Ultra-efficient peroxymonosulfate utilization and trichloroethylene degradation in heterogeneous catalytic system guided by sheet-like Cu2MnO4 nanoparticles: The role of Cu(III)-O species and free radicals

Synthesizing cubic spinel Cu2MnO4 with nanosheet structure (SCMO) aimed to construct a "non-radical-mediated radical-oxidative reaction", for increasing PMS utilization efficiency, and solving the defects of SO4•- and •OH through indirect PMS activation by electron transfer process. Compared with box-like Cu2MnO4 (11.1%, 0.0035 min-1) and ordinary Cu2MnO4 nanoparticles (21.3%, 0.0070 min-1), SCMO/PMS showed excellent trichloroethylene removal (98.8%, 0.1577 min-1). The pivotal role of Cu(III) was determined based on EPR analysis, quenching experiments, chemical probe experiments, hydrogen temperature-programmed reduction and Raman spectroscopy analysis, in-situ FTIR and Raman analyses. In brief, the interaction between PMS and SCMO could produce surface-bonded reactive complexes and the subsequent breaking of O-O bond in the sub-stable structure allowed the conversion of Cu(II) to Cu(III), which in turn facilitates the generation of •OH and SO4•-. The density functional theory (DFT) calculations provided supporting evidence for the electron donor role of SCMO and the increase of the electron acceptance capacity of PMS. SCMO/PMS system showed good resistance and degradation efficiency to complex composition and combined pollutants in actually contaminated groundwater, respectively. However, the coexistence of high concentrations of arsenic could significantly affect SCMO performance due to their adsorption on -OH groups, which still need in-depth study.

Synthesis of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite as a superior and reusable heterogeneous catalyst for the preparation of pyrimidine derivatives and investigation of their antimicrobial activities

In this report, we synthesized some pyrimidine derivatives by multi-component reaction of urea, benzaldehydes, and 1,3-indandione in the presence of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite under reflux conditions. Initially, graphene oxide was prepared from graphite, and then it was sulfonated using ClOSO3H. Next, GO-OSO3H nanosheets were used to support ZIF-8/ZnFe2O4 nanostructure. The construction of the synthesized structure was established using different spectral techniques such as X-ray crystallography (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX/Mapping), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET). The present method provides various benefits including the efficiency of outcomes, easy separation of the catalyst, and excellent yield of the products within short reaction times. Moreover, the antibacterial activities of pyrimidine derivatives were investigated via the agar-well diffusion method on gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria and the obtained results illustrated reasonable effects.

Metal-Organic Frameworks: Versatile Platforms for Biomedical Innovations

This review article explores the multiple applications and potential of metal-organic frameworks (MOFs) in the biomedical field. With their highly versatile and tunable properties, MOFs present many possibilities, including drug delivery, biomolecule recognition, biosensors, and immunotherapy. Their crystal structure allows precise tuning, with the ligand typology and metal geometry playing critical roles. MOFs' ability to encapsulate drugs and exhibit pH-triggered release makes them ideal candidates for precision medicine, including cancer treatment. They are also potential gene carriers for genetic disorders and have been used in biosensors and as contrast agents for magnetic resonance imaging. Despite the complexities encountered in modulating properties and interactions with biological systems, further research on MOFs is imperative. The primary focus of this review is to provide a comprehensive examination of MOFs in these applications, highlighting the current achievements and complexities encountered. Such efforts will uncover their untapped potential in creating innovative tools for biomedical applications, emphasizing the need to invest in the continued exploration of this promising field.

Highly sensitive electrochemical peptide-based biosensor for marine biotoxin detection using a bimetallic platinum and ruthenium nanoparticle-tethered metal-organic framework modified electrode

Saxitoxin (STX) is a highly toxic small-molecule cyanotoxin that is water-soluble, stable in acidic media, and thermostable. STX is hazardous to human health and the environment in ocean, thus it is an important to detect it at very low concentrations. Herein, we developed an electrochemical peptide-based biosensor for the trace detection of STX in different sample matrix utilizing differential pulse voltammetry (DPV) signal. We synthesized the nanocomposite of zeolitic imidazolate framework-67 (ZIF-67) decorated bimetallic platinum (Pt) and ruthenium (Ru) nanoparticles (Pt-Ru@C/ZIF-67) using impregnation method. The nanocomposite modified with screen-printed electrode (SPE) was subsequently used to detect STX in the range of 1-1,000 ng mL^-1, with a detection limit (LOD) of 26.7 pg mL^-1. The developed peptide-based biosensor is highly selective and sensitive towards STX detection, thus it represents a promising strategy for the development of novel portable bioassay for monitoring various hazardous molecules in aquatic food chains.

Ni-Co bimetallic decorated dodecahedral ZIF as an efficient catalyst for photoelectrochemical degradation of sulfamethoxazole coupled with hydrogen production

In this work, a NiCo bimetallic ZIF (BMZIF) dodecahedron material has been synthesized by the precipitation approach and then used for simultaneously photoelectrocatalytic degradation of sulfamethoxazole (SMX) and hydrogen production. The combination of Ni/Co loading in ZIF structure increased the specific surface area 1484 (m² g^-1) and photocurrent density (0.4 mA cm^-2), which can facilitate the good charge transfer efficiency. In presence of peroxymonosulfate (PMS, 0.1 mM), the complete degradation of SMX (10 mg L^-1) was achieved at initial pH of 7 within 24 min, with the pseudo-first-order rate constants of 0.18 min^-1 and TOC removal efficiency of 85 %. Radical scavenger experiments affirm that ^•OH radicals were the primary oxygen reactive species to drive the SMX degradation. Along with SMX degradation at the anode, the H₂ production was observed at the cathode (140 μmol cm^-2 h^-1), which was 1.5 and 3 times higher than that of Co-ZIF and Ni-ZIF, respectively. The superior catalytic performance of BMZIF was assigned to the distinctive internal structure and synergistic effect between ZIF and Ni/Co bimetals, which improves light absorption and charge conduction efficiency. This study may provide insight into the new way to treat polluted water and simultaneously produce green energy using bimetallic ZIF in a PEC system.

ZIF-67 blended PVDF membrane for improved Congo red removal and antifouling properties: A correlation establishment between morphological features and ultra-filtration parameters

Dye effluents from various sectors have constantly imperilled the environment and ecosystem. Nano-composite membrane technology incorporating metal-organic frameworks (MOFs) has shown tremendous potential for toxic pollutant remediation. This study details the impact of ZIF-67 MOF nanoparticles on the structural properties of polyvinylidene fluoride (PVDF) ultrafiltration membrane during the non-solvent induced phase separation (NIPS) process. In order to outline the properties that determine the performance parameters in a MOF-modified mixed matrix membrane, the corresponding changes in mean pore size (MPS), surface porosity, solvent viscosity, and hydrophilicity have been discussed with appropriate surface characterization analysis. The suitability of ZIF-67 as filler nanoparticles were established based on polymer compatibility, dispersibility, and water stability studies. The ZIF-67 incorporated PVDF mixed matrix membranes (MMM) showed 99.5% CR dye removal with 2.6 times DI water permeability than the neat. The flux recovery ratio (FRR) improved by 1.9 times and the membranes were found suitable for up to 5 filtration cycles. Based on the overall results, a correlation analysis between the MMM surface properties and membrane performance parameters were established to determine the key performance parameters. It was observed that in comparison to MPS, surface porosity was more correlated to J_d/J_w (r = 0.96) and FRR (r = 0.95).

Transition-metal-catalyzed synthesis of quinazolines: A review

Quinazolines are a class of nitrogen-containing heterocyclic compounds with broad-spectrum of pharmacological activities. Transition-metal-catalyzed reactions have emerged as reliable and indispensable tools for the synthesis of pharmaceuticals. These reactions provide new entries into pharmaceutical ingredients of continuously increasing complexity, and catalysis with these metals has streamlined the synthesis of several marketed drugs. The last few decades have witnessed a tremendous outburst of transition-metal-catalyzed reactions for the construction of quinazoline scaffolds. In this review, the progress achieved in the synthesis of quinazolines under transition metal-catalyzed conditions are summarized and reports from 2010 to date are covered. This is presented along with the mechanistic insights of each representative methodology. The advantages, limitations, and future perspectives of synthesis of quinazolines through such reactions are also discussed.

3D Electron-Rich ZIF-67 Coordination Compounds Based on 2-Methylimidazole: Synthesis, Characterization and Effect on Thermal Decomposition of RDX, HMX, CL-20, DAP-4 and AP

ZIF-67 is a three-dimensional zeolite imidazole ester framework material with a porous rhombic dodecahedral structure, a large specific surface area and excellent thermal stability. In this paper, the catalytic effect of ZIF-67 on five kinds of energetic materials, including RDX, HMX, CL-20, AP and the new heat-resistant energetic compound DAP-4, was investigated. It was found that when the mass fraction of ZIF-67 was 2%, it showed excellent performance in catalyzing the said compounds. Specifically, ZIF-67 reduced the thermal decomposition peak temperatures of RDX, HMX, CL-20 and DAP-4 by 22.3 °C, 18.8 °C, 4.7 °C and 10.5 °C, respectively. In addition, ZIF-67 lowered the low-temperature and high-temperature thermal decomposition peak temperatures of AP by 27.1 °C and 82.3 °C, respectively. Excitingly, after the addition of ZIF-67, the thermal decomposition temperature of the new heat-resistant high explosive DAP-4 declined by approximately 10.5 °C. In addition, the kinetic parameters of the RDX+ZIF-67, HMX+ZIF-67, CL-20+ZIF-67 and DAP-4+ZIF-67 compounds were analyzed. After the addition of the ZIF-67 catalyst, the activation energy of the four energetic materials decreased, especially HMX+ZIF-67, whose activation energy was approximately 190 kJ·mol^-1 lower than that reported previously for HMX. Finally, the catalytic mechanism of ZIF-67 was summarized. ZIF-67 is a potential lead-free, green, insensitive and universal EMOFs-based energetic burning rate catalyst with a bright prospect for application in solid propellants in the future.

Dual-ZIF-derived "reassembling strategy" to hollow MnCoS nanospheres for aqueous asymmetric supercapacitors

Construction of delicate nanostructures with a facile, mild-condition and economical method is a key issue for building high-performance electrode materials. We demonstrate a facile and novel "reassembling strategy" to hollow MnCoS nanospheres derived from dual-ZIF for supercapacitors. The spherical shell's surface structure, thickness and Mn distribution were controlled by regulating the solvothermal reaction time. The chemical composition, phases, specific surface areas and microstructure were studied and the electrochemical performances were systematically estimated. As the unique low-crystalline and optimized hollow nanosphere structure contributes to increasing active sites, MnCoS nanospheres exhibit excellent electrochemical performance. The test results show that the specific capacitance increases with increasing solvothermal time, and the MCS with a 5 h reaction time exhibits optimal electrochemical properties with a high specific capacity of 957 C g-1 (1 A g-1). Furthermore, an MCS-5//AC asymmetric supercapacitor device delivers a specific energy as high as 36.9 W h kg-1 at a specific power of 750 W kg-1.

Hybrid Ce-Fe2O3/ZIF-67 Photoanode with Efficient Photoelectrochemical Water Oxidation Performance

Surface states and slow water oxidation kinetics greatly limit the photoelectrochemical (PEC) water oxidation performance of Fe₂O₃. To solve the above problems, coupling Fe₂O₃ with a passivation layer and an oxygen evolution cocatalyst, respectively, is the common method. Though this method may improve its PEC performance, this also results in a low charge-transfer efficiency caused by the interface resistance between Fe₂O₃ and the modification materials (passivation layer and oxygen evolution cocatalyst). Therefore, it is important to identify a multifunctional modifier material to reduce the interfacial resistance due to the presence of multiple different materials. In this work, we introduced a thin cobalt-based metal-organic framework layer (ZIF-67) as a dual-functional material that acted as both a passivation layer and a water oxidation cocatalyst for a photoanode based on Ce-Fe₂O₃ nanorod arrays. The ZIF-67 layer inhibited charge carrier recombination by passivating the surface states. The PEC performance was improved due to the rich Co²⁺ photogenerated hole-capture sites, which facilitated charge transfer and separation. As expected, the Ce-Fe₂O₃/ZIF-67 photoanode exhibited superior water oxidation performance, with a photocurrent of 2.07 mA cm^-2 at 1.23 V_RHE, which is 1.74 times higher than that of the Ce-Fe₂O₃ photoanode. The onset potential was negatively shifted by 71 mV. This study provides basic insights and a strategy for reducing interfacial resistance in hybrid materials.

Cucurbit[6]uril supported β-Ni(OH)2 nanoparticles as a heterogeneous catalyst for the synthesis of quinazolines via acceptorless dehydrogenative coupling of alcohols with nitriles

Synthesis of a series of quinazolines using β-Ni(OH)2-CB[6] as a heterogeneous nanocatalyst.

Construction of a Tl(I) voltammetric sensor based on ZIF-67 nanocrystals: optimization of operational conditions via response surface design

An electroanalytical sensor was constructed constituted on a carbon paste electrode (CPE) with a ZIF-67 modifier and devoted to the quantification of Tl(I). Several characterization tests including XRD, BET, FT-IR, SEM/EDS/mapping, TEM, impedance spectroscopy (EIS), and cyclic voltammetry (CV) were performed on the synthesized ZIF-67 nanocrystals and CPE matrix. Central composite design (CCD) was used to assess the impact of variables affecting the sensor response, including the weight percent of ZIF-67 (14%), the pH of the thallium accumulation solution (6.4), and accumulation time (315 s) as well as the accumulation potential (-1.2 V). The direct linear relationship between the sensor response and the concentration of Tl(I) is in the interval of 1.0×10^-10 to 5.0×10^-7 M (coefficient of determination = 0.9994). The detection limit is approximately 1.0 × 10^-11 M. The right selection of the MOF makes this sensor highly resistant to the interference of other ions. High selectivity against common interferences in the measurement of thallium (such as Pb(II) and Cd(II)) is an important feature of this sensor. To confirm the performance of the prepared sensor, the amount of thallium in the real sample was determined.

Carbon Dioxide Enrichment PEBAX/MOF Composite Membrane for CO2 Separation

Zeolitic imidazole framework (ZIF-8) was incorporated into poly(ether-block-amide) (Pebax-1657) in differing ratios to prepare mixed matrix membranes (MMMs) for gas separation. As ZIF-8 loading is increased, gas separation selectivity also gradually increases. For economic considerations, the proportion of the increase in selectivity to the amount of MOF loaded per unit was calculated. The results show that mixing 5% MOF gives the best unit performance. With this, a variety of MOFs (UiO-66, UiO-66-NH₂, A520, MIL-68(Al) and MIL-100(Fe)) were mixed with PEBAX at 5 loading to prepare MMMs. In this work, metal-organic frameworks (MOFs) were processed using the dry-free method, where in the synthesized MOF was not dried prior to incorporation. The gas separation performance test carried out shows the highest separation performance was exhibited by P-UiO-66, wherein the CO₂/N₂ gas selectivity was 85.94, and the permeability was 189.77 (Barrer), which was higher than Robeson’s Upper bound in 2008, and obtained a high permeability and selectivity among mixed matrix membranes. In the preparation of high quality MMMs for gas separation, details regarding the interface phenomenon were assessed.

Chemical Insights Into the Synthetic Chemistry of Quinazolines: Recent Advances

In medicinal chemistry, one of the most significant heterocyclic compounds are quinazolines, possessing broad range of biological properties such as anti-bacterial, anti-fungal, anti-HIV, anti-cancer, anti-inflammatory, and analgesic potencies. Owing to its numerous potential applications, in the past two decades, there is an increase in the importance of designing novel quinazolines, exploring promising routes to synthesize quinazolines, investigating different properties of quinazolines, and seeking for potential applications of quinazolines. The present review article describes synthesis of quinazolines via eco-friendly, mild, atom-efficient, multi-component synthetic strategies reported in the literature. The discussion is divided into different parts as per the key methods involved in the formation of quinazoline skeletons, aiming to provide readers an effective methodology to a better understanding. Consideration has been taken to cover the most recent references. Expectedly, the review will be advantageous in future research for synthesizing quinazolines and developing more promising synthetic approaches.

Self-ZIF template-directed synthesis of a CoS nanoflake array as a Janus electrocatalyst for overall water splitting

Self-ZIF template-directed synthesis of a CoS nanoflake array as a Janus electrocatalyst for overall water splitting.

Influence of the 2-methylimidazole/zinc nitrate hexahydrate molar ratio on the synthesis of zeolitic imidazolate framework-8 crystals at room temperature

The effect of the 2-methylimidazole (Hmim)/zinc nitrate hexahydrate (Zn) molar ratio on the physicochemical characteristics of the zeolitic imidazolate framework-8 (ZIF-8) was investigated. ZIF-8 crystals were synthesized by mixing Hmim with Zn at room temperature without any additives in methanol solution. It was found that Hmim/Zn molar ratio had significant influence on the crystallinity, yield, particle size and porosity of ZIF-8. The samples synthesized at low Hmim/Zn molar ratio showed a cubic shape, whereas at higher Hmim/Zn ratios truncated rhombic dodecahedron or rhombic dodecahedron morphologies were obtained. The particle size is decreased upon increasing the Hmim/Zn molar ratio. Besides, higher Hmim/Zn molar ratio in a certain range resulted in improving crystallinity, yield, surface area and micropore volume of ZIF-8. The ZIF-8 crystals produced at Hmim/Zn molar ratio of 8 exhibited the best characteristics. The present work provides new insights in relation to the role of Hmim/Zn molar ratio on the synthesis process of ZIF-8.

Zeolitic imidazole framework-67 as an efficient heterogeneous catalyst for the conversion of CO2 to cyclic carbonates

ZIF-67 acts as a very efficient catalyst for the cycloaddition of CO₂ to epoxides affording cyclic carbonates with high selectivity, without any need for a solvent or a co-catalyst.