- Chemical vapor deposition of silver films for superconducting wire applications
-
Chemical vapor deposition (CVD) was used to deposit silver films for superconducting wire applications. AgI, silver trifluoroacetate (Ag(TFA)), and perfluoro-1-methylpropenylsilver (Ag(PF)) produced the most promising silver films. CVD processing was optimized on these three precursors using thermodynamic calculations performed using a modified version of the SOLGASMIX-PV computer program. Ag(PF) produced the highest quality silver films at low temperatures and pressures. A fiber tow which contained a silver barrier layer and a YBa2Cu3Ox overlayer was found to be a superconductor at 72 K.
- Shapiro,Lackey,Haruigofsky,Hill,Carter,Barefield
-
-
Read Online
- Crystalline roughness as a morphological characteristic of the surface of electroplated silver coatings
-
Structure and morphology of electroplated silver coatings deposited from a borate-phosphate-carbonate electrolyte were studied in relation to the current density and temperature. Average values of the crystalline roughness were determined.
- Bersirova,Kublanovskii
-
-
Read Online
- Trimethylphosphite stabilized N-silver(I) succinimide complexes as CVD precursors
-
The preparation of [(MeO)3Pn?AgNC 4H4O2] (n = 1, 2a; n = 2, 2b) is described. The molecular structure of 2a was determined by using X-ray single crystal analysis. Complex 2b was tested as Metal Organic Chemical Vapor Deposition (MOCVD) precursor in the deposition of silver for the first time. The thin films obtained were characterized using scanning electron microscopy (SEM) and energy-dispersion X-ray analysis (EDX). SEM and EDX studies show that the dense and homogeneous silver films could be obtained.
- Tao, Xian,Wang, Yu-Long,Shen, Ke-Cheng,Shen, Ying-Zhong
-
-
Read Online
- D-metal folates and the folic acid-imidazole conjugate
-
Metal folates MFol ? nH2O (M2+ = Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+; n = 4-6), silver folate Ag2Fol ? 3H2O, and the folic acid-imidazole conjugate H2Fol ? 3Im ? 2H2O were synthesized in aqueous solutions at a 1: 1 M2+: H2Fol molar ratio and pH 5.5-6.6. The compositions of the resulting compounds were determined by chemical, thermal, and gravimetric analysis. The composition of copper(II) folate was confirmed by elemental analysis; the solubility product of nickel folate (9.65 × 10-9) was estimated using solubility data. IR and electron absorption spectroscopy was used to show that oxygen atoms of carboxyl groups in folic acid and the pyridine nitrogen atom in imidazole are involved in bond formation in folates and the conjugate.
- Skorik
-
-
Read Online
- Preparation and optical properties of silica@Ag-Cu alloy core-shell composite colloids
-
The silica@Ag-Cu alloy core-shell composite colloids have been successfully synthesized by an electroless plating approach to explore the possibility of modifying the plasmon resonance at the nanoshell surface by varying the metal nanoshell composition for the first time. The surface plasmon resonance of the composite colloids increases in intensity and shifts towards longer, then shorter wavelengths as the Cu/Ag ratio in the alloy shell is increased. The variations in intensity of the surface plasmon resonance with the Cu/Ag ratio obviously affect the Raman bands of the silica colloid core. The report here may supply a new technique to effectively modify the surface plasmon resonance.
- Zhang, Jianhui,Liu, Huaiyong,Wang, Zhenlin,Ming, Naiben
-
-
Read Online
- Pulse radiolysis study of absorption spectra of Ag0 and Ag2+ in water from room temperature up to 380 °C
-
The reduction of silver ions by hydrated electrons is observed at different temperatures (from 25 to 300 °C) at 200 atm pressure in aqueous solutions and also in supercritical water (380 °C at 300 atm) using nanosecond pulse radiolysis techniques. An Arrh
- Mostafavi, Mehran,Lin, Mingzhang,Wu, Guozhong,Katsumura, Yosuke,Muroya, Yusa
-
-
Read Online
- Thermal and MS studies of silver(I) 2,2-dimethylbutyrate complexes with tertiary phosphines and their application for CVD of silver films
-
[Ag2(CH3CH2C(CH3)2COO)2] (1), [Ag2(CH3CH2C(CH3)2COO)2(PMe3)2] (2) and [Ag2(CH3CH2C(CH3)2COO)2(PEt3)2] (3) were prepared and characterized by MS-EI; 1H, 13C, 31P NMR, variable temperature IR (VT-IR) spectroscopy and thermal analysis. MS and VT-IR data analysis suggests bidentate bridging carboxylates and monodentately bonded phosphines in the solid phase. The same methods used for gas phase analysis of 1-2 proved [(CH3CH2C(CH3)2COO)Ag2]+ as the main ion, which could be transported in the gas phase during the CVD process. In the case of 3, similar intensity to the latter ion revealed [Ag{P(C2H5)}]+ and it is responsible for the CVD performance of 3. Thermal analysis results revealed that decomposition of 1-3 proceed in one endothermic process, with metallic silver formation between 197 and 220 °C. In the case of 1, VT-IR studies of the gaseous decomposition products demonstrate the presence of ester molecules and CO2, whereas for 2 the main gaseous product appeared to be acid anhydride. Therefore, 2 was not used as a silver CVD precursor. Metallic layers were produced from 3 in hot-wall CVD experiments, (between 200 and 280 °C), under a total reactor pressure of 2.0 mbar, using argon as a carrier gas. Thin films deposited on Si(1 1 1) substrate were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Silver films obtained at moderate temperature (220-250 °C) revealed a thickness below 50 nm, and were whitish colored and slightly matt.
- Szymańska,Piszczek,Szczesny,Sz?yk
-
-
Read Online
- Oscillatory circulation of copper particles during silver-displacement plating in a high magnetic field
-
Motion of copper particles during silver-displacement plating in a high magnetic field was investigated. Immediately after injecting a silver nitrate solution to a vessel filled with copper powder and suspending the powder in the solution, the particles start to circulate along a vessel under a vertical magnetic field with suddenly changing their directions. The velocity of the motion increased with the magnetic field strength though the deposition rate remained constant.
- Yonemochi, Shin-Ichi,Aogaki, Ryoichi
-
-
Read Online
- Thermal and chemical decomposition of di(pyrazine)silver(ii) peroxydisulfate and unusual crystal structure of a Ag(i) by-product
-
High purity samples of a [Ag(pyrazine)2]S2O 8 complex were obtained using modified synthetic pathways. Di(pyrazine)silver(ii) peroxydisulfate is sensitive to moisture forming [Ag(pyrazine)2](S2O8)(H2O) hydrate which degrades over time yielding HSO4- derivatives and releasing oxygen. One polymorphic form of pyrazinium hydrogensulfate, β-(pyrazineH+)(HSO4-), is found among the products of chemical decomposition together with unique [Ag(i)(pyrazine)] 5(H2O)2(HSO4)2[H(SO 4)2]. Chemical degradation of [Ag(pyrazine) 2]S2O8 in the presence of trace amounts of moisture can explain the very low yield of wet synthesis (11-15%). Attempts have failed to obtain a mixed valence Ag(ii)/Ag(i) pyrazine complex via partial chemical reduction of the [Ag(pyrazine)2]S2O8 precursor with a variety of inorganic and organic reducing agents, or via controlled thermal decomposition. Thermal degradation of [Ag(pyrazine) 2]S2O8 containing occluded water proceeds at T > 90 °C via evolution of O2; simultaneous release of pyrazine and SO3 is observed during the next stages of thermal decomposition (120-285 °C), while Ag2SO4 and Ag are obtained upon heating to 400-450 °C.
- Leszczynski, Piotr J.,Budzianowski, Armand,Dobrzycki, Lukasz,Cyranski, Michal K.,Derzsi, Mariana,Grochala, Wojciech
-
-
Read Online
- Encapsulation of Ag films on SiO2 by Ti reactions using Ag-Ti alloy/bilayer structures and an NH3 ambient
-
Thin encapsulated silver films have been prepared on oxidized silicon by nitridation of ～200-nm-thick Ag-19 at.% Ti alloy films and Ag(120 nm)/Ti(22 nm) at 300-700°C in an ammonia ambient. The encapsulation process has been studied in detail by Rutherford
- Alford,Adams, Daniel,Laursen,Manfred Ullrich
-
-
Read Online
- Structure and decomposition of the silver formate Ag(HCO2)
-
Crystal structure of the silver formate Ag(HCO2) has been determined (orthorhombic, sp.gr. Pccn, a=7.1199(5), b=10.3737(4), c=6.4701(3)?, V=477.88(4) ?3, Z=8). The structure contains isolated formate ions and the pairs Ag22+ which form the layers in (001) planes (the shortest Ag–Ag distances is 2.919 in the pair and 3.421 and 3.716?? between the nearest Ag atoms of adjacent pairs). Silver formate is unstable compound which decompose spontaneously vs time. Decomposition was studied using Rietveld analysis of the powder diffraction patterns. It was concluded that the diffusion of Ag atoms leads to the formation of plate-like metal particles as nuclei in the (100) planes which settle parallel to (001) planes of the silver formate matrix.
- Puzan, Anna N.,Baumer, Vyacheslav N.,Mateychenko, Pavel V.
-
-
Read Online
- Low temperature sintering of Ag nanoparticles for flexible electronics packaging
-
We achieve robust bonding of Cu wires to Cu pads on polyimide with silver nanopaste cured at 373 K. The paste is prepared by simply condensing Ag nanoparticle (NP) solution via centrifuging. The bonding is formed by solid state sintering of Ag NPs through
- Hu,Guo,Alarifi,Patane,Zhou,Compagnini,Xu
-
-
Read Online
- Y2O3:Eu3+ (5 mol%) with Ag nanoparticles prepared by citrate precursor
-
Y2O3:Eu3 (5 mol% Eu3) and Y2O3:Eu3 (5 mol% Eu3) containing 1 mol% of Ag nanoparticles were prepared by heat treatment of a viscous resin obtained via citrate precursor. TEM and EDS analyses showed that Y 2O3:Eu3 (5 mol% Eu3) is formed by nanoparticles with an average size of 12 nm, which increases to 30 nm when Ag is present because the effect of metal induced crystallization occurs. Ag nanoparticles with a size of 9 nm dispersed in Y2O 3:Eu3 (5 mol% Eu3) were obtained and the surface plasmon effect on Ag nanoparticles was observed. The emission around 612 nm assigned to the Eu3 (5D0→ 7F2) transition enhanced when the Ag nanoparticles were present in the Y2O3:Eu3 luminescent material.
- Ferrari,Cebim,Pires,Couto Dos Santos,Davolos
-
-
Read Online
- Kinetics and mechanism of reactions occurring in electrodeposition of silver from thiosulfate solutions
-
The kinetics and mechanism of processes occurring in reduction of silver thiosulfate complexes on stationary and rotating disc electrodes and on fluidized glass-bead electrode were studied voltammetrically.
- Shvab,Gur'yanova,Omel'chuk
-
-
Read Online
- Molecular-level design of binary self-assembled monolayers on polycrystalline gold electrodes
-
In this study, we followed up, by measuring the reductive desorption patterns, the time-dependent growth of the self-assembled monolayer (SAM) of a thiol compound (typically cysteine) formed on polycrystalline Au (poly-Au) electrode. Cysteine molecules appeared to adsorb preferentially and consecutively at the Au(110), Au(100) and then at the Au(111) surface domains of the poly-Au. A 95% surface coverage of cysteine (Γcysteine) was attained after 5s, 120s and more than 300s for the Au(110), Au(100) and Au(111) domains, respectively, of the poly-Au electrode. The electrochemical reduction of molecular oxygen (O2) in O2-saturated 0.5M KOH was utilized as a probing reaction for the extent of the compactness of the SAM. A binary SAM of two thiols (cysteine and cystamine) has been successfully designed over the poly-Au electrode at which a precise positioning of cysteine was achieved, i.e., cysteine was attached to the Au(111) domains, while cystamine to the Au(100) and Au(110) domains. SEM images for the electrodeposited Ag over the cysteine sub-SAM/Au electrode gave a possible mapping of the Au(111) domains of the poly-Au electrode.
- El-Deab, Mohamed S.,Ohsaka, Takeo
-
-
Read Online
- PVP protective mechanism of ultrafine silver powder synthesized by chemical reduction processes
-
Polyvinyl pyrrolidone (PVP) as a protective agent plays a decisive part in controlling superfine silver particle size and size distribution by reducing silver nitrate with hydrazine hydrate. The particle size and particle aggregation decrease with the PVP/AgNO3 mole ratio. Mechanisms of PVP protection were divided into three stages. First, PVP donates loan pair electrons of oxygen and nitrogen atoms to sp orbitals of silver ions, and thus the coordinative complex of Ag ions and PVP forms in aqueous solution. Second, PVP promotes the nucleation of the metallic silver because the Ag ions-PVP complex is more easily reduced by hydrazine than the pure Ag ions owing to Ag ions receiving more electronic clouds from PVP than from H2O. Third, PVP prohibits silver particle aggregation and grain growth as a result of its steric effect. All of the hypotheses were supported by ultraviolet spectra, infrared spectra, and heterogeneous nucleation and grain growth by addition of silver nuclei.
- Zhang, Zongtao,Zhao, Bin,Hu, Liming
-
-
Read Online
- Structure and morphology controllable synthesis of Ag/carbon hybrid with ionic liquid as soft-template and their catalytic properties
-
Ag/carbon hybrids were fabricated by the redox of glucose and silver nitrate (AgNO3) in the presence of imidazolium ionic liquid ([C14mim]BF4) under hydrothermal condition. Monodisperse carbon hollow sub-microspheres encapsulating Ag nanoparticles and Ag/carbon cables were selectively prepared by varying the concentration of ionic liquid. Other reaction parameters, such as reaction temperature, reaction time and the mole ratio of silver nitrate to glucose, play important roles in controlling the structures of the products. The products were characterized by XRD, TEM (HRTEM), SEM, energy-dispersive X-ray spectroscopy (EDX), FTIR spectroscopy and a Raman spectrometer. The possible formation mechanism was proposed. The catalytic property of the hybrid in the oxidation of 1-butanol by H2O2 was also investigated.
- Wu, Shu Ying,Ding, Yun Sheng,Zhang, Xiao Min,Tang, Hai Ou,Chen, Long,Li, Bo Xuan
-
-
Read Online
- Molecules versus Nanoparticles: Identifying a Reactive Molecular Intermediate in the Synthesis of Ternary Coinage Metal Chalcogenides
-
The identification of reactive intermediates during molecule-to-nanoparticle (NP) transformation has great significance in comprehending the mechanism of NP formation and, therefore, optimizing the synthetic conditions and properties of the formed products. We report here the room temperature (RT) synthesis of AgCuSe NPs from the reaction of di-tert-butyl selenide with trifluoroacetates (TFA) of silver(I) and copper(II). The isolation and characterization of a molecular species during the course of this reaction, [Ag2Cu(TFA)4(tBu2Se)4] (1), which shows extraordinary reactivity and interesting thermochromic behavior (blue at 0 °C and green at RT), confirmed that ternary metal selenide NPs are formed via this intermediate species. Similar reactions with related dialkyl chalcogenide R2E resulted in the isolation of molecular species of similar composition, [Ag2Cu(TFA)4(R2E)4] [R = tBu, E = S (2); R = Me, E = Se (3); R = Me, E = S (4)], which are stable at RT but can be converted to ternary metal chalcogenides at elevated temperature. Density functional theory calculations confirm the kinetic instability of 1 and throw light on its thermochromic properties.
- Gahlot, Sweta,Jeanneau, Erwann,Singh, Deobrat,Panda, Pritam Kumar,Mishra, Yogendra Kumar,Ahuja, Rajeev,Ledoux, Gilles,Mishra, Shashank
-
-
Read Online
- Visible light induced electron transfer behavior of a CeO 2-loaded HfO2/carbon cluster nanocomposite material
-
The microwave-irradiated calcination of HfOCl2/starch complex I under an air atmosphere produced the HfO2/carbon cluster composite material which is denoted as Ic. The obtained composite material could decompose methylene blue under the irradiation of light (λ > 460 nm). The surface of Ic was loaded with CeO2 particles to obtain CeO 2-loaded composite material, which can decompose the aqueous silver nitrate solution and produce O2 and Ag in the ratio of 1:4.2. Water photo-decomposition experiment was also carried out using Pt-modified composite materials.
- Matsui,Nishii,Karuppuchamy,Jeong,Hassan,Yoshihara
-
-
Read Online
- Linear and nonlinear optical response of silver nanoprisms: Local electric fields of dipole and quadrupole plasmon resonances
-
By means of femtosecond pump and probe spectroscopy, linear and nonlinear optical properties of silver nanoprisms have been investigated, focusing on enhancement of local electric fields due to dipole and quadrupole surface plasmons. Ag nanoprsims were prepared by direct reduction of AgNO3 by the solvent N,N-dimetnylformamide in the presence of poly(vinylpyrrolidone). The average edge length and thickness of the nanoprisms (triangles and truncated triangles) were 67 and 35 nm, respectively. In the absorption spectra, dipole and quadrupole plasmon resonance bands have been observed. The values of the imaginary part of nonlinear susceptibility Im??(3) measured at the dipole and quadrupole plasmon bands are -5.7 ?? 10-15 and -3.0 ?? 10-15 esu, respectively. The local electric field factors fQ and fD of quadrupole and dipole plasmon resonances were obtained from the observed dispersion curve of Im??(3) and absorption spectra, yielding a ratio fQ/fD of a??0.7. The nonlinear response times of both resonances were found to be a??2 ps, which is close to the value for spherical nanoparticles, indicating that the relaxation process via electron-phonon interaction is governed by bulk crystal properties.
- Okada, Noriyuki,Hamanaka, Yasushi,Nakamura, Arao,Pastoriza-Santos, Isabel,Liz-Marzaì?n, Luis M.
-
-
Read Online
- Nanopowders of 3D AgI coordination polymer: A new precursor for preparation of silver nanoparticles
-
Nanopowders of novel three-dimensional AgI coordination polymer, [Ag2(μ8-SB)]n (1) [H2SB = 4-[(4-hydroxyphenyl)sulfonyl]-1-benzenol] has been synthesized by the reaction of SB2- and AgNOsu
- Bashiri, Robabeh,Akhbari, Kamran,Morsali, Ali
-
-
Read Online
- Dependence of the reliability of electrochemical quartz-crystal nanobalance mass responses on the calibration constant, Cf: Analysis of three procedures for its determination
-
The acquisition of accurate results in use of the electrochemical quartz-crystal nanobalance (EQCN) for surface-electrochemical studies depends on reliability of the value of the calibration constant relating changes of the crystal oscillator frequency to the specific surface mass change resulting from some chemisorption or electrosorption process. Three electrochemical methods are employed comparatively to determine the calibration constant for use of an EQCN. In the present paper, study of electrodeposition/electrodissolution of silver on Pt(poly) electrode surfaces provides a means of determining values of the calibration constant for the EQCN response using cyclic voltammetry, chronopotentiometry and chronoamperometry. The experimentally determined value of the calibration constant (Cf) is found to depend on the electrochemical methodology and technique used for its measurement as well as the thickness of the Ag deposit. Use of these three complementary procedures applied under well-defined conditions provides a basis for adoption of a preferred and reliable procedure for determination of the calibration constant; the resulting mean value is precise and very reproducible.
- Vatankhah,Lessard,Jerkiewicz,Zolfaghari,Conway
-
-
Read Online
- Silver Coordination to exo-Dithio-7,8-dicarba-nido-undecaborate Derivatives. Sulfur to Metal and Open Face to Metal: Two Ways of Bonding
-
exo-Dithiocarbaborane compounds display two different silver coordinations (Ag-S and AgC2B3) depending on the length of the exo-cluster chain.
- Teixidor, Francesc,Ayllon, Jose A.,Vinas, Clara,Rius, Jordi,Miravitlles, Carles,Casabo, Jaume
-
-
Read Online
- Four new silver-based complexes constructed from 3-nitrophthalic acid and pyrazine-like ligands: Syntheses, crystal structures and photodegradation activities
-
Four Ag-based coordination polymers, Ag4(H2O)2(npth)2 (1), Ag4(epyz)2(npth)2 (2), [Ag(pyz)(Hnpth)]·H2O (3) and Ag(epyz)0.5(Hnpth) (4) (H2npth?=?3-nitrophthalic acid, pyz?=?pyrazine, epyz?=?2,3,5,6-tetramethylpyrazine), have been synthesized by ultrasonic or hydrothermal reactions of Ag(I) salts with H2npth and various pyrazine derivatives ligands. Compound 1 presents a 2D 44-sql network with Ag4 units, and compound 2 features novel cage-like Ag8 SBUs (secondary building unit), which are linked by epyz ligands to form a 3D framework. Compound 3 shows a 1D chain and compound 4 exhibits a 2D coordination polymer construction. The photocatalytic properties for the degradation of organic dye molecules have been examined, and the experiments show that compound 3 has a good degradation effect to Rhodamine B.
- Yang, Yuan-Yuan,Zhou, Lin-Xia,Zheng, Yue-Qing,Zhu, Hong-Lin
-
-
Read Online
- Polymers or supramolecules generated from a new V-shaped bis-monodentate ligand and the effect of steric hindrance on coordination modes of the ligand
-
A new V-shaped bis-monodentate ligand L (L = 2,3′-dipyridylamine) (1) has been designed and synthesized by alkylation reaction of pyridylamine. An investigation of the charge distributions of the coordination atoms and single-point energy calculations of four conformers of ligand L based on the geometry of conformers optimized by the DFT (density functional theory) method was carried out. The results show that the four conformers of ligand L take on two stable and two less stable configurations. Theory forecasts that two relatively stable configurations present in complexes as probable coordination motifs of the ligand, and that steric hindrance of pyridine nitrogen atoms in isomers will affect its coordination ability together with the electronic factor. This forecast has been demonstrated by the coordination chemistry of ligand L, that is, configuration (a) and (b) of the ligand occur in the following reported complexes, which combines with AgI or Cu II through two coordination modes (bidentate bridging or a monodentate mode) resulting in coordination polymers {[Ag (L) 2]NO3}n (2), [Cu2(L) 2(maa)4]n (maa = methacrylic acid) (3), and the mononuclear molecule [Cu(L)4]-(ClO4)2· 2CH3CH2OH (4). The ligand assumes different coordination modes in the three complexes because of different levels of steric hindrance of the pyridine nitrogen atoms in the conformers. Interestingly, polymers 2 and 3 assume a 1D helical structure and a linear framework, respectively, and 4 has a 2D supramolecular architecture induced from hydrogen bond interactions. In addition, the magnetic properties of 3 have been explored, which shows a strong antiferromagnetic interaction. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Zhou, Caihua,Wang, Yaoyu,Li, Dongsheng,Zhou, Lijun,Liu, Ping,Shi, Qizhen
-
-
Read Online
- Dimeric and polymeric silver(I) saccharinato complexes of two bis(pyridine) ligands: Synthesis, structural, spectroscopic, fluorescent and thermal properties
-
The reaction of silver(I) with 1,2-bis[1-(pyridin-2-yl)ethylidene]hydrazine (bpeh) and N,N-bis(pyridin-2-ylmethyl)amine (bpma) in the presence of Na(sac) (sac = saccharinate) yielded [Ag2(sac)2(bpeh)] (1) and [Ag(sac)(bpma)]n (2) with conformational chirality. Both complexes have been characterized by elemental analysis, IR, thermal analysis and X-ray single crystal diffraction. Complex 1 displays a binuclear composition, in which each silver(I) ion is bound to one monodentate sac ligand and one of the bidentate pyridylimino groups of the bpeh ligand in a distorted trigonal coordination geometry. Complex 2 is a one-dimensional helical polymer, in which silver(I) centers are bridged by tridentate bpma ligands, and each silver(I) ion is coordinated in a distorted tetrahedral geometry by one monodentate sac ligand, a bidentate pyridylamine group of one bpma ligand, and a py group of another bpma ligand. Weak intermolecular C-H?O hydrogen bonds and C-H?π interactions lead to assembly of 1 and 2 into three-dimensional supramolecular frameworks. Spectral and thermal analysis data for 1 and 2 are in agreement with the crystal structures. In addition, both complexes in the solid state display intraligand π-π* fluorescence.
- Guney, Emel,Yilmaz, Veysel T.,Buyukgungor, Orhan
-
-
Read Online
- Morphology-control in microwave-assisted synthesis of silver particles in aqueous solutions
-
The morphologies of Ag particles can be controlled between distorted sphere and prism by employing microwave-promoted reductions of highly concentrated 0.1 M silver nitrate in aqueous solutions. Microwave (MW)-induced 1-min heating of aqueous solutions (≤ 0.1 M) of silver nitrate gave aggregates of sphere-nanoparticles in the presence of trisodium citrate (0.1-1.5 M) and excess of formaldehyde (1.5 M). Sample A1, prepared in the presence of an equal quantity (0.1 M) of trisodium citrate to silver nitrate, resulted in the formation of sphere-Ag particles with a smaller average particle size (24 nm) and a narrower particle size distribution (10-90 nm) than sample A2, prepared by the conventional heating (average size 71 nm, size distribution 20-360 nm). In addition to the MW effect, when the concentration of sodium citrate was increased, the inter-molecule hydrogen bonding of the citrate moieties associated with Ag particles should enhance the collision probability of the particles. Thus, large Ag particles with a wide particle distribution were produced in the presence of a larger amount of trisodium citrate under MW irradiation.
- Yamamoto, Tetsushi,Yin, Hengbo,Wada, Yuji,Kitamura, Takayuki,Sakata, Takao,Mori, Hirotaro,Yanagida, Shozo
-
-
Read Online
- Observation of enhanced photocurrent response in M-CuInS2 (M = Au, Ag) heteronanostructures: phase selective synthesis and application
-
We report controlled synthesis of CuInS2 in wurtzite and zinc blende phases by solution based thermal decomposition of dual precursors [In(acda)3] (acda = 2-aminocyclopentene-1-dithiocarboxylic acid) and [Cu(PPh3)2(acda)] (PPh3 = triphenylphosphine) in the presence of appropriate surface-active agents. Furthermore, the preparation of M-CuInS2 (M = Au and Ag) heteronanostructures on both the phases has been achieved successfully by hot injection of respective gold and silver precursor solutions into the reaction mixture. The characterization of both pure and hybrid nanostructures was carried out by X-ray diffraction (XRD), UV-vis spectroscopy, energy dispersive X-ray (EDX) study and transmission electron microscopy (TEM). A detailed photovoltaic study has been performed with both pure materials and the twin structures and their photocurrent and photoresponse behavior have been compared. The study reveals that upon loading Au and Ag, the material exhibits high photocurrent efficiency compared to pure CuInS2. An appreciable increase in the light to dark current density ratio confirms that these materials can be used in the fabrication of promising photovoltaic devices.
- Ghosh, Abhisek Brata,Saha, Namrata,Sarkar, Arpita,Dutta, Amit Kumar,Maji, Swarup Kumar,Adhikary, Bibhutosh
-
-
Read Online
- Straightforward green synthesis of "naked" aqueous silver nanoparticles
-
Water-soluble, exceptionally stable, "naked" silver nanoparticles were obtained in a single step by simple decomposition of a commercial silver complex at room temperature without the need of external reducing agents and conventional stabilizing ligands.
- Giuffrida, Salvatore,Ventimiglia, Giorgio,Sortino, Salvatore
-
-
Read Online
- Thermogravimetric investigation of manganese(ii), silver and thorium diliturates
-
Thermolysis curves for manganese(II), silver and thorium diliturates were obtained. Manganese diliturate precipitated as the octahydrate and dehydrated in two steps. Silver diliturate formed as a monohydrate from aqueous solutions. Thorium diliturate formed as a hydrate containing 20 moles of water and dehydrated in two steps. Methods for the thermogravimetric determination of manganese(II) and thorium by precipitation as the diliturates are suggested.
- Goheen, Milton W.,Robinson, Rex J.
-
-
Read Online
- A study on oxygen insertion in dinuclear silver cryptates
-
Two novel silver(I) cryptates are reported in this paper. [Ag 2(L1O)](ClO4)2·H 2O 1 and [Ag2L1](ClO4) 2·1.5H2O 2 were synthesized by the condensation of tris (3-aminopropyl) amine with m-phthalaldehyde in the presence of silver(I) ion, under aerobic and anaerobic conditions, respectively. (The ligand L 1O represents the oxygen insertion product of L1.) Cryptates 1, 2, and their hydrogenated ligand H12(L1O) 3 and H12L14 (obtained by reduction of the cryptates) were investigated by electrospray mass spectroscopy (ES-MS). 1 and 2 were also decomposed by HCl treatment and their products were separated and identified by HPLC and ES-MS. Our experiments show that cryptate 2 is able to activate dioxygen that results in quantitative aliphatic hydroxylation of L1 on one of its HC=N bonds. Crystal structure analysis shows an interesting difference between 1 and 2 in that 1 is an oxygenated and 2 is a non-oxygenated cryptate. Up to date, ligand hydroxylation has not been achieved in silver(I) complex-O2 systems.
- Wang, Zhi-Lin,Luo, Qin-Hui,Duan, Chun-Ying,Shen, Cheng-Yu,Li, Yi-Zhi
-
-
Read Online
- Transmetalation reaction between hydrophobic silver nanoparticles and aqueous chloroaurate ions at the air-water interface
-
The transmetalation reaction between a sacrificial nanoparticle and more noble metal ions in solution has emerged as a novel method for creating unique hollow and bimetallic nanostructures. In this report, we investigate the possibility of carrying out the transmetalation reaction between hydrophobic silver nanoparticles assembled and constrained at the air-water interface and subphase gold ions. We observe that facile reduction of the subphase gold ions by the sacrificial silver nanoparticles occurs resulting in the formation of elongated gold nanostructures that appear to cross-link the sacrificial silver particles. This transmetalation reaction may be modulated by the insertion of an electrostatic barrier in the form of an ionizable lipid monolayer between the silver nanoparticles and the aqueous gold ions that impacts the gold nanoparticle assembly. Transmetalation reactions between nanoparticles constrained into a close-packed structure and appropriate metal ions could lead to a new strategy for metallic cross-linking of nanoparticles and generation of coatings with promising optoelectonic behavior. ? 2005 American Chemical Society.
- Pasricha, Renu,Swami, Anita,Sastry, Murali
-
-
Read Online
- Solid-state thin film cell for in situ transmission electron microscopy of electrodeposited silver on gold
-
A cell to permit in situ imaging of the electrodeposition of silver on gold 〈100〉 from a polymer electrolyte by TEM is described. The extremely thin electrochemical cells were composed of a layer of polyethylene oxide containing a silver salt between evaporated silver and gold electrodes. Cyclic voltammetry experiments in larger cells show the deposition and stripping behavior of silver on polycrystalline gold from the polymer electrolyte as a function of temperature. Observations in preliminary in situ TEM experiments include the nucleation and growth, and coalescence of silver islands oriented epitaxially to the gold electrode.
- Hanson,Gibson,McDonald
-
-
Read Online
- Investigation of silver-glass nanocomposites by positron lifetime spectroscopy
-
Nanocrystalline silver particles were grown in a glass medium by ion-exchange and reduction techniques and studied by positron lifetime spectroscopy. The particle sizes varied from 5 to about 25 nm as observed by transmission electron microscopy. The positron lifetime spectra of all the samples could be decomposed into three components having lifetimes of around 160 ps, 400 ps and 1500 ps. The first is ascribed to positron annihilation at the interfaces of the nanocrystalline silver and the glass matrix, and it decreases and stabilizes as the silver grain size increases. The second component is explained as arising from positrons trapped and annihilated at the free-volume defects in the glass matrix. The third component arises because of the annihilation of orthopositronium at large free-volume defects. The effects of temperature on the interfacial defects and the processes leading to the formation of additional positron trapping centres are discussed.
- Mukherjee,Nambissan,Chakravorty
-
-
Read Online
- SELF-DECOMPOSITION PROCESSES IN SILVER ELECTRODES.
-
The self-decomposition of silver oxide (AgO) electrode material in KOH electrolyte has been studied to determine the effects of metallic additions, preparation techniques, and carbonate content. The study employed a multi-technique approach that involved direct gas evolution measurements, thermal analysis, and electrical resistivity measurements. The results indicate that small amounts (10 ppm) of cobalt and nickel substantially increase the rate of decomposition in electrolyte. High levels of copper also increase the decomposition rate, but to a lesser extent. Other metals, such as indium and gold, tend to suppress AgO decomposition. A third group, including lead and mercury, have little or no effect on the decomposition rate. Binary mixtures of several elements were also tested as a means of counteracting the destabilizing properties of cobalt in particular.
- Salkind,Freeman,Weckesser,West,Dallek
-
-
Read Online
- Green and rapid synthesis of porous Ag submicrocubes via Ag3PO4 templates for near-infrared surface-enhanced Raman scattering with high accessibility
-
Noble metal particles (Au and Ag) with porous structure are promising surface-enhanced Raman scattering (SERS) substrates, but their preparation processes are generally complex. Here, we report a remarkably facile, rapid and inexpensive method to synthesize two kinds of porous Ag submicrocubes, cage- and sponge-like submicrocubes with highly clean and accessible surfaces. These particles were synthesized in a completely green solvent (water) by using Ag3PO4 submicrocubes as templates at room temperature. Merely by optimizing the concentration of a reducing agent (NaBH4), three-dimensional cage- and sponge-like Ag submicrocubes were fabricated. As a result, as SERS substrates, the cage- and sponge-like Ag submicrocubes can achieve near-infrared (NIR)-SERS activity because they have broad absorption throughout the visible and NIR regions. Moreover, compared with the sponge-like Ag submicrocubes, cage-like submicrocubes with a highly rough surface had higher SERS enhancement due to the presence of narrow and deep nanoslits on their shells. Due to the high-density of ‘‘hot spots’’ produced by the narrow and deep nanoslits on the shell, cage-like Ag submicrocubes have a low SERS detection limit, 1.479 × 10?11 M for 4-aminothiophenol and 1.50 × 10?9 M for thiram. Thus, a new SERS substrate based on highly rough cage-like submicrocubes was obtained by an easy and green method.
- Hang, Lifeng,Wu, Yingyi,Zhang, Honghua,Xiang, Junhuai,Sun, Yiqiang,Zhang, Tao,Men, Dandan
-
-
Read Online
- Preparation of p-type AgCrO2 nanocrystals through low-temperature hydrothermal method and the potential application in p-type dye-sensitized solar cell
-
Abstract The synthesis of nano-sized ternary delafossite oxides with pure crystal phases is of great challenge. We present a novel hydrothermal method for the synthesis of AgCrO2 nanocrystals with ultrafine size of 10-20 nm at relatively low temperature range (190-230 °C). It is the first time to report that AgCrO2 nanocrystals can be hydrothermally synthesized at such a low temperature (190°C) and applied as photocathode in dye sensitized solar cells (DSSCs). The as-synthesized AgCrO2 nanoproducts, including their crystal phases, morphologies, element compositions, valence state information, thermal stability, electrical and optical properties, have been systematically studied. This facile method employed metal nitrates (AgNO3 and Cr(NO3)3) as the starting materials and NaOH as the mineralizer, where Cr(NO3)3 undertook the dual functions of Cr3+ source material and weak reducing reagent. The in-situ oxidation-reduction reaction between Cr3+ and Ag+/Cu2+ during the hydrothermal crystal growth is the noteworthy feature of this general method. The crystal formation mechanism disclosed in the synthesis of chromium based delafossite oxides will certainly be benefit for the preparation of other delafossite oxides.
- Xiong, Dehua,Wang, Huan,Zhang, Wenjun,Zeng, Xianwei,Chang, Haimei,Zhao, Xiujian,Chen, Wei,Cheng, Yi-Bing
-
-
Read Online
- Synthesis, characterization, and electrochemical properties of nanocrystalline silver thin films obtained by spray pyrolysis
-
Silver thin films were prepared using a spray pyrolysis method, silver acetate as the precursor, and stainless steel, heated at 225 and 300°C, as the substrate. Structural and morphological analyses carried out using X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy methods revealed the formation of highly homogeneous, porous coatings ca. 1 μm thick and with nanometric Ag particles as the main component. The presence of small amounts of Ag2O was also inferred from XPS data. The reduction process of these films, which are used as electrodes over the potential range 3.0-0.0 V in lithium cells, consisted of several steps involving the formation of a solid electrolyte interface between 1.5 and 0.2 V, and at least two Ag-Li alloys below 0.2 V, the patterns of which were indexed in the cubic and tetragonal systems, respectively. The alloying/dealloying processes are reversible, and the cell can deliver a capacity of 600 Ah kg-1 in the potential window 1.0-0.0 V.
- Morales,Sanchez,Martin,Ramos-Barrado,Sanchez
-
-
Read Online
- Metal Complexes of Two 7-oxo-vic-TriazoloPyrimidine Derivatives
-
Seven Hg(II), Pd(II), Cu(II), and Ag(I) complexes of two 7-oxo-vic-triazolopyrimidine derivatives have been obtained.The complexes were characterized by spectroscopic studies (IR, 1H-NMR and UV-visible) and magnetic measurements.On the basis of the
- Garzon, Rafael Lopez,Valero, Dolores Gutierrez,Calahorro, Cristobal Valenzuela,Perez, Nicolas Cruz,Rodriguez, Antonio Garcia
-
-
Read Online
- Preparation of long silver nanowires from silver matrix by electron beam irradiation
-
Long silver nanowires with a high aspect ratio of up to 2000 could be obtained from Ag-containing matrix with NASICON structure by electron beam irradiation.
- Makita, Yoji,Ikai, Osamu,Ookubo, Akira,Ooi, Kenta
-
-
Read Online
- An unusual ligand in copper chemistry: Coordination oligomers and polymers containing the [{CpMo(CO)2}2(μ,η2- Sb2)] cluster
-
The coordination behavior of [{CpMo(CO)2}2(μ, η2-Sb2,)] (1; Cp = cyclopentadiene) toward Cu(I) was investigated. Its reaction with CuX (X = Br, Cl, and I) produced oligomers or polymers of the general formula [{CpMo(CO)2}2-(μ, η2-Sb2)(μ-CuX)]n. While 2 (X = Cl, n = 2) and 3 (X = Br, n = 2) proved to be halogen-bridged dimers in both solution and solid state, the molecules of 4 (X = I, n = ∞) self-assembled in the crystal forming a linear polymer with a Cu-I skeleton supported by Sb-Cu bonds. The reaction of 1 with Cu[GaCl4] resulted in the formation of the ionic complex [{CpMo(CO)2}2(μ,η2-Sb 2)]4Cu2[GaCl4]2 (5). Its dication contains four [{CpMo(CO)2}2(μ,η2-Sb 2)] ligands arranged around a Cu-Cu dumbbell. All new compounds were characterized using IR, electrospray ionization mass spectrometry, 1H NMR, elemental analysis, and single-crystal X-ray diffraction. The ligand was oxidized by both silver(I) and copper(II), and a cyclovoltammetric study revealed that 1 suffered irreversible reduction and oxidation in a dichloromethane solution at -2.04 and 0.10 V, respectively, versus ferrocene.
- Ly, Hanh V.,Parvez, Masood,Roesler, Roland
-
-
Read Online
- Spectroscopic studies, DFT calculations, thermal analysis, anti-cancer evaluation of new metal complexes of 2-hydroxy-N-(4-phenylthiazol-2-yl)benzamide
-
2-Hydroxy-N-(4-phenylthiazol-2-yl)benzamide was reacted with Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Ag(I) metal ions to synthesize the corresponding coordination compounds. From the study, 2-hydroxy-N-(4-phenylthiazol-2-yl)benzamide was rearranged to 2-hydroxy-N-(4-phenyl-1,3-thiazole-2-yl)carboxymidic acid (HL) due to the keto-enol tautomeric forms, where the enol form is more dominant. The structures of the HL ligand and the newly synthesized coordination compounds have been characterized by elemental analysis, IR, UV-Visible, 1H NMR, ESR and mass spectral data, in addition to thermal gravimetric analysis (TGA) and magnetic and molar conductance measurements. The ligand behaves as a monobasic bidentate ON sites, where the bidentate binding of the ligand involving the phenolic oxygen and azomethine nitrogen. The binding modes of the coordination compounds were further confirmed using Gaussian 09 software. The complexes of Co(II), Cu(II), Zn(II), and Ag(I) were tested in vitro against human colon carcinoma cells (HCT-116). The IC50 values showed dramatic toxicity results for cobalt(II), copper(II) and zinc(II) complexes versus human colon carcinoma (HCT-116) cell line, compared to African green monkey kidney (VERO) normal cell line. According to the results of the IC50 values obtained for Co(II), Cu(II), Zn(II), and Ag(I) 1.5, 1.0, 1.8 and 7.3 μg/ml, respectively, compared to the reference drug (2.49 μg/ml), Co(II), Cu(II), Zn(II) compounds are considered strong antitumor agent while Ag(I) compound can be considered as a weak one. For both antifungal and antibacterial activities, HL and all its coordination compounds were evaluated. HL ligand has only high activity against B. subtilis and C. albicans while Co(II) and Zn(II) compounds have the highest activity against S. aureus, P. aeruginisa, B. subtilis and E. coli.
- Emara, Adel A. A.,Mahmoud, Nelly H.,Rizk, Mariam G.
-
-
- Halides of macrocyclic silver(II) complexes: Crystal structures with hydrogen bond network and reaction kinetics of the decomposition
-
A series of silver(II) complexes of 5RS,12SR-1,5,8,12-tetramethyl-1,4,8,11-tetraazacyclotetradecane (L) have been synthesized and characterized by X-ray crystallographic analysis and UV–vis absorption spectra. The crystal structure of [AgL(ClO4)2] (1), [AgL(NO3)2]·CH3OH (2), [AgL(H2O)2]Cl2 (3), and [AgL(H2O)2]Br2 (4) showed the macrocyclic ligand L to be in the stable trans-III structure with C-methyl groups at equatorial positions. To our knowledge, this is the first report on the single crystal X-ray structural analysis of halides of silver(II) complex. Usually, silver ions form insoluble inorganic halides, but the stabilization of divalent silver ion by L, enabled characterization of the complex both in the solutions and in crystals. UV–vis analysis revealed that all complexes were in the form of [AgL(H2O)2]2+ in aqueous solution. These complexes in aqueous solution were found to decompose gradually and lose orange color. The decomposition rate constants of these complexes were evaluated as 0.1012, 0.0971, 0.0981, and 0.2104 h?1 for complexes 1–4, respectively. The decomposition was accelerated by Br? and I? anions.
- Honda, Akinori,Kakihara, Shunta,Ichimura, Shuhei,Tomono, Kazuaki,Matsushita, Mina,Yamamoto, Rie,Kikuta, Emi,Tamaki, Yoshinori,Miyamura, Kazuo
-
-
- In situ synthesis of Ag/NiO derived from hetero-metallic MOF for supercapacitor application
-
Nanocomposite metal oxides have been attracted great attention in the electrode material of supercapacitor. Herein, a novel Ag/Ni hetero-metallic complex with the hamburger-like structure was prepared, which was then calcined to form Ag/NiO nanocomposite via in-situ preparation. The in-situ formed Ag/NiO exhibits a very high capacitance of 1480 F g ?1 at a current density of 0.6 A g?1 in 1?M KOH solution, and the cycling stability was retained about 85% after 3000 cycles with the current of 5 A g?1. The results showed that the in-situ formed Ag/NiO derived from hetero-metallic MOF possess high specific capacitance, which could provide a new effective strategy to improve the conductivity of metal oxides nanocomposite.
- Zhou, Lin-Xia,Yang, Yuan-Yuan,Zhu, Hong-Lin,Zheng, Yue-Qing
-
p. 1795 - 1807
(2020/11/30)
-
- Silver(I) and gold(I) complexes with sulfasalazine: Spectroscopic characterization, theoretical studies and antiproliferative activities over Gram-positive and Gram-negative bacterial strains
-
The emergence of bacterial strains resistant to antibiotics, such as the sulfonamides (sulfa drugs), is currently a case of concern. The synthesis of metal complexes using well-known antibacterial agents and bioactive metals has proven to be an excellent strategy in the development of new and more active metallodrugs. Herein, we report the synthesis, structural characterization and antibacterial analysis of new gold(I) and silver(I) complexes with the sulfa drug sulfasalazine (ssz). Elemental, thermal and high-resolution mass spectrometric measurements indicated a 1:1:1 Au/ssz/Ph3P molar composition for the gold(I) complex (Ph3P - triphenylphosphine), while for the silver(I) complex the molar composition was 1:1 Ag/ssz. Solution state NMR and infrared spectroscopic data suggest that ssz coordinates to silver(I) and gold(I) by the oxygen atoms of the deprotonated carboxylic group. The coordination mode of the carboxylate was supported by density functional theory (DFT) calculations, which reinforces a monodentate coordination for the gold(I) complex and a bridged bidentate mode for the silver(I) one, with the molecular formulas [(Ph3P)Au(ssz)] and [Ag(ssz)]2, respectively. Antibacterial activity assays indicated the sensitivity of Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacterial strains to [Ag(ssz)]2 and [(Ph3P)Au(ssz)] complexes, while the free ligand was not able to inhibit the growth of any tested bacteria. The non-interaction of the complexes with deoxyribonucleic acid (DNA) was also demonstrated, which suggests that this biomolecule is not a preferential target for the compounds.
- Corbi, Pedro P.,Fiori-Duarte, Ana Thereza,Lustri, Wilton R.,Manzano, Carlos M.,de Paiva, Raphael Enoque F.
-
-
- Synthesis and Characterization of Ag-Delafossites AgBO2 (B: Al, Ga, In) from a Rapid Hydrothermal Process
-
A single-step rapid hydrothermal low-temperature process for the formation of high purity polycrystalline Ag-based delafossite oxides 3R-AgBO2 (B: Al, Ga, In) is reported. For the synthesis process reusable and widely available PTFE-lined pressure vessels are used. The presence of an elemental Ag by-phase is traced back to the metastability of the Ag-delafossite under the reaction conditions. High-purity products were obtained by decreasing the synthesis time requirements by up to 90 %. The effect of the isoelectronic B-site atoms on the structure and bonding situation were comparatively studied experimentally and by ab-initio calculations. Distorted coordination environments are observed in all cases, and the nature of the chemical bond changes qualitatively along the series of group 13 B-site atoms Al, Ga, and In. This is reflected in systematic changes of the (optical) band gap, the contactless conductivity, the thermal stability, and the energetic position of Raman modes, which are strongly affected and decrease with increasing atomic number. The establishment of a facile synthesis strategy allows the application of these Ag-delafossite systems in many disciplines, i.e. in heterogeneous catalysis and as optoelectronic devices.
- Zwiener, Leon,Jones, Travis,Wolf, Elisabeth Hannah,Girgsdies, Frank,Plodinec, Milivoj,Klyushin, Alexander Yu.,Willinger, Elena,Rosowski, Frank,Schl?gl, Robert,Frei, Elias
-
p. 2333 - 2345
(2019/04/01)
-
- Facile synthesis of macroporous Ag and CuO monoliths as an efficient nonenzymatic electrochemical sensor and antimicrobial agent
-
An efficient, green, acid free, reliable synthetic approach has been explored for the synthesis of macroporous silver and copper oxides monoliths. The concise tuning of macroporous materials using surfactants and structural directing agents like TiO2 nanoparticles, and carbon nanotubes produces the monolith with a random network of pores, high porosity and surface area. The FESEM and BET analysis demonstrated the pore sizes of 40–500 nm and surface area in the range 40–114 m2/g. The XRD, EDAX and TGA analysis confirms the purity and crystallinity of monoliths. A comparative account of electrochemical sensing and antimicrobial applications has been developed. The electrochemical characterization reveals that Ag/TiO2 and CuO/TiO2 show excellent electrochemical properties and thus utilized as a nonenzymatic electrode material for simultaneous determination of Levodopa (L-dopa) and ascorbic acid (AA). The results show Ag/TiO2/GCE show excellent sensing ability with a low detection limit as 0.034 μg mL?1 and 0.014 μg mL?1 in the concentration range of 0.1–20.0 μg mL?1 and 0.01–2.0 μg mL?1 for L-dopa and AA respectively. The synthesized monoliths have been tested for antimicrobial susceptibility against the 8 g-positive and gram-negative strains. The macroporous Ag/CNT exhibited better antimicrobial results against strains of Klebsiellapneumoniae, Listeria monocytogenes, Vibriovulnificus and Bacillus subtilis.
- Ahirwar, Devendra,Bano, Mustri,Khan, Imran,Gound, Surendra Singh,Sheikh, Mehraj Ud Din,Mondal, Rajesh,Khan, Farid
-
p. 233 - 242
(2019/03/19)
-
- Electrical and magnetic properties of La1-xAgxMnO3 (0 ≤ x ≤ 0.5) polycrystalline ceramics by combination of first principles calculations and experimental methods
-
In this work, electrical and magnetic properties of La1-xAgxMnO3 (LAMO, 0 ≤ x ≤ 0.5) polycrystalline ceramics with double?exchange (DE) effect and Jahn?Teller (JT) distortion were studied using a combination of first principles calculations and experimental methods. The GGA + U method was used to correct the self-interaction error (SIE) that was encountered in first principles calculations. With the increasing of Ag, energy band gaps (Ei or Ed) of LAMO ceramics and the JT effect decreased, while the DE effect was enhanced. LAMO polycrystalline ceramics (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) were prepared by conventional sol?gel method in order to verify the calculation results. The X?ray diffraction revealed that the structure of LAMO ceramics transformed from single phase to multiphase as x was increased. The ρ?T curves suggested that the metal to insulator transition temperature (Tp) and DE effect were improved as x increased, which was in good agreement with the first principles calculations. In addition, the temperature coefficient of resistance (TCR) at the peak temperature (Tk) and magnetoresistance (MR) at the peak temperature (Tm) were obtained with different x. For x = 0.5, the value of TCR and MR reached 8.58% K?1 and 21.6%, and the Tp, Tk and Tm were 304, 291 and 298 K, respectively, implying that the electrical and magnetic devices of LAMO ceramics could operate at room temperature (300 K). XPS results indicated that the concentration of Mn4+ ion increased with increasing x. The ratio of Mn4+/Mn3+ reached 1 ∶ 2, which had the strongest DE and magnetoelectric coupling effect for x = 0.5.
- Zhang, Shuai,Sun, Tao,Ji, Fuquan,Dong, Gang,Liu, Yang,Li, Zhidong,Zhang, Hui,Chen, Qingming,Liu, Xiang
-
-
- Silica-supported silver nanoparticles as an efficient catalyst for aromatic C-H alkylation and fluoroalkylation
-
The efficient catalysis of oxidative alkylation and fluoroalkylation of aromatic C-H bonds is of paramount importance in the pharmaceutical and agrochemical industries, and requires the development of convenient Ag0-based nano-architectures with high catalytic activity and recyclability. We prepared Ag-doped silica nanoparticles (Ag0/+@SiO2) with a specific nano-architecture, where ultra-small sized silver cores are immersed in silica spheres, 40 nm in size. The nano-architecture provides an efficient electrochemical oxidation of Ag+@SiO2 without any external oxidant. In turn, Ag+@SiO2 5 mol% results in 100% conversion of arenes into their alkylated and fluoroalkylated derivatives in a single step at room temperature under nanoheterogeneous electrochemical conditions. Negligible oxidative leaching of silver from Ag0/+@SiO2 is recorded during the catalytic coupling of arenes with acetic, difluoroacetic and trifluoroacetic acids, which enables the good recyclability of the catalytic function of the Ag0/+@SiO2 nanostructure. The catalyst can be easily separated from the reaction mixture and reused a minimum of five times upon electrochemical regeneration. The use of the developed Ag0@SiO2 nano-architecture as a heterogeneous catalyst facilitates aromatic C-H bond substitution by alkyl and fluoroalkyl groups, which are privileged structural motifs in pharmaceuticals and agrochemicals.
- Khrizanforov, Mikhail N.,Fedorenko, Svetlana V.,Mustafina, Asiya R.,Kholin, Kirill V.,Nizameev, Irek R.,Strekalova, Sofia O.,Grinenko, Valeriya V.,Gryaznova, Tatiana V.,Zairov, Rustem R.,Mazzaro, Raffaello,Morandi, Vittorio,Vomiero, Alberto,Budnikova, Yulia H.
-
p. 9608 - 9616
(2018/08/06)
-
- Structure and magnetic properties of trinuclear copper(II) complex [Cu3(bipy)6(μ3-CO3)][B12H12]2·4.5DMF·2H2O
-
Trinuclear copper(II) complex [CuII3(bipy)6(μ3-CO3)][B12H12]2·4.5DMF·2H2O is isolated as a result of the redox reaction proceeding when [AgI2B12H12] was allowed to react with CuICl in the presence of bipy. Crystal structure, magnetic properties, and EPR spectrum of the compound are studied. It has been found that in the range 300–2 K, magnetic moment decreases from 1.98 to 1.33 μB with decreasing the temperature. In the EPR spectrum, the transition ΔM = ±3 transition is observed indicating the existence of the S = 3/2 state. This transition is explained by the effect of fine coupling tensor which admixes the |?1/? state into the |3/2? state and the |1/2? state into the |?3/2? state. The EPR spectrum is simulated by the spin Hamiltonians for S = 3/2 and S = 1/2.
- Malinina, Elena A.,Kochneva, Irina K.,Polyakova, Irina N.,Avdeeva, Varvara V.,Buzanov, Grigorii A.,Efimov, Nikolai N.,Ugolkova, Elena A.,Minin, Vadim V.,Kuznetsov, Nikolai T.
-
p. 249 - 253
(2018/05/22)
-
- Synthesis, characterization and behavior in water/DMSO solution of Ru(II) arene complexes with bioactive carboxylates
-
The reactions of [RuCl(μ-Cl)(η6-p-cymene)]2 with sodium carboxylates, in methanol or acetonitrile solution, afforded the complexes [RuCl(κ2O-RCO2)(η6-p-cymene)] (RCO2 = valproate, 1; aspirinate, 2; diclofenate, 3), in 79–96% yields. Analogously, [RuCl(κ2O-dfCO2)(η6-benzene)], 4, was obtained in admixture with minor by-products from [RuCl(μ-Cl)(η6-benzene)]2 and sodium/silver diclofenate. The sequential reaction of [RuCl(μ-Cl)(η6-p-cymene)]2 with sodium salicylate and PPh3 gave [Ru(κ2O,O′-salCO2)(PPh3)(η6-p-cymene)], 5, in 70% yield. The hydride complex [Ru2Cl2(μ-Cl)(μ-H)(η6-p-cymene)2], 6, was produced in 36% yield from [RuCl(μ-Cl)(η6-p-cymene)]2 and sodium formate. An optimization of the experimental work-up allowed to isolate [RuCl(μ-Cl)(η6-p-cymene)]2 with an improved yield respect to the literature (98% vs. 65%). The bidentate coordination mode of the carboxylato ligands in 1–5 was unambiguously ascertained by IR and NMR spectroscopy, moreover the solid state structure of 1 was elucidated by single crystal X-ray diffraction. Complexes 1–3 experience rapid and quantitative dissociation of the carboxylato anion in DMSO/water/NaCl mixtures, mainly converting into [RuCl2(DMSO)(η6-p-cymene)], 7.
- Biancalana, Lorenzo,Pampaloni, Guido,Zacchini, Stefano,Marchetti, Fabio
-
supporting information
p. 201 - 211
(2018/07/06)
-
- Thermal stability of nanoparticle size and phase composition of nanostructured Ag2S silver sulfide
-
The thermal stability of phase composition and particle size of nanocrystalline silver sulfide Ag2S powder has been examined for the first time by in situ high-temperature X-ray diffraction, scanning electron microscopy and Raman spectroscopy methods. It was shown that in oxidizing environment or in the presence of oxidizing impurities, heating of nanostructured silver sulfide is accompanied by its decomposition (dissociation) with isolation of metallic silver. Reduction of silver sulfide particles leads to decreasing the decomposition temperature of Ag2S. The decomposition of Ag2S nanopowder with isolation of silver metal as a result of heating in air by high-power laser radiation was confirmed by Raman scattering. In the absence of oxidizing environment, heating of silver sulfide does not lead to its decomposition and nanoparticle growth up to the temperature of ～450 K. The nanoparticle size increases as a result of annealing at a temperature of 450–930 K corresponding to the region of collective recrystallization of silver sulfide nanopowder. For nanostructured silver sulfide, the activation energy Q of collective recrystallization in the temperature range 450–900 K is ～0.12 eV?atom?1.
- Sadovnikov, Stanislav I.,Vovkotrub, Emma G.
-
p. 140 - 148
(2018/07/13)
-
- COMPOSITIONS AND METHODS FOR FORMING ARTICLES HAVING SILVER METAL
-
Electrically-conductive silver metal can be provided in a thin film or pattern on a substrate from a silver complex having reducing silver ions and represented by: [in-line-formulae](Ag+)a(L)b(P)c?? (I)[/in-line-formulae] wherein L represents an α-oxy carboxylate; P represents a 5- or 6-membered N-heteroaromatic compound; a is 1 or 2; b is 1 or 2; and c is 1, 2, 3, or 4, provided that when a is 1, b is 1, and when a is 2, b is 2. The silver complex is mixed in a hydroxy-free, nitrile-containing aprotic solvent with a polymer that is either (i) a hydroxy-containing cellulosic polymer or (ii) a non-cellulosic acrylic polymer having a halo- or hydroxy-containing side chain. The reducible silver ions in the a thermally sensitive thin film or pattern can be thermally converted to electrically-conductive metallic silver under suitable heating conditions to provide a product article that can be used in various devices.
- -
-
Paragraph 0251
(2019/01/04)
-
- Reactivity and Structural Defects in Glaserite-Type Iron-Vanadates
-
We investigated (a) the redox reaction of FeO and Ag2O in the presence of BaCO3 and V2O5 under inert atmosphere and (b) the oxidation of FeO in air in the presence of BaCO3, Na2CO3, and V2O5. The reaction products are members of the glaserite-type of compounds: Ba(Ag□)Fe[VO4]2 [a = 5.47397(4) ?, c = 7.1780(1) ?, P3]; BaNa1.63Fe0.79[VO4]2 [a = 9.672(1) ?, b = 5.5860(6) ?, c = 14.1505(4) ?, β = 90.042(9)°, C2/c]; and Ba(Ba,Na)Na[VO4]2 [a = 5.8478(2) ?, c = 7.3835(3) ?, P3m1]. The latter presents an example for a statistical distribution of differently charged ions with differences in ionic radii (Ba2+ and Na+) on the B site of the general formula AB2M[VO4]2. The iron compounds exhibit differences in the defect concentration and localization of voids. For Ba(Ag□)Fe[VO4]2 the Fe3+-triangular lattice remains intact and the Ag substructure is depleted by 50 % through the redox reaction (a). In contrast, for BaNa1.63Fe0.79[VO4]2 defects occur on both sites (B = Na+ and M = Fe3+) with a total of 0.58 defects per formula unit. Extended 57Fe-M?ssbauer studies on a series of Fe-glaserite compounds relate structural findings from Rietveld refinements of X-ray diffraction data with defect concentrations, substitution variants, and charge distributions.
- Reu?, Anna,Ksenofontov, Vadim,Tapp, Joshua,M?ller, Angela
-
p. 1849 - 1853
(2018/11/10)
-
- New bimetallic dicyanidoargentate(I)-based coordination compounds: Synthesis, characterization, biological activities and DNA-BSA binding affinities
-
Four compounds -two (2 and 3) completely new- of composition [Ni(edbea)Ag3(CN)5] (1), [Cu(edbea)Ag2(CN)4]·H2O (2), [Cd(edbea)Ag3(CN)5]·H2O (3) and [Cd(edbea)2] [Ag(CN)2]2·H2O (4) {edbea; 2,2′-(ethylenedioxy)bis (ethylamine)}, were synthesized and characterized using elemental, FT-IR, X-Ray (4), thermal, variable temperature magnetic measurement (1 and 2) and biological techniques. The DNA/BSA binding affinities of 2 and 3 were evaluated by UV–Vis spectrophotometric titrations, ethidium bromide exchange experiments and electrophoretic mobility measurements. Compounds 1 and 4 have previously been characterized and shown to reduce the proliferation and migration of tumor cells. For the sake of clarity, 1 precise mechanism of action on microbial organisms and temperature magnetic measurement were determined. The crystallographic analyses showed that 4 was built up of [Cd(edbea)2]II cations and [Ag2(CN)4]II anions. Complexes demonstrated a remarkable antibacterial (1–4), antifungal (1–4) and antiproliferative activities (2 and 3) to ten human bacterial pathogens, four plant pathogenic fungi or three tumor cells (HeLa, HT29, and C6), respectively. Therefore, our results strongly confirm that cell proliferation, cell morphology, Bcl-2, P53 changes and apoptosis can be related to the pharmacological effects of the complexes as suitable candidate for clinical trials.
- Korkmaz, Nesrin,Ayd?n, Ali,Karada?, Ahmet,Yanar, Yusuf,Maa?o?lu, Yelis,?ahin, Ertan,Tekin, ?aban
-
supporting information
p. 1007 - 1022
(2016/12/16)
-
- Synthesis and characterization of new Ag(I) coordination networks based on saccharinate and bis(isopropylimidazole) ligands exhibiting very close C–H?Ag interactions
-
Two Ag(I) coordination networks, formulated as [Ag(sac)(μ-bisopib)]n(1) and [Ag(sac)(μ-pbisopix)]·H2O (2), have been synthesized based on the bis(isopropylimidazole) ligands 1,4-bis(2-isopropyl-1H-imidazol-1-yl)butane (bisopib) and 1,4-bis((2-isopropyl-1H-imidazol-1-yl)methyl)benzene (pbisopix), respectively, along with saccharinate (sac) ligands. All the complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction studies. The X-ray crystallographic studies of 1 and 2 revealed that the Ag(I) ions are μ-bridged by the bis(isopropylimidazole) derivative ligands to generate 1D zig-zag polymer and dinuclear structures, respectively. As far as we know, complex 1 shows the closest C–H?Ag interaction distance among similar literature examples. In complex 1 adjacent 1D coordination polymers are further joined by C–H?O hydrogen bonds and π?π interactions, generating a 3D supramolecular network. The C–H?O hydrogen bonds and C–H?π interactions play a crucial role in the architecture of the 3D network of complex 2. Thermal decompositions and photoluminescent properties of the Ag(I) complexes are also discussed herein.
- Semerci, Fatih,?ahin, Onur,Erer, Hakan
-
p. 316 - 322
(2017/01/09)
-
- Silver(I) thiosemicarbazone complex [Ag(catsc)(PPh3)2]NO3: Synthesis, characterization, crystal structure, and antibacterial study
-
We report the synthesis, characterization and crystal structure of a new mononuclear silver(I) complex, [Ag(catsc)(PPh3)2]NO3 (catsc?=?3-phenylpropenalthiosemicarbazone). The complex was prepared by the reaction of catsc and AgNO3 in the presence of PPh3 and characterized by elemental analysis (CHN), FTIR, 1H, 13C and 31P NMR spectroscopy, and single-crystal X-ray diffraction. In the complex, catsc acts as a bidentate NS ligand while the nitrate is a counter ion. The silver ion is coordinated by a bidentate ligand and two PPh3 in the form of a distorted tetrahedron. In addition, the antibacterial effect of the complex was studied against the standard strains of two gram-positive (Staphylococcus aureus and Enterococcus faecalis) and two gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria.
- Dehno Khalaji, Aliakbar,Shahsavani, Ensieh,Feizi, Nourollah,Kucerakova, Monika,Dusek, Michal,Mazandarani, Raouf
-
p. 534 - 539
(2017/05/19)
-
- A facile synthesis of Ag/AgCl hybrid nanostructures with tunable morphologies and compositions as advanced visible light plasmonic photocatalysts
-
This paper describes a simple and fast aqueous-phase route to the synthesis of Ag/AgCl hybrid nanostructures. These hybrid nanostructures were synthesized by reduction of AgCl nanoparticles with controlled shapes prepared by reacting Ag+ with Cl- in the presence of polyethyleneimine (PEI) in an aqueous-phase. We could easily control the morphology and composition of the nanostructures by varying the experimental conditions, including the reaction temperature and the amount of the reducing agent. The as-synthesized Ag/AgCl hybrid nanostructures exhibited enhanced photocatalytic activity and stability during the degradation of methyl orange under visible light irradiation because of their strong surface plasmon resonance (SPR) effect.
- Shahzad, Aasim,Kim, Woo-Sik,Yu, Taekyung
-
p. 9158 - 9165
(2016/06/15)
-
- Synthesis, structural characterization, stability, antibacterial activity and spectroscopic properties (THz) of five new polynuclear silver(I) complexes with 1,10-phenanthroline derivative and 1,3-bis(diphenylphosphino)propane (dppp)
-
The reactions of 1,3-bis(diphenylphosphino)propane (dppp) and 1,10-phenanthroline derivative with Ag salts in the mixed solvent of methanol and dichloromethane generate the corresponding complexes, {[Ag2(dppp)2(phen)2](BF
- Yuan, Yuan,Han, Hong-Liang,Lin, Sen,Cui, Yang-Zhe,Liu, Min,Li, Zhong-Feng,Jin, Qiong-Hua,Yang, Yu-Ping,Zhang, Zhen-Wei
-
p. 184 - 193
(2016/09/28)
-
- A scalable, Nonenzymatic synthesis of highly stereopure difunctional C4 secondary methyl linchpin synthons
-
In response to the continuing widespread use of heterodifunctional C4 secondary methyl building blocks in asymmetric synthesis, we have developed a mole-scale, two-step synthesis of a 1:1 mixture of the diastereomers of 3-bromo-2-methyl-1-propyl camphorsulfonate (casylate). One isomer (2S) has been crystallized to >99:1 dr in ～25% yield. Equilibration of the mother liquor (enriched in 2R) to a 1:1 mixture and recrystallization significantly raises the overall yield of 2S. Applications of 2S include chemoselective Grignard coupling, enabling the very short synthesis of highly stereopure long-chain natural products containing remote, methyl-bearing stereogenic centers [e.g., (R)-tuberculostearic acid], with complete control of configuration. Also, Ag-mediated, completely chemoselective Br displacement from 2S leads to a range of >99:1 er difunctional synthons. Both applications incorporate concurrent recovery of CasO. The enantiomer of 2S can be made from commercial (1R)-10-CasOH.
- Mekala, Shekar,Hahn, Roger C.
-
p. 1610 - 1617
(2015/02/19)
-
- Macrocyclic dinuclear, helical, layered and 3-D Ag(i) complexes constructed from AgX (X = NO3- and ClO4-) and flexible bis(pyridyl) ligands with a chelating spacer: Syntheses, structures and photoluminescence properties
-
Reaction of AgX (X = NO3- and ClO4-) and three flexible bis(pyridyl) ligands with a chelating spacer leads to the formation of eight novel Ag(i)-bis(pyridyl) coordination complexes: {[Ag2L1(NO3)2]n·2nH2O} (1), {[AgL1]n·nClO4} (2), {[AgL2]n·nNO3} (3), {[AgL2]n·nClO4} (4), [Ag2(H2L2)2]·6ClO4·9H2O (5), {[AgL3]n·nNO3·nH2O} (6), {[AgL3]n·nClO4·nH2O} (7), and {[Ag3(L3)2(ClO4)]n·2nClO4} (8) (L1 = N,N′-bis(pyridin-2-ylmethyl)propane-1,3-diamine, L2 = N,N′-bis(pyridin-3-ylmethyl)propane-1,3-diamine, L3 = N,N′-bis(pyridin-4-ylmethyl)propane-1,3-diamine), which have been characterized by elemental analysis, IR, TG, UV-Vis DRS, PL, powder and single-crystal X-ray diffraction. Complex 1 presents a (4,4) layered motif which is furnished by the bridging of L1 molecules and nitrate anions in μ4 (κ1N1:κ1N2:κ1N3:κ1N4) and μ2 (κ1O4:κ1O6) modes. With a different μ2 (κ1N1:κ1N2:κ1N3:κ1N4) mode, L1 molecules in complex 2 join the adjacent Ag(i) cations to form a helical chain structure. Complexes 3 and 4 also show helical chain structures with the L2 molecules displaying the same μ3 (κ1N1:κ1N2:κ1N3:κ1N4) mode. The protonation of -NH- groups in the chelating spacer leads to the formation of H2L22+ cations which further results in a macrocyclic dinuclear motif in complex 5. Complexes 6 and 7 are 3-D svi-x nets with the counter-anions and lattice water molecules being encapsulated in the 1-D channels. Complex 8 exhibits a snake-shaped chain with the L3 molecules presenting μ3 (κ1N:κ1N′:κ1N″:κ1N) mode. The structural diversities of complexes 1-8 can be attributed to the coordination modes and conformations of L1-L3. The photoluminescence properties demonstrate that complexes 1, 2 and 5 exhibit ligand-based blue emission maxima from 455 to 462 nm at room temperature in the solid state. This journal is
- Huang, Jing,Deng, Zhao-Peng,Xiao, Ying-Hui,Huo, Li-Hua,Zhao, Shu-Nan,Ge, Fa-Yuan,Gao, Shan
-
supporting information
p. 5837 - 5847
(2015/03/30)
-
- A microfluidic-based controllable synthesis of rolled or rigid ultrathin gold nanoplates
-
A continuous, microfluidic-based, seed-mediated synthesis of high-purity gold nanoplates with different thicknesses was developed. The thickness of the nanoplates can be fairly tuned from less than 1 nm to a few nm by varying the flow rate. Depending on the thickness, the obtained nanoplates could be rigid and flat-surfaced with thicknesses larger than 2 nm or flexible with crumpled or rolled shapes when the thickness is around 1 nm. These nanoplates are poly-crystalline with different crystal faces and show high electrochemical activity towards glucose oxidation.
- Fu, Qiang,Ran, Guangjun,Xu, Weilin
-
p. 37512 - 37516
(2015/07/15)
-
- Decarboxylation and simultaneous reduction of silver(I) β-ketocarboxylates with three types of coordinations
-
A series of silver(I) β-ketocarboxylates were prepared by reaction of β-ketocarboxylic acids with silver nitrate in the presence of diethanolamine. The silver(I) β-ketocarboxylates decomposed over a narrow temperature range to form metallic silver, CO2, and the corresponding ketones. In addition, products derived from radical intermediates were detected by mass spectroscopic analysis for some silver(I) β-ketocarboxylates. Infrared and solid state 13C-NMR spectra of silver(I) β-ketocarboxylates suggested the presence of two types of structures involving a carbonyl group in addition to the dimeric eight-membered ring structure as in the structure of silver(I) stearate. The silver(I) β-ketocarboxylate model compound used was HCOCH2COOAg and its structures were determined using density functional theory (DFT) and atoms-in-molecules (AIM) methods. Three types of coordinations around the Ag ion differing significantly in Ag-O bond strengths were found. Based on the calculated structures and experimental results, the relationships between the structures and decomposition temperatures are discussed in terms of the thermal decomposition process.
- Hatamura, Mariko,Yamaguchi, Shunro,Takane, Shin-Ya,Chen, Yu,Suganuma, Katuaki
-
p. 8993 - 9003
(2015/05/20)
-
- Two new coordination polymers containing dicyanidoargentate(I) and dicyanidoaurate(I): Synthesis and characterization, and a detailed in vitro investigation of their anticancer activities on some cancer cell lines
-
Two novel cyanido-bridged bimetallic polymeric complexes, [Ni(edbea)Ag3 (CN)5 ]n (C1) and [Ni(bishydeten) Au2 (CN)4]n (C2), where edbea = [2,2′-(ethylenedioxy)bis(ethylamine)] and bishydeten = [(N ,N′-bis(2-hydroxyethyl) ethylenediamine)] are ligands, were synthesized and characterized by elemental, infrared, and thermal measurement techniques and investigated for their biological activity in cultured cancer cell lines. The results show that both compounds and free anions, [Ag(CN)2]- and [Au(CN)2]- , exhibited very high antiproliferative activity compared to the anticancer drug 5FU against the cancer cell lines tested. The antiproliferative and cytotoxic activities of C1 and C2 were significantly lower than those of free anions, indicating that the extreme cytotoxicity of free anions decreased to safe levels in C1 and C2. In conclusion, the results show that these novel compounds possess anticancer activities.
- Aydin, Ali,Karada, Ahmet,Tekin, aban,Korkmaz, Nesrin,?zdemir, Aslihan
-
p. 532 - 549
(2015/08/06)
-
- Ag(I) and Zn(II) isonicotinate complexes: Design, characterization, antimicrobial effect, and CT-DNA binding studies
-
Trinuclear Ag(I) (1) and dinuclear and mononuclear Zn(II) isonicotinate (2 and 3) complexes were prepared and characterized by X-ray crystallography, elemental analysis, IR spectroscopy, and thermal analysis. Single-crystal analysis of the Ag(I) complex reveals two different monodentate carboxylate coordination modes, protonated and deprotonated, respectively. IR spectra showed correlations between isonicotinate coordination modes and Δ(νas-νs)IR values. In addition, the hydrogen bonds significantly influence a position of carboxylate absorption bands. Moreover, IC50 and MIC data for bacteria, yeasts, and filamentous fungi were determined and the binding of Ag(I) and Zn(II) complexes to calf thymus DNA was investigated using electronic absorption, fluorescence, and CD measurements. Biological tests showed that the Ag(I) complex is more active than commercially used Ag(I) sulfadiazine against Escherichia coli. The fluorescence spectral results indicate that the complexes can bind to DNA through an intercalative mode. The Stern-Volmer quenching constants for investigated complexes obtained from the linear quenching plot are in the range of 1.67 × 104-3.42 × 104 M-1.
- Almi, M.,Vargov, Z.,Kuchr, J.,Gy?ryov, K.,Sabolov, D.,Kudlov, J.,Hudecov, D.,Oenov, L.
-
p. 4423 - 4443
(2016/01/20)
-
- Controlled Redox Chemistry at Cerium within a Tripodal Nitroxide Ligand Framework
-
Ligand reorganization has been shown to have a profound effect on the outcome of cerium redox chemistry. Through the use of a tethered, tripodal, trianionic nitroxide ligand, [((2-tBuNOH)C6H4CH2)3N]3- (TriNOx3-), controlled redox chemistry at cerium was accomplished, and typically reactive complexes of tetravalent cerium were isolated. These included rare cationic complexes [Ce(TriNOx)thf][BArF4], in which ArF=3,5-(CF3)2-C6H3, and [Ce(TriNOx)py][OTf]. A rare complete Ce-halide series, Ce(TriNOx)X, in which X=F-, Cl-, Br-, I-, was also synthesized. The solution chemistry of these complexes was explored through detailed solution-phase electrochemistry and 1H NMR experiments and showed a unique shift in the ratio of species with inner- and outer-sphere anions with size of the anionic X- group. DFT calculations on the series of calculations corroborated the experimental findings. The use of a bulky and strongly donating tethered tripodal nitroxide ligand allowed the controlled redox chemistry at cerium. As a result, rare examples of cationic CeIV complexes were synthesized and fully characterized. The full Ce-halide series supported by the tripodal ligand framework is also reported (see scheme).
- Bogart, Justin A.,Lippincott, Connor A.,Carroll, Patrick J.,Booth, Corwin H.,Schelter, Eric J.
-
p. 17850 - 17859
(2015/12/08)
-
- Crooked Ag2Te nanowires with rough surfaces: Facile microwave-assisted solution synthesis, growth mechanism, and electrical performances
-
Crooked Ag2Te nanowires with rough surfaces have been successfully fabricated via a one-pot microwave-assisted solution process in a short time. A possible formation mechanism related to the oriented attachment crystal growth mechanism and the incomplete Ostwald ripening process is presented. The obtained Ag2Te shows a maximum power factor of about 13.4 × 10-4 W m-1 K-2. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2014.
- Pei, Jian,Chen, Gang,Jia, Dechang,Yu, Yaoguang,Sun, Jingxue,Xu, Haiming,Qiu, Zhuangzhuang
-
-
- Fabrication of nanoporous copper by dealloying of amorphous Ti-Cu-Ag alloys
-
Ternary TiCuAg amorphous alloys were used as the starting materials for fabricating nanoporous copper (NPC) in HF solutions. NPC with a pore size of 8-55 nm was fabricated through dealloying from an amorphous Ti 60Cu40-xAgx (x = 1, 2 at.%) ribbon alloy under free immersion conditions. A 3-dimensional bicontinuous NPC structure formed on Ti60Cu40, Ti60Cu 39Ag1, and Ti60Cu38Ag2 ribbon alloys with pore sizes of 130 nm, 48 nm, and 55 nm, respectively, after immersion in 0.13 M HF solution for 43.2 ks. The pore sizes of dealloyed ribbon alloys in 0.03 M HF solution were confirmed to be 71 nm, 41 nm and 39 nm, respectively. The pore size of NPCs dealloyed from Ag-added alloys was smaller than that of the Ti-Cu alloy. Smaller pores formed in the beginning of dealloying because even distributed Ag atoms in amorphous precursors suppressed the diffusion of Cu adatoms. The final characteristic pore size showed a weak dependence on the solution concentrations. Diffusivity decreased more than two orders due to the alloying of Ag. The dealloying residue was fcc Cu-Ag and Ag, with Ag adatoms concentrated at the grain boundary. The uneven distribution of Ag atoms caused the coarsening of nanoporous Cu after the prolonged dealloying.
- Dan, Zhenhua,Qin, Fengxiang,Makino, Akihiro,Sugawara,Muto, Izumi,Hara, Nobuyoshi
-
p. S134-S138
(2014/01/06)
-
- Ag1+xTlO2 (0.03 ≤ x ≤ 0.18), novel adaptations of the delafossite structure type featuring subvalent silver
-
A family of novel variations of the delafossite type of structure, Ag 1+xTlO2, was synthesized and characterized. For three members the crystal structures were solved and refined on single crystal data: Ag1+αTlO2 [α = 0.18, P{3}m1, Z = 1, a = 3.40427(9), c = 6.1296(1) A, R1 = 0.033, 126 independent reflections]; Ag1+βTlO2 [β = 0.09, R{3}m, Z = 6, a = 3.40685(8), c = 37.5953(9) A, R1 = 0.039, 214 independent reflections]; Ag1+γTlO2 [γ = 0.03, R{3}m, Z = 9, a = 3.403(2), c = 56.67(3) A, R1 = 0.038, 397 independent reflections]. Different from the conventional delafossite structure, part of the silver layers accommodate an excess of ca. 0.18 silver atoms per layer, thus generating a subvalent bonding state of silver. In accordance with the structural findings, the new silver oxthallates(III) are metallic conductors, and show reduced binding energies for the silver 3d5/2 states, compared to silver(I) oxide. Copyright
- Nuss, Juergen,Dietrich, Volker,Curda, Jan,Jansen, Martin
-
p. 1063 - 1068
(2014/06/09)
-
- PROCESS FOR THE PREPARATION OF AN ANTIMICROBIAL ARTICLE
-
Disclosed is a process for preparing an antimicrobial article, wherein a silver colloid is formed in situ as a result of the components employed. The process comprises the steps of (i) providing a liquid, which contains a soluble polar polymer in a solvent selected from certain polar organic solvents; (ii) adding a silver salt selected from alpha-functionalized silver carboxylates to said liquid; (iii) allowing the mixture to react with formation of a silver colloid; and (iv) separating the solvent from the mixture and forming of the antimicrobial article. The antimicrobial articles thus obtained may be sheets, films, fibres, coating layers, and especially membranes like a semipermeable membrane for ultrafiltration, water separation or gas separation.
- -
-
Paragraph 0076; 0077; 0078; 0079
(2013/03/26)
-
- Solid-state structural transformations of two AgI supramolecular polymorphs to another polymer upon absorption of HNO3 vapors
-
Solid-state structural transformation of two polymorphic forms of [Ag(8-HqH)(8-Hq)]n (1α and 1β, where 8-HqH = 8-hydroxyquinoline and 8-Hq- = 8-hydroxyquinolate) to {[Ag(8-HqH)2]NO3}n (2) has been observed upon solid-gas reaction of compounds 1α and 1β with HNO3 vapors. Solid-gas reaction of compound 2 with hydrated vapors of NH3 results in the formation of only the 1β polymorph, while solid-solid reaction of compound 2 with KOH results in the formation of a 1α and 1β mixture with chiral and achiral space groups of P212 121 and Pbcn, respectively.
- Akhbari, Kamran,Morsali, Ali
-
supporting information
p. 2787 - 2789
(2013/04/24)
-
- Facile catch and release of fullerenes using a photoresponsive molecular tube
-
A novel M2L2 molecular tube capable of binding fullerene C60 was synthesized from bispyridine ligands with embedded anthracene panels and Ag(I) hinges. Unlike previous molecular cages and capsules, this open-ended tubular host can accommodate a single molecule of various C60 derivatives with large substituents. The fullerene guest can then be released by using the ideal, noninvasive external stimulus, light.
- Kishi, Norifumi,Akita, Munetaka,Kamiya, Motoshi,Hayashi, Shigehiko,Hsu, Hsiu-Fu,Yoshizawa, Michito
-
p. 12976 - 12979
(2013/09/24)
-
- Construction of homo- and heterometallic-pyridine-2,3-dicarboxylate metallosupramolecular networks with structural diversity: 1D T5(2) water tape and unexpected coordination mode of pyridine-2,3-dicarboxylate
-
Five new homo and heterometallic Cu(ii), Cd(ii), Cu(ii)-Ag(i), Cu(ii)-Cd(ii) supramolecular networks with pyridine-2,3-dicarboxylate (pydc), {[Cu(μ-pydc)(dmpen)2]}n (1), [Cu2(μ-pydc) 2(emim)4]·2H2O (2), [Cd(μ-pydc)(emim) 2]n (3), [Cu(en)2(H2O) 2][Ag2(pydc)2(μ-en)]·6H2O (4) and {[Cd(H2O)4Cu(μ-pydc)2] ·2H2O}n (5) have been synthesized and structurally characterized (en = ethylenediamine, dmpen = 1,3-diamino-2,2-dimethylpropane and emim = 2-ethyl-4-methyl-imidazole). Owing to diverse binding modes and conformations of the pydc ligand and the different diamine or imidazole-containing coligands, these complexes exhibit structural and dimensional diversity. Complex 1 exhibits a new unexpected coordination mode of pydc, which is known as a chelating ligand, leading to the formation of a 1D coordination polymer. Complex 2 is the first dinuclear copper(ii)-pydc complex containing a dinuclear metalloligand. Complex 3 is a one dimensional coordination polymer and the Cd(ii) ion is six-coordinated in a distorted octahedral geometry. Complex 4 is the first 3d-4d heterometallic complex and shows two different coordination behaviors of the ethylenediamine ligand: common chelate mode and rare bridging mode. The most striking feature of 4 is the existence of a infinite T5(2) water tape. Complex 5 is the first 3d-4d heteropolynuclear complex obtained from a polynuclear metalloligand. Neighboring metalloligand double-chains bind to Cd(ii) ions to form a two dimensional (2D) layered structure. Complex 4 exhibits weak emission due to the quenching effect of Cu(ii) ions. Complexes 3 and 5 exhibit rare green emission and blue photoluminesence, respectively. Atomically detailed simulations were used to assess the potential of complexes in gas storage and gas separation applications. The antimicrobial properties of the complexes were also investigated by the broth dilution method (MIC). Complexes 4 and 5 are determined to be highly effective for antimicrobial activity.
- Semerci, Fatih,Yesilel, Okan Zafer,Keskin, Seda,Darcan, Cihan,Tas, Murat,Dal, Hakan
-
p. 1244 - 1256
(2013/03/14)
-
- Nitric oxide release from a nickel nitrosyl complex induced by one-electron oxidation
-
Reaction of [Ni(NO)(bipy)][PF6] (2) with AgPF6 or [NO][PF6] in MeCN results in formation of [Ni(bipy) x(MeCN)y]2+ and release of NO gas in moderate yields. In contrast, the addition of the inner sphere oxidant Ph 2S2 to 2 does not result in denitrosylation. Instead, the diphenyldisulfide adduct [{(bipy)(NO)Ni}2(μ-S2Ph 2)][PF6]2 (3) is formed in good yield. However, oxidation of 2 with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) does results in cleavage of the Ni-NO bond and generation of NO. The metal-containing product, [(bipy)Ni(η2-TEMPO)][PF6] (4), can be isolated as an orange-brown solid in excellent yields. In the solid state, complex 4 contains a side-on bound TEMPO- ligand, which is characterized by a long N-O bond length [1.383(2) A]. The contrasting reactivity of Ph2S2 and TEMPO likely relates to their different redox potentials, as Ph2S2 is a relatively weak oxidant. Finally, the addition of pyridine-N-oxide to 2 results in the formation of the adduct, [(bipy)Ni(NO)(ONC5H5)][PF6] (5). No evidence of NO release is observed in this reaction, probably because of the low one-electron (1e-) reduction potential of pyridine-N-oxide.
- Wright, Ashley M.,Zaman, Homaira T.,Wu, Guang,Hayton, Trevor W.
-
p. 3207 - 3216
(2013/04/24)
-
- Synthesis and reactivity of the unsaturated trinuclear phosphanido complex [(C6F5)2Pt(μ-PPh2) 2Pt(μ-PPh2)2Pt(PPh3)]
-
The reaction of [NBu4][(C6F5) 2Pt(μ-PPh2)2Pt(μ-PPh2) 2Pt(O,O-acac)] (48 VEC) with [HPPh3][ClO4] gives the 46 VEC unsaturated [(C6F5)2Pt 1(μ-PPh2)2Pt2(μ-PPh 2)2Pt3(PPh3)](Pt2-Pt 3) (1), a trinuclear compound endowed with a Pt-Pt bond. This compound displays amphiphilic behavior and reacts easily with nucleophiles L, yielding the saturated complexes [(C6F5) 2PtII(μ-PPh2)2Pt II(μ-PPh2)2PtII(PPh 3)L] [L = PPh3 (2), py (3)]. The reaction with the electrophile [Ag(OClO3)PPh3] affords the adduct 1·AgPPh3, which evolves, even at low temperature, to a mixture in which [(C6F5)2PtIII(μ- PPh2)2PtIII(μ-PPh2) 2PtII(PPh3)2]2+(Pt III-PtIII) and 2 (plus silver metal) are present. The nucleophilic nature of 1 is also demonstrated through its reaction with cis-[Pt(C6F5)2(THF)2], which results in the formation of [Pt4(μ-PPh2)4(C 6F5)4(PPh3)] (4). The structure and NMR features indicate that 1 can be better considered as a Pt II-PtIII-PtI complex instead of a Pt II-PtII-PtII derivative. Theoretical calculations (density functional theory) on similar model compounds are in agreement with the assigned oxidation states of the metal centers. The strong intermetallic interactions resulting in a Pt2-Pt3 metal-metal bond and the respective bonding mechanism were verified by employing a multitude of computational techniques (natural bond order analysis, the Laplacian of the electron density, and localized orbital locator profiles).
- Forniés, Juan,Fortu?o, Consuelo,Ibá?ez, Susana,Martín, Antonio,Mastrorilli, Piero,Gallo, Vito,Tsipis, Athanassios
-
p. 1942 - 1953
(2013/03/28)
-
- Synthesis and spectroscopic and spectroelectrochemical characterization of a new family of 44e- tris-phosphido-bridged palladium triangles
-
Triangular clusters containing a [M3(μ-PR2) 3]+ core are very common in platinum chemistry but were virtually unknown for M = Pd. Herein we describe the synthesis and characterization of several palladium derivatives belonging to this class. The trinuclear monohalide clusters {Pd3}(CO)2X [{Pd 3} = Pd3(μ-PBut2)3; X = Br, I] were prepared by reacting [nBu4N]X or KX with the dinuclear complex [Pd(PBut2H)(μ-PBut 2)]2 and H2O under an atmosphere of CO. The reaction of {Pd3}(CO)2I with CNBut leads to the substitution of all the terminal ligands to afford the symmetrical cluster [{Pd3}(CNBut)3]I. The latter reacts with TlPF6 (excess) or AgCF3SO3 (1:1 ratio) to give anion metathesis, whereas the addition of a second equivalent of Ag+ causes cluster oxidation to the thermally stable paramagnetic 43e- dication [{Pd3}(CNBut)3]2+. The cationic clusters [{Pd3}(CO)2(L)]PF6 (L = NCCH3, Py or CO) were obtained by reacting {Pd3}(CO) 2I with TlPF6, under nitrogen in acetonitrile or in pyridine or under 1 atm of carbon monoxide in THF. Finally, {Pd 3}(CO)2Cl was achieved by the reaction of [{Pd 3}(CO)3]PF6 with [(PPh3) 2N]Cl. All clusters have been obtained in good yields and purity and have been characterized by microanalysis and IR and multinuclear NMR spectroscopy. Single crystal X-ray diffraction studies on {Pd 3}(CO)2Br and [{Pd3}(CNBut) 3]CF3SO3 are also reported. The cyclovoltammetric profile exhibited by the palladium clusters prepared in this work is characterized by the presence of two monoelectronic oxidation processes whose reversibility and potentials depend on the nature of the ligands. Moreover, the UV-vis and IR spectroelectrochemical analysis of {Pd 3}(CO)2I, [{Pd3}(CO)3]PF6 and [{Pd3}(CNBut)3]PF6 allowed the spectroscopical characterization of some electrogenerated oxidized species and provided some detail for the redox-coupled reactions of metastable products.
- Bonuccelli, Veronica,Funaioli, Tiziana,Leoni, Piero,Marchetti, Fabio,Marchetti, Lorella
-
p. 8759 - 8769
(2013/09/02)
-
- Triple-meso helices as alcohol reservoirs and discriminators: Structural properties and thermal behaviors of silver(i) coordination molecular braids containing diethylbis(4-pyridyl)silanes
-
Self-assembly of silver triflate with L in alcohol solvent produces characteristic triple-meso helices [Ag3(L)3(ROH)](CF 3SO3)3 (L = diethylbis(4-pyridyl)silane; R = Me, Et, n-Pr, and n-Bu) with six units in each turn. Their unit cell volumes are sensitive to the size of the coordinated alcohol molecules. An unusual alcohol molecules at triple-meso helices system is a characteristic reversible alcohol container and discriminator via appropriate association/dissociation. The meso helical solids are favored in the order MeOH > EtOH > n-PrOH > n-BuOH via an interaction between the silver(i) ion and the alcohol molecule. The crystals evaporate the coordinated alcohol molecules at low temperatures, and finally calcination at 600 °C produces micro-sized chaotic surface materials consisting of silver(0) without silicon(iv) oxide.
- Moon, So Yun,Kim, Euni,Noh, Tae Hwan,Lee, Young-A,Jung, Ok-Sang
-
supporting information
p. 13974 - 13980
(2013/09/24)
-
- Impact of microwave power on the preparation of silver nanowires via a microwave-assisted method
-
The microwave-assisted method is rapid in synthesizing silver nanowires. However, a by-product of silver particles is often simultaneously produced. For better utilization of microwaves to produce silver nanowires, the effect of microwave power on the morphologies of silver nanostructures was studied. The synthesis was conducted at various single microwave powers, 80, 160, 320, 560 and 800 W and with a combination of 800 W and 320 W with different sequences and time assignments. The results showed that 320 W produced silver nanowires of 6-8 μm, while when a lower power was used, silver nanowires were shortened to 2-4 μm. At higher microwave power, vast silver particles dominated the product with short nanowires of about 3-4 μm. In addition, the combination of 800 W × 0.5 min + 320 W × 2.5 min ideally resulted in mainly uniform silver nanowires up to 10 μm in length, with a small quantity of silver particles. However, prolonged treatment at 800 W during the first heating phase and the reversed combination of 320 W + 800 W led to a high yield of silver particles. We believe that different microwave powers lead to products of various morphologies by impacting on the reduction rate and seed growth. Generally, this study highlights the microwave power dependent effects on silver nanostructures and a better utilization of microwave power combination to synthesize silver nanowires.
- Yang, Yang,Hu, Yongyou,Xiong, Xuhua,Qin, Yanzhe
-
p. 8431 - 8436
(2013/09/02)
-
- The diammine silver(I) acetate [Ag(NH3)2]OAc
-
Silver acetate AgOAc reacts with dry liquid ammonia under the formation of colorless needle-shaped crystals of diammine silver(I) acetate [Ag(NH 3)2]OAc (1). The compound crystallizes in the monoclinic space group P21/c with a = 8.0205(2), b = 12.4161(3), c = 6.0938(2) A, β = 107.741(4)°, and V = 577.98(3) A3 at 123 K with Z = 4. The crystal structure shows the presence of almost linear [Ag(NH3)2]+ cations, which are arranged in a corrugated chain of equidistant silver atoms. The Ag-Ag distance is 3.1089(11) A, which falls in the range of "argentophilic" interactions. After warming to room temperature and removal of the solvent, compound 1 was found unchanged as evidenced by powder X-ray diffraction, thermogravimetric and mass-spectrometric analysis, as well as IR and Raman spectroscopy. Copyright
- Woidy, Patrick,Kraus, Florian
-
p. 2643 - 2647
(2013/11/19)
-
- Ag3PO4/SnO2 semiconductor nanocomposites with enhanced photocatalytic activity and stability
-
Ag3PO4/SnO2 semiconductor nanocomposites exhibit much higher photocatalytic activity and good stability than pure Ag 3PO4 for the photodegradation of organic compounds (methyl orange) in the absence o
- Zhang, Lili,Zhang, Hengchao,Huang, Hui,Liu, Yang,Kang, Zhenhui
-
p. 1541 - 1544
(2012/10/08)
-
- Quantitative analysis of the role played by poly(vinylpyrrolidone) in seed-mediated growth of Ag nanocrystals
-
This article presents a quantitative analysis of the role played by poly(vinylpyrrolidone) (PVP) in seed-mediated growth of Ag nanocrystals. Starting from Ag nanocubes encased by {100} facets as the seeds, the resultant nanocrystals could take different shapes depending on the concentration of PVP in the solution. If the concentration was above a critical value, the seeds simply grew into larger cubes still enclosed by {100} facets. When the concentration fell below a critical value, the seeds would evolve into cuboctahedrons enclosed by a mix of {100} and {111} facets and eventually octahedrons completely covered by {111} facets. We derived the coverage density of PVP on Ag(100) surface by combining the results from two measurements: (i) cubic seeds were followed to grow at a fixed initial concentration of PVP to find out when {111} facets started to appear on the surface, and (ii) cubic seeds were allowed to grow at reduced initial concentrations of PVP to see at which concentration {111} facets started to appear from the very beginning. We could calculate the coverage density of PVP from the differences in PVP concentration and the total surface area of Ag nanocubes between these two samples. The coverage density was found to be 140 and 30 repeating units per nm2 for PVP of 55 000 and 10 000 g/mol in molecular weight, respectively, for cubic seeds of 40 nm in edge length. These values dropped slightly to 100 and 20 repeating units per nm2, respectively, when 100 nm Ag cubes were used as the seeds.
- Xia, Xiaohu,Zeng, Jie,Oetjen, L. Kyle,Li, Qingge,Xia, Younan
-
p. 1793 - 1801
(2012/03/10)
-
- Guanidine electron donors and silver halides: Interplay and competition between redox, coordination and polymerization reactions
-
Redox reactions compete with coordination and polymerization reactions when the organic electron donor and ligand, 1,2,4,5-tetrakis(tetramethylguanidino) benzene (1), is dissolved together with silver halides AgX (X = Cl, Br or I) in solvents of different polarity. The complex results obtained for the relatively simple system 1/AgX highlight the importance of solvent effects. A variety of chain polymers have been synthesized in which the guanidine electron-donor building blocks are connected by silver halide clusters of different sizes. Copyright
- Emeljanenko, Dimitri,Horn, Julian,Kaifer, Elisabeth,Wadepohl, Hubert,Himmel, Hans-Joerg
-
p. 695 - 704
(2012/04/04)
-
- Photochemical conversion of AgCl nanocubes to hybrid AgCl-Ag nanoparticles with high activity and long-term stability towards photocatalytic degradation of organic dyes
-
The performance of a photocatalytic reaction is mainly determined by the quality of the photocatalyst. For real applications, significantly enhancing the stability and activity of the photocatalysts still remains a challenge for materials scientists and chemists. In this paper, we have achieved a highly efficient plasmonic AgCl-Ag nanophotocatalyst via photochemical conversion of AgCl nanocubes. Compared with reported photocatalysts, the as-achieved nanophotocatalyst exhibits superior activity, long-term stability, and wide applicability in the decomposition of organic dye pollutants. For example, only 30 s is needed to bleach methyl orange molecules assisted by AgCl-Ag nanoparticles. Furthermore, the catalyst can be reused up to 50 times without significant loss of activity. A possible mechanism was discussed and the specified photocatalytic reactions verified that both O2 ?- and OH? radicals were the main active species in decomposing pollutants. The excellent performance of the present photocatalyst suggests promising applications in environmental remediation, clean energy creation, and solar cells.
- Wang, Jizhuang,An, Changhua,Zhang, Meiyu,Qin, Chuan,Ming, Xijuan,Zhang, Qinhui
-
p. 858 - 864
(2013/02/22)
-
