Atomically-dispersed heterogeneous metal catalysts can be considered as an “upgraded” version of classical solid metal catalysts. Unlike traditional heterogeneous metallic catalysts that contain nanoparticles or bulk micro-sized transition metal species, the active sites of these novel types of catalysts are atomically distributed on the support’s surface. This provides several advantages compared to classical catalysts such as higher activity and need for just very small amounts of metal precursors for the catalyst preparation. The latter issue is a key point in green chemical processes and of importance to achieve low-cost pathways for industrial-scale synthesis. The atomically dispersed metal sites permit a maximum of metal dispersion and additionally allow to achieve more reproducible heterogeneous catalysts. This review summarizes an overview on breakthrough findings in synthesis, applications and characterization techniques developed in the area of single-atom, dual-atom, single-atom-layer, single-site as well as single-atom nanozyme/enzyme catalysis. The characteristics and properties of each system provide an appropriate understanding for designing a nanomaterial that is optimized for a specific requirement.
Cyclometallated Platinum(II) Complexes Featuring an Unusual, C^N‐Coordinating Pyridyl‐pyridylidene Ligand and L X Coligands: Synthesis, Structures and Dual Luminescence Behavior
Abstract
Thanks to an unusual protodemethylation reaction, a series of luminescent cyclometallated platinum(II) complexes can be prepared, which incorporate a rare NC-chelating, pyridyl-pyridylidene ligand, in combination with OO-coordinating acetylacetonate (acac) or NO-coordinating 2-picolinate (pic) or 8-hydroxyquinolate. The acac and pic complexes show unusual dual emission in a frozen glass.
A series of cyclometallated platinum(II) complexes incorporating a rare, N^C-chelating, pyridyl-pyridylidene ligand are described, in which the coordination sphere is completed by two chlorides or an L X co-ligand, namely O O-coordinating acetylacetonate (acac), or N^O-coordinating 2-picolinate (pic) or 8-hydroxyquinolinate. The acac and pic complexes have been structurally characterized in the solid state by single-crystal X-ray diffraction. These two complexes display red phosphorescence in the solid state at room temperature. In a frozen glass at 77 K, all four complexes show two broad emission bands that span much of the visible spectrum, apparently from two unequilibrated excited states.
Direct Synthesis of Aldoximes: Ruthenium‐Catalyzed Coupling of Alcohols and Hydroxylamine Hydrochloride
A ruthenium pincer catalyzed direct synthesis of oximes from alcohols and hydroxyl amine hydrochloride salt is reported. Notably, the reaction requires only a catalyst and base, and water and liberated hydrogen are the only byproducts making this protocol attractive and environmentally benign.
Abstract
A catalytic method for the direct synthesis of oximes from alcohols and hydroxyl amine hydrochloride salt is reported. The reaction is catalyzed by a ruthenium pincer catalyst, which oxidizes alcohols involving amine-amide metal-ligand cooperation, and the in situ formed aldehydes condense with hydroxyl amine to deliver the oximes. Notably, the reaction requires only a catalyst and base; water and liberated hydrogen are the only byproducts, making this protocol attractive and environmentally benign.
Chemoenzymatic Tagging of Tn/TF/STF Antigens in Living Systems
Abstract
Truncated mucin-type O-glycans, such as Tn-associated antigens, are aberrantly expressed biomarkers of cancer, but remain challenging to target. Reactive antibodies to these antigens either lack high affinity or are prone to antigen escape. Here, we have developed a robust chemoenzymatic strategy for the global labeling of Tn-associated antigens, i. e. Tn (GalNAcα-O-Ser/Thr), Thomsen-Friedenreich (Galβ1-3GalNAcα-O-Ser/Thr, TF) and STF (Neu5Acα2-3Galβ1-3GalNAcα-O-Ser/Thr, STF) antigens, in human whole blood with high efficiency and selectivity. This method relies on the use of the O-glycan sialyltransferase ST6GalNAc1 to transfer a sialic acid-functionalized adaptor to the GalNAc residue of these antigens. By tagging, the adaptor functionalized antigens can be easily targeted by customized strategies such as, but not limited to, chimeric antigen receptor T-Cells (CAR-T). We expect this tagging system to find broad applications in cancer diagnostics and targeting in combination with established strategies.
5‐Nitrofuryl‐Containing Thiosemicarbazone Gold(I) Compounds: Synthesis, Stability Studies, and Anticancer Activity
“Supergold” is a very powerful gender-neutral warrior with superpowers who fights against cancer! The warrior's golden armor and sword represent the pharmacological power of the gold atom. Engraved on the shield, the gold-thiosemicarbazones molecules are the warrior's coat of arms. Supergold selectively destroys different cancer cells. More information can be found in the Research Article by Esteban Rodríguez-Arce, María Contel, and co-workers.
Economics of Emerging Ammonia Fertilizer Production Methods – a Role for On‐Farm Synthesis?
Making ammonia: How and where? Novel biological and electrochemical pathways require further large improvements to compete with Haber-Bosch. While their production flexibility improves the economics of on-farm synthesis, other drivers will encourage centralized green ammonia production.
Abstract
Prospects of recent promising methods of producing ammonia without fossil fuels are discussed. Despite demonstrating efficiency gains over previous similar approaches, the novel biological and electrochemical pathways require further large improvements to compete with electricity-powered Haber-Bosch. As some literature asserts that future production will shift to smaller scales, such as on-farm, we qualitatively discuss the economics of scale of future green ammonia production.
A Novel Polysaccharide Separated from Panax Notoginseng Residue Ameliorates Restraint Stress‐ and Lipopolysaccharide‐induced Enteritis in Mice
Abstract
Polysaccharides are rich in Panax notoginseng residue after extraction. This study aims to explore the structural characteristics of PNP-20, which is a homogeneous polysaccharide, separated from P. notoginseng residue by fractional precipitation and evaluate the anti-enteritis effect of PNP-20. The structure of PNP-20 was determined by spectroscopic analyses. A mouse model with enteritis induced by restraint stress (RS) and lipopolysaccharide (LPS) was used to evaluate the pharmacological effect of PNP-20. The results indicated that PNP-20 consisted of glucose (Glc), galactose (Gal), Mannose (Man) and Rhamnose (Rha). PNP-20 was composed of Glcp-(1→, →4)-α-Glcp-(1→, →4)-α-Galp-(1→, →4,6)-α-Glcp-(1→, →4)-Manp-(1→ and →3)-Rhap-(1→, and contained two backbone fragments of →4)-α-Glcp-(1→4)- α-Glcp-(1→ and →4)-α-Galp-(1→4)-α-Glcp-(1→. PNP-20 reduced intestinal injury and inflammatory cell infiltration in RS- and LPS-induced enteritis in mice. PNP-20 decreased the expression of intestinal tumor necrosis factor-α, NOD-like receptor family pyrin domain containing 3, and nuclear factor-κB and increased the expression of intestinal superoxide dismutase 2. In conclusion, PNP-20 may be a promising material basis of P. Notoginseng for the treatment of inflammatory bowel disease.
Development and Verification of a Diagnostic Technology for Waste Battery Deterioration Factors
Analytical methods for diagnosing the deterioration of waste batteries are reported. More specifically, the study focuses on: (1) trend analysis based on eleven key performance indicators as a method of deterioration diagnosis by fitting fifth-degree polynomial curves, and (2) comparison analysis of the second derivatives of open circuit voltage, V′′ ocv,t and simulated open circuit, voltage V′′ ocv,t,sim using a concept of model-in-the-loop simulation to verify the effectiveness of the former.
Abstract
We defined four major deterioration factors (electrolyte loss (EL), lithium loss (LL), lithium precipitation (LP), and compound deterioration (CD)). Then, we derived eleven key performance indicators (KPIs) for comparative analysis. After that, we fabricated three deteriorated cells for each of three deterioration factors (EL, LL, and LP) and one cell with CD (for verification) with four individual (dis)charging experiment manuals. The two major contributions of this study are the performance of 1) trend analysis to determine a suitable diagnostic metric by inspecting the eleven KPIs and 2) comparison analysis of and to verify the effectiveness of utilizing as a real-time deterioration diagnostic factor using a concept of model-in-the-loop simulation. The results show that 1) has the most conspicuous trendline tendency among the eleven comparison targets for all four major deterioration factors, and 2) the angle difference between the two trends of and lies within a minimum of 9° and a maximum of 43° (with a sscale on the x-axis and a scale on the y-axis for a clear trend line analysis). From this, we can conclude that the trendline-based real-time deterioration analysis employing may be practically applicable to a limited extent.
Correcting charge distribution in reduced Li‐molecule pair for computational screening of battery solvents
When an electron is added to the Li-molecule pair, it may go to the lithium-ion and neutralize it. Instead, we suggest placing this additional electron on the molecule using constrained density functional theory (CDFT).
Abstract
Li-molecule pair is a widely used model for the simulation of reduction in Li-ion batteries. We demonstrate that this model provides incorrect results for some solvents. When an electron is added to the Li-molecule pair, it may go to the lithium-ion and neutralize it. Instead, we suggest placing this additional electron on the molecule using constrained density functional theory (CDFT). This approach resembles electron behaviour in the condensed phase and reproduces the physics of the reduction. We demonstrate that suggested in this work approach provides improved agreement with experimental data. Suggested CDFT-based method is fast, reliable and may be used in computational screening of solvents. We demonstrate the practical application of the method by benchmarking it on a set of 30 molecules from the electrolyte solvent database.
Speciation analysis of inorganic arsenic in water samples using thiol-ligand and cotton fibres followed by ICP-OES determination
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