Urea Metal–Organic Frameworks for Nitro-Substituted Compounds Sensing

Accelerative Solid-State Oxidation Behaviour of Amorphous and Partially Crystalline Venetoclax

There is a growing focus on solid-state degradation, especially for its relevance in understanding interactions with excipients. Performing a solid-state degradation of Venetoclax (VEN), we delve into VEN's stability in different solid-state oxidative stress conditions, utilizing Peroxydone™ complex and urea peroxide (UHP). The investigation extends beyond traditional forced degradation scenarios, providing insights into VEN's behavior over 32 h, considering temperature and crystallinity conditions. Distinct behaviors emerge in the cases of Peroxydone™ complex and UHP. The partially crystalline (PC-VEN) form proves more stable with Peroxydone™, while the amorphous form (A-VEN) shows enhanced stability with UHP. N-oxide VEN, a significant degradation product, varies between these cases, reflecting the impact of different oxidative stress conditions. Peroxydone™ complex demonstrates higher reproducibility and stability, making it a promising option for screening impurities in solid-state oxidative stress scenarios. This research not only contributes to the understanding of VEN's stability in solid-state but also aids formulators in anticipating excipient incompatibilities owing to presence of reactive impurities (peroxides) and oxidation in the final dosage form.

Bioinspired Framework Catalysts: From Enzyme Immobilization to Biomimetic Catalysis

Enzymatic catalysis has fueled considerable interest from chemists due to its high efficiency and selectivity. However, the structural complexity and vulnerability hamper the application potentials of enzymes. Driven by the practical demand for chemical conversion, there is a long-sought quest for bioinspired catalysts reproducing and even surpassing the functions of natural enzymes. As nanoporous materials with high surface areas and crystallinity, metal-organic frameworks (MOFs) represent an exquisite case of how natural enzymes and their active sites are integrated into porous solids, affording bioinspired heterogeneous catalysts with superior stability and customizable structures. In this review, we comprehensively summarize the advances of bioinspired MOFs for catalysis, discuss the design principle of various MOF-based catalysts, such as MOF-enzyme composites and MOFs embedded with active sites, and explore the utility of these catalysts in different reactions. The advantages of MOFs as enzyme mimetics are also highlighted, including confinement, templating effects, and functionality, in comparison with homogeneous supramolecular catalysts. A perspective is provided to discuss potential solutions addressing current challenges in MOF catalysis.

A Dihydrotetrazine-Functionalized Metal-Organic Framework as a Highly Selective Luminescent Host-Guest Sensor for Detection of 2,4,6-Trinitrophenol

Pore decoration of metal-organic frameworks (MOFs) with functional groups is a useful strategy to attain high selectivity toward specific analytes, especially in the presence of interfering molecules with similar structures and energy levels, through selective host-guest interactions. In this work, we applied a dihydrotetrazine-decorated MOF, TMU-34, with the formula [Zn(OBA)(H₂DPT)_0.5]_n·DMF, where H₂OBA is 4,4'-oxybis(benzoic acid) and H₂DPT is 3,6-bis(pyridin-4-yl)-1,4-dihydro-1,2,4,5-tetrazine, for the highly selective detection of phenolic NACs, especially TNP (94% quenching efficiency, detection limit 8.1 × 10^-6 M, K_SV = 182663 mol L^-1), in the presence of other substituted NACs especially -NH₂-substituted NACs. Investigations reveal that the quenching mechanism is dominated by photoinduced MOF-to-TNP electron transfer through possible hydrogen-bonding interactions between the phenolic hydroxyl group of TNP and dihydrotetrazine functions of TMU-34. Despite extensive publications on the detection of TNP in the presence of other NACs, the significance of this work will be elucidated if attention is paid to the fact that TMU-34 is among the rare and highly selective MOF-based TNP sensors in the presence of -NH₂-substituted NACs as the serious interferers.

An aggregation-induced emission-active bis-heteroleptic ruthenium(ii) complex of thiophenyl substituted phenanthroline for the selective “turn-off” detection of picric acid

A bis-heteroleptic Ru(ii) polypyridine complex-based AIEgen has been developed for the selective detection of nitroaromatic explosive picric acid in aqueous media.

Magnetically Recyclable Fe3O4@TMU-32 Metal-Organic Framework Photocatalyst for Tetracycline Degradation Under Visible Light

Metal-organic frameworks (MOFs) are a new class of porous crystalline materials being used as photocatalysts for efficient pollutant removal and environmental remediation. In this study, the TMU-32 MOF was synthesized as an effective photocatalyst for the photodegradation of tetracycline (TC) with 96% efficiency in 60 min under visible light. The high photocatalytic activity of the TMU-32 MOF is mainly due to its large specific surface area, which is beneficial for promoting both the adsorption of TC and the separation of the photoinduced charges. Moreover, its desired crystallinity makes it a semiconductor with an appropriate band gap energy. Next, a composite of the TMU-32 MOF with Fe₃O₄ nanoparticles (as Fe₃O₄@TMU-32) was prepared as a magnetically recyclable photocatalyst. The results showed that the photocatalytic activity of the Fe₃O₄@TMU-32 nanocomposite is slightly lower (68% degradation of TC within 60 min) than that of TMU-32 toward TC degradation since Fe₃O₄ nanoparticles are not acting as a photocatalyst and are used only to make the host photocatalyst (here, TMU-32) magnetically separable. The effects of the photocatalyst concentration and recyclability on the photodegradation of TC were studied under similar conditions. We found that the Fe₃O₄@TMU-32 composite is easily recycled without a significant loss of photocatalytic activity after being used several times, indicating the stability of the photocatalyst. Finally, a density functional theory study was also conducted to investigate the structural and electronic properties such as the band gap energy and density of states of the TMU-32 MOF and the Fe₃O₄@TMU-32 composite. Our computational results are in good agreement with the experimental ones. A photocatalytic degradation mechanism was finally proposed under visible-light photoirradiation.

Synthesis and Selective Au(III) Adsorption of Ureido Polymers Containing Large Repeating Rings

Two polymers (polyBAUEE and polyBAUP) containing 25- and 20-membered rings are synthesized by the cyclopolymerization of bifunctional monomers 1,2-bis(acryloyloxyethyl-ureidoethoxyl)-ethane (BAUEE) and 1,3-bis(acryloyloxyethylureido)propane (BAUP) and studied for the adsorption of precious metal ions. PolyBAUEE and polyBAUP selectively adsorb Au(III) with the adsorption efficiencies above 99.0% after adsorption equilibrium. PolyBAUEE adsorbed faster than polyBAUP, and the Au(III) adsorption is selective in the presence of nine interfering metal ions with similar concentrations (ca. 1 mg/L) in an aqueous solution including Pd(II) and Pt(II). The maximum Au(III) adsorption capacities of polyBAUEE and polyBAUP are 37.6 and 31.8 mg/g, respectively. Au(III) is reduced to Au(0) nanoparticles during the adsorption process. The selective adsorption behavior depends on the controlling regioselective recognition of the ring structure and the ureido groups.

Nanoscale Metal-Organic Frameworks: Recent developments in synthesis, modifications and bioimaging applications

Porous Metal-Organic Frameworks (MOFs) have emerged as eye-catching materials in recent years. They are widely used in numerous fields of chemistry thanks to their desirable properties. MOFs have a key role in the development of bioimaging platforms that are hopefully expected to effectually pave the way for accurate and selective detection and diagnosis of abnormalities. Recently, many types of MOFs have been employed for detection of RNA, DNA, enzyme activity and small-biomolecules, as well as for magnetic resonance imaging (MRI) and computed tomography (CT), which are valuable methods for clinical analysis. The optimal performance of the MOF in the bio-imaging field depends on the core structure, synthesis method and modifications processes. In this review, we have attempted to present crucial parameters for designing and achieving an efficient MOF as bioimaging platforms, and provide a roadmap for researchers in this field. Moreover, the influence of modifications/fractionalizations on MOFs performance has been thoroughly discussed and challenging problems have been extensively addressed. Consideration is mainly focused on the principal concepts and applications that have been achieved to modify and synthesize advanced MOFs for future applications.

A Water-Stable Tb-MOF As a Rapid, Accurate, and Highly Sensitive Ratiometric Luminescent Sensor for the Discriminative Sensing of Antibiotics and D2O in H2O

The design and development of self-calibrating ratiometric luminescent sensors for the fast, accurate, and sensitive discrimination and determination of pollutants in wastewater is highly desirable for public and environmental health. Herein, a 3D porous Tb(III)-based metal-organic framework (MOF), {[Tb(HL)(H₂O)₂]·x(solv)}_n (1), was facilely synthesized using a urea-functionalized tetracarboxylate ligand, 5,5'-(((1,4-phenylenebis(azanediyl))bis(carbonyl))bis(azanediyl))diisophthalic acid (H₄L). The activated framework showed a good water stability in both aqueous solutions at a wide pH range of 2-14 and simulated antibiotic wastewaters. Interestingly, this Tb-MOF exhibited dual luminescence owing to the partial energy transfer from the antenna H₄L to Tb³⁺. More importantly, activated 1 (1a) that was dispersed in water showed a fast, accurate, and highly sensitive discrimination ability toward antibiotics with a good recyclability, discriminating three different classes of antibiotics from each other via the quenching or enhancement of the luminescence and tuning the emission intensity ratio between the H₄L ligand and the Tb³⁺ center for the first time. Simultaneously, 1a is a ratiometric luminescent sensor for the rapid, accurate, and quantitative discrimination of D₂O from H₂O. Furthermore, this complex was successfully used for the effective determination of antibiotics and D₂O in real water samples. This work indicates that 1a represents the first ever MOF material for the discriminative sensing of antibiotics and D₂O in H₂O and promotes the practical application of Ln-MOF-based ratiometric luminescent sensors in monitoring water quality and avoiding any major leak situation.

Phenolic nitroaromatics detection by fluorinated metal-organic frameworks: Barrier elimination for selective sensing of specific group of nitroaromatics

Many piesce of research have been performed to detect nitroaromatic-compounds (NACs) by metal-organic frameworks (MOFs). Despite extensive studies, there are still significant challenges like selective detection of specific NAC group in presence of other NACs. Here, we have integrated two functionalization strategies through decoration of pore-walls of the MOFs with trifluoromethyl groups and extension in π-conjugated system. Based on this idea, trifluoromethyl TMU-44 (with the formula [Zn₂(hfipbb)₂(L1)]_n.DMF, H₂hfipbb = 4,4'-(hexafluoroisopropylidene) bis(benzoic acid), L1 = N,N'-bis-pyridin-4-ylmethylene-benzene-1,4-diamine) and TMU-45 (with formula [Zn₂(hfipbb)₂(L2)]_n.DMF, L2 = N,N'-bis-pyridin-4-ylmethylene-naphthalene-1,5-diamine) frameworks have been synthesized. The aromatic skeleton of TMU-44 is based on phenyl rings while TMU-45 aromatic skeleton is extended by replacement of phenyl with naphthyl core. Measurements reveal that these MOFs are highly sensitive to phenolic NACs especially 2,4,6-trinitrophenol (TNP) with high quenching efficiency of 90% for TMU-44 (K_SV = 10,652 M^-1, LOD = 6.9 ppm) and 99% for TMU-45 (K_SV = 34,741 M^-1, LOD = 2.07 ppm). The proposed detection mechanism can be associated with hydrogen bonding between OH group of phenolic NACs and trifluoromethyl groups of TMU-MOFs as well as π(rich)∙∙∙π(deficient) interaction between π-conjugated backbone of TMU-frameworks and π-deficient ring of NACs.

Anchoring Drugs to a Zinc(II) Coordination Polymer Network: Exploiting Structural Rationale toward the Design of Metallogels for Drug-Delivery Applications

A new series of coordination polymers (CPs) were synthesized and crystallographically characterized by single-crystal X-ray diffraction with the aim of developing drug-delivery systems via metallogel formation. Structural rationale was employed to design such coordination-polymer-based metallogels. As many as nine CPs were obtained by reacting two bis(pyridyl)urea ligands, namely, 1,3-dipyridin-3-ylurea (3U) and 1,3-dipyridin-4-ylurea (4U), and the sodium salt of various nonsteroidal antiinflammatory drugs, namely, ibuprofen (IBU), naproxen (NAP), fenoprofen (FEN), diclofenac (DIC), meclofenamic acid (MEC), mefenamic acid (MEF), and Zn(NO₃)₂. All of the CPs displayed 1D polymeric chains that were self-assembled through various hydrogen-bonding interactions involving the urea N-H and carboxylate O atoms and, in a few cases, lattice-occluded water molecules. The reacting components of the CPs produced five metallogels in dimethyl sulfoxide/water. The gels were characterized by rheology and transmission electron microscopy. Three selected metallogelators, namely, 3UMEFg, 3UNAPg, and 3UMECg, showed in vitro anticancer, cell imaging, and multidrug delivery for antibacterial applications, respectively. The shear-thinning properties of 3UMECg (rheoreversibility and injectability) make it a potential candidate for plausible topical application.

Aqueous assembly of a (pseudo)rotaxane with a donor–π–acceptor axis formed by a Knoevenagel condensation

The incorporation of a linear D–π–A “push–pull” chromophore synthesized by a Knoevenagel condensation as axle of a rotaxane is reported.

Metal-organic framework MIL-100(Fe) for dye removal in aqueous solutions: Prediction by artificial neural network and response surface methodology modeling

In this study, a metal organic framework MIL-100(Fe) was synthesized for rhodamine B (RB) removal from aqueous solutions. An experimental design was conducted using a central composite design (CCD) method to obtain the RB adsorption data (n = 30) from batch experiments. In the CCD approach, solution pH, adsorbent dose, and initial RB concentration were included as input variables, whereas RB removal rate was employed as an output variable. Response surface methodology (RSM) and artificial neural network (ANN) modeling were performed using the adsorption data. In RSM modeling, the cubic regression model was developed, which was adequate to describe the RB adsorption according to analysis of variance. Meanwhile, the ANN model with the topology of 3:8:1 (three input variables, eight neurons in one hidden layer, and one output variable) was developed. In order to further compare the performance between the RSM and ANN models, additional adsorption data (n = 8) were produced under experimental conditions, which were randomly selected in the range of the input variables employed in the CCD matrix. The analysis showed that the ANN model (R² = 0.821) had better predictability than the RSM model (R² = 0.733) for the RB removal rate. Based on the ANN model, the optimum RB removal rate (>99.9%) was predicted at pH 5.3, adsorbent dose 2.0 g L^-1, and initial RB concentration 73 mg L^-1. In addition, pH was determined to be the most important input variable affecting the RB removal rate. This study demonstrated that the ANN model could be successfully employed to model and optimize RB adsorption to the MIL-100(Fe).

In situ self-assembled cationic lanthanide metal organic framework membrane sensor for effective MnO4- and ascorbic acid detection

Developing portable membrane sensors to accurately detect the biomolecule ascorbic acid (AA) is extremely important for food safety and human health. Herein, we successfully design and synthesize a novel cationic metal organic framework (Eu-pbmc, Hpbmc = 2-(pyridine-2-yl)-1H-benzimidazole-5-carboxylic acid) and assemble polyacrylonitrile/Eu-pbmc membrane (PEM) by an in-situ growth strategy. Benefiting from the appreciable loading of Eu-pbmc nanoparticles and high water permeation flux, PEM possesses effective detection for MnO₄^- with a limit of detection (LOD) of 17 nM. Utilizing the cationic porous framework, we load MnO₄^- into PEM and construct a "on-off-on" system for effective AA detection. The oxidative MnO₄^- can be reduced by AA and the resulting turn-on luminescence can reflect the concentration of AA. Compared with pure Eu-pbmc crystals, PEM exhibits improved AA detection performance with LOD of 48 nM and detection time of 1 min via a concise detection operation. The stable membrane sensor realizes an accurate detection in real biological samples, meeting the practical requirement. Moreover, an IMP logic gate is helpful to analyze MnO₄^- and AA in water. The proposed novel luminescence platform as well as reasonable "on-off-on" luminescence mode provide a promising method for AA detection.

Rational morphology control of nano-scale amide decorated metal-organic frameworks by ultrasonic method: Capability to selective and sensitive detection of nitro explosives

One of the key challenges in rational design and synthesis of metal-organic frameworks (MOFs) is defined control over size and morphology for using these materials in many more advanced applications. Combining ultrasonic method and capping groups makes it possible to control the size and change the morphology of metal organic frameworks without changing material compositions. Nano TMU-46, 47 and 48 with copper metal center and amide functionalized pillar were synthesized by using ultrasonic irritation and characterized by FE-SEM, powder X-ray diffraction, elemental analysis, and FTIR spectroscopy. Sensing properties of these nano scale materials and the correlation between the nano structure and nitroaromatic compounds detection were studied. Nano TMU-46 due to its special and porous structure and available functional group show strong luminescence emission, which is selectively sensitive to Trinitrophenol (TNP) with a detection limit of 10^-3 M. Furthermore, multiple morphological transition in the structure of these crystals were observed with using different modulators. This morphology transition, in fact, successfully led to significant change in sensing properties of this structure and decreased the detection limit to 10^-5 M.

Nitrogen-doped carbon quantum dots conjugated isoreticular metal-organic framework-3 particles based luminescent probe for selective sensing of trinitrotoluene explosive

Amine group-containing isoreticular metal-organic framework (IRMOF-3) particles are utilized for the first time as a trinitrotoluene (TNT) sensing material. IRMOF-3 particles are synthesized using zinc nitrate as a metal precursor and 2-amino-1,4-benzenedicarboxylic acid as a linker. The nitrogen-doped carbon quantum dots (NCQDs) are synthesized from citric acid and ethylenediamine as carbon and nitrogen precursor, respectively. The NCQDs are conjugated with IRMOF-3 particles as IRMOF-3/NCQDs. The TEM micrograph revealed the average size of IRMOF-3 particles to be 363.66 nm. The photoluminescence emission intensity of IRMOF-3 particles at λ_em 430 nm is highly increased in the presence of NCQDs (λ_ex 330 nm). Both the as-synthesized IRMOF-3 and IRMOF-3/NCQD particles are explored for TNT detection to compare the effect of NCQDs on the IRMOF-3 particle surface. Lower limit of detection (7.5 × 10^-8 M) and higher Stern-Volmer constant (4.46 × 10⁶ M^-1) are achieved by IRMOF-3/NCQD particles. The association constant also increased from 5.3 × 10⁴ to 2.78 × 10⁶ M^-1 after the conjugation of IRMOF-3 particles with NCQDs. Moreover, enhanced selectivity for TNT over trinitrophenol is achieved using the IRMOF-3/NCQD particles. Graphical Abstract.

Anion recognition by urea metal-organic frameworks: remarkable sensitivity for arsenate and fluoride ions

Functionalized metal-organic frameworks (F-MOFs) are known as a promising chemical sensors since they have specific merits like fixed functionalized ligands projecting into the pores which can be utilized to enhance sensitivity and selectivity. Due to the important role of anions in biological process and environmental systems, there is an increasing interest in synthesis and design of new receptors for anions. Urea groups can operate as a hydrogen bond donating site with hydrogen bond acceptor molecules. Strong and directional hydrogen-bonding between the positive urea groups and anions could reduce vibrational quenching and enhance the fluorescence intensity. In this study, two luminescent porous urea decorated MOFs have been successfully assembled and structurally characterized. Luminescence studies of these MOFs toward anions revealed that these F-MOFs exhibit high sensitivity and selectivity toward H₂AsO₄^- and F^- anions as two major ground water pollutants. Moreover, the proposed materials have been applied for the removal of arsenate and nitrate in contaminant well water samples. Graphical abstract.

Coordination Polymers Based on a Biphenyl Tetraphosphonate Linker: Synthesis Control and Photoluminescence

In this work, we used the rigid tetrapodal organic linker, [1,1'-biphenyl]-3,3',5,5'-tetrayltetrakis(phosphonic acid) (H₈btp), for the preparation of two lanthanide-organic framework families of compounds: layered [Ln₇(H₅btp)₄(H_5.5btp)₂(H₆btp)₂(H₂O)₁₂]∙23.5H₂O∙MeOH [where Ln³⁺ = Eu³⁺ (1Eu) and Gd³⁺ (1Gd)], prepared using microwave-irradiation followed by slow evaporation; 3D [Ln₄(H₃btp)(H₄btp)(H₅btp)(H₂O)₈]∙3H₂O [where Ln³⁺ = Ce³⁺ (2Ce), Pr³⁺ (2Pr), and Nd³⁺ (2Nd)], obtained from conventional hydro(solvo)thermal synthesis. It is shown that in this system, by carefully selecting the synthetic method and the metal centers, one can increase the dimensionality of the materials, also increasing structural robustness (particularly to the release of the various solvent molecules). Compound 1 is composed of 2D layers stacked on top of each other and maintained by weak π-π interactions, with each layer formed by discrete 1D organic cylinders stacked in a typical brick-wall-like fashion, with water molecules occupying the free space in-between cylinders. Compound 2, on the other hand, is a 3D structure with small channels filled with crystallization water molecules. A full solid-state characterization of 1 and 2 is presented (FT-IR spectroscopy, SEM microscopy, thermogravimetric studies, powder X-ray diffraction and thermodiffractometry). The photoluminescence of 1Eu was investigated.

High capacity Hg(II) and Pb(II) removal using MOF-based nanocomposite: Cooperative effects of pore functionalization and surface-charge modulation

Water pollution by heavy metal ions especially Hg(II) and Pb(II) is one of the most important concerns because of their harmful effects on human health and environment sustainability. Here, we developed Fe₃O₄@TMU-32 metal-organic framework (MOF)-based nanocomposite by applying pore functionalization and surface-charge modulation strategies. Based on synergic effects of these strategies, Fe₃O₄@TMU-32 nanocomposite shows very high capacity toward Hg(II) and Pb(II) metal ions. TMU-32 (with formula [Zn(OBA)(DPU)]·2DMF·H₂O where H₂OBA and DPU are (4,4'-oxybis(benzoic acid)) and 1,3-di(pyridin-4-yl)urea)) is decorated with urea functional groups containing carbonyl and amine groups that can interact with metal ions. As results, TMU-32 show very high capacity toward Hg(II) and Pb(II) ions. To improve the TMU-32 capacity toward Hg(II) and Pb(II) cations, we tried to modulate the surface-charge of TMU-32 as a host-framework. Surface-charge modulation strategy had been conducted through encapsulation of Fe₃O₄ nanoparticles by TMU-32 in an in-situ synthesis procedure and synthesis of Fe₃O₄@TMU-32 nanocomposite. Fe₃O₄@TMU-32 nanocomposite shows improved removal capacity (45 % and 54 % toward Pb(II) and Hg(II)) rather pristine TMU-32 framework because of urea decorated framework and charge modulated surface. Fe₃O₄@TMU-32 nanocomposite adsorb 1600 mg.g^-1 of Pb(II) and 905 mg.g^-1 of Hg(II) which extremely rare in the literature. Such improvement can be related to the electrostatic interaction between cationic nature of Pb(II) and Hg(II) and negative charge of the Fe₃O₄@TMU-32 adsorbent.

Cobalt Nanoparticles and Atomic Sites in Nitrogen-Doped Carbon Frameworks for Highly Sensitive Sensing of Hydrogen Peroxide

In situ monitoring of hydrogen peroxide (H₂ O₂ ) during its production process is needed. Here, an electrochemical H₂ O₂ sensor with a wide linear current response range (concentration: 5 × 10^-8 to 5 × 10^-2 m), a low detection limit (32.4 × 10^-9 m), and a high sensitivity (568.47 µA mm^-1 cm^-2 ) is developed. The electrocatalyst of the sensor consists of cobalt nanoparticles and atomic Co-N_x moieties anchored on nitrogen doped carbon nanotube arrays (Co-N/CNT), which is obtained through the pyrolysis of the sandwich-like urea@ZIF-67 complex. More cobalt nanoparticles and atomic Co-N_x as active sites are exposed during pyrolysis, contributing to higher electrocatalytic activity. Moreover, a portable screen-printed electrode sensor is constructed and demonstrated for rapidly detecting (cost ≈40 s) H₂ O₂ produced in microbial fuel cells with only 50 µL solution. Both the synthesis strategy and sensor design can be applied to other energy and environmental fields.

An Efficient Synthesis of Benzimidazole and Benzothiazole Derivatives Using a Nickel(II) Metal-Organic Framework

BACKGROUND

The benzimidazoles and benzothiazoles have shown relatively high pharmaceutical and biological activities. In recent years, numerous methods have been developed for synthesis of benzimidazole and benzothiazole derivatives using different catalysts. However, only some of the reported procedures are quite satisfactory and most of them have drawbacks. Herein, we report a convenient method for synthesis of benzimidazole and benzothiazole derivatives using a nickel (II) metal-organic framework (Ni- MOF) as a novel and reusable catalyst. The presence of unsaturated metal centers makes metal-organic frameworks to be used as Lewis acid catalysts.

OBJECTIVE

The primary objective of this study was to describe an efficient method for synthesis of benzimidazole and benzothiazole derivatives.

METHOD

Ni-MOF was prepared using the modified evaporation method and was characterized by FE-SEM, FT-IR, TGA, and XRD techniques.The catalyst was then used to test the synthesis of some benzimidazole and benzothiazole derivatives. The benzimidazoles and benzothiazoles were characterized by Elemental analyses, HNMR and IR techniques.

RESULT

A variety of aromatic aldehydes bearing electron donating groups or electron-withdrawing were reacted with 1,2-phenylenediamine or 2-aminothiophenol using Ni-MOF in good to excellent yields.

CONCLUSION

In summary, a new and highly efficient method was developed and reported for the synthesis of benzimidazole and benzothiazole derivatives using nickel(II) metal-organic framework. The advantages are short reaction times, good to excellent yields, the environmentally benign and simple procedure, stability, nontoxicity, recyclability, and easy separation of the catalyst.

Sensing organic analytes by metal–organic frameworks: a new way of considering the topic

In this review, our goal is comparison of advantageous and disadvantageous of MOFs about signal-transduction in different instrumental methods for detection of different categories of organic analytes.

Two urea-functionalized metal–organic frameworks based on a pillared-layer strategy for gas adsorption and separation

Two pcu type Cu-MOFs based on urea-functionalized ligands have been synthesized by a pillared-layer strategy. Compound 1 shows good adsorption and separation behaviors of CO₂, C₂H₆, and C₃H₈ over CH₄, compound 2 exhibits a gate-opening behavior for N₂ adsorption.

Investigation of the Anticancer Activity of Coordination-Driven Self-AssembledTwo-Dimensional Ruthenium Metalla-Rectangle

Coordination-driven self-assembly is an effective synthetic tool for the construction of spatially and electronically tunable supramolecular coordination complexes (SCCs), which are useful in various applications. Herein, we report the synthesis of a two-dimensional discrete metalla-rectangle [(η6-p-cymene)4Ru4(C6H2O4)2(2)2](CF3SO3)4 (3) by the reaction of a dinuclear half-sandwich ruthenium (II) complex [Ru2(η6-p-cymene)2(C6H2O4)Cl2] (1) and bis-pyridyl amide linker (2) in the presence of AgO3SCF3. This cationic ruthenium metalla-rectangle (3) has been isolated as its triflate salt and characterized by analytical techniques including elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), carbon nuclear magnetic resonance spectroscopy (13C-NMR), 1H-1H correlation spectroscopy (COSY), 1H-1H nuclear Overhauser effect spectroscopy (NOESY), diffusion ordered spectroscopy (DOSY), and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). Significantly, the 2D cationic ruthenium metalla-rectangle showed better anticancer activity towards three different cell lines (A549, Caki-1 and Lovo) as compared with the parent ruthenium complex (1) and the commercially used drug, cisplatin.

Urea-Functionalized Poly(ionic liquid) Photonic Spheres for Visual Identification of Explosives with a Smartphone

Current effort merging rational design of colorimetric sensor array with portable and easy-to-use hand-held readers delivers an effective and convenient method for on-site detection and discrimination of explosives. However, on the one hand, there are rare relevant reports; on the other hand, some limitations regarding direct sensing, color retention, and array extendibility still remain. Herein, urea-functionalized poly(ionic liquid) photonic spheres were employed to construct a brand-new colorimetric sensor array for directly identifying five nitroaromatic explosives with a smartphone. It is found that the strong hydrogen bonding between the urea motifs and the nitro groups offers the spheres high affinity for binding the targets, whereas the existence of other abundant intermolecular interactions in poly(ionic liquid) units renders one single sphere eligible for prominent cross-responses to a broad range of analytes. Besides, in our case, opal-like photonic crystal structures other than chemical dyes are used to fabricate a new style of colorimetric array. Such structural colors can be vivid and unchanged over a long period even in hazard environments. Importantly, through simply altering the preparation conditions of our PIL spheres, a pool of sensing elements could be added to the developed array for discrimination of extended target systems such as more explosives and even their mixtures in real-world context.

The targeted design of dual-functional metal–organic frameworks (DF-MOFs) as highly efficient adsorbents for Hg2+ ions: synthesis for purpose

Designing adsorbents with accessible chelating sites and achieving high contaminant purification efficiency are still important to overcome environmental remediation challenges.

Ultrasensitive "signal-on" electrochemical aptasensor for assay of acetamiprid residues based on copper-centered metal-organic frameworks

In present work, a versatile "signal-on" electrochemical aptasensor with ultra-sensitivity and high selectivity for detecting acetamiprid residues has been successfully constructed. Electrochemistry behaviors of as-synthesized copper-centered metal-organic frameworks (CuMOF) on various electrodes were investigated in details. The results indicated that CuMOF exhibited well-behaved redox events. Thus, we used Au-CuMOF as signaling element to label probe DNA (pDNA). The gold nanoparticles-reduced graphene oxide (Au-rGO) has a high specific surface area and excellent conductivity, which was utilized to immobilize complementary strand (cDNA). In the presence of acetamiprid, Au-CuMOF-labeled pDNA would hybridize with the exposed cDNA, allowing CuMOF to approach the electrode and produce a sensitive signaling current. Such a "signal-on" method does not suffer from the drawbacks of "signal-off" methods. The linear range of this proposed electrochemical aptasensor was 0.1 pM-10.0 nM and the detection limit was as low as 2.9 fM. This platform exhibited wonderful selectivity, stability, and repeatability, and was successfully applied to detect acetamiprid residues in tea samples exhibiting enormous practical application potential.