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Ag‐catalyzed enantioselective 1,3‐dipolar cycloaddition of N‐2,2,2‐trifluoroethylisatin ketimines with conjugated exocyclic double bonds including α‐alkylidene succinimides and aurone derivatives was developed for the first time. Using a catalyst system consisting of a ferrocenyl P,N‐ligand and AgNO2, the reaction provides a facile method for the construction of chiral pyrrolidines bearing four consecutive stereocenters and two adjacent spiro‐quaternary chiral centers, as well as offers a direct route to structurally diverse enantioenriched CF3‐containing 3,2′‐pyrrolidinyl spirooxindole derivatives. [ABSTRACT FROM AUTHOR]

Transition metal‐catalyzed carbonylation functionalization reaction of alkenes is an attractive research area in modern organic chemistry. However, there have been very few reports on silver‐catalyzed reactions in carbonylation reactions. Herein we developed a silver‐catalyzed carbamoylation and carbonylative cyclization of alkenes with oxamic acids to obtain 2‐acetylamino‐1‐tetralone derivatives. Various desired cyclized products were formed in moderate to good yields through radical intermediates. [ABSTRACT FROM AUTHOR]

Oxide derived catalyst displays outstanding catalytic activity and selectivity in electrochemical carbon dioxide reduction reaction (CO2RR), in which, it is found that residue oxygen atoms play a pivotal role in regulating the catalyst's electronic structure and thus the CO2RR process. Unfortunately, the intrinsic thermodynamic instability of oxygen atoms in oxide derived catalyst under cathodic CO2RR potentials makes it unstable during continuous electrolysis, greatly hindering its practical industrial applications. In this work, we develop a pulsed‐bias technique that is able to dynamically stabilize the residue oxygen atoms in oxide derived catalyst during electrochemical CO2RR. As a result, the oxide derived catalyst under pulsed bias exhibits super catalytic stability in catalyzing electrochemical CO2RR, while keeping excellent catalytic activity and selectivity. [ABSTRACT FROM AUTHOR]

The exaltation of the photodegradation performance of dichalcogenide MoS2 grown on top of silver nanoparticles (Ag‐NPs) is reported on. The fabricated MoS2 nanosheets nucleate vertically from Ag‐NPs seeds, enabling the growth of both metallic and semiconductor phases 1T/2H‐MoS2. Findings reveal remarkable enhancement of the Raman scattering and an exceptional broadband optical absorption attributed to plasmonic effects induced by the presence of both metallic 1T‐MoS2 and Ag‐NPS at 2H‐MoS2 interfaces. To leverage this effect, photodegradation tests are conducted to remove methyl orange pollutant. Notably, results reveal a significant increase in photodegradation efficiency and rate constant, reaching up to 120% and 550% over pristine 2H‐MoS2, respectively. This finding underscores the role of Ag‐NPs and 1T‐MoS2 tandem to unlock the superior photodegradation properties of vertically aligned 2H‐MoS2 toward methyl orange, paving the way for the development of dichalcogenide‐based hybrid photocatalyst for wastewater treatment and environmental remediation. [ABSTRACT FROM AUTHOR]

Electrolyte cations have been demonstrated to effectively enhance the rate and selectivity of the electrochemical CO2 reduction reaction (CO2RR), yet their implementation in electrolyte‐free membrane electrode assembly (MEA) electrolyzer presents significant challenges. Herein, an anchored cation strategy that immobilizes Cs+ on carbon vacancies was designed and innovatively implemented in MEA electrolyzer, enabling highly efficient CO2 electroreduction over commercial silver catalyst. Our approach achieves a CO partial current density of approximately 500 mA cm−2 in the MEA electrolyzer, three‐fold enhancement compared to pure Ag. In situ Raman and theoretical analyses, combined with machine learning potentials, reveal anchored Cs induces an electric field that significantly promotes the adsorption of *CO2− intermediates through performing muti‐point energy calculations on each structure. Furthermore, reduced adsorption of *OH intermediates effectively hampers competing hydrogen evolution reaction, as clarified by disk electrode experiments and density functional theory studies. Additionally, coupling our system with commercial polysilicon solar cells yields a notable solar‐to‐CO energy conversion efficiency of 8.3 %. This study opens a new avenue for developing effective cation‐promoting strategy in MEA reactors for efficient CO2RR. [ABSTRACT FROM AUTHOR]

Transition‐metal‐catalyzed decarboxylative cross‐coupling reaction provides a powerful method for the construction C−C, C−N, C−O bonds, which have great impact on synthetic chemistry. The use of silver salts as catalyst in decarboxylative reaction gradually increases because of their easy availability, low toxicity, biocompatibility and adequate stability. In fact, various radical cyclization reactions have been accomplished by exploiting single electron transfer (SET) ability of silver salts. The present review highlights recent advances (2015‐mid 2023) in the silver‐catalyzed decarboxylative radical cyclizations for the construction of cyclic molecular scaffolds. The content of the review is organized on the basis of decarboxylative reagents, such as, α‐keto acids, aliphatic/aromatic carboxylic acids, α,α‐difluoroacetic acids, amino acids, alkynyl carboxylic acids, oxamic acids and miscellaneous acids. Additionally, mechanistic insights of most of the reactions are highlighted for well understanding of the reaction mode. [ABSTRACT FROM AUTHOR]

Conventional routes for the production of formaldehyde rely on the use of methanol and air, with the presence of catalysts such as silver or mixed‐metal oxides. These processes are highly energy intensive and therefore raise concerns in terms of cost‐effectiveness and environmental impact. In that respect, sodium or sodium compounds are more favorable as catalysts for the direct dehydrogenation of methanol to water‐free formaldehyde. A method is presented for the coproduction of hydrogen and anhydrous formaldehyde – both valuable products – on the laboratory scale, with a particular focus on the design and testing of a sodium vapor catalyst dosing unit that enables the process to be performed continuously. [ABSTRACT FROM AUTHOR]

Olefination of aldehydes is one of the fundamental reactions in organic synthesis. The commonly used Wittig olefination reaction however uses stoichiometric quantities reagents under basic conditions resulting in stoichiometric amounts of byproducts. Known catalytic alternate to the Wittig reaction requires stoichiometric amounts of silane reducing agents and high temperature. Herein, we report a base‐free olefination of aryl aldehydes using propiolates as a surrogate for the Witting reagent under silver catalysis. Trimethyl orthoformate, in the presence of a silver catalyst adds to the alkynoate to form the nucleophilic silver allenolate which reacts with the reactive oxocarbenium ion formed from aldehyde under the reaction conditions. Subsequently, decarbonylation occurs to form the olefin. Trans olefin is formed exclusively from simple aryl aldehydes and cinnamaldehydes. Such a silver allenolate is conceptually novel and has not been explored so far. [ABSTRACT FROM AUTHOR]

Electrolysis of bicarbonate‐containing CO2 capture solutions is a promising approach towards achieving low‐cost carbon‐neutral chemicals production. However, the parasitic bicarbonate‐mediated hydrogen evolution reaction (HER) and electrode instability in the presence of trace impurities remain major obstacles to overcome. This work demonstrates that the combined use of titanium dioxide (TiO2) overlayers with the chelating agent ethylene diamine tetra‐acetic acid (EDTA) significantly enhances the selectivity and stability of Ag‐based electrocatalysts for bicarbonate electrolysis. The amorphous TiO2 overlayers suppress the HER by over 50 % at potentials more negative than −0.7 V vs. RHE, increasing the CO faradaic efficiency (FE) by 33 % (relative). In situ surface‐enhanced Raman spectroscopy (SERS) measurements reveal the absence of near‐surface bicarbonate species and an abundance of CO2 reduction intermediates at the Ag|TiO2 buried interface, suggesting that the overlayers suppress HER by blocking bicarbonate ions from reaching the buried active sites. In accelerated degradation tests with 5 ppm of Fe(III) impurity, the addition of EDTA allows stable CO production with >47 % FE, while the electrodes rapidly deactivate in the absence of EDTA. This work highlights the use of TiO2 overlayers for enhancing the CO : H2 ratio while simultaneously protecting electrocatalysts from impurities likely to be present in "open" carbon capture systems. [ABSTRACT FROM AUTHOR]

A series of supported N‐heterocyclic carbene silver complexes (NHC‐Ag(I)) were prepared and characterized as catalysts for the borono‐Minisci reaction. After characterization, the synthesized catalysts were evaluated in batch mode to determine the reaction performance and kinetics. Interestingly, cyclic voltammetric analysis showed that the structure of both the complex and the ligand significantly influences the Ag(I)/Ag(II) redox potential and, in turn, the catalytic efficiency. Among the tested catalysts, the Si‐supported NHC‐Ag(I) 6 afforded the desired products in good to excellent yields in only 15 min, providing a complementary tactic to standard homogeneous approaches. [ABSTRACT FROM AUTHOR]

Sustainable hydrogen generation is preferred over production from fossil sources in the context of a carbon‐neutral economy. As a result, production costs for CO2‐based products are estimated to be much higher than those of their fossil equivalents. Hence, it is essential to optimize process chains regarding their hydrogen efficiency. In this study, a concept for the directly coupled production of CO2‐based methanol and formaldehyde in a modified silver catalyst process is evaluated regarding the utilization of H2. Detailed simulations in Aspen Plus allow the comparison to the separately operated synthesis of green methanol and formaldehyde. By directly connecting both production steps, utilization ratios of introduced H2 and CO2 could be improved, reaching values of 98 % and 99 %, respectively. [ABSTRACT FROM AUTHOR]

Sustainable hydrogen generation is preferred over production from fossil sources in the context of a carbon‐neutral economy. As a result, production costs for CO2‐based products are estimated to be much higher than those of their fossil equivalents. Hence, it is essential to optimize process chains regarding their hydrogen efficiency. In this study, a concept for the directly coupled production of CO2‐based methanol and formaldehyde in a modified silver catalyst process is evaluated regarding the utilization of H2. Detailed simulations in Aspen Plus allow the comparison to the separately operated synthesis of green methanol and formaldehyde. By directly connecting both production steps, utilization ratios of introduced H2 and CO2 could be improved, reaching values of 98 % and 99 %, respectively. [ABSTRACT FROM AUTHOR]

Metal‐modified catalysts have attracted extraordinary research attention in heterogeneous catalysis due to their enhanced geometric and electronic structures and outstanding catalytic performances. Silver (Ag) possesses necessary active sites for ethylene epoxidation, but the catalyst activity is usually sacrificed to obtain high selectivity towards ethylene oxide (EO). Herein, we report that using Al can help in tailoring the unoccupied 3d state of Ag on the MnO2 support through strong electronic metal‐support interactions (EMSIs), overcoming the activity‐selectivity trade‐off for ethylene epoxidation and resulting in a very high ethylene conversion rate (~100 %) with 90 % selectivity for EO under mild conditions (170 °C and atmospheric pressure). Structural characterization and theoretical calculations revealed that the EMSIs obtained by the Al modification tailor the unoccupied 3d state of Ag, modulating the adsorption of ethylene (C2H4) and oxygen (O2) and facilitating EO desorption, resulting in high C2H4 conversion. Meanwhile, the increased number of positively charge Ag+ lowers the energy barrier for C2H4(ads) oxidation to produce oxametallacycle (OMC), inducing the unexpectedly high EO selectivity. Such an extraordinary electronic promotion provides new promising pathways for designing advanced metal catalysts with high activity and selectivity in selective oxidation reactions. [ABSTRACT FROM AUTHOR]

An acylative fluorination of two different alkenes is developed, assisted by the interaction of silver catalyst and Selectflour. Various α‐ketonic acids can be decarboxylated to form acyl radicals at 35 °C, sequentially add to the electron‐deficient and electron‐ rich alkenes to provide the benzyl fluorinated compounds containing diversified functional groups. [ABSTRACT FROM AUTHOR]

Given the prevalence of heterocyclic scaffolds in drug‐related molecules, converting these highly modular heterocyclic scaffolds into structural diversified and dearomatized analogs is an ideal strategy for improving their physicochemical and pharmacokinetic properties. Here, we described an efficient method for silver carbene‐mediated dearomative N−N bond cleavage leading to skeletal hopping between indazole and 1,2‐dihydroquinazoline via a highly selective single‐carbon insertion procedure. Using this methodology, a series of dihydroquinazoline analogues with diarylmethylene‐substituted quaternary carbon centers were constructed with excellent yields and good functional group compatibility, which was further illustrated by the late‐stage diversification of important pharmaceutically active ingredients. DFT calculations indicated that the silver catalyst not only induces the formation of the silver carbene, but also activates the diazahexatriene intermediate, which plays a crucial role in the formation of the C−N bond. [ABSTRACT FROM AUTHOR]

Molecular Dynamics (MD) simulations constitute a powerful tool that provides a 3D perspective of the dynamical behavior of chemical systems. Herein the first MD study of the dynamics of a catalytic organometallic system, in micellar media, is presented. The challenging methane catalytic functionalization into ethyl propionate through a silver‐catalyzed process has been targeted as the case study. The intimate nature of the micelles formed with the surfactants sodium dodecylsulfate (SDS) and potassium perfluorooctane sulfonate (PFOS) has been ascertained, as well as the relative distribution of the main actors in this transformation, namely methane, the diazo reagent and the silver catalyst, the latter in two different forms: the initial compound and a silver‐carbene intermediate. Catalyst deactivation occurs with halide containing surfactants dodecyltrimethylammonium chloride (DTAC) and Triton X‐100. Computed simulations allow explaining the experimental results, indicating that micelles behave differently regarding the degree of accumulation and the local distribution of the reactants and their effect in the molecular collisions leading to net reaction. [ABSTRACT FROM AUTHOR]

The stereodivergent asymmetric synthesis of 2,5‐trans/cis pyrrolidines by 1,3‐dipolar cycloaddition using two different types of activated alkenes is described. When ylidene‐isoxazolones were employed as dipolarophiles, the Ag/(S,Sp)‐iPr‐FcPHOX‐catalyzed asymmetric [3+2] cycloaddition of imino lactones proceeded with 2,5‐trans selectivity. Subsequent decarboxylation of the isoxazolone rings produced pyrrolidines with 2,5‐trans stereoretention. In the reaction using acyclic enones as activated alkenes, the Ag/(R,Sp)‐ThioClickFerrophos complex‐catalyzed asymmetric [3+2] cycloaddition afforded 2,5‐cis substituted pyrrolidines in high yields and enantioselectivities. Therefore, these methods can be considered as a formal stereodivergent synthesis of 2,5‐cis/trans pyrrolidines. [ABSTRACT FROM AUTHOR]

α‐Alumina is a non‐porous metal oxide with applications in ceramics and catalysis. Introducing pores into this material to create catalytically relevant surface area is challenging due to phase transitions over a wide temperature range. Current synthesis strategies involve hard templates such as synthetic polymers, e. g. polymethylmethacrylate (PMMA). Here, we compare cellulose and carbonized glucose as low‐cost and natural alternative templates for high surface area α‐alumina with a two‐step heating method. Quantitative XRD was used to methodically investigate alumina phase purity. Increasing the template size in the range of 220–1000 nm improved α‐alumina purity from 75 to 98 %, while maintaining high surface areas (21–29 m2 g−1). Phase purity increases substantially by prolonging the calcination time. The synthesized high surface area α‐alumina was studied as support for silver catalysts in the epoxidation of ethylene and allowed high silver loadings. Ethylene oxide selectivity increased with enhanced α‐alumina phase purity. Our 30 wt % silver catalyst on pure high surface area α‐alumina did not show loss in selectivity compared to a 15 wt % silver catalyst on commercial non‐porous α‐alumina. This shows the potential of carbohydrate templates, the importance of templating parameters and the benefits of pure high surface area α‐alumina as support for silver catalysts. [ABSTRACT FROM AUTHOR]

Ethylene epoxidation is industrially and commercially one of the most important selective oxidations. Silver catalysts have been state‐of‐the‐art for decades, their efficiency steadily improving with empirical discoveries of dopants and co‐catalysts. Herein, we perform a computational screening of the metals in the periodic table, identify prospective superior catalysts and experimentally demonstrate that Ag/CuPb, Ag/CuCd and Ag/CuTl outperform the pure‐Ag catalysts, while they still confer an easily scalable synthesis protocol. Furthermore, we show that to harness the potential of computationally‐led discovery of catalysts fully, it is essential to include the relevant in situ conditions e.g., surface oxidation, parasitic side reactions and ethylene epoxide decomposition, as neglecting such effects leads to erroneous predictions. We combine ab initio calculations, scaling relations, and rigorous reactor microkinetic modelling, which goes beyond conventional simplified steady‐state or rate‐determining modelling on immutable catalyst surfaces. The modelling insights have enabled us to both synthesise novel catalysts and theoretically understand experimental findings, thus, bridging the gap between first‐principles simulations and industrial applications. We show that the computational catalyst design can be easily extended to include larger reaction networks and other effects, such as surface oxidations. The feasibility was confirmed by experimental agreement. [ABSTRACT FROM AUTHOR]

CO is usually the dominant product on silver‐based catalysts in electrochemical CO2 reduction reaction (CO2RR) possibly due to weak *CO adsorption. In this report, a hydroxypillar[5]arene‐extended porous polymer‐confined silver catalyst (PAF‐PA5‐Ag‐0.8) for electrochemical CO2RR which can selectively produce ethanol with a maximum Faradaic efficiency of 55% at 11 mA cm−1 is described. The study reveals that the hydroxypillar[5]arene‐confined Ag clusters are the active sites for ethanol formation. Moreover, temperature‐programmed desorption measurements demonstrate an enhanced adsorption strength of CO* on PAF‐PA5‐Ag‐0.8 compared with that on commercial Ag nanoparticles, which is favored by the C‐C coupling to form ethanol. The density functional theory study indicates that the confined Ag clusters in PAF‐PA5‐Ag‐0.8 contribute to high C2 selectivity in CO2RR through facilitating *COOH formation, stabilizing *CO intermediates, and inhibiting hydrogen evolution. This work provides a new design strategy by modulating *CO adsorption strength on non‐copper electrocatalysts in converting CO2 into "green" C2 products. [ABSTRACT FROM AUTHOR]

Tandem catalysis presents a promising strategy to improve the selectivity toward multicarbon products in the electrocatalytic carbon dioxide reduction reaction (CO2RR). For CO2RR, CO is a critical intermediate for producing multicarbon products. However, the management of CO localization and CO diffusion remains underexplored despite its critical role. Herein, a 3D tandem catalyst electrode with silver nanoparticles (Ag NPs) is designed to generate CO as an intermediate product within a copper (Cu) nanoneedle array. Via this nanostructured design, CO2 forms C2+ products with a high Faradaic efficiency (FEC2+) of 64% in an H‐cell and 70% in a flow cell with a current density of 350 mA cm−2. These figures‐of‐merit are currently among the top literature reports. More importantly, in situ Raman spectroscopy and finite‐element method calculations are employed to elucidate the origins of enhanced selectivity. These approaches reveal the crucial role of prolonging the CO diffusion path length for improving CO utilization during CO2 conversion with tandem catalyst systems. The favorable CO2RR FEC2+ in two distinct environments (H‐cell and flow cell) further corroborates that this effect is not limited to a particular reactor environment. Overall, this study provides new insights for designing tandem catalysts for improved CO2RR selectivity to C2+ products. [ABSTRACT FROM AUTHOR]

Selective oxidation of ethylene to ethylene oxide (EO) is performed industrially over catalysts comprised of silver particles supported on α‐Al2O3. In addition to various oxy‐anion and alkali promotors, alkyl chloride species ("chloride moderators") are continuously introduced into commercial reactors. The effect and usage of chloride moderators is a key requirement for industrial ethylene epoxidation catalysts to reach optimal selectivity. While not an exhaustive review, the aim of this perspective is to provide guidance to academic researchers on the operation of EO catalysts under commercially relevant conditions with particular focus on the importance of performance optimization. [ABSTRACT FROM AUTHOR]

An Ag/Au‐catalyzed divergent cascade reaction of alkyne embedded diazoketones with indoles has been described. Preliminary mechanistic studies indicate that the reaction goes through a [4+2]‐cycloaddition of an in situ formed isobenzopyrylium intermediate with indole, followed by a sequential retro‐Michael addition/carbene N−H insertion process to give the benzo[i]phenanthridines products with gold catalysis; whereas a dearomatization/rearomatization sequence occurs favourably when the reaction is catalyzed by a silver catalyst, delivering benzo[b]carbazoles in generally high to excellent yields. Notably, this is a rare example of using indole as the dienophile for cycloaddition with the isobenzopyrylium species, providing a concise and practical approach for the selective construction of N‐doped polycyclic aromatic hydrocarbons (PAHs) with structural diversity and broad functional‐group compatibility. [ABSTRACT FROM AUTHOR]

Zero‐gap anion exchange membrane (AEM)‐based CO2 electrolysis is a promising technology for CO production, however, their performance at elevated current densities still suffers from the low local CO2 concentration due to heavy CO2 neutralization. Herein, via modulating the CO2 feed mode and quantitative analyzing CO2 utilization with the aid of mass transport modeling, we develop a descriptor denoted as the surface‐accessible CO2 concentration ([CO2]SA), which enables us to indicate the transient state of the local [CO2]/[OH−] ratio and helps define the limits of CO2‐to‐CO conversion. To enrich the [CO2]SA, we developed three general strategies: (1) increasing catalyst layer thickness, (2) elevating CO2 pressure, and (3) applying a pulsed electrochemical (PE) method. Notably, an optimized PE method allows to keep the [CO2]SA at a high level by utilizing the dynamic balance period of CO2 neutralization. A maximum jCO of 368±28 mA cmgeo−2 was achieved using a commercial silver catalyst. [ABSTRACT FROM AUTHOR]

Natural enzymes accelerate substrate‐specific reactions making them of exquisite interest for various applications. However, their appeal is lost in a practical setting due to low stability and high preparation expenses. This is the primary reason behind the flourishing in the research of nanozyme, i.e., artificial enzymes, in the past decade. Their unique physicochemical properties make them a promising candidate for various applications, especially in diagnostics and detection. They possess an enzyme‐like activity and can overcome the drawbacks of natural protein‐based enzymes. Nanozymes are nanomaterials that show enzyme‐like catalytic activity and have great potential to replace natural enzymes for industrial applications. The scope of tuning these nanozymes enhances their catalytic activity and provides specificity, benefiting disease diagnosis and drug delivery. This review aims to report the applications of silver nanozymes in disease diagnosis, glucose detection, and cancer therapy. Their role in detecting heavy metal ions for environmental safety has also been highlighted. [ABSTRACT FROM AUTHOR]

The rechargeable all‐solid‐state Na–O2 battery is one of the most promising candidates for next‐generation energy storage devices owing to its high theoretical specific energy, safety, electrochemical stability, and abundant Na resources. However, the practical implementation of current all‐solid‐state Na–O2 batteries is still limited by low‐resistance interfaces, low energy efficiency, and poor cycle life. Herein, an all‐solid‐state Na–O2/H2O battery that can sustain highly reversible cycling with a low overpotential is reported. Using a customized silver–polymer composite cathode, this battery can be operated under ≈7% relative humidity (RH) at 80 °C and cycled for more than 100 times with a low overpotential (≈75 mV at 100th cycle) and high round trip efficiency >97% at 100th cycle) at an energy density of 20 mA g−1. Furthermore, mechanistic insight that the RH intimately controls the type and hydration state of the discharge product is also provided, and thereby the charge kinetics and battery performance are modulated. It is also revealed that silver catalyst can efficiently reduce the reaction barrier of NaOH decomposition. With the further optimization, this battery potentially can be implemented in real‐world applications and confer practical applicability that can extend to other energy‐storage systems, such as other metal–air batteries. [ABSTRACT FROM AUTHOR]

The synthesis of silver nano particles has acquired more attention in terms of its applicability in various fields including medicine, environmental, electronics and energy. Owing to its exceptionally good catalytic activity, this particular study is focused on the synthesis of silver nanoparticles in bulk scale, free from capping agents. Apart from the conventional colloidal green synthesis, the silver nanoparticles were synthesized in solid form using a cheap green medium lime fruit extract. The green mediated sol‐gel auto combustion method eliminates the use of hazardous reducing agents and tedious purification processes. The structure, morphology and purity of the synthesized material were explored through various analytical techniques. TEM studies revealed that the synthesized silver nanoparticles were spherical in shape with average particle size of 8 nm. The potential of the silver nanoparticle as a catalyst towards reduction of organic compounds and dye degradation was established by conducting nitrophenol reduction and methylene blue degradation as a basic reaction. The nanoparticles were found to have effectively catalysed the reduction of p‐nitrophenol and degradation of methylene blue with the aid of sodium borohydride as reducing agent. It may open up new path for the chemical free synthesis of crystalline silver nanoparticles with enhanced catalytic property. [ABSTRACT FROM AUTHOR]

Hand shadow puppetry is the art of making shadow images, especially of animals, by using hands and light. Just like this, we have made α,β‐unsaturated ester by treating arylaldehyde and propiolate as arms activated by trimethyl orthoformate in presence of a shiny silver catalyst. More information can be found in the Research Article by R. R. Manwar and R. Balamurugan co‐workers (DOI: 10.1002/chem.202401905)...By Rina Raju Manwar and Rengarajan BalamuruganReported by Author; Author [Extracted from the article]

The development of alternative benign reaction conditions to perform multicomponent reactions is an interesting and desirable strategy to increase the sustainability of organic synthesis. In this paper, we report a new version of A3‐coupling MCR for the preparation of differently substituted propargylamines starting from aldehydes, alkynes and amines in an acidic DES as reaction media, under dielectric heating, and in the presence of a tetraaza‐macrocyclic silver complex as catalyst. The reaction scope is broad in terms of aldehyde partners. Electron‐rich phenylacetylenes are the more reactive alkynes partners, whereas the nature of the amine is the more serious limitation as only secondary cyclic amines are tolerated. [ABSTRACT FROM AUTHOR]

Olefin production from polyols via deoxydehydration (DODH) was carried out over Ag‐modified CeO2‐supported heterogeneous Re catalysts with H2 as a reducing agent. Both high DODH activity and low hydrogenation ability for C=C bonds were observed in the reaction of erythritol, giving a 1,3‐butadiene yield of up to 90 % under "solvent‐free" conditions. This catalyst is applicable to other substrates such as methyl glycosides (methyl α‐fucopyranoside: 91 % yield of DODH product; methyl β‐ribofuranoside: 88 % yield), which were difficult to be converted to the DODH products over the DODH catalysts reported previously. ReOx‐Ag/CeO2 was reused 3 times without a decrease of activity or selectivity after calcination as regeneration. Although the transmission electron microscopy energy‐dispersive X‐ray spectroscopy and X‐ray absorption fine structure analyses showed that Re species were highly dispersed and Ag was present as metal particles with various sizes from well‐dispersed species (<1 nm) to around 5 nm particles, the catalysts prepared from size‐controlled Ag nanoparticles showed similar performance, indicating that the catalytic performance is insensitive to the Ag particle size. [ABSTRACT FROM AUTHOR]

Base catalysed exchange with sodium hydroxide, calcium oxide or N,N,N,N‐tetramethylguanidine in deuterium oxide is a viable procedure for the preparation of terminally deuterated alkynes for those alkynes stable to strong base. The use of silver perchlorate as a catalyst is an alternative practical option when labelling alkynes which are sensitive to base or contain functionalities which would lead to labelling elsewhere in the molecule. Labelling with this catalyst takes place smoothly at ambient temperature in a mixture of N,N‐dimethylformamide and deuterium oxide. [ABSTRACT FROM AUTHOR]

Supported silver catalysts with small and uniform particle sizes are promising for selective hydrogenation or oxidation reactions. However, during catalyst preparation, transport of the silver precursors often leads to large silver particles, especially at higher silver loadings. In this paper, the use of silver silicate as an intermediate for the preparation of silica‐supported silver nanoparticles is reported. Supported silver silicate was prepared by reacting silver nitrate with silica. Subsequently, the silver silicate was reduced to prepare supported silver nanoparticles of ∼2 nm in size at a loading of 15 wt% Ag. The utilization of silver silicate limited the transport of silver species during precursor decomposition, resulting in silver nanoparticles 20 times smaller than those formed by direct reduction of a supported silver nitrate precursor. The catalysts were applied in carbon monoxide oxidation, which confirmed the high dispersion as well as the excellent stability of the supported silver nanoparticles thus prepared. [ABSTRACT FROM AUTHOR]

A novel approach for the synthesis of regioselective pyrano[3,4‐b]quinolines from 3‐alkynylquinoline aldehydes with alcohols as nucleophiles has been elucidated. This protocol has shown high generality of functional group and provides the pyrano‐annulated products good to excellent yields. This methodology was adopted a new synthetic strategy to develop the 3‐alkynylquinolinealdehydes by using methanol as a C1 source. [ABSTRACT FROM AUTHOR]

A variety of chiral nine‐membered N‐heterocycles were prepared in moderate to good yields with high diastereoselectivity through a silver(I)‐catalyzed [3+2] cycloaddition and [3,3]‐rearrangement of N‐vinyl‐α, β‐unsaturated nitrones and chiral 3‐propioloyloxazolidin‐2‐ones. Experimental studies showed that silver catalyst promoted the cycloaddition and rearrangement process, and the stereochemistry of the nine‐membered N‐heterocycles was controlled via [3,3]‐rearrangement by chiral oxazolidinone‐auxiliary through a boat‐like transition state. Moreover, the obtained nine‐membered N‐heterocycle diastereomers were converted to chiral pyrrolizines with high diastereoselectivity and pyrrolizine carboxylate was obtained in 54% yield with 90% ee by the removal of chiral auxiliary. [ABSTRACT FROM AUTHOR]

Invited for this issue's Front Cover are researchers from the Carbon Initiative at Lawrence Livermore National Laboratory and the SUNCAT Center at Stanford University. The front cover shows a cross‐section of the cathode of a membrane electrode assembly for CO2 electrolysis looking down the feed channel. CO2 molecules flow down the channel and diffuse up through the gas diffusion layer to the silver catalyst, where CO2 reacts to form CO, while also competing against hydrogen reduction from water. Some of the CO2 molecules react to form bicarbonate and carbonate ions, which can diffuse across the membrane, where they react at the anode to form CO2 again. The top of the image shows CO2 that has crossed over through the membrane into the anolyte. Cover design by Brendan Thompson. Read the full text of the Research Article at 10.1002/celc.202300566. [ABSTRACT FROM AUTHOR]

The exploitation of recycled carbonaceous catalysts from renewable biomass resources such as chitin is a crucial issue for the development of the sustainable society. In this article, the chitin‐based N and O doped carbon microspheres (ChC) were fabricated by a simple dissolution, sol–gel transformation, and the carbonization methods. Subsequently, the novel magnetic Ag‐Fe3O4@chitin‐based carbon microspheres catalyst (MChC) was successfully constructed through the in situ redox reaction. The as‐prepared MChC possessed rich micropores with high‐surface area, and a narrow size distribution (50–120 μm). The Ag‐Fe3O4 nanoparticles were immobilized through the interaction with C, N, and O atoms in the pores of MChC. The reduction of 4‐nitrophenol was applied to evaluate the catalytic activity of MChC. 4‐Nitrophenol (4‐NP) could be fully reduced to 4‐aminophenol (4‐AP) in 5 min with the catalyst MChC‐45. Moreover, MChC could be collected in solution with an external magnet in 8 s and remained relatively high‐catalytic activity after 10 cycle times. This work provided novel ideas for the fabrication of doped carbon material from biomass and promoted its utilization in nanocatalytic applications. [ABSTRACT FROM AUTHOR]

Background: Hyperthyroid cats might have a predisposition to arterial thrombus formation. The mechanism for thrombogenesis currently is unknown but could be associated with systemic hypercoagulability as seen in hyperthyroid humans. Objective: Our purpose was to evaluate markers of hemostasis in hyperthyroid cats compared to healthy cats, and in hyperthyroid cats before and after radioactive iodine treatment (RIT). Animals Twenty‐five cats with hyperthyroidism and 13 healthy euthyroid cats >8 years of age. Methods: Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration, antithrombin (AT), D‐dimers, thrombin‐antithrombin complexes (TAT), von Willebrand Factor antigen (vWF : Ag), and activity of factors VIII and IX were measured. An echocardiogram was performed in all cats. Hemostatic markers and echocardiogram were evaluated again 6 to 9 months after successful RIT in 7 cats. Results: Hyperthyroid cats had higher fibrinogen concentration (P <.0001), AT activity (P <.0001), and vWF : Ag concentration (P =.01) than healthy control cats with all results decreasing significantly post‐RIT. Hyperthyroid cats were not more likely to be in a hypercoaguable state than euthyroid cats (P =.08). Serum T4 concentration was not a predictor of a hypercoagulable state (P =.53). Conclusions and Clinical Importance: Hyperthyroid cats have evidence of altered hemostasis that does not appear to be solely attributable to cardiac abnormalities, but no evidence of a hypercoagulable state. Findings suggest altered hemostasis resolves after RIT. Hyperthyroid cats could have endothelial dysfunction as indicated by increased vWF : Ag which could potentiate thrombogenesis. [ABSTRACT FROM AUTHOR]

The electrocatalytic activity of commercial silver nanowires (AgNWs) with different diameters (35, 90, and 120 nm) was investigated towards the oxygen reduction reaction (ORR) in 0.1 M KOH solution. The rotating disc electrode (RDE) data analysis revealed that the ORR onset potential and half‐wave potential shift positively for AgNWs as compared to a polycrystalline Ag electrode. The enhanced ORR performance of AgNWs with a diameter of 35 nm was attributed to the elongated porous structure of the catalyst material, which facilitated the mass transport in the catalyst layer. The Koutecky‐Levich analysis was used to determine the kinetic parameters of O2 reduction and to confirm that the ORR proceeds via 4‐electron pathway on AgNW‐modified electrodes. Stability tests showed that 35 nm thick AgNWs had high stability during long‐term potential cycling. Based on the obtained results, the AgNWs have great potential as efficient catalysts for alkaline membrane fuel cell technologies. [ABSTRACT FROM AUTHOR]

Over the past two decades, there has been a substantial increase in the number of synthetically useful transformations catalyzed by silver. Across the range of silver‐catalyzed reactions that have been reported, dinuclear species often emerge as a common feature, either as the (pre‐)catalysts themselves or as intermediates during catalysis. This Minireview explores the role of dinuclear silver complexes in homogeneous catalysis, which we hope will aid in the development of improved design principles for silver catalysts. [ABSTRACT FROM AUTHOR]

ortho‐Carbonylarylacetylenol, can be utilized for the synthesis of several important core structures. In this work, a method is developed for the diastereoselective synthesis of spirocyclic ethers using a silver catalyst under the presence of acid. This protocol can be applied to a variety of substrates resulting in the corresponding products in 35–97% yields with good diastereoselectivity. The proposed reaction mechanisms and stereoselectivity outcome of the corresponding products are investigated using DFT calculation. This current protocol can be applied to a broad range of substrates which would be useful for the creation of libraries of spirocylic ethers [ABSTRACT FROM AUTHOR]

Aqueous silver ethylene diamine oxalate complex solution is a critical precursor in the production of supported silver catalysts. Crystals precipitating from such complex solutions are characterized by single‐crystal structure analysis as [Ag(μ‐en)]2(C2O4)×2H2O. Silver atoms are bridged by ethylenediamine molecules in a molar ratio of 1 : 1 forming slightly distorted one‐dimensional polymeric Ag(μ‐en)‐chains along the c axis. Oxygen atoms of oxalate groups show no direct coordination to silver atoms. Oxygen atoms of lattice water molecules show a weak lateral coordination to silver atoms within slightly bent N−Ag−N fragments. [ABSTRACT FROM AUTHOR]

The weakly coordinating dianion [B12Cl12]2− originates from a family of carboranes typically reserved for application in coordination chemistry. Herein, we show that its readily accessible Ag(I) salt, [Ag]2[B12Cl12], can be used as a catalyst in the PhICl2 mediated chlorination of arenes, alkenes, and alkynes. The promising activity displayed by [Ag]2[B12Cl12] over a variety of commercially available Ag(I) sources merits its incorporation to the toolkit of commonly screened silver catalysts in synthesis. [ABSTRACT FROM AUTHOR]

The [2+1] cycloaddition reaction of a metal carbene with an alkene can produce important cyclopropane products for synthetic intermediates, materials, and pharmaceutical applications. However, this reaction is often accompanied by side reactions, such as coupling and self‐coupling, so that the yield of the cyclopropanation product of non‐silver transition‐metal carbenes and hindered alkenes is generally lower than 50 %. To solve this problem, the addition of a low concentration of diazo compound (decomposition of sulfonyl hydrazones) to alkenes catalyzed by either CuOAc or PdCl2 was studied, but side reactions could still not be avoided. Interestingly, however, the yield of cyclopropanation products for such hindered alkenes were as high as 99 % with AgOTf as a catalyst. To explain this unexpected phenomenon, reaction pathways have been computed for four different catalysts by using DFT. By combining the results of these calculations with those obtained experimentally, it can be concluded that the efficiency of the silver catalyst is due to the barrierless concerted cycloaddition step and the kinetic inhibition of side reactions by a high concentration of alkene. [ABSTRACT FROM AUTHOR]

The direct functionalization of C−H bonds is a fundamental task in organic chemistry. Because of the extraordinary catalysis performance, reaction selectivity, stability, and relatively lower cost than other noble transition metals, silver catalysts had successfully captured lots of interest and been widely in C−H bond functionalization. In this review, the development in the last decade of silver‐mediated C(sp2)‐H bond functionalization is summarized, categorized by the type of newly formed bond, C−C bond, C−N bond, C−O bond, etc. The mechanism, scope, and limitations of the reported references were introduced. [ABSTRACT FROM AUTHOR]

A new strategy for the straightforward alkylation of heteroarenes under mild conditions was developed. It employed silver catalyst for the cross dehydrogenative coupling between heteroarenes and cyclic ethers to construct a new C(sp2)−C(sp3) bond. This reaction was carried out in water under room temperature and applicable to various heteroarenes such as pyridines, quinolines and isoquinolines derivatives with good functional group compatibility. [ABSTRACT FROM AUTHOR]

Silver complexes with 5‐(4‐(tert‐butyl)‐1H‐imidazol‐1‐yl)‐imidazo[1,5‐a]pyridin‐3‐ylidene ligands were synthesized as metal‐imidazole acid‐base cooperative catalysts. Single crystal XRD analysis revealed that the silver atom was located in the vicinity of the imidazole ring and that cationic silver complexes formed dimers through coordination between the silver metal and the imidazole pendant. These cationic silver complexes served as catalysts for cyclization of alkyne‐tethered carboxylic acids. NMR experiments indicated that the dimeric cationic silver complex dissociated to a monomer upon protonation of the imidazole moiety, resulting in coordination of an acetonitrile to the silver atom. DFT calculations supported the acid‐base cooperative action of the silver‐imidazole for the efficient alkyne‐carboxylic acid cyclization. [ABSTRACT FROM AUTHOR]

We report an Ag1 single‐atom catalyst (Ag1/MnO2), which was synthesized from thermal transformation of Ag nanoparticles (NPs) and surface reconstruction of MnO2. The evolution process of Ag NPs to single atoms is firstly revealed by various techniques, including in situ ETEM, in situ XRD and DFT calculations. The temperature‐induced surface reconstruction process from the MnO2 (211) to (310) lattice plane is critical to firmly confine the existing surface of Ag single atoms; that is, the thermal treatment and surface reconstruction of MnO2 is the driving force for the formation of single Ag atoms. The as‐obtained Ag1/MnO2 achieved 95.7 % Faradic efficiency at −0.85 V vs. RHE, and coupled with long‐term stability for electrochemical CO2 reduction reaction (CO2RR). DFT calculations indicated single Ag sites possessed high electronic density close to Fermi Level and could act exclusively as the active sites in the CO2RR. As a result, the Ag1/MnO2 catalyst demonstrated remarkable performance for the CO2RR, far surpassing the conventional Ag nanosized catalyst (AgNP/MnO2) and other reported Ag‐based catalysts. [ABSTRACT FROM AUTHOR]

The combination of metal catalyst and inorganic silica frameworks provides a greener approach to recyclable catalysis. In this study, three phosphine–gold chloride complexes have been successfully covalently grafted onto chiral silica nanohelices. The resulting 3D ensembles showed chiroptical properties that allowed the monitoring of the supported ligands. The heterogeneous gold chloride catalysts in cooperation with silver triflate exhibited high reactivity in various reactions, especially in the spirocyclization of aryl alkynoate esters, for which a catalytic loading of 0.05 mol % could be employed. The heterogeneous catalysts could be easily recovered and recycled seven or eight times without any loss of efficiency. By adding more silver triflate, 25 cycles with full conversion were achieved owing to a complex catalytic system based on silica and metallic species. [ABSTRACT FROM AUTHOR]

Strain‐promoted azide–alkyne cycloaddition using dibenzoazacyclooctyne (DBCO) is widely applied in copper‐free bioorthogonal reactions. Reported here is the efficient acid‐promoted rearrangement and silver‐catalyzed amidation of DBCO, which alters its click reactivity robustly. In the switched click reaction, DBCO, as a caged acylation reagent, enables rapid peptide/protein modification after decaging facilitated by silver catalysts, rendering site‐specific conjugation of an IgG antibody by a Fc‐targeting peptide. [ABSTRACT FROM AUTHOR]

Brønsted solid acids have popularly been used as catalysts or supports for many hydrogenation reactions, while it is uncertain if their structural H species could significantly enhance velocity and reusability for these reactions. In this work, a series of tantalate‐supported silver catalysts Ag/MxH2–xTa2O6 (M=H, Li, Na, K, Sr) were prepared, along with abundant solid acid catalysts (Ag/Al2O3, Ag/SiO2−Al2O3, Ag/ZrO2−SO42−, and Ag/heteropolyacid). By assessing activity of a model reaction from p‐nitrophenol to the corresponding aniline together with an isotope comparative test (Ag/D2Ta2O6 and Ag/H2Ta2O6), a previously unknown route was uncovered, which involves that intrinsic proton H species of the Brønsted solid acid support directly participate in the formation of products. Meanwhile, Ag NPs could form an embedded distribution by exchanging with structural H species, responsible for the stabilization of catalytic active sites. The results reported here could give a deep understanding on proton chemistry of solid acids in construction of catalysts and/or supports in H‐participating reactions. [ABSTRACT FROM AUTHOR]