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Anion-sensing systems

Surface Confined Redox Anion-Sensing Systems. 63... [Pg.45]

The study of anion coordination has implications for a number of areas in chemistry and biochemistry. These include analytical applications concerned with anion sensing or separation as well as model studies for anion-specific biochemical systems. With respect to the latter, it is of interest that the majority of enzymic systems so far characterized bind substrates which are anionic. [Pg.152]

An analogous system to the cation sensors is the use of optically nonactive anion ionophores together with a pH-sensitive chromophore for the anion sensing. In this system, simultaneous extraction of H+ and anion X- from the aqueous solution into an organic phase results in protonation of the chromophore anion C, e.g. [Pg.768]

Cuest-Induced Changes in Membrane Permeability. Calixarene derivatives are also used for sensing systems other than ISEs or optodes. Recently, a systematic investigation on the control of membrane permeability by use of oriented monolayers composed of calixarene esters was carried out. The hosts used were short alkyl chain esters of calix[6]arene [28 (R = Bu )] and calix[4]arene [26 (R = Bu ), 30 both cone conformers]. The permeabilities through the intermo-lecular voids of these monolayers were evaluated by cyclic voltammetry, as described earlier for oriented membranes of nucleobase derivatives. Cationic, anionic, and neutral electroactive compounds were used as the permeability markers. The voltammetric measurements were carried out either for a monolayer... [Pg.236]

Anionic Catalysis Several bulky methacrylates afford highly isotactic, optically active polymers having a single-handed helical structure by asymmetric polymerization. The effective polymerization mechanism is mainly anionic but free-radical catalysis can also lead to helix-sense-selective polymerization. The anionic initiator systems can also be applied for the polymerization of bulky acrylates and acrylamides. The one-handed helical polymethacrylates show an excellent chiral recognition ability when used as a chiral stationary phase for high-performance liquid chromatography (HPLC) [97,98]. [Pg.769]

Metal nanoparticles have extraordinary size-dependent optical properties, not present in the bulk metal and have, consequently, been the subject of intense research during the past decade or so.27 Attention has recently focused on functionalising colloidal nanoparticles with molecular recognition components for potential sensing applications.28,29,30 We have prepared a new amido-disulfide functionalised zinc metalloporphyrin (8) which was self-assembled on to gold nanoparticles to produce a novel anion-selective optical sensing system (9) (Scheme 3).4... [Pg.109]

Method A has been successfully applied in anion sensing. As mentioned previously, lanthanide ions can coordinate to anions such as acetate, fluoride, etc., which modulates the lanthanide luminescence. Examples of such systems will now be discussed. [Pg.19]

In this section, various crowned spirobenzopyrans for use as alkali metal cation receptors have been presented. This new type of chromoionphore is conceptually different from the crown ether dyes because, in the case of the crown ether dyes, the absorption bands of the chromophones are shifted by complexation of cations. Crowned spirobenzopyrans might provide sophisticated ion-sensing systems such as ion sensors whose ion selectivity can be photochemically switched between cations and anions.104... [Pg.112]

A transformation of some synthetic versatility is the oxidation of methyl groups in a methylcobaltocenium salt by Mn04 to give the respective carboxylic acid. In this way, mono- and dicarboxylatocobaltocenium salts have been prepared. These acids can be further functionalized and used as receptors for the selective recognition of anion guest species. A pyrrole-fimctionalized cobaltocenium salt has also been electropolymerized on an electrode surface this system displays anion sensing in solution and when immobilized. ... [Pg.870]

Anion sensing development in terms of both sensitivity and selectivity lags behind that of cations for the entire range of sensing systems, from solution state to... [Pg.93]

A variety of other gas-detecting sensors are also available. Sensors for NH3 and SO2 are similar to the CO2 system in that they make use of an H ISE which responds to the acid-base reaction between the gas molecule and water. Other gas-sensing systems use other ISEs. For example, a sensor for H2S can be based on the S ISE. The sulfide anion is produced when H2S dissolves in water by an acid-base reaction. The S ISE then responds to the resulting activity of the sulfide anion. [Pg.501]

G. B. Martin and M. E. Meyerhoff, Membrane-Dialyzer Injection Loop for Enhancing the Selectivity of Anion-Responsive Liquid-Membrane Electrodes in Flow Systems. Part I. A Sensing System for NOx and Nitrite. Anal. Chim. Acta, 186 (1986) 71. [Pg.470]

Surface Confined Systems for Optical Anion Sensing. 88... [Pg.45]

Nishizawa. S. Kaneda, H. Uchida. T. Teramae. N. Anion sensing by a donor-spacer-acceptor system An intramo-leeular exciplex emission enhanced by hydrogen bond-mediated complexation. J. Chem. Soc., Perkin Trans. 2 1998. (11). 2325-2327. [Pg.571]


See other pages where Anion-sensing systems is mentioned: [Pg.140]    [Pg.1973]    [Pg.140]    [Pg.1973]    [Pg.167]    [Pg.289]    [Pg.41]    [Pg.169]    [Pg.171]    [Pg.182]    [Pg.186]    [Pg.768]    [Pg.20]    [Pg.21]    [Pg.67]    [Pg.146]    [Pg.160]    [Pg.196]    [Pg.290]    [Pg.289]    [Pg.573]    [Pg.31]    [Pg.3]    [Pg.277]    [Pg.735]    [Pg.36]    [Pg.45]    [Pg.76]    [Pg.91]    [Pg.50]   
See also in sourсe #XX -- [ Pg.22 , Pg.23 ]




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