Silver Carboxylate Research Articles

ChemInform Abstract: Highly Selective Carboxylative Cyclization of Allenylmethylamines with Carbon Dioxide Using N‐Heterocyclic Carbene‐Silver(I) Catalysts

Abstractleading to 5‐alkenyl‐1.3‐oxazolidin‐2‐ones

Synthesis of silver nanoparticles via reduction of silver carboxylates by ethylene glycol

The products formed within the reduction of silver butyrate, capronate, caprylate, and stearate by ethylene glycol are explored via chemical, X-ray phase and differential thermogravimetric analysis, as well as electron microscopy and X-ray photoelectronic spectroscopy. It is shown that the reduction of these silver carboxylates by ethylene glycol is a promising method for synthesis of silver nanoparticles.

Highly selective carboxylative cyclization of allenylmethylamines with carbon dioxide using N-heterocyclic carbene-silver(I) catalysts.

Silver(I) carboxylate complexes promote the carboxylative cyclization of allenylmethylamines to afford 5-alkenyl-1,3-oxazolidin-2-ones in 2-propanol. The use of an N-heterocyclic carbene ligand (IPr) under pressurized CO2 is effective in suppressing the intramolecular hydroamination that leads to 2,5-dihydropyrroles. The mechanism involving a nucleophilic attack of the carbamate of the allene moiety and a subsequent protonation was realized on the basis of experimental and theoretical results involving a model intermediate, the alkenylgold(I) complex, which was synthesized from Au(OH)(IPr) and 1-methylamino-2,3-butadiene.

ChemInform Abstract: Sequential Multicomponent Synthesis of α‐Ketoimides, from Acyl Chlorides, Isocyanides, and Silver Salts of Carboxylic Acids.

AbstractThe sequential three component reaction of acyl chlorides, isocyanides, and silver carboxylates affords moderately stable keto‐iminoanhydrides which spontaneously undergo a Mumm rearrangement to produce the target α‐ketoimides (IX) and (XI).

Facile synthesis of silver‐nanobeadwire transparent conductive film by organic‐precursor paint reduction

A new facile process has been developed to synthesize silver nanowire transparent conductive films by reducing high‐aspect‐ratio, needle‐shaped silver carboxylates, prepared as the precursor, while retaining their morphology. Nanowire precursors are simply obtained by ultrasound irradiation when silver (I) oxide and carboxylic acids are used as starting materials. The aspect ratio of the precursors is increased when the ultrasound irradiation is followed by microwave irradiation. Silver nanowires can be easily obtained by reducing these precursors with hydrazine gas or irradiating them with Ar plasma for a short time. The morphology of the resulting nanowires is different from that of typical nanowires that have been reported. The nanowires have porous morphology, where small nanoparticles are connected to form nanobeadwire. The nanobeadwire is considered to increase the transparency of the film because of its rough morphology. This new method can synthesize silver nanobeadwires and fabricate the transparent conductive film simultaneously, in one‐step, so that it can significantly simplify manufacturing processes.

Solid state 13C-NMR, infrared, X-ray powder diffraction and differential thermal studies of the homologous series of some mono-valent metal (Li, Na, K, Ag) n-alkanoates: A comparative study

A comparative study of the molecular packing, lattice structures and phase behaviors of the homologous series of some mono-valent metal carboxylates (Li, Na, K and Ag) is carried out via solid state FT-infrared and 13C-NMR spectroscopes, X-rays powder diffraction, density measurements, differential scanning calorimetry, polarizing light microscopy and variable temperature infrared spectroscopy. It is proposed that, for lithium, sodium and potassium carboxylates, metal-carboxyl coordination is via asymmetric chelating bidentate bonding with extensive intermolecular interactions to form tetrahedral metal centers, irrespective of chain length. However, for silver n-alkanoates, carboxyl moieties are bound to silver ions via syn–syn type bridging bidentate coordination to form dimeric units held together by extensive head group inter-molecular interactions. Furthermore, the fully extended hydrocarbon chains which are crystallized in the all-trans conformation are tilted at ca. 30°, 27°, 15° and 31° with respect to a normal to the metal plane, for lithium, sodium, silver and potassium carboxylates, respectively. All compounds are packed as lamellar bilayer structures, however, lithium compounds are crystallized in a triclinic crystal system whilst silver, sodium and potassium n-alkanoates are all monoclinic with possible P1 bravais lattice. Odd–even alternation observed in various physical features is associated with different inter-planar spacing between closely packed layers in the bilayer which are not in the same plane; a phenomenon controlled by lattice packing symmetry requirements.All compounds, except silver carboxylates, show partially reversibly first order pre-melting transitions; the number of which increases with increasing chain length. These transitions are associated, for the most part, with lamellar collapse followed by increased gauche-trans isomerism in the methylene group assembly, irrespective of chain length. It is proposed that the absence of mesomorphic transitions in their phase sequences is due to a lack of sufficient balance between attractive and repulsive electrostatic and van der Waals forces during phase change. The evidence presented in this study shows that phase behaviors of mono-valent metal carboxylates are controlled, mainly, by head group bonding.

Synthesis and characterization of novel antibacterial poly(imidosulfide)/Ag nanocomposite

Novel poly(imidosulfide) containing acidic pendent group has been synthesized by Michael addition reaction between dithiol and new synthesized bismalimide (BMI) monomer which was synthesized from 3,5-diaminobenzoic acid and 4-maleimidobenzoyl chloride. This new BMI that characterized completely with FT-IR, 1H-NMR, 13C-NMR spectroscopy and elemental analysis, copolymerized with glycol bis(mercaptoacetate) in N,N-dimethylacetamide in presence of p-toluenesulfonic acid as catalyst. The resulting polymer with carboxylic acid pendent group is soluble in polar solvents such as NMP, DMF, DMSO and DMAc. Reaction conditions were modified based on the reaction time, yield and viscosity. Synthesized poly(imidosulfide) was characterized by FT-IR, 1H-NMR, elemental analysis, thermogravimetric analysis (TGA) and X-ray diffraction (XRD) techniques. Acidic pendent group of the polymer has potential to form silver carboxylate metal salt. The synthesized poly(imidosulfide) silver complex reduced to form, new antibacterial bionanocomposite. The resulting nanocomposite was characterized by FT-IR, UV/Vis, XRD, TGA, FE-SEM/EDX and TEM. Also antibacterial properties and bacterial degradation of nanocomposite and polymer were investigated.

A simple approach for the synthesis of silver nanoparticles and their application as a catalyst for the photodegradation of methyl violet 6B dye under solar irradiation

In the present study, we established for the first time a simple method for the preparation of silver nanoparticles (Ag NPs) using saturated fatty acid and tryptophan as capping and reducing agent, respectively. The -NH2 group of tryptophan and the carboxylate group of saturated long chain carboxylate endow them as reducing and stabilising property respectively. The -NH2 group of the tryptophan reduced the Ag+ ions while the carboxylate group bounded strongly to the surface of the nanoparticles (NPs). This approach is a very special, size controlled synthetic approach for the large-scale synthesis of Ag NPs. The sizes of the synthesised Ag NPs were controlled by varying the processing parameters, such as reaction time and the chain length of the silver carboxylate (C12–C16). Studies showed that the particle size of Ag NPs increases with increase in reaction time and carbon chain length. The synthesised Ag NPs were characterized by ultra-violet spectroscopy (UV–vis), transmission electron spectroscopy (TEM), selected area electron diffraction (SAED), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The synthesised Ag NPs was used to evaluate the photo catalytic degradation of the methyl violet 6B dye under solar irradiation. The efficiency and rate of photo degradation of methyl violet 6B dye were also studied.

Twin Polymerization: A Unique and Efficient Tool for Supporting Silver Nanoparticles on Highly Porous Carbon and Silica

Invited for the cover of this issue is the group of Heinrich Lang at the University of Chemnitz, Germany. The cover image shows highly porous materials of type Ag@C (red) and Ag@SiO2 (blue), obtained by twin polymerization from the appropriate silver(I) carboxylate as silver source and 2,2'-spirobi[4H-1,3,2-benzodioxasiline] as the specific twin monomer.

Silver carboxylate metal–organic frameworks with highly antibacterial activity and biocompatibility

Two novel Ag-based metal–organic frameworks (MOFs) [Ag2(O-IPA)(H2O)·(H3O)] (1) and [Ag5(PYDC)2(OH)] (2) were synthesized under the hydrothermal conditions using aromatic–carboxylic acids containing hydroxyl and pyridyl groups as ligands (HO-H2IPA=5-hydroxyisophthalic acid and H2PYDC=pyridine-3, 5-dicarboxylic acid). Single crystal X-ray diffraction indicated that two compounds exhibit three-dimensional frameworks constructed from different rod-shaped molecular building blocks. Both compounds favor slow release of Ag+ ions leading to excellent and long-term antimicrobial activities towards Gram-negative bacteria, Escherichia coli (E. coli) and Gram-positive bacteria, Staphylococcus aureus (S. aureus). Their antibacterial potency was evaluated by using a minimal inhibition concentration (MIC) benchmark and an inhibition zone testing. High-resolution transmission electron microscope images indicate that the Ag-based MOFs could rupture the bacterial membrane resulting in cell death. Hematological study showed that these MOFs exhibit good biocompatibility in mice. In addition, good thermal stability and optical stability under UV–visible and visible light are beneficial for their antibacterial application.

In Situ Self-Assembly of Silver Nanoparticles

We have found that the thermal decomposition of [Ag(O2CnH2n–1)]2, where n = 14, 16, 18, and 22, produces the ordered 3D nanostructure (supracrystals) directly during the chemical reaction, which makes it possible to obtain self-assembled structures in large quantities without requiring additional processing steps. The process of self-assembling of silver nanoparticles is characterized by TEM and in situ time-resolved SAXRD and WAXS data. The calculated unit-cell parameters of the fcc nanostructures formed correlate with the aliphatic chain length: these are 9.55 nm for silver myristate (n = 14), 9.8 nm for silver palmitate (n = 16), 10.46 nm for silver stearate (n = 18), and 12.5 nm for silver behenate (n = 22). Structural and morphological characteristics of supracrystals formed in situ during the thermal decomposition of silver carboxylates are found to be dependent on the sample heating rate. The self-assembled ordering of the silver nanoparticles was observed to begin at ∼180, and above ∼280 °C the supracrystalline structures begin to decompose.

ChemInform Abstract: Silver Carboxylate Promoted Lactonization: A General Method Applicable to Prepare Medium and Large‐Sized Lactones Without High Dilution or Slow Addition.

AbstractThe title method is advantageous with regards to simple operation and ready availability of starting materials.

Silver carboxylate promoted lactonization: a general method applicable to prepare medium and large-sized lactones without high dilution or slow addition

Efficient and applicable approach to macrolactonizations, with ready availability of starting materials and simple operation, remains a challenging task for the organic community. We developed a ‘freshman-can-do’ protocol to medium- and large-sized lactones, not depending on high-dilution or slow addition techniques. Application of this method for the synthesis of natural lactones or potentially pharmaceutical compounds might be useful for organic chemists and pharmacists.

Dip-pen-based direct writing of conducting silver dots

Direct fabrication of micro- and nanoscale metallic structures is advantageous for many applications. Here, we use dip-pen lithography with silver(I) carboxylate [AgO2C(CH2OCH2)3H] in diethylene glycol as precursor ink for the generation of conducting metal structures. After annealing the written dots, solid silver structures are generated. We investigate the influence of several parameters such as substrate functionalization and ink composition on the pattern formation. We found that a substrate coating with perfluorinated silane is necessary, if diethylene glycol will be used as ink carrier. By variation in ink concentration and ink carrier composition, structures with diameters ranging from ∼20μm to ∼2μm and with metal fractions ranging from ∼5% to ∼80% were fabricated. After gold enhancement of the written patterns, resistivities in the range of 4×10−5Ωm on the structures were determined. The ink system introduced here appears promising for the direct fabrication of various metal or metal oxide patterns.

Exothermic and Recursive Reaction of Self-Sinterable Silver Ink for Flexible Electronics

ABSTRACTFor the construction of highly conductive printed electrodes on a polymeric substrate with a low glass transition temperature, the development of a low temperature sinterable conductive ink has been a crucial issue in printed electronics and display applications. In this work, we introduce a novel type of self-sinterable silver ink, whose sintering is triggered at a low temperature and completed with the aid of its own exothermic reaction, and propose its exothermic reaction mechanism. Although individual components of this self-sinterable silver ink, Ag2O and silver carboxylate, exhibit endothermic behaviors, their mixture form shows a strong exothermic reaction when heated at 150 °C. It is found that the dissociated form of the used silver carboxylate contributes to the reduction of Ag2O to Ag through its recursive reaction and produces silver nanoparticles. The major source of an exothermic reaction results from the nucleation and fusion of silver nanoparticles.

Gold(III) Carboxylate Complexes with N, N‐Chelating Ligands: Synthesis, Structure, and Features of IR Spectra

AbstractNew gold(III) carboxylate complexes [(L)Au(RCO2)2]BF4 (R = CH3, CMe3, CF3) with N, N‐chelating ligands L (L = phenanthroline, 2, 2′‐bipyridine), were obtained by the treatment of corresponding chloride complexes [(L)AuCl2]BF4 with silver(I) carboxylates. The structure of [(bipy)Au(CF3CO2)2]BF4 complex was determined by X‐ray diffraction analysis. When five‐coordinate gold(III) complexes [(L)AuCl3] (L = 2, 9‐dimethyl‐1, 10‐phenanthroline, 2, 2′‐biquinoline) were used as starting materials the same reaction led to unstable products, which could not to be isolated and characterized. The reactivity of chloride complexes towards different carboxylates as well as properties of resulting carboxylate compounds depends on the nature of substitute R in carboxylate groups as it was predicted by us earlier using quantum‐chemical calculations. In order to explain a difference in behaviors of four‐ and five‐coordinate gold(III) complexes infrared and far‐infrared spectra of chlorides and carboxylates were studied.

Phosphine‐Free Palladium‐Catalyzed Direct C‐3 Arylation of 2‐Phenylimidazo[1,2‐a]pyridine Using Silver(I) Carboxylate

Phosphine‐free palladium‐catalyzed direct arylation of 2‐phenyl‐imidazo[1,2‐a]pyridine has been developed with the concept of using silver(I) carboxylate. This protocol efficiently catalyzes the C‐H arylation of 2‐phenyl‐imidazo[1,2‐a]pyridine with aryl iodides to afford the corresponding 2‐phenyl‐3‐aryl‐imidazo[1,2‐a]pyridines in moderate to‐good yields.

Synthesis of Monodisperse Silver Nanoparticles by Sonolysis of Silver Carboxylates

AbstractMonodisperse, crystalline silver nanoparticles are synthesized by sonolytically assisted decomposition of silver oxalate and oleate precursors in dibenzylether. Oleic acid and oleylamine are used as capping agents. The diameters of the obtained particles vary from 6 to 10 nm depending on the sonification time and the precursor material. The particles are stable in non‐polar media. A 2D and 3D assembly of the as‐prepared nanoparticles is observed. Particle sizes and dispersities are characterized by transmission electron microscopy and image analysis. The decomposition characteristics of the different precursor compounds are investigated using UV–Vis spectroscopy and thermogravimetry.

Thermal decomposition of some silver(I) carboxylates under nitrogen atmosphere

The thermal decomposition reactions of CH3CH2C(CH3)2COOAg (1), (CH3)3SiCH2COOAg (2), CF3COOAg (3), (CH3)3CCOOAg (4), C2H5COOAg (5), C3F7COOAg (6), C6F13COOAg (7) and (CF2)3(COOAg)2 (8) were studied in N2 atmosphere using thermogravimetry (TG), derivative thermogravimetry and differential thermal analysis. Characterized compounds decomposed in one- or multi-step processes with metallic silver formation in the range 215–465 °C. TG-IR studies of gases evolved during thermolysis revealed products of decomposition, such as carboxylic acids, CO2 and recombination reactions.

Silver-Catalyzed Decarboxylative Chlorination of Aliphatic Carboxylic Acids

Decarboxylative halogenation of carboxylic acids, the Hunsdiecker reaction, is one of the fundamental functional group transformations in organic chemistry. As the initial method requires the preparations of strictly anhydrous silver carboxylates, several modifications have been developed to simplify the procedures. However, these methods suffer from the use of highly toxic reagents, harsh reaction conditions, or limited scope of application. In addition, none is catalytic for aliphatic carboxylic acids. In this Article, we report the first catalytic Hunsdiecker reaction of aliphatic carboxylic acids. Thus, with the catalysis of Ag(Phen)(2)OTf, the reactions of carboxylic acids with t-butyl hypochlorite afforded the corresponding chlorodecarboxylation products in high yields under mild conditions. This method is not only efficient and general, but also chemoselective. Moreover, it exhibits remarkable functional group compatibility, making it of more practical value in organic synthesis. The mechanism of single electron transfer followed by chlorine atom transfer is proposed for the catalytic chlorodecarboxylation.