This work presents the design, synthesis, and MAO-B inhibitor activity of a series of chalcogenyl-2,3-dihydrobenzofurans derivatives. Using solvent- and metal-free methodology, a series of chalcogen-containing dihydrobenzofurans 7–9 was obtained with yields ranging from 40% to 99%, using an I2/DMSO catalytic system. All compounds were fully structurally characterized using 1H and 13C NMR analysis, and the unprecedented compounds were additionally analyzed using high-resolution mass spectrometry (HRMS). In addition, the mechanistic proposal that iodide is the most likely species to act in the transfer of protons along the reaction path was studied through theoretical calculations. Finally, the compounds 7b–e, 8a–e, and 9a showed great promise as inhibitors against MAO-B activity.
Monthly Archives: September 2023
Surface Modification Driven Initial Coulombic Efficiency and Rate Performance Enhancement of Li1.2Mn0.54Ni0.13Co0.13O2 Cathode
Due to its high energy density and low cost, Li-rich Mn-based layered oxides are considered potential cathode materials for next generation Li-ion batteries. However, they still suffer from serious obstacles of low initial Coulombic efficiency, which is detrimental to their practical application. Here, an efficient surface modification method via NH4H2PO4 assisted pyrolysis is performed to improve the Coulombic efficiency of Li1.2Mn0.54Ni0.13Co0.13O2, where appropriate oxygen vacancies, Li3PO4 and spinel phase are synchronously generated in the surface layer of LMR microspheres. Under the synergistic effect of the oxygen vacancies and spinel phase, the unavoidable oxygen release in the cycling process was effectively suppressed. Moreover, the induced Li3PO4 nanolayer could boost the lithium-ion diffusion and mitigate the dissolution of transition metal ions, especially manganese ions, in the material. The optimally modified sample yielded an impressive initial Coulombic efficiency and outstanding rate performance.
Single Atom Catalysts for Photoelectrochemical Water Splitting
Single atom catalysts (SACs) have attracted increasing attention in electrocatalysis due to their unprecedented catalytic activity with excellent atomic utilization efficiency derived from unique electronic states and coordination environments. In photoelectrochemical (PEC) water splitting, atomically dispersed metal catalysts anchored to photoelectrodes offer the breakthrough to outperform the conventional thin-film PEC catalysts by enlarging the catalytic sites and facilitating photogenerated charge carrier kinetics. Herein, we present a comprehensive review of SAC-incorporated photoelectrodes for efficient PEC water splitting. Firstly, the representative characterization techniques for the identification of SACs and investigations in respect of photogenerated charge carrier kinetics and photon-to-current efficiency will be discussed. Then, we will introduce the state-of-the-art PEC-SACs classified into noble metal, non-noble metal, and dual metal SACs. Finally, critical outlooks to realize the full potential of SACs in photoelectrocatalysis will be highlighted.
Multi‐Functional Organofluoride Catalysts for Polyesters Production and Upcycling Degradation
The production and degradation of polyesters are two crucial processes in polyester materials’life cycle. In this work, multi-functional organocatalysts based on fluorides for both processes are described. Organofluorides were developed as catalysts for ring-opening polymerization of lactide (lactone). Compared with a series of organohalides, organofluoride performed the best catalytic reactivity because of the hydrogen bond interaction between F– and alcohol initiator. The Mn values of polyester products could be up to 72 kg mol–1. With organofluoride catalysts, the ring-opening copolymerization between various anhydrides and epoxides could be established. Furthermore, terpolymerization of anhydride, epoxide, and lactide could be constructed by the self-switchable organofluoride catalyst to yield a block polymer with a strictly controlled polymerization sequence. Organofluorides were also efficient catalysts for upcycling polyester plastic wastes via alcoholysis. Mixed polyester materials could also be hierarchically recycled.
Role of TLR4 signaling pathway in the mitigation of damaged lung by low‐dose gamma irradiation
Abstract
Organisms frequently suffer negative effects from large doses of ionizing radiation. However, radiation is not as hazardous at lower doses as was once believed. The current study aims to evaluate the possible radio-adaptive effect induced by low-dose radiation (LDR) in modulating high-dose radiation (HDR) and N-nitrosodiethylamine (NDEA)-induced lung injury in male albino rats. Sixty-four male rats were randomly divided into four groups: Group 1 (control): normal rats; Group 2 (D): rats given NDEA in drinking water; Group 3 (DR): rats administered with NDEA then exposed to fractionated HDR; and Group 4 (DRL): rats administered with NDEA then exposed to LDR + HDR. In the next stage, malondialdehyde (MDA), glutathione reduced (GSH), catalase (CAT), and superoxide dismutase (SOD) levels in the lung tissues were measured. Furthermore, the enzyme-linked immunoassay analysis technique was performed to assess the Toll-like receptor 4 (TLR4), interleukin-1 receptor-associated kinase 4 (IRAK4), and mitogen-activated protein kinases (MAPK) expression levels. Histopathological and DNA fragmentation analyses in lung tissue, in addition to hematological and apoptosis analyses of the blood samples, were also conducted. Results demonstrated a significant increase in antioxidant defense and a reduction in MDA levels were observed in LDR-treated animals compared to the D and DR groups. Additionally, exposure to LDR decreased TLR4, IRAK4, and MAPK levels, decreased apoptosis, and restored all the alterations in the histopathological, hematological parameters, and DNA fragmentation, indicating its protective effects on the lung when compared with untreated rats. Taken together, LDR shows protective action against the negative effects of subsequent HDR and NDEA. This impact may be attributable to the adaptive response induced by LDR, which decreases DNA damage in lung tissue and activates the antioxidative, antiapoptotic, and anti-inflammatory systems in the affected animals, enabling them to withstand the following HDR exposure.
The role of single‐walled carbon nanotubes functionalized with gold to increase radiosensitivity of cancer cells to X‐ray radiation
The application of high Z-based metallic nanomaterials as radiosensitizers is limited due to some challenges such as non-ideal selection for the target tissue. In this work, we prepared BSA-FA functionalized O-SWCNTs-Au nanosystems as a targeted radiosensitizer for breast cancer therapy in the 4T1 mouse model. The MTT assay was used to investigate the therapeutic effects of nanoparticles in the presence and absence of X-rays so that cancer cells experienced less survival after receiving O-SWCNTs-Au-BSA-FA + 8 G.
The improvement of high-Z-based metallic nanostructures as radiosensitizers with high monolithicity and versatility by superadditive therapeutic track and the good protective effect is considerable, but they are limited by some problems such as nonideal selectivity for the target tissue. In this study, nanosystems were developed to enhance the efficacy of radiotherapy and reduce cancer cell survival based on innovative gold (Au) functionalized oxygen-single-walled carbon nanotubes (O-SWCNTs). We illustrate the use of folic acid (FA) as a targeting agent and bovine serum albumin (BSA) to stabilize the physiological environment and increase durability. The physical and chemical properties of the nanosystems were evaluated using transmission electron microscopy (TEM), selected area electron diffraction (SAED), dynamic light scattering (DLS), zeta potential, X-ray diffraction (XRD), ultraviolet–visible (UV–Visible), and Fourier transform infrared (FTIR) techniques. Finally, the MTT assay was used to investigate the therapeutic effects of nanoparticles in the 4 T1 mouse breast cancer model in the presence and absence of X-rays. So, the cancer cells experienced a more effective reduction in survival after receiving O-SWCNTs-Au-BSA-FA + 8 Gy than O-SWCNTs-BSA, Au-BSA-FA, and O-SWCNTs-Au-BSA + 8 Gy groups.
Aldol/Brook/Carbon Skeletal Rearrangement Cascade Reactions of β‐Silyl Ketones with Aldehydes
β-Silyl ketones reacted with aldehydes by treatment with KMMDS in the presence of 18-crown-6 to give β,γ-unsaturated ketones accompanied with a skeletal rearrangement. The reactions proceeded by aldol reaction of β-silyl ketones with aldehydes followed by [1,4]-Brook rearrangement and intramolecular 1,2-addition to form cyclopropanol derivatives, in which carbon-carbon bond cleavage took place to afford β,γ-unsaturated ketones. The β,γ-unsaturated ketones were prepared in a one-pot manner by conjugate addition of silyl anions to α,β-unsaturated ketones followed by reactions with aldehydes. The Brook rearrangement proceeded with complete inversion of configuration at the carbon center.
Crystal structure, optical properties, mobility, and photoelectric performance of [PEA]3[Bi2I9]
![Crystal structure, optical properties, mobility, and photoelectric performance of [PEA]3[Bi2I9]](https://onlinelibrary.wiley.com/cms/asset/f2de4750-9cfb-4245-aada-58eb41c69ad7/aoc7245-toc-0001-m.png)
We synthesized [PEA]3[Bi2I9] single crystals, and their crystal structure was analyzed. The spectroscopy data of the ground state and excited state show that the band gap is 2.048 eV. [PEA]3[Bi2I9] thin film has been proven to be an n-type semiconductor and has good coverage on the ITO interdigital electrode. The ITO interdigital electrode can effectively confirm the photoelectric conversion properties of [PEA]3[Bi2I9] thin film. The photocurrent density-time curves of the photodetector based on [PEA]3[Bi2I9] SC under different voltages (0.5, 1, 1.5, 2, and 2.5 V) at 386 nm with 30 W m−2 light intensity indicate the photocurrent density changes regularly with turning-on/off of the light. These methods provide ideas for screening lead-free optoelectronic material.
Lead halide-based salts exhibit good photoelectric properties; however, the use, leakage, and recovery of toxic lead require careful consideration. Therefore, developing a lead-free optoelectronic material conveniently and quickly is very important. Moreover, there is relatively little research on the salts of bismuth halides. In this study, we synthesized [PEA]3[Bi2I9] single crystals (SC) by volatilizing N,N-dimethylformamide (DMF) solvent at 70°C. The crystal system and spatial group of [PEA]3[Bi2I9] are monoclinic and P21/n, respectively. The Tauc plot reveals the optical band gap of the [PEA]3[Bi2I9] SC at 2.048 eV. The carrier mobility of [PEA]3[Bi2I9] SC is 47.4 cm2 V−1 s−1. Steady-state fluorescence and time-resolved fluorescence spectrum indicate that there are four fluorescence peaks and about 7 μs lifetime, respectively. The photodetector based on [PEA]3[Bi2I9] SC under different voltages (0.5, 1, 1.5, 2, and 2.5 V) exhibits stability and regularity with turning-on/off of the light. In addition, thermogravimetric analysis (TGA) tests indicate that [PEA]3[Bi2I9] SC has considerable thermal stability at temperatures up to 260°C, showing promise for becoming a high temperature resistant and nontoxic sensor with good application prospects.
Catalytic Conversion of Cellulose to 5‐Hydroxymethylfurfural: Advancements in Heterogeneous Catalysts and Cutting‐Edge Hydrolysis Strategies
This review examines the potential of converting cellulose into valuable 5-hydroxymethylfurfural (HMF) for sustainable chemical production. Catalyst types, hydrolysis strategies, and reactor systems are explored for their contributions to improving cellulose-to-HMF conversion. The review also covers challenges, future perspectives, and development directions.
Abstract
The catalytic conversion of lignocellulose-derived carbohydrates, particularly cellulose, into 5-hydroxymethylfurfural (HMF), holds significant potential as a crucial step in the sustainable production of valuable platform chemicals. This review presents the remarkable progress made in the field, with a specific emphasis on the role of heterogeneous catalysts, innovative methods for accelerating cellulose hydrolysis, and the design of flow reactor technologies. The distinctive properties and surface functionalities of catalysts facilitate the efficient breakdown of cellulose's intricate structure, thereby promoting selective hydrolysis leading to HMF formation. Therefore, this review comprehensively examines various categories of heterogeneous catalysts, including metal oxides/phosphates, zeolites, functionalized silica/carbon-based materials, heteropolyacids (HPAs), and metal-organic frameworks (MOFs), highlighting their unique mechanisms and performance in cellulose conversion. Furthermore, the review describes the intriguing progress in hydrolysis strategies (pretreatment techniques and advanced heating systems) that have been crucially involved in overcoming the challenges associated with cellulose recalcitrance and achieving enhanced HMF yields. The synergistic interactions between catalysts and innovative hydrolysis methods have played a central role in the breakthroughs within cellulose conversion technology. Another aspect covered in this work is the advancement in using fixed-/fluidized-bed reactors and slug microreactors for the continuous production of HMF. Lastly, the current challenges and future perspectives are presented to propose the dilemma and development direction for efficient cellulose-to-HMF conversion.
Solid‐State Electrolyte‐Based Electrochemical Conversion of Carbon Dioxide: Progress and Opportunities
Progress and opportunities related to the application of SSEs as central compartments for electrochemical catholyte-free CO2RR have been described, with key parameters such as SSE type, product carrier, ion exchange membrane, and catalyst hydrophilicity, which affect the performance parameters, to produce a pure product with a high concentration.
Abstract
Research on electrocatalytic CO2 reduction reaction (CO2RR) has been growing rapidly owing to the urgent requirement of sustainable renewable energy. However, several obstacles hinder the application of liquid salt electrolytes in CO2RR, such as high costs, low concentrations of the product, and low purity due to the separation process of the product. Solid-state electrolytes (SSEs) have been introduced as viable alternatives to liquid electrolytes and their salts to address this challenge. Here, we summarize the recently demonstrated studies and opportunities related to catholyte-free CO2RR using SSEs. The recent studies are classified based on the product, including the CO2RR electrolyzer performance. Different SSEs are briefly discussed to highlight the new opportunities in CO2RR application. We also describe the basic operation parameter of the catholyte-free CO2RR using SSE, which has been studied before as the key variable of the reactor. This review provides insights on minimizing the use of salt electrolytes for CO2RR and reveal opportunities for using this technique to improve the efficiency of CO2RR on a large scale. The exploration of utilizing solid-state electrolytes (SSE) on a scale-up production has been pursued to showcase their viability in integrating them into commercial CO2RR technology.