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Many efforts have been made either to provide the typical three‐dimensional (3D) printing materials with new and specific properties or to enhance their overall stability. The use of nanomaterials in 3D printing is gaining attention due to the tremendous functionality that this approach provides for those materials. This article presents a method of producing poly(lactic acid) (PLA)‐silver nanoparticle antibacterial filament for additive manufacturing. Polymer dope of silver salts within PLA was prepared by the solution‐phase and solvent‐less methods, followed by extrusion into filaments. Silver nanoparticles were synthesized in situ by thermal decomposition of silver salt during the thermal extrusion of the filament. The formation and dispersion of the nanoparticles within the polymer structure were examined and confirmed with transmission electron microscope and X‐ray diffraction. The solution‐phase method proposed in this study may prevent failure with nanoparticle dispersion occurring in melt blending. The filament was used for the fabrication of predesigned specimens for antimicrobial and mechanical testing. Printed objects exhibited antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. This study revealed that the incorporation of silver nanoparticles (0.01‐5 wt%) into PLA does not significantly change its bulk properties but renders the composite antibacterial. The filament may be used for manufacturing on‐demand customized antimicrobial objects. [ABSTRACT FROM AUTHOR]

Two similar types of dienes, one rigid and the other flexible, were explored for their gel formation abilities with Ag(I) salts. The rigid and angular dienes have shown an exceptional ability for gel formation with silver salts of nitrate, triflate, tetrafluoro borate and hexafluorophosphate. These metal–organic gels (MOGs) and their xerogels are found to have an excellent ability to undergo the photochemical [2 + 2] polymerization reaction upon irradiation. The reactions were monitored, and the products were characterized via1H NMR and MALDI-TOF analyses. Further, the solid-state luminescence behaviour and the selective dye-sorption of the gels have been explored before and after the photo-polymerization reaction. [ABSTRACT FROM AUTHOR]

A simple approach to achieve high SERS enhancement for bio-analyte detection at visible wavelength through a resonance Raman (RR) effect has been proposed in this study. Usually, SERS accompanies a significant drop in background fluorescence signals leading to a dramatic increase in signal strength. Under resonance conditions, however, the SERS increment is limited by the loss of electromagnetic (EM) enhancement. The extent of loss in signal could be as high as 100-fold, which is typically significant when sampling low concentrations of molecules with small cross-sections such as biomolecules. EM loss could be compensated either by tuning the optical properties of the substrate or by finding alternative enhancement pathways. In order to achieve this, a one-step reduction protocol for synthesizing highly stable SERS-active dendritic silver nanostructures was optimised, which took into account the optical tuning under visible light due to their hot-spot-rich morphology. Adopting multiple roles, metabolite-enriched green tea used as a bio reductant triggered silver salt reduction, stabilized the nanostructure through capping and also functionalized the surface, leaving numerous active chemical groups on the nanostructure surface. The surface groups identified as amides and glycosides work as anchorage points allowing interaction with the analytes, facilitating inter-charge transfers. A 1013 order enhancement factor (EF) has been achieved through using the substrate. The substrate shows excellent reproducibility and acceptable relative standard deviation (RSD) values (<10%). Notably, the RR spectra were characterised by sharp and significantly high not totally symmetric (b2) vibrations, confirming the effective chemical enhancement contribution to the achieved SERS enhancement. For a test analyte, S. aureus, the RR spectrum exhibited selective vibrational enhancements only, which are plausibly ascribed to signal acquisition below the conventional ensemble averaging regime and are also due to specific cell–nanostructure interaction on account of indigenous surface functionalization achieved using green tea extract. [ABSTRACT FROM AUTHOR]

Herein, we report a highly efficient and practical method for pyridine‐derived heterobiaryl synthesis through palladium‐catalyzed electrophilic functionalization of easily available pyridine‐derived quaternary phosphonium salts. The nice generality of this reaction was goes beyond arylation, enabling facile incorporation of diverse carbon‐based fragments, including alkenyl, alkynyl, and also allyl fragments, onto the pyridine core. Notably, the silver salt additive is revealed to be of vital importance for the success of this transformation and its pivotal role as transmetallation mediator, which guarantees a smooth transfer of pyridyl group to palladium intermediate, is also described. [ABSTRACT FROM AUTHOR]

Complexation of bicyclo[6.1.0]nonynes with a cationic silver or gold salt results in protection from a click reaction with azides. The cycloalkyne protection using the silver or gold salt enables selective strain-promoted azide–alkyne cycloadditions of diynes keeping the bicyclo[6.1.0]nonyne moiety unreacted. [ABSTRACT FROM AUTHOR]

Silk fibers served as a matrix for the reduction of nanoparticles from a silver salt solution. A mathematical model describing the dependence of the total content of reduced silver on a fiber Y on the input parameters X1, X2, X3, X4 (silver concentration in the treatment solution, concentration of reducing agent, temperature and duration of the reduction process, respectively) is constructed. A chemically substantiated nonlinear regression model and a two-layer perceptron are proposed, which make it possible to obtain mathematical expressions for the dependence of the silver content on silk fibers on the input parameters. Both models adequately reflect the experimental data – the error of the regression model is 0.16, the error of the two-layer perceptron is 0.14. [ABSTRACT FROM AUTHOR]

The process of synthesis of ultradisperse silver particles by the reduction of silver salts differing in solubility by 5–40 orders of magnitude was studied by spectrophotometry, dynamic light scattering, and visual observation. The solubility of the precursor salt was shown to significantly affect the silver reduction rate. Examination by photon correlation spectroscopy confirmed the formation, upon completion of the reduction reaction, of silver nanoparticles with ~20 nm hydrodynamic radius, including the stabilizer shell. The biological activity of the sols synthesized against test cultures such as Staphylococcus aureus, Escherichia coli, and Candida albicans was assessed, and its dependence on the size of the particles formed was revealed. For the textile materials doped with the sols synthesized, the resistance to the action of the natural complex of microflora and of soil microflora was studied depending on the solubility of the precursor salts and on the size of the particles formed. [ABSTRACT FROM AUTHOR]

A novel approach in fabricating anionic inter-polymeric complex polysaccharide bio-platform with enhanced mechanical, structural and chemical properties for burn wound dressings. This approach implies a facile, insitu method to design soft nano-floral inter-polymeric complexes. In particular, sodium alginate (SA) and kappa-carrageenan (k-Ca) treated silver salt results in nano-floral inter-polymeric complex with self-stability. SEM images depict nano-floral complexes with surface plasmon resonance at 412–425 nm. These were resistant towards Staphylococcus aureus and Escherichia coli bacterium. These nano-floral complexes were then subjected to wound closure diameter and histological analysis. Designed polymeric complexes enhanced exudate absorption thus promotes effective proliferation, the appearance of compact fibrous arrangement and hair follicles i.e. facilitates healing for second-degree burn wound. Unlabelled Image • Fabrication of anionic inter-polymeric complex polysaccharide bio-platform • Single step and in-situ synthesized silver nanoparticle based bio-platform • Polymeric bio-platform was resistant towards S. aureus and E. coli bacteria • Bio-inspired dressings were tested on mice for second degree burn healing. • Hair follicles, fibrous tissues and 97% wound area contraction were observed. [ABSTRACT FROM AUTHOR]

Objectives: In this study, silver nanoparticles (AgNPs) were synthesized using healthy plant parts like fruits, stem and leaves of Ficus racemosa. Methods: The collected plant samples were processed by cleaning, drying and grinding. Bioactive compounds were extracted by using Soxhlet extraction method. The 10mg of plant extract was added to 1mM AgNO3 solution and incubated at 80°C for 3min. The UV-Vis spectroscopy was used for characterization of produced AgNPs. The synthesis process was optimized for pH (3 to 9), plant extracts conc. (0.5, 1, 2, 4 and 8mg/2ml), incubation temp. (50°C, 60°C upto 100°C) and silver salt conc. (0.125, 0.25, 0.50, 1.0 and 2mM). Finally the antimicrobial and seed germination ability of synthesized AgNPs was determined. Results: The λmax values were found to be 464.50nm, 422nm and 489nm for fruits, stem and leaves respectively. FTIR spectra of control and test were determined which showed the different functional groups in the synthesized AgNPs. The optimum pH (9, 8 and 8), plant extracts conc. (8, 4 and 8mg), incubation temp. (80°C, 90°C and 100°C) and silver salt conc. (2mM, 1.5mM and 2mM) for fruit, stem and leaves AgNPs were determined. The selective NPs showed notable antibacterial activity against Gram positive bacteria like S. equorum and B. subtilis and significant effect on wheat (Triticum aestivum L.) seed germination. Conclusion: The green synthesis process was found to be time saving and effective approach for the synthesis of the AgNPs from different plant parts. Produced NPs have potential applications in therapeutics and agriculture. [ABSTRACT FROM AUTHOR]

The use of chiral transient directing groups (TDGs) is a promising approach for developing PdII‐catalyzed enantioselective C(sp3)−H activation reactions. However, this strategy is challenging because the stereogenic center on the TDG is often far from the C−H bond, and both TDG covalently attached to the substrate and free TDG are capable of coordinating to PdII centers, which can result in a mixture of reactive complexes. We report a PdII‐catalyzed enantioselective β‐C(sp3)−H arylation reaction of aliphatic ketones using a chiral TDG. A chiral trisubstituted cyclobutane was efficiently synthesized from a mono‐substituted cyclobutane through sequential C−H arylation reactions, thus demonstrating the utility of this method for accessing structurally complex products from simple starting materials. The use of an electron‐deficient pyridone ligand is crucial for the observed enantioselectivity. Interestingly, employing different silver salts can reverse the enantioselectivity. [ABSTRACT FROM AUTHOR]

Two coordination polymers, namely [Ag2(L)(SO3CF3)(H2O)](SO3CF3)•CH2Cl2 (1) and [Ag5(L)4(H2O)2](SbF6)5•5THF (2), were obtained by reacting oxadiazole-containing tri-armed ligand 1,3,5-tri(2-methylthio-1,3,4-oxadiazole-5yl) benzene (L) and silver salts in CH2Cl2/THF medium. The two complexes crystallized in the tetragonal space group I41/a and orthorhombic space group Fdd2, respectively. The Single-crystal X-ray diffraction revealed that the two complexes exhibit strikingly different 3D polymeric structures, which can be ascribed to the different counter anions. L in compound 1 acted as a hexa-dentate ligand, binding to two types of Ag+ atoms to form a 3D polymeric structure. L in compound 2 acted as a hexa- and penta-dentate ligand, binding to three types of Ag+ atoms to form the 3D polymeric structure. The antibacterial activity of the complexes was also investigated. [ABSTRACT FROM AUTHOR]

Methods for direct C-H trifluoromethoxylation of arenes and heteroarenes are rare, despite the importance of trifluoromethoxylated compounds for pharmaceuticals, agrochemicals, and material sciences. Especially selective C-H trifluoromethoxylation of pyridines remains a formidable challenge. Here we show a general late-stage C-H trifluoromethoxylation of arenes and heteroarenes as limiting reagent with trifluoromethoxide anion. The reaction is mediated by silver salts under mild reaction conditions, exhibiting broad substrate scope and wide functional-group compatibility. In addition, ortho-position selective C-H trifluoromethoxylation of pyridines is observed. The method is not only applicable to the gram-scale synthesis of trifluoromethoxylated products but also allows efficient late-stage C-H trifluoromethoxylation of marketed small-molecule drugs, common pharmacophores and natural products. Selective C-H trifluoromethoxylation of pyridines remains a formidable synthetic challenge. Here, the authors report a silver-mediated late-stage C-H trifluoromethoxylation of arenes and heteroarenes as limiting reagents with trifluoromethoxide anion. [ABSTRACT FROM AUTHOR]

Potassium salts of arylmethylidene derivatives of malononitrile trimer were obtained by the reactions of aromatic aldehydes with malononitrile trimer in an aqueous medium under micellar catalysis. The optical properties of the synthesized salts were studied to show they absorb in the range of 313–436 nm, depending on the substituent. Exchange reactions with various metal salts showed that the synthesized derivatives of malononitrile trimer form difficultly soluble compounds with silver salts. [ABSTRACT FROM AUTHOR]

Uniform silver nanoparticles with diameters smaller than 10 nm have been synthesized by the hydrothermal method on micro/nanofibrils of cellulose, which is used as a substrate, in a solution consisting of a water/ethylene glycol (reductant) mixture, a silver salt, poly(vinylpyrrolidone), and silver chloride used as a seed. Cellulose plays the role of an additional mild reductant, which prevents the formed nanoparticles from coalescence and provides the formation of their linear assemblies, in which the density of the nanoparticles and the gaps between them are regulated by varying silver salt concentration in the reaction mixture. Experiments performed with rhodamine 6G dye have shown that the synthesized assemblies of silver nanoparticles exhibit surface-enhanced Raman scattering. The proposed synthesis method may be used for the production of inexpensive sensor elements for surface-enhanced Raman scattering spectroscopy analysis. [ABSTRACT FROM AUTHOR]

A series of new methyl (2Z)-4-aryl-2-{4-[(4,6-dimethylpyrimidin-2-yl)-sulfamoyl]phenylamino}-4-oxobut-2-enoates was synthesized by the reaction of methyl esters of aroylpyruvic acids with 2-(4-aminobenzenesulfamido)-4,6-dimethylpyrimidine in a mixture of acetic acid–ethanol (1 : 1). The obtained 4-oxobut-2-enoates reacted with silver nitrate in ethanol–DMF (2 : 1) to form their silver salts. The antimicrobial activity of the compounds was studied. [ABSTRACT FROM AUTHOR]

A silver-free amination procedure, here called "complexation", was developed to obtain a class of Pt(II) complexes bearing a payload (such as a diagnostic or a therapeutic moiety). These complexes are crucial intermediates for the efficient development and production of antibody–drug conjugates (ADCs) based on a novel Pt(II)-based linker technology. We termed this metal–organic linker, [ethylenediamineplatinum(II)]2+, "Lx"®. The present, newly developed procedure is a greener alternative for the classically applied activation reaction of Pt-halido complexes with silver salts, followed by amination. The crucial finding is that the leaving ligand of the classical process, chloride, can now be replaced by its higher homologue iodide. This not only decisively improved the manufacturing process of the intermediate, but also was found to be key to a more efficient conjugation procedure, i.e. a subsequent step in which this intermediate is coupled to an antibody. The new process allowed upscaling to be readily realized and the desired intermediate was successfully manufactured on a multigram scale. The obtained Ag-free procedure can be generalized and has a great potential to be applied for other Pt(II) complexes of high importance, such as anti-cancer therapeutics. [ABSTRACT FROM AUTHOR]

An oxidative catalytic vanadium(V) system was developed to access the naturally nonabundant diastereomers of carpanone from the corresponding alkenyl phenol monomer in one pot by tandem oxidation, oxidative coupling, and 4+2 cyclization. This system was applied to the synthesis of two other analogues of carpanone. Mild oxidizing silver salts were used as the terminal oxidant to minimize background oxidation which produces the natural diastereomer of carpanone. Further, the first examples of enantioselective oxidative benzoxanthenone formation are reported. Solvent polarity has a strong effect on enantioselectivity, consistent with a mechanism involving binding of vanadium Schiff base catalysts to the alcoholic moiety of the alkenyl phenols during the cyclization step. [ABSTRACT FROM AUTHOR]

A facile, straightforward, and low-cost method is proposed to synthesize gold@silver@gold core double-shell nanoparticles. The technique is a seed-mediated growth protocol that contains four steps of (1) gold seed synthesis, (2) gold seed growth, (3) silver layer coating through silver salt reduction, and (4) gold layer deposition via gold precursor reduction. The prepared nanoparticles had a narrow size distribution and the average particle size of 28 ± 1 nm. Cysteine was introduced to the nanoparticles solution as a coupling agent to assemble nanoparticles. Aggregation-induced two-photon photoluminescence enhancement of three types assembled nanoparticles, i.e., gold@silver@gold, gold@silver, and gold nanoparticles, was studied. It was observed that the assembled core double-shell nanoparticles presented huge enhancement in two-photon photoluminescence signal in comparison with two other nanoparticles. Moreover, the gold@silver@gold nanoparticle is a stable and biocompatible plasmonic nanosystem. This paper provides a novel candidate for two-photon photoluminescence excitation sensing and imaging for biomedical applications. [ABSTRACT FROM AUTHOR]

This chapter discusses the reactions of 4-phosphorylated 5-hydroxypenta-2,3-dienoates with protected or unprotected hydroxy group involving 5-endo-trig cyclizations. Reactions with electrophiles produce mixtures of the 2,5-dihydro-1,2-oxaphosphole-5-carboxylates and the 5-phosphoryl-furan-2(5H)-ones by competitive electrophilic cyclization due to the neighboring phosphonate (phosphine oxide) and the carboxylate groups participation. 4-Phosphorylated 5-hydroxypenta-2,3-dienoates were smoothly converted into the corresponding 4-phosphoryl-2,5-dihydrofuran-2-carboxylates by using 5 mol% of a silver salt as a catalyst in the 5-endo-trig cycloisomerization reaction. [ABSTRACT FROM AUTHOR]

Silver nanocrystals made by a chemical reduction of silver salts (AgNO3) by sodium borohydride (NaBH4) were studied using transmission electron microscopy and light scattering simulations. For various AgNO3/NaBH4 molar ratios, the size distributions of the nanocrystals were found to be approximately log-normal. In addition, a linear relation was found between the mean nanocrystal size and the molar ratio. In order to relate the size distribution of Ag nanocrystals of the various molar ratios to the scattering properties of Ag nanocrystals in solar cell devices, light scattering simulations of Ag nanocrystals in Si, SiO2, SiN, and Al2O3 matrices were carried out using MiePlot. These light scattering spectra for the individual nanocrystal sizes were combined into light scattering spectra for the fitted size distributions. The evolution of these scattering spectra with respect to an increasing mean nanocrystal size was then studied. From these findings, it is possible to find the molar ratio for which the corresponding nanocrystal size distribution has maximum scattering at a particular wavelength in the desired matrix. [ABSTRACT FROM AUTHOR]

The biological synthesis of silver nanoparticles (Ag-NPs) with fungi has shown promising results in antibacterial and antioxidant properties. Fungi generate metabolites (both primary and secondary) and proteins, which aid in the formation of metal nanoparticles as reducing or capping agents. While several studies have been conducted on the biological production of Ag-NPs, the exact mechanisms still need to be clarified. In this study, Ag-NPs are synthesized greenly using an unstudied fungal strain, Sarocladium subulatum AS4D. Three silver salts were used to synthesize the Ag-NPs for the first time, optimized using a cell-free extract (CFE) strategy. Additionally, these NPs were assessed for their antimicrobial and antioxidant properties. Various spectroscopic and microscopy techniques were utilized to confirm Ag-NP formation and analyze their morphology, crystalline properties, functional groups, size, stability, and concentrations. Untargeted metabolomics and proteome disruption were employed to explore the synthesis mechanism. Computational tools were applied to predict metabolite toxicity and antibacterial activity. The study identified 40 fungal metabolites capable of reducing silver ions, with COOH and OH functional groups playing a pivotal role. The silver salt type impacted the NPs' size and stability, with sizes ranging from 40 to 52 nm and zeta potentials from −0.9 to −30.4 mV. Proteome disruption affected size and stability but not shape. Biosynthesized Ag-NPs using protein-free extracts ranged from 55 to 62 nm, and zeta potentials varied from −18 to −27 mV. Molecular docking studies and PASS results found no role for the metabolome in antibacterial activity. This suggests the antibacterial activity comes from Ag-NPs, not capping or reducing agents. Overall, the research affirmed the vital role of specific reducing metabolites in the biosynthesis of Ag-NPs, while proteins derived from biological extracts were found to solely affect their size and stability. [Display omitted] • Sarocladium subulatum AS4D, a novel fungal strain, synthesizes Ag-NPs. • Silver salt type influences size and stability of Ag-NPs. • Reductive metabolites crucial in Ag-NPs synthesis and stabilization. • Fungal extract proteome affects size, stability, and reduction of Ag-NPs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chromatography paper was used to develop an analytical device to detect salt. • Chloride ions reacted with silver nanoparticles and carboxymethyl cellulose. • Stability and interference against Cl− detection were good. • The device detected salt in twenty-five food samples. Using silver nanoparticles (AgNPs) and carboxymethyl cellulose (CMC), a simple distance-based paper analytical device (dPAD) was developed for the determination of chloride ions in food products. The determination of chloride ions was based on the Mohr argentometric method without the chromium compound. A hydrophobic barrier was created on chromatography paper using a wax-printing technique. The barrier protected a channel that was impregnated with AgNPs and CMC. In the presence of chloride, chloride ions moved along the channel, reacting with AgNPs, and forming an AgNPs-Cl sediment deposited as a white/gray precipitation in the orange-colored channel. The chloride ion concentration was interpreted from the length of the color change visualized with the naked eye without external equipment. The amount and volume of AgNPs and CMC impregnated on the chromatography paper were optimized. The response of the AgNPs-CMC/dPAD to the chloride ion was linear from 0.01 to 1.00 % w/v (r = 0.9931). In addition, the proposed device was stable for more than 28 days, with a relative response of 105 ± 3 % compared to day one, resulting in consistent and precise results. Intra-day (6 measurements) and inter-day (over 6 days) precision were excellent with RSDs less than 6 %. The developed dPAD was used to detect salt in twenty-five real samples, including instant noodles, condiments and sauces, and snacks. Recoveries ranged from 96 ± 5 to 105 ± 5 %. The proposed method showed acceptable accuracy, precision and good shelf life for monitoring chloride in food products at the point of need and demonstrated potential for commercial development. [ABSTRACT FROM AUTHOR]

The isolation of simultaneously low‐coordinate and low‐valent compounds is a timeless challenge for preparative chemists. This work showcases the preparation and full characterization of tri‐coordinate rhodium(‐I) and rhodium(0) complexes as well as a rare rhodium(I) complex. Reduction of [{Rh(μ‐Cl)(IPr)(dvtms)}2] (1, IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolyl‐2‐ylidene; dvtms=divinyltetramethyldisiloxane) with KC8 gave the trigonal complexes K[Rh(IPr)(dvtms)] and [Rh(IPr)(dvtms)], whereas the cation [Rh(IPr)(dvtms)]+ results from their oxidation or by abstraction of chloride from 1 with silver salts. The paramagnetic Rh0 complex is a unique fully metal‐centered radical with the unpaired electron in the dz2 orbital. The Rh(‐I) complex reacts with PPh3 with replacement of the NHC ligand, and behaves as a nucleophile, which upon reaction with [AuCl(PPh3)] generates the trigonal pyramidal complex [(IPr)(dvtms)Rh‐Au(PPh3)] with a metal–metal bond between two d10 metal centers. [ABSTRACT FROM AUTHOR]

Selective C–H bond alkynylation toward modular access to material and pharmaceutical molecules is of great desire in modern organic synthesis. Disclosed herein is rhodium(III)‐catalyzed selective C–H bond mono‐/bialkynylation of 4‐aryl phthalazin‐1(2H)‐one was developed. The silver salt AgSbF6 are demonstrated to play a vital role in promoting the bialkynylation reactions. The present alkynylation strategy is simple, efficient, and features high functional group tolerance and broad substrate scope under an air atmosphere. Additionally, 6‐aryl pyridazin‐3(2H)‐one scaffold is amenable to the selective monoalkynylation and sequential bialkynylation, respectively. [ABSTRACT FROM AUTHOR]

This work is aimed at obtaining mixed cluster ions of amino acids with copper salts using soft ionization methods. We have shown that amino acid molecules are capable of forming aggregates stabilized by d-metals. In particular, such clusters can form in the presence of silver salts. In the present work, it is revealed that the largest cluster ions can be obtained using the electrospray ionization method. It is found that, upon ionization of amino acids (leucine, alanine, proline, tyrosine, and tryptophan) in the presence of copper salts, cluster associates with a mass of up to 1500 Da are formed. It is also found that the formation of cluster ions strongly depends on the nature of the amino acid and polarity of the charge in the cluster. [ABSTRACT FROM AUTHOR]

Aryl iodides and 2‐(trifluoromethyl)acrylic acid reacted together in ligand‐free Mizoroki‐Heck reaction furnishing a quick and efficient access to highly valuable α‐trifluoromethylacrylic acids. The useful transformation was independent with regard to the electronic nature of the aryl group substituent. A three‐component one‐pot version was also developed to give diverse substituted acrylates. The versatility of α‐trifluoromethylacrylic acids was demonstrated by quick access to 3‐CF3‐coumarins as well as fluorinated analogues of therapeutic or cosmetic agents. Finally, we proposed a catalytic cycle based on the silver carboxylate salt, identified as a key intermediate in the reaction. [ABSTRACT FROM AUTHOR]

An expedient approach to C-glycosylated isoquinolines was established based on the coupling of vinyl isonitriles with tetrafuranos-4-yl and pentapyranos-5-yl radicals generated from oxidative decarboxylation of uronic acids derived from monosaccharides and complex oligosaccharides. This approach enjoyed a broad substrate scope and good functional group tolerance, and afforded structurally diverse C-glycosylated isoquinolines in the presence or absence of silver salts. Deprotection of the coupling products was conducted to yield C-glycosylated isoquinolines with multiple hydroxyl groups. These novel architectures would offer opportunities for investigation of their bioactivities. Structurally novel C-glycosylated isoquinolines have been achieved by treating isonitriles with uronic acids through oxidative radical decarboxylation process. [ABSTRACT FROM AUTHOR]

Following the recent discovery that traditional silver(I) oxide‐promoted glycosidations of glycosyl bromides (Koenigs–Knorr reaction) can be greatly accelerated in the presence of catalytic TMSOTf, reported herein is a dedicated study of all major aspects of this reaction. A thorough investigation of numerous silver salts and careful refinement of the reaction conditions led to an improved mechanistic understanding. This, in turn, led to a significant reduction in the amount of silver salt required for these glycosylations. The progress of this reaction can be monitored by naked eye, and the completion of the reaction can be judged by the disappearance of characteristic dark color of Ag2O. Further evidence on higher reactivity of benzoylated α‐bromides in comparison to that of their benzylated counterparts has been acquired. [ABSTRACT FROM AUTHOR]

Biosynthesis of nanoparticles has gained great attention in moving towards an economic and environmentally friendly process. However, there is a limited number of studies that describe the parameters for tuning the dimension and geometry of nanoparticles in the biosynthesis process. Therefore, in this study, silver nanoparticles were synthesized by varying the synthesis parameters in aqueous extract of Imperata cylindrica. The particles were characterized by visual observation; color changes, UV-visible spectroscopy, dynamic light scattering, field scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Changing the parameters such as plant extract concentration, silver salt concentration, the temperature of biosynthesis and pH of reaction mixture influence the size and dispersion of the nanoparticles. The optimum parameters for synthesizing silver nanoparticles are 10% of aqueous extract, 10 mM of silver nitrate, pH 5.7 with a reaction temperature of 60°C. The synthesized silver nanoparticles are in spherical with a diameter below 100 nm. [ABSTRACT FROM AUTHOR]

Plant-mediated nanoparticles synthesis is considered as one of the appealing options in bionanoparticles synthesis, however, there is contradictory information about the positive or negative impacts of nanoparticles on plants. Investigating the toxic effects of Ag NPs on model plants, such as onion, can reveal the probability of damage. Thus, the present study was conducted to compare the germination indices and biochemical parameters of edible onion seeds treated with different concentrations of two types of silver nanoparticles (green synthesized and chemical synthesized) to examine the oxidative stress. Based on our results, the interaction between leaf extract and silver salt resulted in a color change from pale yellow to dark brown, the first sign of the AgNPs formation. The green AgNPs treatment improved the onion germination indices. The green AgNPs-exposed seeds displayed a nosignificant reduction in protein content and same protease activity as the control treatment, but chemical AgNPstreated displayed a significant rise of protease and reduction in protein content in concentration more than 0.06 gL-1. In chemical AgNPs-treated seeds both peroxidase and catalase displayed an ascending linear trend and the most activities belonged to chemical AgNPs at 0.05 g L-1 (315.62 and 51.45 µmol min-1g-1 FW, respectively). Both nanoparticle types made an increase in MDA, but green AgNPs did not significantly differ with control treatment. It can be concluded that the green synthesis of nanoparticles is a safe and suitable alternative for chemicalsynthesized metal nanoparticles. [ABSTRACT FROM AUTHOR]

The research work was arranged to check the role of AgNPs and silver ions on callus cells of sugarcane (Saccharum spp. cv CP-77,400). AgNPs were synthesized chemically and characterized by UV-Vis spectra, XRD and SEM. AgNPs and silver ions were applied in various concentrations (0, 20, 40, 60 ppm) to sugarcane calli and the induced stress was characterized by studying various morphological and biochemical parameters. AgNPs and silver ions treatments produced high levels of malondialdehyde, proline, proteins, TP and TF contents. Similarly, CAT, SOD and POX activity was also significant in both treatments. The lower concentration of AgNPs and silver ions (20 ppm) provided maximum intracellular GSH level. This work mainly showed effects of AgNPs and silver ions on sugarcane calli in terms of morphological aberrations and cell membrane damage due to severe oxidative stress and production of enhanced levels of enzymatic and non-enzymatic antioxidants as self-defence to tolerate oxidative stress by scavenging reactive oxygen species. These preliminary findings will provide the way to study ecotoxicity mechanism of the metal ions and NPs in medicine industry and in vitro toxicity research. Furthermore, silver ions alone and their chemically synthesised AgNPs can be used for various biomedical applications in future. [ABSTRACT FROM AUTHOR]

In this paper, humic acid (HA) was used as stabilizer to prepare silver nanoparticles (Ag NPs) by chemically reducing silver salts in water phase, which were employed to produce Ag NPs inks for inkjet printing conductive silver patterns. The obtained silver nanoparticles stabilized with HA (HA-Ag NPs) were all in spherical shape and the particle size was about 7–12 nm. By re-dispersing HA-Ag NPs in ultrapure water, conductive ink with excellent storage stability was prepared, which can be placed at room temperature for 30 days without any precipitation. The as-prepared HA-Ag NPs conductive ink was printed onto photopapers to fabricate conductive silver patterns with a domestic inkjet printer. The resistivity of the printed pattern could reach 135 μΩ cm after printed for 40 layers and sintered at 180 °C for 60 min. In addition, the printed conductive silver patterns could be integrated into a LED device or alarm apparatus, indicating it could be widely used in flexible printing electronics. [ABSTRACT FROM AUTHOR]

Transition metal catalyzed C−H phosphorylation remains an unsolved challenge. Reported methods are generally limited in scope and require stoichiometric silver salts as oxidants. Reported here is an electrochemically driven RhIII‐catalyzed aryl C−H phosphorylation reaction that proceeds through H2 evolution, obviating the need for stoichiometric metal oxidants. The method is compatible with a variety of aryl C−H and P−H coupling partners and particularly useful for synthesizing triarylphosphine oxides from diarylphosphine oxides, which are often difficult coupling partners for transition metal catalyzed C−H phosphorylation reactions. Experimental results suggest that the mechanism responsible for the C−P bond formation involves an oxidation‐induced reductive elimination process. [ABSTRACT FROM AUTHOR]

Here, two series of structurally and electronically varied benzonitrile and coumarin substituted imidazolium (2 – 5) and benzimidazolium (7 – 10) hexafluorophosphate salts and corresponding NHC silver(I) complexes (11 – 18) are reported. Substituents on the coumarin ring are varied with an intention of bringing appropriate electronic changes in the complex, which facilitates the targeted activity. Additionally, the structure of two azolium salts (2 and 7) has been established by SCXRD technique. Extended structure of these salts witnessed a series of hydrogen bonds between the azolium cations and the hexafluorophosphate anions along with moderate π–π stacking interactions operating between the adjacent heterocyclic and/or aromatic rings such as coumarin, (benz)imidazole and benzonitrile phenyl systems. Further, a preliminary antibacterial study of the representative salts and silver complexes against a Gram positive (S. aureus , ATCC 29213) and a Gram negative (E. coli , ATCC 25922) bacteria has been carried out. Both the series of silver complexes demonstrated potent antibacterial activity with a MIC of 8/16 μg/mL against E. coli , while there activity against S. aureus found moderate with a MIC in the range 32–128 μg/mL. Furthermore, the salts evidenced no activity in the working concentration range against tested bacteria, indicating that the activity of the complexes is due to the metal center. Image 1 • Two series of silver complexes possessing coumarin-appended NHC ligands were reported. • Successive N-alkylation is followed to prepare NHC precursors. • Two of the NHC precursors were characterized by SCXRD method. • Complexes displayed good to moderate activity against two bacterial strains. [ABSTRACT FROM AUTHOR]

A new cascade oxidative cyclization reaction of N-Cbz hydrazones with internal alkynes has been explored for the preparation of isoquinoline derivatives using Cp*CoIII-catalyst through C–H and N–N bond functionalization. N-Cbz hydrazones are rarely explored as directing group for redox-neutral [4 + 2] cyclization reaction through the cyclometallation and this catalyst system does not require any external oxidizing agent, as well as, silver or antimony salt. The current efficient approach has been utilized for the synthesis of different isoquinoline derivatives with good regioselectivity and yields. [ABSTRACT FROM AUTHOR]

[3+2]-Cycloaddition of arenediazonium salts with diazo compounds (earlier exemplified only for trimethylsilyldiazomethane and 2,2,2-trifluorodiazoethane) has been developed to include a wide range of readily available α-diazocarbonyl compounds. The resulting 2-aryl-5-acyl-2 H -tetrazoles are of high value in medicinal chemistry. [ABSTRACT FROM AUTHOR]

A new two‐component alkylarylation of N‐benzyl‐N‐(2‐ethynylaryl)amides with α‐bromoalkyl esters using visible light photoredox catalysis promoted by silver salts for producing substituted dibenzazepines is described. Employing α‐bromoalkyl esters to form the alkyl carbon‐centered radicals enables the alkylarylation of alkynes where two carbon‐centered functional groups are introduced across the C≡C bond in a single reaction. [ABSTRACT FROM AUTHOR]

This Essay deals with the fascinating and highly explosive compounds fulminating gold and fulminating silver, which are easily made by treatment of gold dissolved in aqua regia with ammonia, and by reaction of silver oxide or silver salts with ammonia, respectively. Fulminating gold in particular captivated the alchemists in the 16th to 18th centuries. Numerous preparations were described, as well as numerous attempts to make volatile, sublimable or distillable gold, and to use the products so obtained (which were most likely gold chlorides) to make the sought‐after tincture, which would "heal" the "impure" metals and transform them into gold, and equally be a panacea to cure all human illnesses. [ABSTRACT FROM AUTHOR]

A novel catalytic reaction involving terminal alkynes, carbon disulfide, and aziridines has been described. In this transformation, silver-acetylides react with carbon disulfide and aziridines to form 1,4-thiomorpholine molecules in good yields. The optimum conditions developed using silver iodide and (i-Pr)2EtN in DMF at 70°C. [ABSTRACT FROM AUTHOR]

A simple and highly efficient room temperature catalytic protocol was developed towards the synthesis of thioesters from thiols and acyl chlorides under solvent-free conditions. Ambient reaction conditions, shorter reaction time, excellent product yields are notable features of this methodology. [ABSTRACT FROM AUTHOR]

The synthesis of two dinuclear ionic complexes with chemical formula [Au(PR 3) 2 ][Au(C ≡ CC 5 H 4 N-4) 2 ] that contain the water soluble phosphines, PR 3 , PTA (1, 3,5-triaza-7-phosphaadamantane, 1) and DAPTA (3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane, 2) is herein described. The differences on their intermolecular reorganization have been analyzed and compared with the previously reported for the neutral complexes [Au(PR 3)(C ≡ CC 5 H 4 N-4)]. It has been evidenced that the reorganization of the ligands giving rise to the dinuclear ionic complexes produces a complete change in the properties giving rise to Au⋯Au intermolecular assemblies. These aurophilic contacts are the responsible for the resulting luminescence which is not displayed for the parent compounds [Au(PR 3) 2 ]Cl and [PPh 4 ][Au(C ≡ CC 5 H 4 N-4) 2 ]. Compounds 1 and 2 were made react with three different silver salts (nitrate, triflate and hexafluorophosphate) giving rise to 1:1 heterometallic assemblies with some changes both on the wavelength and emission intensity. Image 1 • The ionic complexes [Au(PR 3) 2 ][Au(C ≡ CC 5 H 4 N) 2 ] gives rise to aggregates. • X-ray structures evidences the presence of aurophilic contacts. • Absorption, emission and NMR are useful tools for the analysis of aggregation. [ABSTRACT FROM AUTHOR]

A cobalt‐catalyzed difunctionalization of styrenes with ethers was developed which initiated through α‐C(sp3)−H bond activation of ethers to give the oxyalkylation products. A safe and stable inorganic silver salt was used as the oxidant instead of organic peroxides. The reaction proceeded under simple and mild conditions and exhibited good regioselectivities and functional group tolerance. It provided a method to easily prepare α‐oxyalkyl ketones from readily available substrates. [ABSTRACT FROM AUTHOR]

The complexes Ag(L)n[WCA] (L=P4S3, P4Se3, As4S3, and As4S4; [WCA]=[Al(ORF)4]− and [F{Al(ORF)3}2]−; RF=C(CF3)3; WCA=weakly coordinating anion) were tested for their performance as ligand‐transfer reagents to transfer the poorly soluble nortricyclane cages P4S3, P4Se3, and As4S3 as well as realgar As4S4 to different transition‐metal fragments. As4S4 and As4S3 with the poorest solubility did not yield complexes. However, the more soluble silver‐coordinated P4S3 and P4Se3 cages were transferred to the electron‐poor Fp+ moiety ([CpFe(CO)2]+). Thus, reaction of the silver salt in the presence of the ligand with Fp−Br yielded [Fp−P4S3][Al(ORF)4] (1 a), [Fp−P4S3][F(Al(ORF)3)2] (1 b), and [Fp−P4Se3][Al(ORF)4] (2). Reactions with P4S3 also yielded [FpPPh3−P4S3][Al(ORF)4] (3), a complex with the more electron‐rich monophosphine‐substituted Fp+ analogue [FpPPh3]+ ([CpFe(PPh3)(CO)]+). All complex salts were characterized by single‐crystal XRD, NMR, Raman, and IR spectroscopy. Interestingly, they show characteristic blueshifts of the vibrational modes of the cage, as well as structural contractions of the cages upon coordination to the Fp/FpPPh3 moieties, which oppose the typically observed cage expansions that lead to redshifts in the spectra. Structure, bonding, and thermodynamics were investigated by DFT calculations, which support the observed cage contractions. Its reason is assigned to σ and π donation from the slightly P−P and P−E antibonding P4E3‐cage HOMO (e symmetry) to the metal acceptor fragment. [ABSTRACT FROM AUTHOR]

The complexes Ag(L)n[WCA] (L=P4S3, P4Se3, As4S3, and As4S4; [WCA]=[Al(ORF)4]− and [F{Al(ORF)3}2]−; RF=C(CF3)3; WCA=weakly coordinating anion) were tested for their performance as ligand‐transfer reagents to transfer the poorly soluble nortricyclane cages P4S3, P4Se3, and As4S3 as well as realgar As4S4 to different transition‐metal fragments. As4S4 and As4S3 with the poorest solubility did not yield complexes. However, the more soluble silver‐coordinated P4S3 and P4Se3 cages were transferred to the electron‐poor Fp+ moiety ([CpFe(CO)2]+). Thus, reaction of the silver salt in the presence of the ligand with Fp−Br yielded [Fp−P4S3][Al(ORF)4] (1 a), [Fp−P4S3][F(Al(ORF)3)2] (1 b), and [Fp−P4Se3][Al(ORF)4] (2). Reactions with P4S3 also yielded [FpPPh3−P4S3][Al(ORF)4] (3), a complex with the more electron‐rich monophosphine‐substituted Fp+ analogue [FpPPh3]+ ([CpFe(PPh3)(CO)]+). All complex salts were characterized by single‐crystal XRD, NMR, Raman, and IR spectroscopy. Interestingly, they show characteristic blueshifts of the vibrational modes of the cage, as well as structural contractions of the cages upon coordination to the Fp/FpPPh3 moieties, which oppose the typically observed cage expansions that lead to redshifts in the spectra. Structure, bonding, and thermodynamics were investigated by DFT calculations, which support the observed cage contractions. Its reason is assigned to σ and π donation from the slightly P−P and P−E antibonding P4E3‐cage HOMO (e symmetry) to the metal acceptor fragment. [ABSTRACT FROM AUTHOR]

In an electrochemical cell with electrolyte containing silver or copper salts, the metal deposition takes place on the surface of a transparent electrically conducting coating. Under certain conditions, the metal film becomes specular and the electrochemical cell periodically switches from transparent to mirror state in response to changes in the voltage. The data obtained on electrochemical cells switchable between transparent to mirror states are analyzed. It is noted that the electrolyte properties play the decisive role in characteristics of such devices. Their prototypes with three optical states: transparent‑transient semitransparent‑mirror are realized recently. The modes are achieved in which the mirror state is preserved for a long period (over 2 h) at switched-off voltage (deenergized state). These results allow us to expect that the development of electrochemically switchable glasses-mirrors for windows will soon reach its commercial stage. [ABSTRACT FROM AUTHOR]

A ruthenium‐catalyzed protocol to access conjugate addition or decarboxylative conjugate addition of aromatic acids with maleimides has been developed. The reaction shows interesting chemoselectivity with different substituted benzoic acids. The reaction pathway of C−H alkylation is controlled by the intrinsic property of aromatic acids but not reaction conditions. Under almost the same reaction conditions, carboxyl can act as either a classical directing group or a traceless directing group, thereby generating two kinds of products, i. e. 2‐alkyl substituted benzoic acids and alkyl substituted benzenes. These two reactions proceeded under mild and redox‐neutral conditions in neat water under the atmosphere of air, and could be easily scaled up to grams. The decarboxylative conjugate addition, where carboxyl acts as a traceless directing group, can be realized without the addition of any ligand, silver or copper salt. [ABSTRACT FROM AUTHOR]

An efficient synthesis of functionalized iminoisoindolinone derivatives has been achieved via a mild electrochemical oxidative C H/N H functionalization/intramolecular annulations with isocyanides in undivided cell equipped with a nickel cathode. • Oxidative C H/N H functionalization by using electricity as oxidant. • Less toxic and earth-abundant cobalt catalyst. • Cheap cathode (Ni) and mild reaction conditions (50 °C Vs 100–170 °C). • The reaction was conducted in an undivided cell. An efficient synthesis of functionalized iminoisoindolinone derivatives has been achieved via a mild electrochemical oxidative C H/N H functionalization/intramolecular annulations with isocyanides in undivided cell equipped with a nickel cathode. In the presence of earth abundant cobalt catalyst, versatile iminoisoindolinone derivatives obtained in good yields and in a sustainable manner by using electricity as an oxidant in place of stoichiometric amount of silver and copper salts. [ABSTRACT FROM AUTHOR]