Tetracarboxylic Acid Research Articles

Enhancing Kinase Activity Detection with a Programmable Lanthanide Metal-Organic Framework via ATP-to-ADP Conversion.

Precise modulation of host-guest interactions between programmable Ln-MOFs (lanthanide metal-organic frameworks) and phosphate analytes holds immense promise for enabling novel functionalities in biosensing. However, the intricate relationship between these functionalities and structures remains largely elusive. Understanding this correlation is crucial for advancing the rational design of fluorescent biosensor technology. Presently, there exists a large research gap concerning the utilization of Ln-MOFsto monitor the conversion of ATP to ADP, which poses a limitation for kinase detection. In this work, we delve into the potential of Ln-MOFs to amplify the fluorescence response during the kinase-mediated ATP-to-ADP conversion. Six Eu-MOFs were synthesized and Eu-TPTC ([1,1':4',1″]-terphenyl-3,3'',5,5''-tetracarboxylic acid) was selected as a ratiometric fluorescent probe, which is most suitable for high-precision detection of creatine kinase activity through the differential response from ATP to ADP. The molecular -level mechanism was confirmed by density functional theory. Furthermore, a simple paper chip-based platform was constructed to realize the fast (20 min) and sensitive (limit of detection is 0.34 U/L) creatine kinase activity detection in biological samples. Ln-MOF-phosphate interactions offer promising avenues for kinase activity assays and hold the potential for precise customization of analytical chemistry.

Transition Behaviors of Isostructural Hydrogen-Bonded Frameworks Composed of Naphthalene, Quinoxaline, and Pyrazinopyrazine Derivatives.

A series of isostructural reticular frameworks with systematic differences on chemical structures allows us to disclose correlations between specific structural factors and properties, providing insights for designing novel porous materials. However, even slight differences in the molecular structure often lead to non-isostructural polymorphic frameworks particularly in the case of hydrogen-bonded organic frameworks (HOFs) because the structures of HOFs are based on a subtle balance of reversible interactions. In this study, we found that three simple analogues of tetracarboxylic acids with naphthalene, quinoxaline, and pyrazinopyrazine cores (NT, QX, and PP, respectively) yielded isostructural solvated HOFs (NT-1, QX-1, and PP-1, respectively), where hydrogen-bonded sql-networked sheets were slip-stacked with closely similar manners. More importantly, these isostructural HOFs underwent structural transformations in different manners upon removal of the guest solvents. Comparison of the crystal structures of the HOFs before and after the transformation revealed that intermolecular interactions of the core significantly affected on rearrangements of hydrogen bonds in the transformation. The results suggest the potential to control the properties and functions of isostructural HOFs by elements in the core.

Preparation of β-cyclodextrin-reduced graphene oxide aerogel and its application for adsorption of herbicides

Herbicides are the primary pesticides that can easily pollute water bodies, attracting significant attention from researchers regarding the effective removal of herbicide residues from the water environment. In this study, a β-cyclodextrin-reduced graphene oxide (β-CD-BTCA-rGO) aerogel was prepared following the self-assembly hydrothermal method using 1,2,3,4-butane tetracarboxylic acid (BTCA) as crosslinkers. The self-assembly process involved the cross-linking of “soft” β-cyclodextrin (β-CD) with “hard” graphene oxide (GO) nanosheets, forming a stable β-CD-BTCA-rGO aerogel. The prepared β-CD-BTCA-rGO aerogel demonstrated excellent adsorption performance. The adsorption capacities were 62.3 and 46.8 mg/g for sulfentrazone and quinclorac, respectively, surpassing the traditional reduced graphene oxide (rGO) aerogel and citric acid cross-linked (β-CD-CA-rGO) aerogel. Correspondingly, its adsorption capacity for quinclorac was 1.8 times and 12 times that of rGO aerogel and β-CD-CA-rGO aerogel, respectively. Quantum chemical calculations at the density functional theory (DFT) level, utilizing the Fukui function to predict chemical reaction sites, indicated that BTCA, as crosslinkers, formed stable chemical bonds (ester bonds) with GO through hydroxyl and carboxyl surface functional groups, leading to the formation of stable porous aerogels. Furthermore, the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gap was quantitatively measured for various adsorption mechanisms, revealing that electrostatic adsorption was the main force of the adsorption on the aerogels. The β-CD-BTCA-rGO aerogels prepared in this study demonstrated economic feasibility as adsorbents and exhibited good reproducibility. Consequently, β-CD-BTCA-rGO aerogels hold promising application prospects in the remediation of pesticide pollution in water systems.

Fast fabrication, gas sense characteristics and kinetics of cubic Ti-BIPA-TC-MOF film composite optical waveguides

A cubic Ti-metal-organic framework (MOF) ([Ti2–(TpA)2–H2BIPA]), constructed from a titanium metal centre and a benzo-imidephenanthroline tetracarboxylic acid (H4BIPA–TC) ligand was photo-inductively grown on the surface of a titanium dioxide (TiO2) composite optical waveguide (COWG) substrate and the influence of photo-inductive growth period on the [Ti2–(TpA)2–H2BIPA] film surface morphology, optical properties and gas adsorption/sensing characteristics was investigated. The results showed that [Ti2–(TpA)2–H2BIPA] formed a cubic structure after grew for only 5 min. As an ideal gas adsorbent, it exhibits a specific response to ethylenediamine (EDA) among various benzene, amine and acid gases, due to the intrinsic electron deficiency, rich COOH active sites of the Ti–BIPA–TC–MOF–5 frame and the higher molar refractive indexes or dipoles of EDA than other gases. In the EDA concentration range from 10 ppt to 100 ppm, the Ti–BIPA–TC–MOF–5 film COWG exhibited a rapid, repeatable response. Moreover, the Ti–BIPA–TC–MOF–5 film COWG was relatively stable, within 17 d of EDA detection, the response intensity was almost constant and slightly decreased within 40 d. In a static gas adsorption stage at 283–313 K, the EDA gas adsorption behaviour of the Ti–BIPA–TC–MOF–5 film is consistent with the pseudo-second-order kinetic model.

Self-assembled from monometallic-organic framework to bimetallic-organic framework materials with promoted supercapacitor performance

Designing new metal–organic frameworks (MOFs) materials with definite structure and introducing heterometallic atom is an effective strategy to develop new electrocatalytic and energy storage materials. Herein, one new 3D close-packed type manganese metal–organic frameworks, namely [Mn2(BPTC)(DMSO)2.5] (Mn-MOF) have been constructed from a rigid biphenylic acid with a rigid biphenyl-3,3′,5,5′-tetracarboxylic acid (H4BPTC) ligand under a solvothermal condition. Besides, adopting the metal doping strategy, a series of bimetallic MnM’-MOF (M’=Co, Ni and Cu) crystalline materials has been successfully grown on nickel foam (NF) and were used for supercapacitor electrode material. By contrast, the MnNi-MOF/NF shows a specific capacitance of 3391.7 mF cm−2 at 1 mA‧cm−2 in 1.0 M KOH, which is 1.6 times that of Mn-MOF/NF electrode. It also displays excellent cycle stability to keep 92.6 % of the initial capacity after GCD 20000 cycles. Finally, a hybrid supercapacitor (HSC) made from on the MnNi-MOF electrode and activated carbon (AC) could deliver an energy density of 0.224 mWh cm−2 at a power density of 1.04 mW cm−2, and a high cycle-to-cycle stability with 90.1 % of the primary capacitance over 20,000 cycles. This work not only confirms the potential supercapacitor properties of as-synthesized new Mn-MOF, but also effectively improves the specific capacity and device stability of pure Mn-MOF by introducing different transition metal ions.

Fabrication of multifunctional polyimide foams with co-polymerized benzimidazole moieties for excellent thermal insulation and flame retardancy applications

In this study, heterocyclic diamine 2-(4-aminophenyl)-5-aminobenzimidazole (APBIA) was employed as a co-polymerization component to improve the properties of polyimide foams (PIFs) which were synthesized from 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) and 4,4′-diaminodiphenyl ether (ODA). The rheological behavior of polyester ammonium salt (PEAS) precursors was regulated by introducing APBIA moieties to the chain backbones, which affected the foaming behavior of PEAS and the microstructure of corresponding PIFs. Anisotropic porous structure was constructed with the help of microwave-assisted foaming strategy due to the directional growth of foam pores, which led to anisotropic mechanical and thermal insulation performance of resultant PIFs. PIFs demonstrated robust mechanical performance in the vertical direction (i.e., parallel to pore growth direction) and mechanical flexibility (compression response rate of 97.1–99.0 %) in the horizontal direction (i.e., perpendicular to the pore growth direction). The co-polymerized PIFs also presented excellent thermal insulation performance, with thermal conductivity ranging from 0.0266 to 0.0517 W/(m·K) within a temperature range of 25∼300 °C. In addition, PIFs exhibited exceptional thermal stability and flame retardancy performance, which demonstrate a great potential for high-temperature thermal protection applications. To summarize, multifunctional PIFs with excellent mechanical, thermal insulation and flame retardancy were successfully prepared by adopting co-polymerization strategy and microwave-assisted foaming technique, which have promising applications in high-end engineering sectors.

Fabrication of a Terbium-Functionalized Cadmium Organic Framework with Proper Energy Levels as a Ratiometric Probe of an Anthrax Biomarker.

Anthrax bacillus is a very dangerous zoonotic pathogen that seriously endangers public health. Rapid and accurate qualitative and quantitative detection of its biomarkers, 2,6-dipicolinic acid (DPA), is crucial for the prevention and treatment of this pathogenic bacterium. In this work, a novel Cd-based MOF (TTCA-Cd) has been synthesized from a polycarboxylate ligand, [1,1':2',1″-terphenyl]-4,4',4″,5'-tetracarboxylic acid (H4TTCA), and further doped with Tb(III), forming a dual-emission lanthanide-functionalized MOF hybrid (TTCA-Cd@Tb). TTCA-Cd@Tb can be developed as a high-performance ratiometric fluorescent sensor toward DPA with a very low detection limit of 7.14 nM and high selectivity in a wide detection range of 0-200 μM, demonstrating a big advancement and providing a new option for the detection of DPA.

Tandem Proton Transfer in Carboxylated Supramolecular Polymer for Highly Efficient Overall Photosynthesis of Hydrogen Peroxide

Proton supply is as critical as O2 activation for artificial photosynthesis of H2O2 via two‐electron oxygen reduction reaction (2e‐ ORR). However, proton release via water dissociation is frequently hindered because of the sluggish water oxidation reaction (WOR), extremely limiting the efficiency of photocatalytic H2O2 production. To tackle this challenge, carboxyl‐enriched supramolecular polymer (perylene tetracarboxylic acid ‐ PTCA) is elaborately prepared by molecular self‐assembly for overall photosynthesis of H2O2. Interestingly, the interconversion between carboxyl as Brønsted acid and its conjugated base realizes rapid proton circulation. Through this efficient tandem proton transfer process, the spatial effect of photocatalytic reduction and oxidation reaction is greatly enhanced with reduced reaction barrier. This significantly facilitates 2e‐ photocatalytic ORR to synthesize H2O2 and in the meanwhile promotes 4e‐ photocatalytic WOR to evolve O2. Consequently, the as‐developed PTCA exhibits a remarkable H2O2 yield of 185.6 μM h‐1 in pure water and air atmosphere under visible light illumination. More impressively, an appreciable H2O2 yield of 78.6 μM h‐1 can be well maintained in an anaerobic system owing to in‐situ O2 generation by 4e‐ photocatalytic WOR. Our study presents a novel concept for artificial photosynthesis of H2O2 via constructing efficient proton transfer pathway to enable rapid proton circulation.

A multifunctional sensor for detecting tetracycline, 4-nitrophenol, and pesticides

In recent years, due to the abuse of antibiotics, nitro explosives and pesticides, which have caused great harm to the environment and human health, social concerns have prompted researchers to develop more sensitive detection platforms for these pollutants. In this paper, a novel two-dimensional Zn (II) coordination polymer, [Zn(L)0.5(1,2-bimb)]·DMF (1), [H4L=[1,1′:4′,1′’-terphenyl]-2, 2′’,4, 4′’ −tetracarboxylic acid, 1,2-bimb = 1,2-bis(imidazol-1-ylmethyl)benzene] was synthesized using a hydro-solvothermal method. Among commonly used organic solvents, 1 exhibits significant stability. Fast and efficient fluorescence response can be achieved for tetracycline (TET), 4-nitrophenol (4-NP), fluazinam (FLU), and abamectin benzoate (AMB) with low detection limits. A binary intelligent logic gate device with FLU and AMB as chemical input signals is successfully constructed, which provides a new idea for biochemical detection. In addition, a portable visual test paper has been prepared, which has high sensitivity, good selectivity, and simple operation. It can be used for rapid detection of pollutants in daily life and has broad application prospects. Finally, a detailed discussion was conducted on the fluorescence sensing mechanism of 1 for detecting TET, 4-NP, AMB and FLU.

Tandem Proton Transfer in Carboxylated Supramolecular Polymer for Highly Efficient Overall Photosynthesis of Hydrogen Peroxide.

Proton supply is as critical as O2 activation for artificial photosynthesis of hydrogen peroxide (H2O2) via two-electron oxygen reduction reaction (2e- ORR). However, proton release via water dissociation is frequently hindered because of the sluggish water oxidation reaction (WOR), extremely limiting the efficiency of photocatalytic H2O2 production. To tackle this challenge, carboxyl-enriched supramolecular polymer (perylene tetracarboxylic acid-PTCA) is elaborately prepared by molecular self-assembly for overall photosynthesis of H2O2. Interestingly, the interconversion between carboxyl as Brønsted acid and its conjugated base realizes rapid proton circulation. Through this efficient tandem proton transfer process, the spatial effect of photocatalytic reduction and oxidation reaction is greatly enhanced with reduced reaction barrier. This significantly facilitates 2e- photocatalytic ORR to synthesize H2O2 and in the meanwhile promotes 4e- photocatalytic WOR to evolve O2. Consequently, the as-developed PTCA exhibits a remarkable H2O2 yield of 185.6 μM h-1 in pure water and air atmosphere under visible light illumination. More impressively, an appreciable H2O2 yield of 78.6 μM h-1 can be well maintained in an anaerobic system owing to in situ O2 generation by 4e- photocatalytic WOR. Our study presents a novel concept for artificial photosynthesis of H2O2 via constructing efficient proton transfer pathway to enable rapid proton circulation.

Chemosensor material as a metal–organic framework with potassium-based perylene tetracarboxylic acid for copper and lead detection

Heavy metal ions stand out as highly toxic pollutants, playing a pivotal role in various human diseases. Consequently, the development of advanced detection methods becomes imperative for global public health. A proven and effective strategy for metal ion detection involves the use of fluorescent chemosensors. In this context, we synthesized metal–organic frameworks (MOFs) based on perylene to create potassium-based MOFs functioning as an efficient detection probe for metal ion detection. Proton nuclear magnetic resonance (NMR) spectral analysis revealed only two distinct types of hydrogen signals are observed from K4PTC, and no hydrogen signals originating from any residual K4PTC are detected. Similarly, In the 13C NMR spectra, the most downfield signal observed at 176.9 ppm is conveniently assigned to the carbonyl carbon of the K4PTC. The probe displayed diminished absorbance and fluorescence intensity upon the introduction of Cu2+ and Pb2+, suggesting K4PTC’s potential as a sensor for detecting these metal ions. The above findings indicate that loading metal ions into the K4PTC system weakens the oxygen-potassium interaction, signifying the interaction between the metal ions and our probe. Interestingly, the limit of detection (LOD) for our sensor material is highly effective for detecting these metal ions. Consequently, this research serves as a significant reference for the sensitive monitoring of metal pollutants in the environment.

Rapid development of Nb-BIPA-TC-MOF film based optical wave- guides for the ‘turn-on-off’ detection of acidic-basic gases

Metal-organic frameworks (MOFs), constructed from organic ligands that are rich in conjugated π bonds, have been gaining significant attention for gas sensing. This paper reports the synthesis of Nb-H2BIPA-TC, an octahedral MOF, starting from niobium as the metal centre and benzoimidephenanthroline tetracarboxylic acid (H4BIPA-TC) as the ligand. The Nb-H2BIPA-TC-MOF was grown under light irradiation on the surface of a lithium niobate waveguide substrate and assessed for its ability to sense acidic and basic gases. The Nb-H2BIPA-TC-MOF formed an octahedral crystal structure after being grown for only 20 min. The obtained film was optically transparent and featured low light attenuation (< 1.28 dB mm−1). Owing to the Lewis acid-base nature of the Nb-H2BIPA-TC-MOF, the designed sensor exhibited a specific ‘turn on-off’ sensing response to H2S, SO2, and ethylenediamine (EDA) gases. The host-guest interaction between the gas-sensitive Nb-H2BIPA-TC -MOF and different analyte gases induced different degrees of ‘on-off’ switching in its refractive index. The designed MOF showed a significant and reproducible ‘turn on-off’ response to H2S and EDA gases in the 0.1–100 ppm concentration range. The designed MOF responded to these two gases for at least 28 days with a 10–23 % reduction in the sensing response per 7 days. Owing to its low immunity to relative humidity, the designed MOF can be employed under low humidity conditions for the detection of H2S/SO2 and EDA.

Heterometallic [FexM3–x(μ3-O)] cluster-based metal–organic frameworks for magnetic properties

In the paper, we construct a class of heterometallic [FexM3–x(μ3-O)] cluster-based MOFs (PCN-250 (Fe2M), M = Fe3, Fe2Co, Fe2Ni and Fe2Co0.5Ni0.5) through modularization by solvothermal method. The structures of PCN-250 (Fe2M) contain heterometallic [FexM3–x(μ3-O)] cluster by carboxylate bridges and further connected with 3,3 ’, 5,5′ − azobenzene tetracarboxylic acid to form 3D networks. Moreover, magnetic investigations indicate that PCN-250 (Fe3) and PCN-250 (Fe2Co) possess antiferromagnetic behavior, while PCN-250 (Fe2Ni) and PCN-250 (Fe2Co0.5Ni0.5) display canted antiferromagnetic behavior with weak ferromagnetism.

Multifunctional fluorescent switch based on a 3D Co-CP for selective detection of hypochlorite, nitrofuran antibiotics and acetylacetone

The abuse of biological and environmental related materials, such as pharmaceutical antibiotics, volatile organic chemicals and toxic ions has become a topical issue that draws the global attention. Thus, the exploration of effective methods for the rapid recognition of contaminants at low concentrations is critical for curtailing pollution and identifing environmental risks. Previous reports have shown that NH2-functionalized LCPs can serve as effective traps of hypochlorite owing to their rapid chemical reaction with hypochlorite. Herein, we strategically prepared a novel three-dimensional (3D) CP, [Co2(edda)(datrz)(H2O)2]·EtOH (Co-CP), using NH2-decorated triazole ligand 3,5-diamino-1,2,4-triazole (datrz) combined with semirigid tetracarboxylic acid 5,5′-(ethane-1,2-diylbis(oxy)) diisophthalic acid (H4edda). The prepared Co-CP features a pcu topology with point symbol of {412.63}. This material exhibits high structural stability in acidic-basic aqueous solution of broad pH scope (1–11), which is favorable for fluorescence detection in aqueous medium. As expected, the open -NH2 sites within the framework endow this fluorescent CP with remarkable detectability towards hypochlorite in aqueous media. Furthermore, Co-CP also displays satisfactory fluorescence response for sensing nitrofuran antibiotics (NFT and NFZ) and acetylacetone with high sensitivity and selectivity along with great interference immunity. Through exhaustive theories calculations and experimental surveys, the possible mechanisms have also been thoroughly investigated. The CP-based multifunctional fluorescent switch designed in this work expands the application of such materials in biological and environmental related areas.

UoC‐2: A Fluorinated Derivative of the Robust Metal‐Organic Framework MFM‐300

By solvothermal reactions of fluoro substituted biphenyl‐3,3’,5,5’‐tetracarboxylic acids (H4BPTC) with the respective metal salts, four new MOFs with the MFM‐300 topology were synthesized, namely [MIII2(OH)2(L)] with MIII = Ga3+, In3+ and L = 4‐mF‐BPTC4‐ and 4,4’‐dF‐BPTC4‐. Three of them were refined from X‐ray single crystal diffraction data (I4122, Z = 4), [Ga2(OH)2(4,4’‐dF‐BPTC)] was confirmed by Le Bail fits based on synchrotron powder diffraction data. To the best of our knowledge, these four compounds represent the very first examples of MFM‐300 type MOFs with a substituted BPTC4‐ linker. With increasing fluorination of the linker, the thermal stability decreases, as the decarboxylation of the linker is facilitated. On the other hand, the gas uptake is enhanced significantly. E.g. the CO2 uptake (273 K, 1 bar) increases from 124 cm3/g for [Ga2(OH)2(4‐mF‐BPTC)] to 136 cm3/g for [Ga2(OH)2(4,4’‐dF‐BPTC)]. Surprisingly, the exact determination of specific surface areas (SBET) turned out to be difficult. It is supposed that due to transient open metal sites, complete removal of solvent molecules (DMF, acetone) is not always possible before degradation of the framework starts.

Magnetic metal-organic frameworks as sensitive aptasensors for coronavirus spike protein

Electrochemical biosensors, known for their low cost, sensitivity, selectivity, and miniaturization capabilities, are ideal for point-of-care devices. The magnetic metal-organic framework (MMOF), synthesized using the in-situ growth method, consists of ferric salt, magnetic nanoparticles, histidine, and benzene tetracarboxylic acid. MMOF was sequentially modified with aptamer-biotin and streptavidin-horseradish peroxidase, serving as a detector for spike protein and a transducer converting electrochemical signals using H2O2-hydroquinone on a screen-printed electrode. MMOF facilitates easy washing and homogeneous deposition on the working electrode with a magnet, enhancing sensitivity and reducing noise. The physical and electrochemical properties of the modified MMOFs were thoroughly characterized using various analytical techniques. The aptasensors' performance achieved a detection limit of 6 pM for voltammetry and 5.12 pM for impedance spectroscopy in human serum samples. This cost-effective, portable MMOF platform is suitable for rapid point-of-care testing for SARS-CoV-2 spike proteins.

Butane Tetracarboxylic Acid Grafted on Polymeric Nanofibrous Aerogels for Highly Efficient Protein Absorption and Separation.

Developing high-performance and low-cost protein purification materials is of great importance to meet the demands for highly purified proteins in biotechnological industries. Herein, a facile strategy was developed to design and construct high-efficiency protein absorption and separation media by combining aerogels' molding techniques and impregnation processes. Poly (ethylene-co-vinyl alcohol) (EVOH) nanofibrous aerogels (NFAs) were modified by grafting butane tetracarboxylic acid (BTCA) over them in situ. This modification was carried out using polyphosphoric acid as a catalyst. The resulting EVOH/BTCA NFAs exhibited favorable comprehensive properties. Benefiting from the highly interconnected porous structure, good underwater compressive properties, and abundant absorption ligands, the obtained EVOH/BTCA NFAs possessed a high static absorption capacity of 1082.13 mg/g to lysozyme and a short absorption equilibrium time of about 6 h. A high saturated dynamic absorption capacity for lysozyme (716.85 mg/g) was also realized solely by gravity. Furthermore, EVOH/BTCA NFAs displayed excellent reusability, good acid and alkaline resistance, and unique absorption selectivity performance. The successful synthesis of such aerogels can provide a potential candidate for next-generation protein absorbents for bio-separation and purification engineering.

Zn(II)-Coordination Polymers Constructed from Isomeric Bis(Imidazole) Derivative Ligands and Tetracarboxylic Acid for the Detection of Iron Ions

Three Zn(II)-coordination polymers, namely, {[Zn2(µ4-L)(µ-obix)2]·4DMF}n (1), {[Zn2(µ4-L)(µ-mbix)2]·6H2O}n (2) and {[Zn2(µ4-L)(µ-pbix)2]·5H2O}n (3), (L4−: 5,5’-(terephthaloylbis(azanediyl))diisophthalate and obix (y = 2), mbix (y = 3), pbix (y = 4): 1,y-bis((1H-imidazol-1-yl)methyl)benzene) were prepared with a tetracarboxylic acid and flexible isomeric bis(imidazole) linkers and characterized. The compounds displayed structural diversity depending on the rotation of imidazole rings around the –CH2- groups on bis(imidazole) ligands. Compounds 1–3 showed 2-fold interpenetrated 3D framework, 2D structure and 3D framework, respectively. The compounds showed high emissions in solid-state and solutions. Luminescence experiments showed that compounds 1–3 displayed sensitive detection towards Fe3+ ions with detection limits of 2.31 ppm, 5.17 ppm and 2.61 ppm, respectively. Moreover, the compounds could selectively detect Fe3+ ions over the other interfering metal ions via luminescence quenching. The detection mechanism could be ascribed to the competitive light absorption between Fe3+ ions and the compounds.

Dual-functional fluorescence sensors based on 3D lanthanide metal–organic framework and its mixed matrix membrane

A new lanthanide metal–organic framework (Ln-MOF) {[Eu(DPB)(H2O)](Me2NH2+)}n (1) (H4DPB = (1,1′:3′,1′’-terphenyl)-3,3′’,5,5′’-tetracarboxylic acid）was synthesized under solvothermal conditions and presented a fascinating three-dimensional (3D) framework with 4,8-connected diamond topology, which were built from Eu3+ ions and tetra carboxylate groups. 1 showed strong red luminescence emission in the solid state at room temperature and exhibited good stability in different solvents. 1 could be used as a multi-responsive luminescent sensor for hemin and p-Nitrophenol (4-NP) with detection limits of 3.91 × 10−6 M and 1.98 × 10−4 mM, respectively. Moreover, using 1 as a filler and poly (vinylidene difluoride) (PVDF) as matrix, a mixed matrix membrane 1@PVDF was successfully prepared. 1@PVDF also exhibited fluorescence emission comparable to that of 1 and could be used for hemin and 4-NP sensing with good selectivity and remarkable recyclability.

New in situ generated acylhydrazidate-coordinated complexes: Syntheses, structural characterizations and magnetic properties

The present study reports the successful synthesis of three new magnetic coordination polymers, namely [Mn(BPTH)(H2O)]n (1), [Co(BPTH)(phen)]n (2), and [Co(BPTA)(phen)(H2O)2]n (3), through a solvothermal method (H2BPTH = biphenyl-3,3′,4,4′-tetracarboxyhydrazide, H2BPTA = biphenyl-3,3′,4,4′-tetracarboxylic acid, phen = 1,10-phenanthroline). In compounds 1 and 2, the bishydrazide ligand H2BPTH is formed by in situ acylation of H2BPTA with hydrazine hydrate. All the three title compounds contain M2O2 clusters (M=Mn(1), Co(2) and Co(3)). In compound 1, the amido-oxygen atoms O1 coordinate with Mn2+ to form a Mn2O2 cluster, while the adjacent Mn2O2 cluster is interconnected by the ligand's oxygen atoms O3 and O4, resulting in an infinite expansion into a 3D network structure. Compound 2 exhibits a 1D chain structure containing Co2O2 clusters, which further extends into a 2D supramolecular layer through π···π stacking interactions. Compound 3 comprises adjacent Co2O2 clusters interconnected by oxygen atoms O1, O2, and O5 on the ligand to form a 2D layered architecture. The 2D layers are linked through intermolecular O–H···O hydrogen bonds of H2BPTA ligands to form a 3D supramolecular network. Magnetic measurements reveal weak ferromagnetic behavior for compound 1 while compounds 2 and 3 exhibit weak antiferromagnetic interactions at different temperatures. Overall, this research presents new insights into the design and synthesis of coordination polymers with diverse structures and magnetic properties.