid and protonated 2 aminobenzimidazole, respectively. Tests for luminescence recognition demonstrate that Zn-CP has potent selectivity, and strong sensitivity to ammonia and PA in both media. In both detection processes, the limit of detection (LOD) values are determined to be 40 nm. Spectroscopic and DFT studies reveal that the detection of Trinitrophenol (TNP) primarily involves a synergistic mechanism of Photoinduced Electron Transfer (PET), Fluorescence Resonance Energy Transfer (FRET), and Charge Transfer (CT). In contrast, the detection of ammonia (NH3) vapor is predominantly driven by hydrogen bonding (H-bonding) formation. The constructed 1D luminous Zn-CP is a new material that guides the development of novel luminous sensors in the future.

A new Cd(II) Complex: Fluorescence Performances, Loading with Budesonide-hydrogels on Pediatric Asthma and Molecular Docking

By applying the phosphonic acid ligand to the solvothermal reaction of nitrobenzylphosphonic acid (H2L) with Cd(NO3)2·4H2O in a mixed solvent of water and DMF, a novel Cd(II)-based coordination polymer, {[Cd(L)(H2O)2](H2O)}n (1), was successfully synthesized in this study. The excellent fluorescence performance of complex 1 was confirmed through fluorescence spectroscopy testing, and the obtained CIE standard coordinates (0.1599, 0.0786) positioned it in the blue fluorescence region. Transparent hyaluronic acid/carboxymethyl chitosan hydrogels were prepared using chemical synthesis, and their internal microstructure was observed. Using budesonide as a drug model, a new budesonide metal gel was prepared, and its therapeutic efficacy in treating pediatric asthma was evaluated. Molecular docking simulations indicated that the Cd complex formed three hydrogen bonding interactions with the target protein through its nitro group, revealing the potential origin of its biological activity.

Coordination Polymers of Vanadium and Selected Metal Ions with N,O-Donor Schiff Base Ligands-Synthesis, Crystal Structure, and Application

This review provides an overview of the synthesis, characterization and application of coordination polymers based on N,O-donor Schiff base ligands. The coordination polymers (CPs) represent a novel class of inorganic-organic hybrid materials with tunable compositions and fascinating structures. They are composed of metal ions and organic ligands. Therefore, the nature of the metal ion and type of organic ligand is the most significant factor in constructing targeted coordination polymers with the desired properties. Due to the versatile coordination modes, N,O-donor Schiff base ligands are also used to construct various CPs.

Combining Simple Deformations to Elicit Complex Motions and Directed Swimming of Smart Organic Crystals with Controllable Thickness

The lack of control over the crystal growth in a systematic way currently stands as an unsurmountable impediment to the preparation of dynamic crystals as soft robots; in effect, the mechanical effects of molecular crystals have become a subject of scattered reports that pertain only to specific crystal sizes and actuation conditions, often without the ability to establish or confirm systematic trends. One of the factors that prevents the verification of such performance is the unavailability of strategies for effectively controlling crystal size and aspect ratio, where crystals of serendipitous size are harvested from crystallization solution. Here we devised a water-assisted precipitation method to prepare crystals of chemical variants of 9-anthracene derivatives with various thicknesses that respond to ultraviolet light with simple mechanical effects, including bending, splintering, and rotation. By capitalizing on the robust mechanical flexibility and deformability of crystals, we demonstrate systematic variations in crystal deformation that are further elevated in complexity to construct crystal-based robots capable of controllable motions reminiscent of sailing and humanoid movements. The results illustrate an approach to eliminate one of the critical obstacles towards complete control over the motility of dynamic molecular crystals as microrobots in non-aerial environments.

Ultrafast Luminescence Detection with Selective Adsorption of Carbon Disulfide in a Gold(I) Metal-Organic Framework

Although a widely used and important industrial chemical, carbon disulfide (CS2) poses a number of hazards due to its volatility and toxicity. As such, the development of multifunctional materials for the selective capture and easy recognition of CS2 is one of the crucial issues. Herein, we demonstrate completely selective CS2 adsorption among trials involving H2O, alcohols, volatile organic compounds (including thiol derivatives), N2, H2, O2, CH4, CO, NO, and CO2. We also showcase its fine detection using remarkable luminescent response in a gold(I)-based metal-organic framework (MOF) of {ZnII(pz)[AuI(CN)2]2} (pz=pyrazine; 1) with a two-fold interpenetration network. Ex situ single crystal X-ray diffraction for 1 and CS2-accommodated 1 suggested that the Au ⋅⋅⋅ Au atoms are not only luminescent centers but also act as interaction sites for CS2 modulating the Au ⋅⋅⋅ Au contacts. These experiments revealed the specificity of CS2 and how changes in the CS2-induced structure. Based on the obtained structural transformation, 1 exhibited a sensitive detecting ability for CS2 with an ultrafast response time of less than 10 s. Moreover, ex situ time-resolved photoluminescence analyses developed in this work implied that CS2 varied the energetic relaxation at the excited states related to the luminescent efficiency of the resultant MOF system.

Two Transition Metal Coordination Polymers: Potential Adsorbents for Contaminant Removal and Photoluminescent Properties

Methylene blue (MB) contamination has become a significant environmental issue due to its widespread presence in industrial effluents, posing serious threats to ecosystems and human health. As a result, there is an urgent need for the development of novel adsorbent materials that can effectively remove these pollutants from water sources. In this context, the present study focuses on the design and synthesis of two coordination polymers (CPs) containing Zn(II) and Mn(II), namely, {[Mn3(L)2(tib)2]·4H2O}n (1) and [Zn(L)(3,5-bibp)]n (2), using a combined-ligand approach under solvothermal conditions. The ligands, H3L is 4-(3,5-dicarboxylatobenzyloxy)benzoic acid), 1,3,5-tris(1-imidazolyl)benzene and 3,5-bibp is 3,5-bis(imidazol-1-yl)biphenyl), were carefully selected to enhance the properties of the resulting polymers. These CPs were thoroughly characterized using a variety of techniques, including IR spectroscopy, elemental analysis (EA), single-crystal X-ray diffraction, thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD). Both CPs demonstrated ligand-dependent blue fluorescence emissions, suggesting their potential for use as photoluminescent materials in various applications. Furthermore, the adsorption capabilities of CP1 and CP2 for methylene blue (MB) were evaluated. The results revealed that both CPs exhibited excellent adsorption efficiencies, with CP1 achieving a 77.6% adsorption efficiency within 1 h and completely removing 20 mg/L of MB within 6 h. These findings highlight the significant potential of CP1 as a highly effective adsorbent for organic dyes, particularly for environmental remediation applications. The ability of these coordination polymers to adsorb MB efficiently underscores the urgent need for the development of innovative and efficient materials to address the growing challenges of water pollution.

Varied CO2 photoreduction activities of UiO-66-NH2 MOFs with different aggregation morphologies

Several kinds of UiO-66-NH2 with different aggregation morphologies were prepared to verify that the morphology of the photocatalyst could influence charge transfer. That showing poor aggregation exhibits superior CO2 photoreduction performance, attributed to the small particle size related to the poor aggregation and to the resulting high efficiency of separation of photogenerated electrons and holes.

Nanorings Resembling Beehives for Ultrasensitive Fluorescence Detection

In this study, we showcase the fabrication of two nanorings resembling beehives using intricately designed donor-acceptor (D-A) fluorophores. The D-A fluorophores, featuring three twisted fluorene groups on each side of the acceptor group, adopt a bent conformation that promotes the creation of a nanoring morphology upon aggregation. With porosity for maximum binding sites, high emission efficiency, and well-organized arrangements, the nanoring-based hives offer exceptional sensitivity and selectivity in the detection of organic sulfides. Particularly, nanorings formed from benzselenodiazole-containing molecules exhibit heightened sensitivity, achieving a limit of detection (LOD) of 0.2 ppb for dimethyl sulfide and 17 ppb for dimethyl disulfide. Due to its unparalleled sensitivity and selectivity, which was not achievable with previous optical sensors, this technology enables the continuous monitoring of meat spoilage in its early stages on an hourly basis. This provides crucial insights into the exact moments when freshness begins to deteriorate and how long the meat can be stored for.

Construction of a Long-Range Quantitative Fluorescence Sensor for Multiple Amine Vapors by π···π Aggregates of Carborane

The exploitation of small molecules as fluorescence sensors represents a minimalistic solution toward the sensing of hazardous volatile organic compounds (VOCs). Compared with the conventional aggregation-induced emitting sensors, the carborane (Cb)-based sensors have exhibited multiple advantages and improved quantitative fluorescence (QF) sensing abilities toward the gaseous VOCs. However, in the current Cb-based sensors, the localization of a single responsive site toward VOCs remains less focused, which results in a bias in the trace detection and short-range testing windows. In this work, we synthesized two pyrene-alkynylated carboranes (Py-1 and Py-2) and investigated their photophysical properties in different cases. We found that Py-1 and Py-2 in the films were consistently self-assembled through π···π aggregation of pyrenylethynyl moieties. Theoretical modeling showed that the highly emissive π···π aggregates were thermodynamically stable and their responsive sites toward VOCs were localized on the electron-poor phenyl or fluorenyl groups. As a result, the Py-1 and Py-2 films showed remarkable emission-off sensibilities toward NEt3 vapors via a major route of photoinduced electron transfer. The optimized QF sensor Py-2 showed linear emission-off response toward three types of static amine vapors in long concentration ranges (1.78-90 g/m3 at most), and the limit of detection could be lowered to 99 mg/m3 in the in situ sensing.

AIEE-active dichlorobenzene and chlorobenzene ratiometric fluorescent probe based on [2.2]paracyclophane

Two AIEE-active [2.2]paracyclophanyl-based diester and monoester (1a and 1b) were facilely synthesized by one-pot method and applied as ratiometric fluorescent probe to detect dichlorobenzene (DCB) and chlorobenzene (CB). Compared with compound 1b, 1a exhibits high sensitivity and low detection limits for DCB and CB in dichloromethane (DCM), particularly, the detection sensitivities for ortho-dichlorobenzene (o-DCB), meta-dichlorobenzene (m-DCB) and chlorobenzene can be modulated by AIEE behavior with lower detection limits of 23.64, 56.27, and 5.92 ppm, respectively in THF/H2O mixed solutions with water fraction (fw) of 70 % due to the formation of aggregation-state. The X-ray structure analysis, theoretical calculations and photophysical properties in different solvents were investigated to reveal the distinctive photophysical behaviors of 1a and 1b. The facile synthesis, X-ray structure, AIEE modulated sensing properties for o-DCB, m-DCB, and CB in DCM and THF/H2O mixed solutions make 1a potential application as fluorescent probe for trace DCB and CB detection in drinking water.

Metal-Organic Framework Based Sensors for Benzene Vapor

Sensing of benzene vapor is a hot spot due to the volatile drastic carcinogen even at trace concentration. However, achieving convenient and rapid detection is still a challenge. As a sort of functional porous material, metal-organic frameworks (MOFs) have been developed as detection sensors by adsorbing benzene vapor and converting it into other signals (fluorescence intensity/wavelength, chemiresistive, weight or color, etc.). Supramolecular interaction between benzene molecules and the host framework, aperture size/shape and structural flexibility are influential factors in the performance of MOF-based sensors. Therefore, enhancing the host-guest interactions between the host framework and benzene molecules, or regulating the diffusion rate of benzene molecules by changing the aperture size/shape and flexibility of the host framework to enhance the detection signal are effective strategies for constructing MOF-based sensors. This concept highlights several types of MOF-based sensors for the detection of benzene vapor.

A Photoelectromagnetic 3D Metal-Organic Framework from Flexible Tetraarylethylene-Backboned Ligand and Dynamic Copper-Based Coordination Chemistry

Porous frameworks that display dynamic responsiveness are of interest in the fields of smart materials, information technology, etc. In this work, a novel copper-based dynamic metal-organic framework [Cu3TTBPE6(H2O)2] (H4TTBPE = 1,1,2,2-tetrakis(4″-(1H-tetrazol-5-yl)-[1,1″-biphenyl]-4-yl)ethane), denoted as HNU-1, is reported which exhibits modulable photoelectromagnetic properties. Due to the synergetic effect of flexible tetraarylethylene-backboned ligands and diverse copper-tetrazole coordination chemistries, a complex 3D tunneling network is established in this MOF by the layer-by-layer staggered assembly of triplicate monolayers, showing a porosity of 59%. These features further make it possible to achieve dynamic transitions, in which the aggregate-state MOF can be transferred to different structural states by changing the chemical environment or upon heating while displaying sensitive responsiveness in terms of light absorption, photoluminescence, and magnetic properties.

A dinuclear CdII cluster-based stable luminescent metal-organic framework for the consecutive and visual detection of H2PO4- and OCN. Dalton Trans 2024;53:5160-5166. [PMID: 38380950 DOI: 10.1039/d3dt03523a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Due to their hazard to biological systems, it is urgent to develop materials that can rapidly and sensitively detect the concentration of H2PO4- and OCN- ions. In this work, a new CdII-based luminescent metal-organic framework with the formula [Cd(BTDB)(2,6-BBIP)]n (JXUST-47, H2BTDB = (benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoic acid, 2,6-BBIP = 2,6-bis(benzimidazol-1-yl)pyridine) and sql topology was successfully synthesized using a mixed-ligand strategy. JXUST-47 shows good chemical and thermal stability. It also exhibits weak quenching and fluorescence blue shift for H2PO4- and red shift for OCN-, with the detection limits of 0.106 and 0.128 mM, respectively. In addition, considering the demand for H2PO4- and OCN- ion detection, by combining this with the functions of a smartphone, the chroma of photographs have been used to realize the consecutive visual detection of the concentration of these ions.

Stimuli-fluorochromic smart organic materials

Smart materials based on stimuli-fluorochromic π-conjugated solids (SFCSs) have aroused significant interest due to their versatile and exciting properties, leading to advanced applications. In this review, we highlight the recent developments in SFCS-based smart materials, expanding beyond organometallic compounds and light-responsive organic luminescent materials, with a discussion on the design strategies, exciting properties and stimuli-fluorochromic mechanisms along with their potential applications in the exciting fields of encryption, sensors, data storage, display, green printing, etc. The review comprehensively covers single-component and multi-component SFCSs as well as their stimuli-fluorochromic behaviors under external stimuli. We also provide insights into current achievements, limitations, and major challenges as well as future opportunities, aiming to inspire further investigation in this field in the near future. We expect this review to inspire more innovative research on SFCSs and their advanced applications so as to promote further development of smart materials and devices.

Cu(II) Coordination Polymers Containing Mixed Ligands with Different Flexibilities: Structural Diversity and Iodine Adsorption

Reactions of N,N'-bis(3-methylpyridyl)oxalamide (L1), N,N'-bis(3-methylpyridyl)adipoamide (L2) and N,N'-bis(3-methylpyridyl)sebacoamide (L3) with tricarboxylic acids and Cu(II) salts afforded {[Cu(L1)(1,3,5-HBTC)]·H2O}n (1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid), 1, {[Cu1.5(L2)1.5(1,3,5-BTC)(H2O)2]·6.5H2O}n, 2, [Cu(L2)0.5(1,3,5-HBTB)]n (1,3,5-H3BTB = 1,3,5-tri(4-carboxyphenyl)benzene), 3, [Cu4(L3)(OH)2(1,3,5-BTC)2]n, 4, {[Cu3(L3)2(1,3,5-BTB)2]·2.5MeOH·2H2O}n, 5, and {[Cu3(L3)2(1,3,5-BTB)2 ]·DMF·2H2O}n, 6, which have been structurally characterized by using single crystal X-ray crystallography. Complexes 1-4 form a 2D layer with the {44.62}-sql topology, a 2D layer with the (4.62)2(42.62.82)-bex topology, a three-fold interpenetrated 3D net with the (412·63)-pcu topology and a 3D framework with the (410·632·83)(42·6)2(43·63) topology, respectively, whereas 5 and 6 are 3D frameworks with the (63)2(64·82)(68·85·102) topology. Complex 5 shows a better iodine adsorption factor of 290.0 mg g-1 at 60 °C for 360 min than the other ones, revealing that the flexibility of the spacer ligand governs the structural diversity and the adsorption capacity.

Fluorescence sensing and device fabrication with luminescent metal-organic frameworks

Metal-organic frameworks (MOFs) are a novel class of hybrid porous multi-functional materials consisting of metal ions/clusters and organic ligands. MOFs have exclusive benefits due to their tunable structure and diverse properties. Luminescent MOFs (LMOFs) exhibit both porosity and light emission. They display abundant host and guest responses, making them conducive to sensing. Currently, LMOF sensing research is gaining more depth, with attention given to their device and practical applications. This work reviews recent advancements and device applications of LMOFs as chemical sensors toward ions, volatile organic compounds, biomolecules, and environmental toxins. Furthermore, the detection mechanism and the correlation between material properties and structure are elaborated. This analysis serves as a valuable reference for the preparation and efficient application of targeted LMOFs.

A Europium Metal-Organic Framework and Its Polymer Composite Membrane as Switch-Off Fluorescence Sensors for Antibiotic Detection in Lake Water

The detection of antibiotic residues is of great significance in monitoring their overuse in healthcare, livestock and poultry farming, and agricultural production. Herein, EuCl3 and 4,4'-dicarboxyl-diphenoxyethene (H2DPOE) ionothermally reacted in 1-methyl-3-butylimidazolium chloride to give a europium metal-organic framework (Eu-DPOE). Eu-DPOE shows different fluorescence quenching rates for sensing eight antibiotics under different excitation wavelengths. Eu-DPOE displays a fast response, high selectivity, and sensitivity in antibiotic detection by fluorescence quenching. Eu-DPOE can sensitively detect TCs (tetracyclines), NOR (norfloxacin), NFT (furazolidone), ODZ (ornidazole), SDZ (sulfadiazine), and CHL (chloramphenicol) with limits of detection below 0.5 μmol/L. It provides a convenient and rapid tool for sensing antibiotics in aqueous solution. The detection mechanism is a competition absorption between DPOE2- and antibiotics with the supports from powder X-ray diffraction (PXRD), UV-vis spectra, and fluorescence lifetime. With a composite membrane of poly(vinylidene fluoride) (PVDF) matrix loading Eu-DPOE (Eu-DPOE@PVDF), Eu-DPOE@PVDF exhibits a visual fluorescence response to NOR under a 254 nm UV lamp and NFT and CTC under 365 nm. Eu-DPOE@PVDF is applied in the quantitative detection of CTC, NOR, and NFT in lake water with recovery rates ranging from 88.37 to 113.8%. Totally, fluorescence-quenched Eu-DPOE@PVDF exhibits a fast response, high selectivity, and sensitivity in sensing CTC, NOR, and NFT.

Structure of Tris[2-(4-pyridyl)ethyl]phosphine, Tris[2-(2-pyridyl)ethyl]phosphine, and Their Chalcogenides in Solution: Dipole Moments, IR Spectroscopy, and DFT Study

Tris(hetaryl)substituted phosphines and their chalcogenides are promising polydentate ligands for the design of metal complexes. An experimental and theoretical conformational analysis of tris[2-(4-pyridyl)ethyl]phosphine, tris[2-(2-pyridyl)ethyl]phosphine, and their chalcogenides was carried out by the methods of dipole moments, IR spectroscopy and DFT B3PW91/6-311++G(df,p) calculations. In solution, these compounds exist as an equilibrium of mainly non-eclipsed (synclinal or antiperiplanar) forms with a predominance of a symmetrical conformer having a gauche-orientation of the Csp3-Csp3 bonds of pyridylethyl substituents relative to the P=X bond (X = lone pair, O, S, Se) and a gauche-orientation of the pyridyl rings relative to the zigzag ethylene bridges. Regardless of the presence and nature of the chalcogen atom (oxygen, sulfur, or selenium) in the studied molecules with many axes of internal rotation, steric factors-the different position of the nitrogen atoms in the pyridyl rings and the configuration of ethylene bridges-determine the realization and spatial structure of preferred conformers.

Tuning the Cerium-Based Metal-Organic Framework Formation by Template Effect and Precursor Selection

The novel metal-organic framework [(CH3)2NH2]2[Ce2(bdc)4(DMF)2]·2H2O (Ce-MOF, H2bdc-terephthalic acid, DMF-N,N-dimethylformamide) was synthesized by a simple solvothermal method. Ce-MOF has 3D connectivity of bcu type with a dinuclear fragment connected with eight neighbors, while three types of guest species are residing in its pores: water, DMF, and dimethylammonium cations. Dimethylamine was demonstrated to have a decisive templating effect on the formation of Ce-MOF, as its deliberate addition to the solvothermal reaction allows the reproducible synthesis of the new framework. Otherwise, the previously reported MOF Ce5(bdc)7.5(DMF)4 (Ce5) or its composite with nano-CeO2 (CeO2@Ce5) was obtained. Various Ce carboxylate precursors and synthetic conditions were explored to evidence the major stability of Ce-MOF and Ce5 within the Ce carboxylate-H2bdc-DMF system. The choice of precursor impacts the surface area of Ce-MOF and thus its reactivity in an oxidative atmosphere. The in situ PXRD and TG-DTA-MS study of Ce-MOF in a nonoxidative atmosphere demonstrates that it eliminates H2O and DMF along with (CH3)2NH guest species in two distinct stages at 70 and 250 °C, respectively, yielding [Ce2(bdc)3(H2bdc)]. The H2bdc molecule is removed at 350 °C with the formation of novel modification of Ce2(bdc)3, which is stable at least up to 450 °C. According to the total X-ray scattering study with pair distribution function analysis, the most pronounced local structure transformation occurs upon departure of DMF and (CH3)2NH guest species, which is in line with the in situ PXRD experiment. In an oxidative atmosphere, Ce-MOF undergoes combustion to CeO2 at a temperature as low as 390 °C. MOF-derived CeO2 from Ce-MOF, Ce5, and CeO2@Ce5 exhibits catalytic activity in the CO oxidation reaction.

A dual-functional 2D coordination polymer exhibiting photomechanical and electrically conductive behaviours

A photoactive two-dimensional coordination polymer (2D CP) [Zn2(4-spy)2(bdc)2]n (1) [4-spy = 4-styrylpyridine and H2bdc = 1,4-benzendicarboxylic acid] undergoes a photochemical [2 + 2] cycloaddition reaction upon UV irradiation. Interestingly, the crystals of 1 show different photomechanical effects, such as jumping, swelling, and splitting, during UV irradiation. In addition, the CP was employed for conductivity measurements before and after UV irradiation via current density-voltage characteristics and impedance spectroscopy, which suggest that they are semiconducting in nature and can be used as Schottky diodes. Thus, this work demonstrates the potential dual applications of a 2D CP based on photosalient and conductivity properties.

Smart Stimulation Response of a Pyrene-Based Lanthanide(III) MOF: Fluorescence Enhancement to HX (F and Cl) or R-COOH and Artificial Applicable Film on HCl Vapor Sensing

Toxic acids produced by industries are major hazards to the environment and human health, and luminescent pyrene-based crystalline metal-organic frameworks (MOFs) demonstrate promising performance in the detection of toxic acids. Herein, two novel isostructural 3D porous lanthanide MOFs, H3O·[Ln3(TBAPy)2(μ2-H2O)2(OH)2]·2DMA·2Diox·6.5H2O (Ln = Pr (1) and Ce (2); H4TBAPy (1,3,6,8-tetrakis(p-benzoic acid)pyrene); and DMA: N,N-dimethylacetamide) were synthesized, which showed alb topology. Based on the protonation and hydrogen bond mechanism, complex 1 could be used as a fluorescence recognition sensor for HX (X = F, Cl, Br, and I) acid solutions with different luminescence behaviors. It is worth noting that complex 1 exhibited high sensitivity in the fluorescence enhancement sensing of hydrofluoric acid, oxalic acid, and trichloroacetic acid. In particular, complex 1 had a low limit of detection (LOD) for OA (0.1 μM) and was applied to real monitoring of orange fruit samples. In addition, the PVA@1 film could selectively, sensitively, and quantitatively respond to hydrochloric acid (HCl) vapor through fluorescent quenching; due to its protonation and adsorption capacity, the LOD was 0.18 ppm. Therefore, the portable optical device, the PVA@1 film, can detect HCl gas in trace amounts, achieving the ultimate goal of real-time and rapid detection, which has potential application value for industrial production safety.

Luminescent Metal-Organic Framework for the Selective Detection of Aldehydes

The detection of toxic, hazardous chemical species is an important task because they pose serious risks to either the environment or human health. Luminescent metal-organic frameworks (LMOFs) as alternative sensors offer rapid and sensitive detection of chemical species. Interactions between chemical species and LMOFs result in changes in the photoluminescence (PL) profile of the LMOFs which can be readily detected using a simple fluorometer. Herein, we report the use of a robust, Zn-based LMOF, [Zn5(μ3-OH)2(adtb)2(H2O)5·5 DMA] (Zn-adtb, LMOF-341), for the selective detection of benzaldehyde. Upon exposure to benzaldehyde, Zn-adtb experiences significant luminescent quenching, as characterized through PL experiments. Photoluminescent titration experiments reveal that LMOF-341 has a detection limit of 64 ppm and a Ksv value of 179 M-1 for benzaldehyde. Furthermore, we study the guest-host interactions that occur between LMOF-341 and benzaldehyde through in situ Fourier transform infrared and computational modeling employing density functional theory. The results show that benzaldehyde interacts more strongly with LMOF-341 compared to formaldehyde and propionaldehyde. Our combined studies also reveal that the mechanism of luminescence quenching originates from an electron-transfer process.

Selective Gas Sensing under a Mixed Gas Flow with a One-Dimensional Copper Coordination Polymer

Structural changes of the coordination polymer associated with gas adsorption (gate opening-type adsorption) can be linked to bulk physical properties such as magnetism, electrical conductivity, and dielectric properties. To enable real-space sensing applications, it is imperative to have a system where the selective adsorption of mixed gases can be correlated with physical properties. In this report, we demonstrate that a crystalline sample of one-dimensional (1D) coordination polymer exhibits selective CO2 adsorption while simultaneously displaying dielectric switching behavior in a mixed N2/CO2 gas environment. In the crystal of {[Cu2(2-TPA)4(pz)]·CH3CN}n (1·CH3CN), where 2-TPA and pz are 2-thiophencarboxylate and pyrazine, respectively, paddle wheel-type units of [Cu2(2-TPA)4] are bridged by pz, forming a 1D chain structure. One of the two crystallographically independent 2-TPA units was interacted with the pz moiety of the adjacent 1D chain by π···π interactions, forming a two-dimensional (2D) layer parallel to the ab plane. Activated 1 shows selective CO2 adsorption by a gate opening-type adsorption mechanism, indicating that the CO2 adsorption process is accompanied by a structural change. The change in the real part of dielectric permittivity (ε') under the mixed N2/CO2 gas flow is a result of the selective CO2 adsorption, which was supported by the enthalpy changes (ΔH) associated with CO2 adsorption in two methods: CO2 adsorption isotherms and temperature-dependent measurements of ε' under a mixed N2/CO2 gas flow. The calculated ΔH values were found to be in good agreement across both methods. The CO2 ratio in the mixed N2/CO2 gas flow increased, and the switching ratio of ε' (Δε') also increased. Notably, Δε' exhibited a marked increase beyond the pressure required for gate opening adsorption.

Recent Advances in Metal-Organic Framework-Based Nanomaterials for Electrocatalytic Nitrogen Reduction

The production of ammonia under moderate conditions is of environmental and sustainable importance. The electrochemical nitrogen reduction reaction (E-NRR) method has been intensively investigated in the recent decades. Nowadays, the further development of E-NRR is largely hindered by the lack of competent electrocatalysts. Metal-organic frameworks (MOFs) are considered as the next-generation catalysts for E-NRR, featuring their tailorable structures, abundant active sites and favorable porosity. To present a comprehensive review on both the fundamental and advanced development in MOFs catalyst-based E-NRR field, this paper first introduces the basic principles of E-NRR, including the reaction mechanism, major apparatus components, performance criteria, and ammonia detection protocols. Next, the synthesis and characterization methods for MOFs and their derivatives are discussed. In addition, a reaction mechanism study via density functional theory calculations is also presented. After that, the recent advancement of MOF-based catalysts in the E-NRR field as well as the modification approaches on MOFs for E-NRR optimization is elaborated. Finally, the current challenges and outlook of MOF catalyst-based E-NRR field are emphasized.

Transitioning from Supramolecular Chemistry to Molecularly Imprinted Polymers in Chemical Sensing

This perspective article focuses on the overwhelming significance of molecular recognition in biological processes and its emulation in synthetic molecules and polymers for chemical sensing. The historical journey, from early investigations into enzyme catalysis and antibody-antigen interactions to Nobel Prize-winning breakthroughs in supramolecular chemistry, emphasizes the development of tailored molecular recognition materials. The discovery of supramolecular chemistry and molecular imprinting, as a versatile method for mimicking biological recognition, is discussed. The ability of supramolecular structures to develop selective host-guest interactions and the flexible design of molecularly imprinted polymers (MIPs) are highlighted, discussing their applications in chemical sensing. MIPs, mimicking the selectivity of natural receptors, offer advantages like rapid synthesis and cost-effectiveness. Finally, addressing major challenges in the field, this article summarizes the advancement of molecular recognition-based systems for chemical sensing and their transformative potential.

In Situ Oxidation of Pyridyl-Dihydrobenzoimidazoquinazoline and the Synthesis of a Highly Luminescent Cd(II) Coordination Polymer: A Promising Candidate for Mutagenic Nitroaromatic Detection and Device Fabrication

Pyridyl-substituted imidazoquinoline, a potent fluorescent framework, is advantageous to architect multifunctional coordination networks for sensing and fabricating emergent electrical conductors. In this work, a Cd(II)-based one-dimensional (1D) coordination polymer (1D CP), [Cd(glu)2(pbiq)2(H2O)]n (1), [H2glu = glutaric acid and pbiq = 4-(6-(pyridin-4-yl)benzo[4,5]imidazo[1,2-c]quinazoline)], has been structurally confirmed by single-crystal X-ray crystallography. The H-bonding and π···π interactions built a three-dimensional (3D) supramolecular structure that strongly emits at 416 nm in acetonitrile suspension. Potentially intrusive nitroaromatics (NAs) and trinitrophenol (TNP) selectively quench the strong emission of 1, and the highest quenching is noted in the case of TNP. A detection limit (limit of detection (LOD)) of 1.51 × 10-7 M for TNP is determined. The band gap (3.31 eV) of 1 recognizes semiconducting behavior, and an electronic device is fabricated. The correlation of current vs voltage (I-V plot) reveals a substantial non-ohmic electrical conductivity of 1 (Λ: 1.10 × 10-5 S m-1) along with a low energy barrier (ΦB: 0.69), and the series resistance (Rs) becomes 6.21 kΩ.

A novel benzothiophene incorporated Schiff base acting as a "turn-on" sensor for the selective detection of Serine in organic medium

A novel fluorogenic sensor N-benzo[b]thiophen-2-yl-methylene-4,5-dimethyl-benzene-1,2-diamine (BTMPD) was synthesized and characterized by using spectroscopic methods including UV-visible, FT-IR, 1H NMR, 13C NMR, and mass spectrometry. The designed fluorescent probe, owing to its remarkable properties, behaves as an efficient turn-on sensor for the sensing of amino acid Serine (Ser). Also, the strength of the probe enhances upon the addition of Ser via charge transfer, and the renowned properties of the fluorophore were duly found. The sensor BTMPD shows incredible execution potential with respect to key performance indicators such as high selectivity, sensitivity, and low detection limit. The concentration change was linear ranging from 5 × 10-8 M to 3 × 10-7 M, which is an indication of the low detection limit of 1.74 ± 0.02 nM under optimal reaction conditions. Interestingly, the Ser addition leads to an increased intensity of the probe at λ = 393 nm which other co-existing species did not. The information about the arrangement and the features of the system and the HOMO-LUMO energy levels was found out theoretically using DFT calculations which is fairly in good agreement with the experimental cyclic voltammetry results. The fluorescence sensing using the synthesized compound BTMPD reveals the practical applicability and its application in real sample analysis.

Chiral metal-organic frameworks for photonics

Recently, there has been significant interest in the use of chiral metal-organic frameworks (MOFs) and coordination polymers (CPs) for photonics applications. The promise of these materials lies in the ability to tune their properties through judicious selection of the metal and ligand components. Additionally, the interaction of guest species with the host framework can be exploited to realise new functionalities. In this review, we outline the methods for synthesising chiral MOFs and CPs, then analyse the recent innovations in their use for various optical and photonics applications. We focus on two emerging directions in the field of MOF chemistry - circularly polarised luminescence (CPL) and chiroptical switching - as well as the latest developments in the use of these materials for second-order nonlinear optics (NLO), particularly second-harmonic generation (SHG). The current challenges encountered so far, their possible solutions, and key directions for further research are also outlined. Overall, given the results demonstrated to date, chiral MOFs and CPs show great promise for use in future technologies such as optical communication and computing, optical displays, and all-optical devices.

Sequential Assembly and Stabilization of Cu6S6 Octahedral Clusters in NaCl-, NiAs-, and CdI2-Related Structures and Their Utility toward Thermochromism and Multicomponent Hantzsch Reaction

Seven new inorganic-organic coordination polymer compounds have been synthesized and their structures are determined by single-crystal structure determination. The compounds were prepared by the sequential assembly of a [Cu₆(mna)₆]^6- moiety in the presence of a Mn salt and a secondary amine ligand. Of the seven compounds, [{Cu₆(mna)₆}Mn₃(H₂O)(H₂O)_1.5]·5.5H₂O (I), [{Cu₆(mna)₆}Mn₃(H₂O)(Im)_1.5]·3.5H₂O (Ia), [{Cu₆(mna)₆}{Mn(BPY)(H₂O)}₂{Mn(H₂O)₄}]·2H₂O (III), and [{Cu₆(mna)₆}{Mn(BPE)_0.5(H₂O)₂}₂{Mn(BPE)(H₂O)₂}] (IV) have a three-dimensional structure, whereas [{Cu₆(mna)_4.5(Hmna)_1.5}{Mn(BPA)(H₂O)₂}{Mn(H₂O)}]{Mn_0.25(H₂O)₃}·7H₂O (II), [{Cu₆(mna)₆}{Mn(4-BPDB)_0.5H₂O}{Mn(H₂O)₂}].{Mn(H₂O)₆}·6H₂O (V), and [{Cu₆(mna)₄(Hmna)₂}·{Mn(H₂O)₃}₂]·(4-APY)₂·6H₂O (VI) have a two-dimensional structure. Some of the prepared compounds exhibit structures that closely resemble the classical inorganic structures, such as NaCl (Ia, III), NiAs (I), and CdI₂ (IV and VI). The stabilization of such simple structures from the assembly of octahedral Cu₆S₆ clusters and different Mn species and aromatic nitrogen-containing ligands suggests the subtle interplay between the constituent reactants. The compounds were examined for the multicomponent Hantzsch reaction, which gave the product in good yields. The compounds, II and VI, on heating to 70 °C change color reversibly from pale yellow to deep red, which suggests the possible use of these compounds as thermochromic materials. The present study suggests that the Cu₆S₆ octahedral clusters can be assembled into structures that resemble classical inorganic structures.

Aggregation-Induced Emission-Active Nanostructures: Beyond Biomedical Applications

The discovery of aggregation-induced emission (AIE) phenomenon in 2001 has had a significant impact on materials development across different research disciplines. AIE-active materials have been widely exploited for various applications in optoelectronics, sensing, biomedical, and stimuli-responsive systems, etc. This is made possible by integrating AIE features with other fields of science and engineering, such as nanoscience and nanotechnology. AIE has been extensively employed, particularly for biomedical applications, such as biosensing, bioimaging, and theranostics. However, development of AIE-based nanotechnology for other applications is comparatively less, although there have been increasing research activities in recent years. Given the significance and potential of the marriage between AIE hallmark and nanotechnology in AIE-active materials development, this review article summarizes and showcases the latest research efforts in AIE-based nanomaterials, including nanomaterials synthesis and their nonbiomedical applications, such as sensing, optoelectronics, functional coatings, and stimuli-responsive systems. A perspective on the outlook of AIE-based nanostructured materials and relevant nanotechnology for nonbiomedical applications will be provided, giving an insight into how to design AIE-active nanostructures as well as their applications beyond the biomedical domain.

Real-Time In Situ Volatile Organic Compound Sensing by a Dual-Emissive Polynuclear Ln-MOF with Pronounced LnIII Luminescence Response

Lanthanide metal-organic frameworks (Ln-MOFs) are promising for luminescence detection of volatile organic compound (VOC) vapors, but usually suffer from the silent or quenched Ln³⁺ emission. Herein, we report a new dual-emissive Eu-MOF composed of the coordinatively unsaturated Eu₉ clusters that afford abundant open metal sites to form a confined "binding pocket" to facilitate the preconcentration and recognition of VOCs. Single-crystal structural analyses reveal that specific analytes can replace the OH oscillators in the first coordination sphere of Eu³⁺ and form a unique hydrogen-bonding second-sphere adduct tying adjacent Eu₉ clusters together to minimize their nonradiative vibrational decay. With the promoted Eu³⁺ luminescence, the MOF realizes real-time in situ visual sensing of THF vapor (<1 s) and shows a quantitative ratiometric response to the vapor pressure with a limit of detection down to 17.33 Pa. Also, it represents a top-performing ratiometric luminescent thermometer.

Identification of folic acid and sulfaquinoxaline using a heterometallic Zn-Eu MOF as a sensor

A d-f heterometallic MOF using the 2,2'-bipyridine-4,4'-dicarboxylic acid ligand (H₂LZ) was obtained by solvothermal synthesis, namely [EuZn(LZ)₂(HCOO)(H₂O)₃]_n (1). The structure analysis shows that compound 1 comprises heterometallic Zn²⁺ and Eu³⁺ ions, which are connected by LZ^2- and HCOO^- anions to form a three-dimensional framework. MOF 1 exhibited high stability of fluorescence intensity in the scope of pH 2-11 in an aqueous solution. Furthermore, MOF 1 served as an excellent selective sensing material for the detection of folic acid in the presence of some imitating materials of the human body and discerned sulfaquinoxaline in sulfonamide drugs with high sensitivity, selectivity, and reusability. Moreover, we designed and manufactured a sensor paper based on MOF 1 as a portable device for the visual detection of folic acid and sulfaquinoxaline. More crucially, this is the first example in which luminescent MOF is used to identify sulfaquinoxaline molecules in an aqueous solution. In addition, the luminescence sensing mechanisms of MOF 1 for the detection of the above analytes were explored in detail.

A New Microporous Lanthanide Metal-Organic Framework with a Wide Range of pH Linear Response

Lanthanide metal-organic frameworks (Ln-MOFs) have attracted extensive attention because of their structural adjustability and wide optical function applications. However, MOFs with a wide linear pH response and stable framework structures in acidic or alkaline solutions are rare to date. Here, we used 4,4',4″-s-triazine-2,4,6-triyltribenzoate (H₃TATB) as an organic ligand, coordinated with lanthanide ions (Eu³⁺/Tb³⁺), and synthesized a new metal-organic framework material. The material has a porous three-dimensional square framework structure and emits bright red or green fluorescence under 365 nm UV light. The carboxyl group of the ligand is prone to protonation in an acidic environment, and negatively charged OH^- and ligand (TATB^3-) have a competitive effect in an alkaline environment, which could affect the coordination ability of ligand. The luminescence degree of the framework decreases with the increase in the degree of acid and base. In particular, such fluorescence changes have a wide linear response (pH = 0-14), which can be used as a potential fluorescence sensing material for pH detection.

Recent progress on MOF-based optical sensors for VOC sensing

The raising apprehension of volatile organic compound (VOC) exposures urges the exploration of advanced monitoring platforms. Metal-organic frameworks (MOFs) provide many attractive features including tailorable porosity, high surface areas, good chemical/thermal stability, and various host-guest interactions, making them appealing candidates for VOC capture and sensing. To comprehensively exploit the potential of MOFs as sensing materials, great efforts have been dedicated to the shaping and patterning of MOFs for next-level device integration. Among different types of sensors (chemiresistive sensors, gravimetric sensors, optical sensors, etc.), MOFs coupled with optical sensors feature distinctive strength. This review summarized the latest advancements in MOF-based optical sensors with a particular focus on VOC sensing. The subject is discussed by different mechanisms: colorimetry, luminescence, and sensors based on optical index modulations. Critical analysis for each system highlighting practical aspects was also deliberated.

Research progress on near-infrared long persistent phosphor materials in biomedical applications

After excitation is stopped, long persistent phosphor materials (LPPs) can emit light for a long time. The most important feature is that it allows the separation of excitation and emission in time. Therefore, it plays a vital role in various fields such as data storage, information technology, and biomedicine. Owing to the unique mechanism of storage and luminescence, LPPs can avoid the interference of sample autofluorescence, as well as show strong tissue penetration ability, good afterglow performance, and rich spectral information in the near-infrared (NIR) region, which provides a broad prospect for the application of NIR LPPs in the field of biomedicine. In recent years, the development and applications in biomedical fields have been advanced significantly, such as biological imaging, sensing detection, and surgical guidance. In this review, we focus on the synthesis methods and luminescence mechanisms of different types of NIR LPPs, as well as their applications in bioimaging, biosensing detection, and cancer treatment in the field of biomedicine. Finally, future prospects and challenges of NIR LPPs in biomedical applications are also discussed.

Design of five two-dimensional Co-metal-organic frameworks for oxygen evolution reaction and dye degradation properties

Two-dimensional (2D) metal-organic frameworks (MOFs) have been extensively investigated as oxygen evolution reaction (OER) materials because of their numerous advantages such as large specific surface areas, ultrathin thicknesses, well-defined active metal centers, and adjustable pore structures. Five Co-metal-organic frameworks, namely, [Co(L) (4.4′-bbidpe)H2O]n [YMUN 1 (YMUN for Youjiang Medical University for Nationalities)], {[Co2(L)2 (4.4′-bbibp)2]·[Co3(L) (4.4′-bbibp)]·DMAC}n (YMUN 2), [Co(L) (3,5-bip)]n (YMUN 3), [Co(L) (1,4-bimb)]n (YMUN 4), and [Co(L) (4.4′-bidpe)H2O]n (YMUN 5), were designed and fabricated from flexible dicarboxylic acid 1,3-bis(4′-carboxylphenoxy)benzene (H2L) and rigid/flexible imidazole ligands. Their frameworks consist of two-dimensional lamellar networks with a number of differences in their details. Their frameworks are discussed and compared, and their oxygen evolution reaction electrochemical activities and photocatalysis dye degradation properties are investigated.

Synergistic Catalytic Performance of Toluene Degradation Based on Non-Thermal Plasma and Mn/Ce-Based Bimetal-Organic Frameworks

A series of Mn/Ce-based bimetal-organic frameworks, recorded as MCDx (x = 1, 2, 4, 6), were prepared by a solvothermal synthesis method to explore their effects and performance in the synergistic catalysis of toluene under the irradiation of non-thermal plasma. The catalytic properties of different manganese loadings in MCDx for degradation of toluene were investigated. The microphysical structures of the material were analyzed by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The results showed that a MCDx coupling with non-thermal plasma can greatly improve the degradation efficiency, the energy efficiency and the CO2 selectivity, and could also significantly reduce the generation of O3 in the by-products. Among the test samples, MCD6 with Mn:Ce = 6:1 (molar ratio) showed the best catalytic performance and stability, exhibited toluene catalytic efficiency 95.2%, CO2 selectivity 84.2% and energy efficiency 5.99 g/kWh, and reduced O3 emission concentration 81.6%. This research provides a reference for the development and application of synergistic catalysis based on bimetal-organic frameworks and non-thermal plasma in the reduction of industrial volatile organic compounds.