Tetracarboxylic Acid Research Articles

Enantioselective complexation of protonated tyrosine by a chiral crown-ether: the nature of the Hydrogen bonds makes the difference.

The complexes formed between (18-crown-6)-tetracarboxylic acid, denoted as 18C6TA, and the two enantiomers of protonated tyrosine, L- and D-Tyr, are studied in a cryogenic ion trap by combining mass spectrometry, laser spectroscopy, and DFT calculations. Both UV and IR photodissociation spectra indicate the formation of multiple isomers for each complex, some of them interconverting upon IR irradiation. Conformer-selective vibrational spectroscopy reveals that all structures involve an internally hydrogen-bonded folded structure of the crown ether. The complexes formed with L-Tyr involve two NH…O interactions with the ether oxygen atoms,and two hydrogen bonds to the crown ether carboxylic function, one from the NH group and the other from the COOH group of tyrosine. TheD-Tyr complexesshow more conformational mobility: two out of the three lowest energy conformers observed are tripodal, with three NH…O interactions between the amino acid ammonium and the crown ether oxygens. An additional conformer shows only one NH…O interaction, but has two interactions involving one of the cavity COOH moieties, one with the NH and one with the phenol OH. The increased calculated stability of the complex made from (-) 18C6TA and L-Tyr parallels its higher abundance in the mass spectrum of an isotopically labelled racemic mixture.

Isoreticular Contraction in Dicopper Paddle-Wheel-Based Metal-Organic Frameworks to Enhance C2H2/CO2 Separation.

Achieving a balance between high selectivity and uptake is a formidable challenge for the purification of acetylene from mixtures with carbon dioxide, particularly when seeking to maximize both C2H2 adsorption capacity and C2H2/CO2 separation selectivity in crystalline porous materials. In this study, leveraging the principles of reticular chemistry, we selected two tetracarboxylate-based linkers and combined them with Cu2+ ions to synthesize two isoreticular dicopper paddle-wheel-based metal-organic frameworks (MOFs): Cu-TPTC (terphenyl-3,3',5,5'-tetracarboxylic acid , H4TPTC) and Cu-ABTC (3,3,5,5-azobenzenetetracarboxylic acid, H4ABTC). The structural and sorption analyses revealed that Cu-ABTC, despite having slightly smaller pores due to the strategic replacement of a phenyl ring with an azo group between two tetratopic ligands, maintains high porosity compared to Cu-TPTC. Furthermore, Cu-ABTC outperforms Cu-TPTC in terms of C2H2 adsorption capacity (196 cm3 g-1 at 298 K and 1 bar) and C2H2/CO2 separation selectivity (16.5~5.6). These findings were corroborated by dynamic breakthrough experiments and computational modeling. This research highlights the potential of the isoreticular contraction strategy in enhancing MOFs for sophisticated gas adsorption and separation processes.

A Novel Mn‐MOF Sensitive Detection of Antibiotic Difloxacin Hydrochloride in Water

ABSTRACTAntibiotic pollution in hydrophytic ecosystems has aroused widespread notice due to its adverse impact on both the ecological environment and human physical well‐being. Thus, the development of effective antibiotic detection materials is not only urgently needed but is also challenging. Herein, the luminescent metal–organic framework [Mn3/2(HBCTC)·5H2O] (1) was successfully synthesized based on [9,9′‐bicarbazole]‐3,3′,6,6′‐tetracarboxylic acid (H4BCTC) under solvothermal conditions. Compound 1 can be employed as a fluorescent probe to detect antibiotic difloxacin hydrochloride (DIF) in water, demonstrating a remarkable linear relationship between fluorescence intensity ratio I0/I and the concentration of DIF (0–40 μM), with Ksv of 79,405 M−1 and LOD of 114 nM. More importantly, 1 represents the first fluorescent sensing material based on MOF for the detection of DIF, exhibiting exceptional selectivity, sensitivity, and anti‐interference capability. Furthermore, the mechanism of fluorescence quenching was studied comprehensively.

Dual-mode electrochemical and electrochemiluminescence detection of dopamine based on perylene diimide self-assembly material.

The self-assembly materialN,N-bis-(3-dimethyl aminopropyl)-3,4,9,10-perylene tetracarboxylic acid diimide (PDI) isreported to show electrochemical (EC)/electrochemiluminescence (ECL) property for designing new dual-mode dopamine (DA) sensors. K2S2O8 significantly improved the EC reduction current at -0.346V and ECL intensity at -0.25V of thePDI self-assembly material. DA largely decreased the EC reduction current and ECL intensity of this homogeneous EC/ECL material due to the competitive consumption of K2S2O8 in theoxidization process of DA and the low electron conductivity of polyDA formed through the oxidization of DA by K2S2O8. In addition, the ECL quenching mechanism involved an energy-transfer process resulting from the collision between the produced o-benzoquinone species (oxidization of DA) and the excited state of PDI, which decreased the ECL intensity. This homogeneous EC/ECL material showed linear EC current response for DA from 5.0 nM to 50.0 µM with a detection of limit of 2.7 nM and linear ECL response for DA from 1.0 nM to 100.0 µM with a detection of limit of 0.41 nM. Theproposed dual-mode EC/ECL sensors also showed good feasibility in urine sample analysis.

Elimination of mutagenic contaminants from water using cellulose bearing ferrous-phthalocyanine

BackgroundWe previously investigated methods for separating mutagenic contaminants from aqueous solutions using cellulose-bearing covalently bound trisulfo-Cu-phthalocyanine (blue cotton and blue rayon). Mutagenic contaminants with three or more fused aromatic rings in their structures were adsorbed onto blue cotton and rayon. Since Cu-phthalocyanine is considered an unsuitable absorption ligand for byproducts of water chlorination, such as 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (Mutagen X or MX), we investigated the development of a new material for the elimination of MX from aqueous solvents.ResultsWe selected green cellulose powder bearing ferrous phthalocyanine (FePh), hereafter referred to as green cellulose or GP, as the candidate material. GP is composed of cationized cellulose (white cellulose, WP) and FePh tetracarboxylic acid. The mutagenicity of MX dissolved in buffer or dimethyl sulfoxide (DMSO) solution significantly decreased after treatment with GP. The effects of GP on the elimination of MX from the solvent were very close to being expired after 70 cycles of repeated adsorption of the same GP, and the capacity of GP for MX removal was estimated to be exhausted after 120 cycles of repeated adsorption based on the extrapolation of the obtained result; thus, the interacting ligands on GP may be saturated after complete MX adsorption. The mutagenicity of MX dissolved in aqueous buffer significantly decreased after treatment at pH7.4 but not at pH 4.0. Since MX is dissociated to be the anionic form at pH 6 or higher, the negative charge of MX in the buffer at pH 7.4 may interact with the positive charge of ferrous ions in GP to create a linkage between MX and GP. After GP adsorbed MX, mutagenicity was extracted with water or acetonitrile and recovered in the eluent. Thus, the reversible interaction between MX and FePh may have caused adsorption of MX onto GP.ConclusionGP could be used as a new eliminator and recovery agent for MX in chlorinated drinking water. Developing new materials for the removal and recovery of agents for the detection of mutagenic contaminant-related chlorination in water is beneficial for environmental health.

Novel visible-light-driven antibacterial film grafted with 3,3,4,4-benzophenone tetracarboxylic acid (BPTCA) for chilled meats preservation

To improve long-term stability and low-toxicity active packaging systems, three visible-light-driven antibacterial packaging films from chitosan (CS), silk fibroin (SF), polyvinyl alcohol (PVA) and 3,3,4,4-benzophenone tetracarboxylic acid (BPTCA) were fabricated in this study. First, CS/PVA, SF/PVA and CS/SF/PVA films by solution casting method, and enhance their water solubility by glutaraldehyde (GA) cross-linking to obtain CS/PVA-G, SF/PVA-G and CS/SF/PVA-G. Then, BPTCA was covalently immobilized onto CS/PVA-G, SF/PVA-G and CS/SF/PVA-G through the esterification to obtain CS/PVA-B, SF/PVA-B and CS/SF/PVA-B, respectively. The chemical structure, photophysical properties, and antibacterial capacities are characterized. The FTIR revealed that BPTCA is covalently grafted with the polymer matrix via ester bond. Furthermore, grafting of BPTCA enhanced the film's UV-blocking, decreased water contact angle, water vapor permeability, and possessed moderate mechanical properties. Meanwhile, CS/SF/PVA-B has the best reactive oxygen species generation ability and antibacterial activity (against Escherichia coli, Staphylococcus aureus, Salmonella enteritidis), and can recycle four times, overall migration value of BPTCA was within the limits of 10 mg/dm2. We apply CS/SF/PVA-B films combined with palletized packaging to different chilled-meat preservation applications, and measure physicochemical changes and microbial counts. Shelf lives of chilled mutton are extended by 3 d and chicken by 6 d, compared with controls without CS/SF/PVA-B film. A covalent immobilized visible-light-driven antibacterial packaging may improve the long-term quality of chilled meats.

Two lanthanide coordination polymers: Syntheses, structures and selective detection of Fe3+, Cr2O72−/ CrO42− and antibiotics

Two new lanthanide coordination polymers (CPs) [Tb(bptc)(4,4′-H2bipy)0.5·2H2O]n (1) and [Gd(bptc)(4,4′-H2bipy)0.5·2H2O]n (2) (H4bptc = 3,3′,4,4′-benzophenone tetracarboxylic acid, 4,4′-bipy = 4,4′-bipyridine) have been synthesized under solvothermal conditions. They were characterized by single crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis. CPs 1 and 2 are isomorphous and display a 2D layer structure with the Schlafli symbol of {46·64}{47·63}. CP 1 exhibits excellent fluorescence properties, which can be used for sensitive and selective detection of Fe3+, Cr2O72− / CrO42− and antibiotics (tetracycline (TC), metronidazole (MDZ), and nitrofurazone (NFZ)) simultaneously. The possible luminescence sensing mechanisms were explored in detail. Cyclic experiments demonstrated that the fluorescence intensity of the CP 1 remained basically unchanged even after five cycles.

High-Strength PVA/Cellulosic hydrogels with Acid/Base and thermo dual-responsive fluorescence

Fluorescent polymer hydrogels (FPHs) with tunable luminous features have attracted immense interest. Nevertheless, until now, the development of most FPHs had been hindered by their poor mechanical properties and limited application range. This study presents a novel strategy to fabricate high-strength, multi-application cellulosic fluorescent hydrogels using polyvinyl alcohol (PVA) and fluorescent nanocellulose (containing pyrene tetracarboxylic acid) through a salting-out process. Such strategy enables cellulosic hydrogels with high tensile strength and toughness (26.45 MPa and 201.27 MJ/m3), compressive strength (165.58 MPa), dual-responsive fluorescence (acid/base and temperature), and multiple applications. Specifically, cellulosic hydrogels exhibit fluorescence switching through the utilization of lanthanide metals (Eu3+/Tb3+), acid/base, and temperature, owing to the presence of perylene tetracarboxylic acid as a fluorescent moiety with an aggregation-caused quenching (ACQ) effect. Based on this, the resulting hydrogels were utilized in rewritable display systems, temperature monitoring, and encrypted QR codes. This study envisions opening new possibilities for the development of high-strength fluorescent hydrogels with multiple applications.

Therapeutic effects of DOX-loaded hydrogel MOF nanocarriers on triple negative breast cancer and derivative design via reinforcement learning

Triple negative breast cancer (TNBC) is one of the most difficult of all types of breast cancer to treat. TNBC is characterized by the absence of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. The development of effective drugs can help to alleviate the suffering of patients. The novel nickel(II)-based coordination polymer (CP), [Ni2(HL)(O)(H2O)3·H2O] (1) (where H4L=[1,1’:2’,1’’-triphenyl]-3,3’’,4’,5’-tetracarboxylic acid), was synthesized via solvothermal reaction in this study. The overall structure of CP1 was fully identified by SXRD, Fourier transform infrared spectroscopy and elemental analysis. Using advanced chemical synthesis, we developed Hyaluronic Acid/Carboxymethyl Chitosan-CP1@Doxorubicin (HA/CMCS-CP1@DOX), a nanocarrier system encapsulating doxorubicin (DOX), which was thoroughly characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis (TGA). These analyses confirmed the integration of doxorubicin and provided data on the nanocarriers’ stability and structure. In vitro experiments showed that this system significantly downregulated Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) in triple-negative breast cancer cells and inhibited their proliferation. Molecular docking simulations revealed the biological effects of CP1 are derived from its carboxyl groups. Using reinforcement learning, multiple new derivatives were generated from this compound, displaying excellent biological activities. These findings highlight the potential clinical applications and the innovative capacity of this nanocarrier system in drug development.

Synthesis of two Cd (II)-MOFs and fluorescence sensing of 2, 4, 6-trinitrophenol and anions

Two new Cd (II) metal-organic frameworks (MOFs), {[Cd (L)0.5]·1.2DMF·H2O} n (1) and [Cd(H2L) (1, 2-die)2] n (2) [H4L = [1, 1′:4′, 1′'-terphenyl]-2, 2′', 4, 4′'-tetracarboxylic acid, 1,2-die = 1,2-di(pyridin-4-yl) ethane], have been synthesized under hydro(solvo)thermal conditions and structurally characterized by X-ray single crystal diffraction. 1 is a three-dimensional framework (3D) formed by the connections between layers, whereas 2 is a one-dimensional (1D) chain structure. Fluorescence sensing experiments show that both 1 and 2 can detect 2, 4, 6-trinitrophenol (TNP) and 2 has a lower detection limit. The detection limits of 1 and 2 were 0.18 μmol·L-1 and 0.054 μmol·L-1, respectively. However, their detection of anions is different, 1 can selectively detect MnO4-, and the detection limit is 0.38 μmol·L-1. 2 can selectively detect CrO42-, and the detection limit is 0.84 μmol·L-1. This indicates that different nitrogen-containing ligands have significant effects on the structure and properties of MOFs. In addition, 2 was used for the detection of sulfasalazine (SECT) in aqueous solution, and the detection limit is 0.29 μmol·L-1. Finally, the mechanism of fluorescence quenching was thoroughly investigated.

Lightweight and highly heat-resistant copolymerized polyimide foams for superior thermal insulation and acoustic absorption

The development of lightweight and highly heat-resistant polyimide foams (PIFs) remains a great challenge in areas of aerospace, military ships, transportation, and industries. Herein, a series of lightweight and highly thermal-resistant copolymerized PIFs are successfully fabricated by the “stepwise heating-holding” thermal foaming of the copolymerized polyester ammonium salts (C-PEAS), using 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) and 2,3,3′,4′-biphenyl tetracarboxylic acid dianhydride (α-BPDA) as codianhydride, and p-phenylenediamine (PDA) as diamine. The introduction of α-BPDA increases the rigidity of PI molecule chains and foamability of C-PEAS, and significantly improves the heat resistance of PIFs. The resultant copolymerized PIFs exhibit ultra-low densities (<10 kg·m-3), excellent heat resistance (Tg ranging from 351.2°C to 405.6°C), and high thermal stability. Moreover, they possess high flame retardancies (LOI>44%) and low thermal conductivities (as low as 0.0463 W·m-1∙K-1 at 20°C and no more than 0.0825 W·m-1∙K-1 at 200°C), demonstrating their excellent thermal insulation properties in a wide temperature range. After the continuous heating at 200°C for 40 min, the upper surface of PIFs present low average temperatures less than 60°C. Additionally, the copolymerized PIFs exhibit remarkable acoustic properties with average acoustic absorption coefficients above 0.6 and noise reduction coefficients (NRC) above 0.3. Therefore, the lightweight and highly heat-resistant copolymerized PIFs show great application potentials in the extreme environments of aerospace, military ships, transportation, and industries.

A mixed Ce/Eu metal-organic framework for ratiometric detection of Al3+ ion.

As a heavy metal ion, excessive aluminum ions pose a serious threat to human health and the ecological environment. Developing a simple, efficient, and fast detection method to detect the content of aluminum ions is of great significance, especially for ensuring human health and ecological safety. Herein, the mixed rare earth metal-organic framework (Ce0.74Eu0.26TPTC and Ce0.62Eu0.38TPTC) were prepared based on simple ligand 1,1':4',1″-Terphenyl-2',4,4″,5'-tetracarboxylic acid (H4TPTC). The Ce0.74Eu0.26TPTC and Ce0.62Eu0.38TPTC have dual luminescence centers, which can be used as ratio fluorescent probes to detect Al3+ ions, making the detection results more accurate and reliable. Therefore, this work can promote the further development of rare earth-based MOFs in the detection of heavy metal ions.

Structural Diversity of 2D Molecular Self-Assemblies Arising from Carboxyl Groups Attached to a Molecule: An STM Study at the Liquid-Solid Interface.

Understanding the molecular self-assembly behavior, especially at the microscopic level, sheds light on the rational design of artificial supramolecular systems at surfaces. In this work, scanning tunneling microscopy (STM) and force field simulations were utilized to explore two molecular systems where two and four carboxyl groups are symmetrically modified onto a skeleton. The two target molecules are 4,4'-(ethyne-1,2-diyl) dibenzoic acid (EBA) and 1,1'-ethynebenzene-3,3',5,5,'-tetracarboxylic acid (TCA). The former molecular assembly led to robust close packing, whereas the latter resulted in low-density arrangements that present significant adaption, namely, undergoing phase transformations upon external stimulations, e.g., sensitive to STM-polarity switching and guest molecule incorporations.

Crosslinking of polyvinyl alcohol with di, tri, and tetracarboxylic acids: an experimental investigation

Crosslinking of polyvinyl alcohol with di, tri, and tetracarboxylic acids: an experimental investigation

Recycling of UO22+ expanded by metal-organic framework bearing pyrazinoquinoxaline tetracarboxylic acid: pH fluorescence sensing and photocatalytic activity

With the wide application of nuclear energy, the recycling of uranium resources and environmental protection have become the focus of scientific research and industrial attention. Uranyl ions have better electronic configurations and optical properties, but poor energy utilization and recycling as ionic states. Drawing on the structural features of Metal-Organic Frameworks (MOFs), the combination of UO22+ nodes with photoactive ligands should be able to effectively regulate the energy level matching between metal nodes and conjugated ligands, improve the electronic configuration and energy band structure, and thus produce better photoresponsive functional properties. In the present work, an example of a novel two-dimensional layered U-MOF was constructed by self-assembly, which utilizes pyrazinoquinoxaline tetracarboxylic acid. Due to the stable coordination structure, matched energy levels and synergistic photoresponsive behavior of UO22+ with pyrazinoquinoxaline ligands, U-MOF enables fluorescence sensing response in aqueous solution at pH=2–5, 9.5–12 and fluorescence quenching detection of a wide range of substrates. Theoretical calculations reveal that the interaction of the hydrogen ion with pyrazinozinoquinoxaline moiety extends the degree of conjugation of the moiety. Meanwhile, the interaction of hydroxide ions with pyrazinozinoquinoxaline groups elevates the highest occupied molecular orbital (HOMO) energy level, which significantly affects the photoelectric properties of U-MOF. In addition, U-MOF can be used as a photocatalyst to realize the conversion of benzylamine to N-benzylbenzylideneimine by oxidation under mild conditions. The effective electron transfer between uranyl ions and ligands ensured the photogenerated electron-hole separation efficiency and enhanced the energy utilization. Therefore, the related results of U-MOFs illustrate the practicality of introducing UO22+ nodes into MOFs to construct novel photoresponsive materials, which provides a new way for the efficient recycling and utilization of uranium resources.

Influence of Cross-Linkers on the Wash Resistance of Chitosan-Functionalized Polyester Fabrics.

This study investigates the wash resistance of polyester fabrics functionalized with chitosan, a biopolymer known for its biocompatibility, non-toxicity, biodegradability and environmentally friendly properties. The interaction of chitosan with synthetic polymers, such as polyester, often requires surface treatment due to the weak natural affinity between the two materials. To improve the interaction and stability of chitosan on polyester, alkaline hydrolysis of the polyester fabric was used as a surface treatment method. The effectiveness of using cross-linking agents 1,2,3,4-butane tetracarboxylic acid (BTCA) and hydroxyethyl methacrylate (HEMA) in combination with ammonium persulphate (APS) to improve the stability of chitosan on polyester during washing was investigated. The wash resistance of polyester fabrics functionalized with chitosan was tested after 1, 5 and 10 washes with a standard ECE detergent. Staining tests were carried out to evaluate the retention of chitosan on the fabric. The results showed that polyester fabrics functionalized with chitosan without cross-linkers exhibited better wash resistance than the fabrics treated with crosslinkers.

Impact of Synthetic Variables on the Structural Diversity of TbIII-Carboxylate Frameworks: Gas Adsorption, Magnetism, and Organocatalysis Investigations.

In this work, three unique TbIII-carboxylate frameworks with the formula {[Tb2(OH)2(H2O)2(abtc)]·2H2O}n (1), {[Tb2(abtc)1.5(H2O)3(DMA)]·H2O}n (2) and {[Tb3(abtc)2.5(H2O)4]·H3O}n (3), each displaying structural variations, have been successfully synthesized by the solvothermal reactions of Tb(NO3)3·6H2O with the azo-containing ligand 3,3',5,5'-azobenzene tetracarboxylic acid (H4abtc) under varying conditions. Detailed single-crystal X-ray diffraction (SC-XRD) analysis manifested a remarkable diversity in these structures, demonstrating various coordination patterns of TbIII-metal nodes with the carboxylate groups of the organic linker, which contributed to the generation of intricate three-dimensional (3D) coordination networks with remarkable chemical resistance. Furthermore, frameworks 2 and 3, characterized by porous networks containing two and three independent TbIII-metal nodes, respectively, were both demonstrated to be efficient heterogeneous catalysts toward the cyanosilylation of imines under mild conditions with excellent reusability. In addition, direct current (Dc) magnetic susceptibility measurements conducted on frameworks 1, 2, and 3 indicated that there were obvious antiferromagnetic interactions among the TbIII-metal nodes, which suggests the involvement of intricate intra- and intertrimer exchange channels, adding another fascinating dimension to their physical properties.

Two new 3D cobalt(II) coordination polymers constructed by semi-rigid carboxylic acid ligand: Syntheses, structures and properties

Two novel coordination polymers, {[Co2(L)(H2O)5]·H2O}n (1), and {[Co5(L)2(H2O)6(μ3-OH)2]·2C3H7NO·2H2O}n (2) (H4L = 3, 3′, 5, 5′-diphenyl ether tetracarboxylic acid, C16H10O9) have been synthesized by assembling semi-rigid aromatic polycarboxylic acids with transition-metal cobalt salts, and structurally characterized by elemental analysis, thermogravimetric analysis, IR spectrum, powder X-ray diffraction, and single crystal X-ray diffraction analysis. Structural analysis showed both the L ligands in CP 1 and CP 2 were regarded as 4 connection points, while the binuclear clusters in CP 1 and the pentanuclear clusters in CP 2 were regarded as 4 connection points and 8 connection points, respectively. Finally, both CP 1 and CP 2 were 3D network structures connected by two nodes (4, 4-connected for CP 1 and 4, 8-connected for CP 2). In addition, temperature-dependent susceptibilities have been measured in the range of 2 to 300 K, indicating that both CP 1 and CP 2 have antiferromagnetic coupling between adjacent Co(II) ions. Finally, Electrochemical experiments show that the CP 1 and CP 2 have good electrochemical behaviors.

Three Polyhedron-Based Metal-Organic Frameworks Exhibiting Excellent Acetylene Selective Adsorption.

The separation of acetylene (C2H2) from ethylene (C2H4) and ethane (C2H6) is crucial for the production of high-purity C2H2 and the recovery of other gases. Polyhedron-based metal-organic frameworks (PMOFs) are characterized by their spacious cavities, which facilitate gas trapping, and cage windows with varying sizes that enable gas screening. In this study, we carefully selected a class of PMOFs based on V-type tetracarboxylic acid linker (JLU-Liu22 containing benzene ring, JLU-Liu46 containing urea group and recombinant reconstructed In/Cu CBDA on the basis of JLU-Liu46) to study the relationship between pore environment and C2 adsorption and separation performance. Among the three compounds, JLU-Liu46 exhibits superior selectivity toward C2H2/C2H4 (2.06) as well as C2H2/C2H6 (2.43). Comparative structural analysis reveals that the exceptional adsorbed-C2H2 performance of JLU-Liu46 can be attributed to the synergistic effects arising from coordinatively unsaturated Cu sites combined with an optimal pore environment (matched pore size and polarity, urea functional group), resulting in a strong affinity between the framework and C2H2 molecules. Furthermore, transient breakthrough simulations of JLU-Liu46 confirmed its potential for separating C2H2 in ternary C2 gas.

Cellulose-based colorimetric/ratiometric fluorescence sensor for visual detecting amines and anti-counterfeiting

Many amines with high toxicity always cause a serious threat to the ecological environment and human health; thus, their detection is important. Herein, a dual-mode colorimetric and ratiometric fluorescent sensor based on cellulose for detecting amines has been constructed by a new strategy. This sensor is made of a “negative response” indicator (Lum-MDI-CA) and a “positive response” indicator (perylene tetracarboxylic acid, PTCA). Lum-MDI-CA was obtained by attaching luminol onto cellulose chains, which emitted blue fluorescence and was quenched upon contact with amines. A possible mechanism of fluorescence quenching phenomenon is proposed by the intramolecular charge transfer (ICT) of Lum-MDI-CA. Subsequently, by simply mixing Lum-MDI-CA with PTCA, a dual-mode fluorescence sensor was designed for visual detection and classification of amines. When adding ammonia (NH3), morpholine (MOR), benzylamine (BNZ), diethylamine (DEA), and triethylamine (TEA), respectively, the dual-mode sensor showed visible different color changes under both UV light and daylight. In addition, owing to the excellent processibility and formability of cellulose acetate backbone, the prepared sensor can be easily processed into different material forms, including inks, coatings, films, and fibers, which still exhibit excellent fluorescence emission. Such sensors based on cellulose fluorescent materials are of great value in anti-counterfeiting and information encryption.