Silver Bonds Research Articles

Poly[(μ-2,3-diethyl-7,8-di-methyl-quinoxaline-κ2N:N)(2,3-diethyl-7,8-di-methyl-quinoxaline-κN)-μ-nitrato-κ2O:O'-nitrato-κ2O,O'-disilver(I)

The structure of the title compound, [C14H18N2)2Ag2](NO3)2, contains subtle differences in ligand, metal, and counter-anion coordination. One quinoxaline ligand uses one of its quinoxaline N atoms to bond to one silver cation. That silver cation is bound to a second quinoxaline which, in turn, is bound to a second silver atom; thereby using both of its quinoxaline N atoms. A nitrate group bonds with one of its O atoms to the first silver and uses the same oxygen to bond to a silver atom (related by symmetry to the second), thereby forming an extended network. The second nitrate group on the other silver bonds via two nitrate O atoms; one silver cation therefore has a coordination number of three whereas the second has a coordination number of four. One of the quinoxaline ligands has a disordered ethyl group.

Applying Anand versus Garofalo creep constitutive models for simulating sintered silver die attachments in power electronics

This paper aims to examine the thermomechanical response of sintered silver die attachments in power electronics using finite element analysis (FEA). In this work, several material parameters of the sintered silver bonds are investigated. Additionally, two common solder creep constitutive laws including Anand and Garofalo models are also studied. To ensure the fidelity of the simulation procedures, the finite element (FE) models are first correlated with digital image correlation data. Afterward, the FE models are utilized to examine the influence of the material and creep models on the die attach stresses, strains, and plastic works. The expected fatigue and lifetime predictions of the sintered silver layer are thoroughly discussed, accordingly. The results proved that the die attach layer mechanical response is highly driven by the material parameters and creep modeling procedures considered throughout the simulations. Thus, the resulting fatigue life is evaluated. Finally, a general modeling guideline for simulating thermomechanical response of sintered silver die attachments in power electronics are provided in great detail.

Asymmetric causality between stock returns and usual hedges: An industry-level analysis

Assets such as gold, silver, government bonds are widely considered good hedges against adverse movements in the stock market. At times, market participants move between these markets in order to hedge against any immediate risks. The shifts from one market to another likely create a dynamic relationship between the stock market and other assets. We investigate short-run and long-run causality between the industry returns and the prices of the four assets: gold, silver, oil, and 10-year Treasury bonds. Using symmetric and asymmetric Granger causality, we try to identify different industries within the S&P500 that are caused by movement in the prices of these four assets. Although we were able to find short-run and long-run bidirectional causality between the four asset prices and share returns in many industries, our findings are industry-specific. We discover overwhelming and robust evidence of symmetric and asymmetric causality between 10-Year Treasury yield and returns of almost all 18 industries we considered.

Silver incorporation on viscose and cotton fibers after air, nitrogen and oxygen DBD plasma pretreatment

Dielectric barrier discharge (DBD) pretreatments in air, nitrogen and oxygen plasma of viscose and cotton fabrics with subsequent immobilization of silver were studied. Surface activation of treated fibers was evaluated through subsequent sorption of silver from aqueous AgNO3 solution, after which changes in the surface morphology were monitored and quantity of silver deposition on fabric was measured. The plasma treatment was done in volume DBD discharge with the gap distance between electrodes of 0.5 and 2 mm. Depending on the gas used in pretreatment, significant difference in the way silver bonds to the textile surface was found. Nitrogen plasma pretreatment with gap distance of 0.5 mm led to the homogeneous fiber coating by silver nanoparticles with average size up to 300 nm estimated by SEM, while fibers treated in oxygen plasma adsorbed silver in a form of ions. The plasma pretreatment in air leads to changes that contain features of fibers treated in both nitrogen and oxygen DBD plasma. Distinct difference of used configuration of the plasma source is a use of gap distance 0.5 mm, which is in order of textile thickness. Observed results allow us to report a new way how to immobilize silver nanoparticles onto textile fibers using plasma pretreatment with subsequent sorption of silver from aqueous solution.

Was the emergence of the international gold standard expected? Evidence from Indian Government securities

The emergence of the gold standard has for a long time been viewed as inevitable. We analyze agents' expectations using the spread between gold and silver bonds issued by the Indian government. We find that bimetallism was credible until France surprised markets by suspending domestic operation of bimetallism, triggering a run away from silver. Thereafter, markets began demanding a premium to hold silver bonds, indicating their belief that silver would depreciate in the future as more countries moved on gold.

Irving Fisher and Price‐Level Targeting in Austria: Was Silver the Answer?

The question of price level versus inflation targeting remains controversial. Disagreement concerns not so much the desirability of price stability but rather the means of achieving it. Irving Fisher argued for a commodity dollar standard where the purchasing power of money was fixed by indexing it to a basket of commodities. We show that movements in the price of silver closely track the movements in overall prices during the classical gold standard era. The one‐to‐one relationship between paper and silver bonds suggests that a simple “silver rule” could have sufficed to fix the purchasing power of money.

Was the Emergence of the International Gold Standard Expected? Melodramatic Evidence from Indian Government Securities

The emergence of the gold standard has for a long time been viewed as inevitable. Fluctuations of the gold-silver exchange rate in world markets were accused to lead to brutal and unsustainable switches of bimetallic countries’ money supplies. However, more recent work has shown that the option character of bimetallism provided a stabilizing feedback loop. Using original data, this paper provides support to the new view. Using quotation prices for Indian Government bonds, we analyze agents’ expectations between 1860 and 1890. The intuition is that the spread between gold and silver bonds issued by the same entity (India) and backed by a credible agent (Britain) is a “pure” measure of the silver risk. The analysis shows that up until 1874 markets were expecting bimetallism to last. It is only after this date that markets gradually started requiring a premium to hold silver bonds indicating their belief that gold would eventually become the only metallic standard.

A rare 2D coordination polymer of graphite-like structure extended by infinite silver–oxygen–silver bonds

The reaction of AgNO3 and H3btb (H3btb=1,2,3-benzenetricarboxylic acid) leads to the isolation of {[Ag(μ2-H2O)(μ2-H2btb)]}n·1.5nH2O (1), which crystallizes in the orthorhombic space group Fddd with a=11.436(2)Å, b=6.876(1)Å, c=58.837(1)Å, V=4626.5(2)Å3, Z=32. Silver ions are connected by both strong Ag⋯Ag interaction and μ2-H2O bridges to form hexagonal Ag6 subunits, and are further assembled into a high ordered 2D grid, presenting an interesting graphite-like 63 net. Both the fluorescence and the crystal transformation after dehydration are studied.

Anion-Dependent Self-Assembly of Silver(I) and Diaminotriazines to Coordination Polymers: Non-Covalent Bonds and Role Interchange between Silver and Hydrogen Bonds

New coordination polymers have been obtained by the self-assembly of silver salts AgX (X = BF 4, PF 6, CF 3SO 3) and 2,4-diamino-6-R-1,3,5-triazines L (R = phenyl and p-tolyl) of formulas AgLX ( 1- 6). A complex of different stoichiometry, [Ag 3L 2(H 2O)(acetone) 2](BF 4) 3, 7 (R = phenyl), has also been synthesized. The three-dimensional structures of five compounds have been determined by X-ray diffraction studies. For the AgLX complexes, when X = BF 4 and R = phenyl or p-tolyl, chiral chains with alternating Ag and L are formed. The chains are cross-linked by the counteranions in a three-dimensional fashion through hydrogen bonds and weak Ag...F interactions giving rise to a structure with solvent-filled channels. Different and more compact structures have been found when the counteranion is CF 3SO 3 (OTf). When R = phenyl, sheets are formed which consist of [Ag 2(OTf) 2L 2] units with double triflate bridges and which contain columns of pi-pi stacked arenes. Hydrogen bonds connect the sheets. When AgOTf is used and R is p-tolyl, a different and unusual ladderlike structure is obtained in which the rungs are double asymmetric bridges consisting of the triflate groups bonded to Ag in kappa (2) O,mu 2- O and kappa (1) O,mu 2- O fashion. The ladders are parallel to each other and are mutually linked by N-H...N hydrogen bonds to give a 3D architecture. A very similar ladderlike structure has been found for 7 but with a water molecule and a BF 4 (-) group acting as bridges. The role played by the hydrogen bonds in complex 6 to form the 3-D structure is played in 7 by [Ag(acetone) 2] fragments. The noncovalent interactions play an important role in the different solid-state 3D structures. The behavior of the new derivatives in solution has also been analyzed. A new species has been detected at low temperatures, and this exhibits restricted rotation of the phenyl ring.

Thermal expansion and interatomic potentials of silver revealed by extended x-ray absorption fine structure spectroscopy using high-order perturbation theory

Extended x-ray absorption fine structure investigations are reported concerning the thermal expansion behavior of silver in a wide range of temperatures from 10 to about 950 K as measured in the transmission mode. Models based on the quantum and classical thermodynamic perturbation theory are used to interpret the experimental data and compared to x-ray diffraction results of the crystalline silver material. To this aim, the third- and fourth-order perturbation formulas of the cumulants and of the thermal expansion coefficient have been developed by means of the quantum-statistical theory and are presented here. By using these formulas, the thermal expansion of silver bonds can be described by the temperature-dependent first cumulants as well as by an anharmonic potential function in correlation with the cumulant expansion in the complete range of temperatures.

Pearson and Public Works Construction in Mexico,1890–1910

S. Pearson & Son, forerunner to the present-day Pearsons PLC, started as a general works contractor in the 1860s and emerged as a global enterprise mainly on the strength of public works contracts undertaken for the Mexican government between 1889 and 1906. This article looks at how this business operated, analysing the capital flows through the contracts. These involved substantial quantities of public debt, mostly in the form of silver bonds. The very favourable terms achieved by Pearson and the fact that he built all the largest public works projects, suggest that he enjoyed a virtual monopoly over this kind of contract in Mexico. Some explanations of this are examined, together with their possible implications regarding technology transfers and modelling the future development of the Mexican construction industry.

Complexes with platinum-gold and -silver bonds: catalysis by silver(I) of alkyl exchange reactions between platinum centers

The electron-rich platinum(II) complex [PtMe 2 (2,2'-bpy)] (bpy=bipyridine) reacts with [Au-(NO 3 )(PPh 3 )], [Au(BF 4 )(PPh 3 )], [Au(PF 6 )(PPh 3 )], [Ag(BF 4 )(PPh 3 )], and AgBF 4 to give the Pt-M bonded complexes ]PtMe 2 (bpy)(AuPPh 3 )]NO 3 , [PtMe 2 (bpy)(AuPPh 3 )]BF 4 , [PtMe 2 (bpy)(AuPPh 3 )]PF 6 , [PtMe 2 (bpy)(AgPPh 3 )]BF 4 , and [{PtMe 2 (bpy)} 2 Ag]BF 4 , respectively. These compounds are shown to contain PtAu or PtAg bonds by their 1 H, 31 P, and 195 Pt NMR spectroscopic properties

Structure of a cyclic hydroxo-bridged PtII trimer with platinum–silver bonds

[AgPt 3 (en) 3 (OH) 3 (NO 3 ) 3 ]NO 3 cristallise dans le systeme monoclinique avec le groupe d'espace Pc. Affinement de la structure jusqu'a 0,039. Les 3 atomes Pt ont une coordination plan carre, legerement deformee en un arrangement pyramidal carre a cause de la presence de l'atome Ag

New compounds with platinum to silver bonds unsupported by covalent bridges

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew compounds with platinum to silver bonds unsupported by covalent bridgesRafael Uson, Juan Fornies, Milagros Tomas, Jose M. Casas, F. Albert Cotton, and Larry R. FalvelloCite this: J. Am. Chem. Soc. 1985, 107, 8, 2556–2557Publication Date (Print):April 1, 1985Publication History Published online1 May 2002Published inissue 1 April 1985https://doi.org/10.1021/ja00294a062RIGHTS & PERMISSIONSArticle Views134Altmetric-Citations40LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (269 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Binuclear shift reagents for nuclear magnetic resonance spectrometry of aromatic and polycyclic aromatic compounds

The effects of adding binuclear lanthanide(III)-silver(I) shift reagents to aromatic compounds and phosphines are discussed. With aromatic compounds, the silver bonds at sites away from alkyl substituents so that selective shifts, leading to significant spectral clarification, are observed. Because of different shifts, the analysis of complex mixtures such as the methylbenzenes in gasoline can be performed in the presence of these shift reagents. A study of the relative shifting ability of the binuclear complexes formed with the ligand 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione (fod), vs. 2,2,6,6-tetramethyl-3,5-heptanedione (thd), revealed that the fluorinated ligands are much more effective shift reagents.

Model of the antimicrobial silver uracil.

A model is proposed for the antimicrobial agent, silver uracil, whereby silver interacts with uracil forming a silver uracil combination with the silver in the +1 state intercalating between stacked uracils in a manner similar to a 'sandwich' model. The uracils maintain stability by hydrogen bonding with the water solvent, and 'flip-flop' through an antiparallism mode at 220 degrees. The silver bonds to the uracil by a charge transfer mechanism, increasing the nuclear shielding field of the pyrimidine. The presence of the water (solvent) is necessary for the structure.