Sensors, anion

Davis F, Collyer SD, Higson SPJ (2005) The Construction and Operation of Anion Sensors Current Status and Future Perspectives. 255 97-124 Deamer DW, Dworkin JP (2005) Chemistry and Physics of Primitive Membranes. 259 1-27 Debaene F, see Winssinger N (2007) 278 311-342... 

Figure 8. Schematic representation of the micro-environment of a PSD (Rhodamine B octadecyl ester) in an anion sensor before (A) and after (B) extraction of nitrite from the aqueous into the lipophilic membrane phase.

J. Di, S. Bi, and M. Zhang, Third-generation superoxide anion sensor based on superoxide dismutase directly immobilized by sol-gel thin film on gold electrode. Biosen. Bioelectron. 19, 1479-1486 (2004). 

Miyaji H, Sessler JL (2001) Off-the-shelf colorimetric anion sensors. Angew Chem Int Ed 40 154-157... 

Suksai C, Tuntulani T (2003) Chromogenic anion sensors. Chem Soc Rev 32 192-202... 

Lee DH, Lee KH, Hong JI (2001) An azophenol-based chromogenic anion sensor. Org Lett 3 5-8... 

Fang L, Chan WH, He YB et al (2005) Fluorescent anion sensor derived from cholic acid the use of flexible side chain. J Org Chem 70 7640-7646... 

Kikuchi K, Hashimoto S, Mizukami S et al (2009) Anion sensor-based ratiometric peptide probe for protein kinase activity. Org Lett 11 2732-2735... 

Mizukami S, Nagano T, Urano Y et al (2002) A fluorescent anion sensor that works in neutral aqueous solution for bioanalytical application. J Am Chem Soc 124 3920-3925... 

The conversion of squaraine 19a to the rotaxane 18 D 19a causes a modest red-shift only in both absorption (10 nm) and emission (7 nm) but an approximately threefold decrease in quantum yield. The addition of two triazole rings (dye 19b) did not significantly alter the quantum yield of 17b (Table 4). A macrocycle-induced quenching effect was verified by fluorescence titration experiments adding aliquots of 18 to a solution of squaraine 17b in methylene chloride [58]. Treatment of the 18 d 17b psuedorotaxane system with the tetrabutylammonium salts of chloride, acetate, or benzoate leads to the displacement of squaraine 17b from the macrocyclic cavity and the nearly complete restoration of its fluorescence intensity. The 18-induced quenching of 17b does not support the utility of this system as a bioimaging probe however, the pseudorotaxane system 18 Z> 17b acts as an effective and selective anion sensor with NIR fluorescence. 

The squaraine rotaxanes based on the macrocycle 16b exhibit intense NIR absorption and emission maxima, and it should be possible to develop them into molecular probes for many types of photonic and bioimaging applications. In contrast, the squaraine fluorescence intensity is greatly diminished when the dye is encapsulated with macrocycle 18. The fluorescence is restored when a suitable anionic guest is used to displace the squaraine dye from a pseudorotaxane complex, which indicates that the multicomponent system might be applicable as a fluorescent anion sensor. 

There a great need for selective anion sensors, but the number of available sensors is rather limited because of difficulties in their design. However, new selective sensors are expected because of the considerable progress made in the synthesis of anion receptors. 

Anionic sensors are based on the same principles, but work in the opposite direction. In this case we must have available ferrocene... 

In an effort to prepare bidentate boranes as colorimetric anion sensors, the incorporation of chromophoric boron moieties has also received attention. Reaction of lO-bromo-9-thia-lO-boranthracene 33 with dimesityl-1,8-naphthalenediylborate 26 affords diborane 34 (Scheme 14). This bright yellow diborane is soluble in chloroform, THF and pyridine. It has been fully characterized but its X-ray crystal structure could not be determined experimentally. Its structure was computationally optimized using DFT methods (B3LYP, 6-31 + G for the boron and sulfur... 

Polyphenylene and polyfluorene have been extensively used as fluorescence-based sensors, and several chromogenic forms of these polymers have been reported. Incorporation of monomers with additional coordination sites into these polymers has led to the development of a variety of different anion sensors, mostly for halide ions (Lee et al. 2004 Zhou et al. 2005 Vetrichelvan et al. 2006 Kim et al. 2007). Extension of these materials toward recognition of more complex analytes should be possible. 

The so-called "trapped sites" of classical mobile-site, liquid ion exchanger electrodes belong to a category of compounds known as ion association extractants. Examples are long-chain diesters of phosphoric acid and tricaprylylmethylammonium (Aliquat) ions. The latter cation was studied extensively by Freiser and co-workers (1-3 ) in the design of anion sensors. 

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