Silver ion incorporation

Under the chosen conditions aromatic compounds are nitrated to nitroaromatics [1]. The detection of rotenone [1] (see below) depends on the reduction of silver ions, incorporated into the layer, to metallic silver in the presence of ammonia [4]. The mechanism of the reaction of many substances leading to fluorescent derivatives has not yet been elucidated [2],... 

The separation of olefin/paraffin gas mixtures is one of the most energy-intensive processes in the petrochemicals industry, because it is mainly performed by cryogenic distillations. Membrane processes using the concept of facilitated transport have been considered as an intriguing alternative to cryogenic distillation, as they can simultaneously improve both permeability and selectivity. Silver ions incorporated in liquid membranes act as olefin... 

Figure 4.12 A solid-state electrode showing a second-order response. The electrode shown in Figure 4.11 can be modified by the incorporation of silver chloride into the membrane to enable the activity of chloride ions in a sample to be measured. A surface reaction between the test chloride ions and the membrane silver ions alters the activity of the latter, resulting in a change in the potential difference across the membrane.

Silver nitrate may be incorporated in the adsorbent slurry (25 g l-1) giving a final concentration of about 5% in the dry plate. The silver ions bind reversibly with the double bonds in the unsaturated compounds, resulting in selective retardation, and the lipids are separated according to the number and configuration (cis or trans) of their double bonds. This technique is extremely useful in fatty acids, mono-, di- and particularly triacylglycerol analyses when even positional isomers may be resolved. Borate ions may also be incorporated in the silica gel and these plates are used to separate compounds with adjacent free hydroxyl groups. 

The IRS has been modified to incorporate a batch step for removal and recovery of silver ions accumulating in the IRS circuit. This removal operation involves the addition of 35 percent HC1 and subsequent collection and treatment of the AgCl precipitate for off-site removal. The process has not been demonstrated on purged anolyte solution with metal, mineral acid, and trace organic impurities. 

The same way was used by Yoon and Kim (2005) for the preparation of 5-(p-methoxyphenyl)thian threnium ion incorporated in a calyx[4]arene. Namely, the ratio of starting materials, methoxycal-ixarene to the thianthrene cation-radical perchorate, was 1 10. The product of such 5-anisylation of thianthrene was further transformed into a calixarene bearing an additional o-phenylene thio-macrocycle. This macrocylization is beyond the scope of this book the original paper by Yoon and Kim (2005) could be recommended for those who interested in. It is worth noting only one practical importance of the calixarene-phenylene thiomacrocycle here It selectively extracts silver(l-l-) by both calixarene and thiomacrocycle. Each molecule of this combined complexon takes up two silver cations, so that extractability achieves 165%. 

Silver Activation. Doping zinc sulfide with silver leads to the appearance of an intense emission band in the blue region of the spectrum at 440 nm, which has a short decay time. Weak luminescence in the green (520 nm) and red regions can also occur. The blue band is assigned to recombination at substitutionally incorporated silver ions [5.314], [5.315]. The red band is caused by luminescence processes in associates of silver ions occupying zinc positions with neighboring sulfur vacancies... 

Agl, in its low temperature form, crystallizes in the (hep) wurtzite structure. The silver ions occupy tetrahedrally coordinated sites. The fast ion conducting Agl (7 >420K) is bcc. One can stabilize structural disorder at low temperature not only by incorporating cations such as Rb+, NH, etc., but also by adding S2 to reconstruct the anion sublattice and obtain Ag3SI. This compound exists in three different structures. At high temperature (>519K), it is bcc and both the cations and... 

Trans olefins form weaker ir-complexes with silver ions than do cis olefins hence cis-trans isomers can be separated using silver ion chromatography. Initially silver ions were used in conjunction with TLC, with silver nitrate being incorporated in the silica gel layer. In recent years the technique has been adapted to HPLC. 

Iridium salts are of current interest as sensitizers for internal latent image formation (189,190). The iridium ions are incorporated in the grains during their preparation, probably as a complex associated with silver ion vacancies. 

An interesting variation on this theme has been reported by Lehn and coworkers. In 1986, they reported the synthesis of macrocycle 33, which consists of a zinc porphyrin bearing two linked cyclic binding subunits [87]. It was later found that addition of silver triflate to a solution of 33 in methanol resulted in the incorporation of a silver ion in each of the binding subunits [88], Thus, the complex may be represented as Ag+-P-Ag+. The porphyrin fluorescence of the silver complex was quenched, and transient absorption studies demonstrated that the porphyrin singlet state was quenched with a rate constant of 5.0 x 109 s 1 to yield a charge separated state Ag°-P+-Ag+. Some quenching of the porphyrin triplet... 

For those redox couples that involve a metal ion plus the metal, the logical electrode system is the metal itself. In other words, if the measured quantity is to be cupric ion [copper(II)], a practical indicator electrode is a piece of copper metal. All second-class electrodes involve an active metal in combination with an insoluble compound or salt. Thus, the silver/silver chloride electrode actually is a silver/silver ion electrode system that incorporates the means to control the silver ion concentration through the chloride ion concentration [Eq. (2.14)]. A related form of this is the antimony electrode, which involves antimony and its oxide (an adherent film on the surface of the antimony-metal electrode) such that the activity of antimony ion is controlled by... 

Research into controlled-release antimicrobials continues with organo-silver compounds and silver zeolites, which are promising candidates for textile finishes. Silver ions, for example, incorporated in glass ceramic, have a very low toxicity profile and excellent heat stability. These principles are also used for fibre modification, an alternative to the antimicrobial finishes with high permanence. In recent years a variety of antimicrobial modified fibres have been developed, including polyester, nylon, polypropylene and acrylic types. An example of these fibre modifications is the incorporation of 0.5-2 % of organic nitro compounds... 

BFr< SbFg. This order parallels that observed for olefin solubility in concentrated silver salt solutions (40, 193). Structural investigations of crystalline silver-olefin complexes have shown a nearly covalent bond between the silver and the nitrate ions (28, 399), but an electrostatic bond only between silver and fluoroborate ions (537). Consequently, the differing complex stability may be largely attributable to the differences in the energy required for the expansion which permits incorporation of the olefin molecule into the salt lattice. These differences will depend upon the anion composition (537), geometry, and size. Similarly, the degree of silver ion-anion association in concentrated solutions will vary with the anion and a similar explanation can account for the dependence of olefin solubility on the anion. In dilute solutions, however, the silver ion environment and thus the olefin solubility may be essentially independent of the anion (193). 

The useful concentradon of emulsion is in the range of 20-50 mg of emulsion per mL of developer. It should be noted, however, that the number of emulsion pieces influences the developing speed, because the silver halide in the emulsion is only slowly soluble in the sodium sulflte incorporated in the developer, and the larger surfaces of several small emulsion pieces accelerate the dissolution of the silver halide. Similarly, the time of stirring the developer, before the section is put on, influences the concentration of silver ions, and thus, the developing speed. 

A minor shift in redox potential is caused by silver ion complexation of the diferrocenyl-monocryptand complex. In fact, the silver-free ferrocene ligand undergoes a single-step two-electron oxidation at E° = -1-0.39 V in MeCN. On incorporation of silver ion, the two-electron redox change occurs at ° = -1-0.50 V. 

The impregnation of the layer with silver ions is performed by either incorporating the silver salt into the silica gel slurry or by immersing or spraying the plate with water, ethanol, methanol, ammonia, or acetonitrile solutions of the salt. Silver nitrate is normally used. The only method that affords proper control of the Ag(I) content in the layer is to add silver nitrate to the slurry. However, this... 

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