M-N-C single-atom catalysts (MN) have gained attention for their efficient use at the atomic level and adjustable properties in electrocatalytic reactions like the ORR, OER, and HER. Yet, understanding MN's activity origin and enhancing its performance remains challenging. Edge-doped substituents profoundly affect MN's activity, explored in this study by investigating their interaction with MN metal centers in ORR/OER/HER catalysis (Sub@MN, Sub = B, N, O, S, CH, NO, NH, OCH, SO; M = Fe, Co, Ni, Cu).
View Article and Find Full Text PDFElectrooxidation of renewable and CO-neutral biomass for low-cost hydrogen production is a promising and green technology. Various biomass platform molecules (BPMs) oxidation assisted hydrogen production technologies have obtained noticeable progress. However, BPMs anodic oxidation is highly dependent on electrocatalysts, and the oxidation mechanism is ambiguous.
View Article and Find Full Text PDFFormation of the gluten network depends on glutenin crosslinking via disulfide bonds, and wheat protein disulfide isomerase (wPDI) plays an important role in this process. Here, we identify a substrate gluten protein of wPDI and the mechanism underlying wPDI-promoted glutenin crosslinking. Farinographic, rheologic, and alveographic analysis unambiguously proves that wPDI improves gluten network formation, which is directly observed by 3D reconstruction of the gluten network.
View Article and Find Full Text PDFSilacycles have exhibited significant potential for application in the fields of medicinal chemistry, agrochemistry, and materials science. Accordingly, the development of effective methods for synthesizing these compounds has attracted increasing attention. Here, we report an efficient Cu-catalyzed enantioselective hydrosilylation of arylmethylenecyclopropanes with hydrosilanes, that allows the rapid assembly of various enantioenriched carbon- and silicon-stereogenic silacyclopentanes in good yields with excellent enantioselectivities and diastereoselectivities under mild conditions.
View Article and Find Full Text PDFGiven the critical importance of novel ligand development for transition-metal (TM) catalysis, as well as the resurgence of the field of organosilicon chemistry and silyl ligands, to summarize the topic of X-type silyl ligands for TM catalysis is highly attractive and timely. This review particularly emphasizes the unique σ-donating characteristics and -effects of silyl ligands, highlighting their crucial roles in enhancing the reactivity and selectivity of various catalytic reactions, including small molecule activation, Kumada cross-coupling, hydrofunctionalization, C-H functionalization, and dehydrogenative Si-O coupling reactions. Additionally, future developments in this field are also provided, which would inspire new insights and applications in catalytic synthetic chemistry.
View Article and Find Full Text PDFThe low cost and high efficiency of microwave-assisted regeneration render it a viable alternative to conventional regeneration methods. To enhance the regeneration performance, we developed a coupled electromagnetic, heat, and mass transfer model to investigate the heat and mass transfer mechanisms of activated carbon during microwave-assisted regeneration. Simulation results demonstrated that the toluene desorption process is governed by temperature distribution.
View Article and Find Full Text PDFThe ignition of anthracite with arc plasma has not been applied due to its low chemical effect and volatile content in anthracite. The nonequilibrium plasma generated by a microwave-induced discharge has the ability to break branch chains and aromatic ring structures by kinetic effects, which has the potential for anthracite cracking and ignition. This work investigated anthracite cracking by microwave-induced discharges under an Ar/N atmosphere.
View Article and Find Full Text PDFEfforts to enhance the efficiency of electrocatalysts for the oxygen reduction reaction (ORR) in energy conversion and storage devices present formidable challenges. In this endeavor, M-N-C single-atom catalysts (MN) have emerged as promising candidates due to their precise atomic structure and adaptable electronic properties. However, MN catalysts inherently introduce oxygen functional groups (OGs), intricately influencing the catalytic process and complicating the identification of active sites.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2023
Catalytic enantioselective intermolecular C-H silylation offers an efficient approach for the rapid construction of chiral organosilicon compounds, but remains a significant challenge. Herein, a new type of chiral silyl ligand is developed, which enables the first iridium-catalyzed atroposelective intermolecular C-H silylation reaction of 2-arylisoquinolines. This protocol features mild reaction conditions, high atom economy, and remarkable yield with excellent stereoselectivity (up to 99 % yield, 99 % ee), delivering enantioenriched axially chiral silane platform molecules with facile convertibility.
View Article and Find Full Text PDFSilanols are valuable and important compounds, which have found widespread applications in the field of materials science, synthetic chemistry, and medicinal chemistry. Although a handful of approaches have been developed for the synthesis of various silanols, access to enantioenriched silicon-stereogenic silanols remains underdeveloped. This Concept article intends to summarize and highlight recent advances in the construction of silicon-stereogenic silanols and endeavors to encourage further research in this area.
View Article and Find Full Text PDFThe deposition of β-amyloid (Aβ) in the brain leads to neurotoxic effects and subsequent Alzheimer's disease (AD). While AD is becoming more and more prevalent in modern society, therapeutic efforts targeting Aβ could be a promising solution. Currently, two natural products are reported to disintegrate preformed Aβ fibril in vitro.
View Article and Find Full Text PDFSatsuma mandarin peel pectin was extracted by high hydrostatic pressure-assisted citric acid (HHPCP) or hydrochloric acid (HHPHP), and the physiochemical, structural, rheological and emulsifying characteristics were compared to those from conventional citric acid (CCP) and hydrochloric acid (CHP). Results showed that HHP and citric acid could both increase the pectin yield, and HHPCP had the highest yield (18.99%).
View Article and Find Full Text PDFCatalytic oxidation plays important roles in energy conversion and environment protection. Boron-doped crystalline carbocatalyst has been demonstrated effective; however, the application potential of boron-doped amorphous carbocatalyst remains to be explored. For amorphous carbon material, finite-sized carbon clusters are the basic structural units, which exhibit unique activity due to edge and size effect.
View Article and Find Full Text PDFNanoporous carbons (NPCs) are ideal materials for the dry process of flue gas desulfurization (FGD) due to their rich pore structure and high specific surface area. To study the effect of edge-functionalized NPCs on the physisorption mechanism of sulfur dioxide, different functional groups were embedded at the edge of NPCs, and the physisorption behavior was simulated using the grand canonical Monte Carlo method (GCMC) combined with density functional theory (DFT). The results indicated that the insertion of acidic oxygenous groups or basic nitrogenous groups into NPCs could enhance the physisorption of SO.
View Article and Find Full Text PDFOxygen-doped carbon materials (OCM) have received a lot of attention for catalyzing the two-electron oxygen reduction reaction (2eORR) towards hydrogen peroxide generation, but the origin of their activity is not well understood. Based on density functional theory calculations, we introduce the Fukui function (f), a more comprehensive and accurate method for identifying active sites and systematically investigating the activity of carbon materials doped with typical oxygen functional groups (OGs). According to the results, only ether or carbonyl has the potential to become the activity origin.
View Article and Find Full Text PDFGluten network formed by oxidation of glutenin sulfhydryl groups is the determinant of dough rheological properties, while chemical reagents including oxidants and reductants are both used as dough rheology improvers under different circumstances. This study compares the impact of sodium metabisulfite (SMBS) and azodicarbonamide (ADA), as the representative reductive and oxidative dough improvers, at series of concentrations that offer or remove the same number of electrons form dough, respectively. The alveographic characterization, protein distribution and glutenin composition analysis, and free sulfhydryl measurement were performed on dough containing redox equivalent SMBS or ADA.
View Article and Find Full Text PDFCrustacean allergy, especially to shrimp, is the most predominant cause of seafood allergy. However, due to the high flexibility of immunoglobulin E (IgE), its three-dimensional structure remains unsolved, and the molecular mechanism of shrimp allergen recognition is unknown. Here a chimeric IgE was built in silico, and its variable region in the light chain was replaced with sequences derived from shrimp tropomyosin (TM)-allergic patients.
View Article and Find Full Text PDFHO generation by 2-electron oxygen electroreduction reaction (2eORR) has attracted great attention as an alternative to the industry-dominant anthraquinone process. Electro-Fenton (EF) process, which relies on the HO electrogeneration, is regarded as an important environmental application of HO generation by 2eORR. However, its application is hindered by the relatively expensive electrode materials.
View Article and Find Full Text PDFCrit Rev Food Sci Nutr
March 2023
Dough rheology improvers, which often are oxidative reagents in nature, have long been used in bread-making industry to enhance protein crosslinking and subsequently improve the dough rheological properties and bread qualities. Numerous studies were conducted to explore the effects of these oxidative agents on dough quality improving, however, the underlying mechanism of their action during dough development has not been fully understood. Due to the public health concerns, multiple oxidative reagents were banned in some countries across the world, while others are still permitted in accordance with regulations.
View Article and Find Full Text PDFCeliac disease (CD) is a prevalent disorder with autoimmune features. Dietary exposure of wheat gluten (including gliadins and glutenins) to the small intestine activates the gluten-reactive CD4 T cells and controls the disease development. While the human leukocyte antigen (HLA) is the single most important genetic factor of this polygenic disorder, HLA-DQ2 recognition of gluten is the major biological step among patients with CD.
View Article and Find Full Text PDFHydrogen peroxide (HO) electrosynthesis from 2-electron O reduction reaction (2eORR) is widely regarded as a promising alternative to the current industry-dominant anthraquinone process. Design and fabrication of effective, low-cost carbon-based electrodes is one of the priorities. Many previous work well confirmed that hydrophilic carbon-based electrodes are preferable for 2eORR.
View Article and Find Full Text PDFDisulfide bonds play a pivotal role in maintaining the natural structures of proteins to ensure their performance of normal biological functions. Moreover, biological molecular assembly, such as the gluten network, is also largely dependent on the intermolecular crosslinking via disulfide bonds. In eukaryotes, the formation and rearrangement of most intra- and intermolecular disulfide bonds in the endoplasmic reticulum (ER) are mediated by protein disulfide isomerases (PDIs), which consist of multiple thioredoxin-like domains.
View Article and Find Full Text PDFA highly regioselective nickel-based catalyst system for the isomerization/hydrocyanation of aliphatic internal olefins is described. This benign tandem reaction provides facile access to a wide variety of aliphatic nitriles in good yields with excellent regioselectivities. Thanks to Lewis acid-free conditions, the protocol features board functional groups tolerance, including secondary amine and unprotected alcohol groups.
View Article and Find Full Text PDFA Ni-catalyzed asymmetric hydrocyanation that enables the formation of 4-cyanotetrahydroquinolines in good yields with excellent enantioselectivities is presented herein. A variety of functional groups are well-tolerated, and a gram-scale reaction supports the synthetic potential of the transformation. Additionally, several crucial intermediates for pharmaceutically active agents, including a PGD2 receptor antagonist, are now accessible through asymmetric synthesis using this new protocol.
View Article and Find Full Text PDFA regiodivergent nickel-catalyzed hydrocyanation of a broad range of internal alkenes involving a chain-walking process is reported. When appropriate diastereomeric biaryl diphosphite ligands are applied, the same starting materials can be converted to either linear or branched nitriles with good yields and high regioselectivities. DFT calculations suggested that the catalyst architecture determines the regioselectivity by modulating electronic and steric interactions.
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