Anion signaling

A rather unique strategy which often works very well for anion signaling involves the recoordination that can take place in the ligating sphere of a metal ion in a stable complex with a fluorescent probe upon anion attack. The basic... 

Comes M, Aznar E, Moragues M et al (2009) Mesoporous hybrid materials containing nanoscopic binding pockets for colorimetric anion signaling in water by using displacement assays. Chem Eur J 15 9024—9033... 

Raman spectrum of aqueous HN03 at 25"C. Signals at 1 360,1 049. and 720 cm 1 arise from N03 anion. Signals denoted by asterisks are from undissociated HN03. The wavenumber unit, cm, is 1/wavelength. 

A detailed PNA analysis of the symmetric stretching mode of the methyl functional group on the butyl chain of the cation and the methyl group from the methyl sulfate anion signal intensity determined minima at 2° 3° for the methyl... 

Similar groups of ions to those described above (L , L Na -iL Na Jj. i) are seen in the spectra of a-olefin sulphonates, alkyl ether sulphates, sarcosinates and sulphosuccinates. Fatty acid salts do not give rise to strong positive ions but do give good anion signals in negative-ion spectra. 

Figure 15 Measured (full line) and calculated (broken line) anion signal produced by electron attachment to an oxygen cluster beam as a function of electron energy. Inset Same data on a log-log scale demonstrating the E- dependence predicted by s-wave scattering theory (dashed line). After Matejcik S, Kiendler A, Stampfli P, Stamatovic Aand MarkTD (1996) Physical Review Letters77 .377. ...

In contrast to metal ion sensing, QDs have been barely used for anion signaling. Toward this objective, Sanz-Medel et al. reported the functionalization of CdSe QDs with tert-butyl-A-(2-mercaptoethyl)-carbamate for the selective and sensitive detection of cyanide in methanol by analyte-induced luminescence quenching. In a further work, the authors prepared water-soluble CdSe QDs coated with 2-mercaptoethane sulfonate also for cyanide... 

Tile low-temperature ESR spectrum of the anion radical of purine disclosed that about 45% of the spin density is localized at position 6 (80BCJ1252), although a single very broad signal for N(7) and N(9) did not allow discussion of the tautomerism. 

Tire and NMR parameters of some 1-alkyl-4-benzimidazolyl-2-idene- (type 72) and l-alkyl-4-(5-methylpyrazolyl-3-idene)-l,4-dihydro pyridines (type 73) were discussed in 89CC1086 and 91JOC4223. Comparison of the shifts for DMSO-dg and CDCI3 solutions with data reported for quaternary pyridinium compounds as well as anionic species in the azole series and data obtained for mesoionic betaines of the azinium azolate class left no doubt that these heterofulvalenes have a betaine character and, therefore, the NMR signals correspond to their dipolar resonance form. 

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