Anions, electrochemical recognition

Smith, D.K. Spencer, P. Transition metal cation and phosphate anion electrochemical recognition in water by new polyaza ferrocene macrocyclic ligands. Inorg. Chim. 35. Acta 1996, 246, 143. 

Transition metal complexes with 2,2 -bipyridine ligands in anion-selective recognition and optical/electrochemical sensing 96CC689. 

Beer P. D. (1996) Anion Selective Recognition and Optical/Electrochemical Sensing by Novel Transition-Metal Receptor Systems, Chem. Commun. 689—96. 

Electrochemical recognition of anionic guest species by redox-active... 

Electrochemical recognition, 39 80 anions, macrocyclic and acyclic polycobalti-cinium ligand systems, 39 134-140 cations, 39 81-133 ammonium cation, 39 128-133 crown ether and bis crow ether ligands containing bipyridyl transition metal recognition sites, 39 111 crown ether dithiocarbamate and dithi-olene complexes, 39 123-124 di-h-cyclopentadienyl-molybdenum(IV) and -tungsten(IV) crown ether complexes, 39 107-108... 

Application of Ferrocenyl-Containing Dendrimers in the Electrochemical Recognition of Anions and as Electron Transfer Mediators in Amperometric Biosensors... 

Beer, P. D. Gale, P. A. Chen. G. Z. Mechanisms of electrochemical recognition of cations, anions and neutral guest species by redox-active receptor molecules, Coord. Chem. Rev. 1999, 185-186, 3-36. 

The nature of the solvent can also have a profound effect on the electrochemical recognition process. All of the redox-responsive ligand systems cited in this review give examples of guest cation/anion redox couple perturbations in organic solvents such as dichloromethane and acetonitile. The next challenge will be to demonstrate analogous redox-responsive behavior in the aqueous environment. 

Supramolecules containing metal-polypyridine units, especially the Ru(dpp)-based dendrimers, could be used as electron reservoirs or components of molecular-electronic devices. Supramolecules in which an electroactive M(N,N) group is attached to a receptor capable of molecular recognition (crown ethers, calixarenes, cryptands etc.) can work as electrochemical sensors. Electrochemical recognition of cations as well as anions has been reported [33-35, 257, 263]. 

Recently, Shinkai and co-workers (85) reported a ferroceneboronic acid receptor (26). This receptor showed selective electrochemical recognition of fluoride ions over other halides, the redox potential for the ferrocene unit being perturbed on the addition of F . There is, however, only one orbital overlap interaction provided by this host and it is likely the selectivity arises solely due to the hardness of the fluoride anion. 

The ruthenium(II) bipyridyl moiety is also capable of functionally sensing the presence of bound anion. Electrochemical anion recognition experiments showed substantial anion induced cathodic perturbation of the ligand centered amide substituted 2,2 -bipyridine (bpy) reduction redox couple. These perturbations were in agreement with stability constant values, with 134 sensing H2PO4- in the presence of 10-fold excess of HS04 and Cl . Fluorescence emis-... 

Beer. P.D. Drew, M.G.B. Smith. D.K. Selective electrochemical recognition of bidentate anionic guests in competitive solvents using novel ferrocenyl thiourea and guanidinium receptors. J. Organomet. Chem. 1997. 

Beer, P.D. Szemes, F. Balzani, V. Sala, C.M. Drew, M.G.B. Dent, S.W. Maestri, M. Anion selective recognition and sensing by novel macrocyclic transition metal receptor systems. H NMR, electrochemical and photophysical investigations. J. Am. Chem. Soc. 1997, 119, 11864-11875. 

Cuadrado. I. del Barrio, J.L. A polymerizable pyn ole-cobaltocenium receptor for the electrochemical recognition of anions in solution and immobilized onto 125. electrode surfaces. Inorg. Chem. Commun. 2002.5. 288-... 

Beer. P.D. Anion selective recognition and optical/ electrochemical sensing by novel transition-metal receptor systems. Chem. Commun. 1994. 6. 689. 

Beer. P.D. Chen. G.Z. Goulden. A.J. Graydon, A.R. Stokes. S.E. Wear, T. Selective electrochemical recognition of the dihydrogen phosphate anion in the presence of hydrogen sulfate and chloride ions by new neutral ferrocene anion receptors. Chem. Commun. 1993, 24. 1834. 

The supramolecular assembly of dendrimers via H-bonding has been accomplished by Astruc, Boisselier, and Ornelas in which commercial dendritic poly(propylenimine) cores are rapidly and reversibly H-bonded to triallyl-or tris-amidoferrocenyl phenol dendrons these novel supramolecular assemblies were used for the electrochemical recognition of H2P04 and adenosine-triphosphate anions. ... 

With the aim of developing electroactive systems capable of electrochemically and specifically recognizing anions [370], some anionic receptors have been bound to redox-active groups such as cobaltocenium, ferrocene, and transition-metal bipyridyl moieties [370-373]. Although such compounds were suitable for the electrochemical recognition of some anionic species in solution, their immobilization on an electrode surface to achieve sensitive layers has been investigated with very few examples. 

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