Recognition of anions

L. Gorski, E. Malinowska, P. Parzuchowski, W. Zhang, and M.E. Meyerhoff, Recognition of anions using metalloporphyrin-based ion-selective membranes state-of-the-art. Electroanalysis 15, 1229-1235 (2003). 

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

Figure 2.17. Examples of fluoroionophores for recognition of anions (Adapted from Refs. 72 and 73.)...

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

The molecular recognition of anionic guest species by positively chaiged or neutral receptors is a relatively new area of research of growing interest in view of the key roles that these anions play in biochemical and chemical processes. For this reason, as part of the electrochemical studies, we decided to examine the use of the redox-active ferrocenyl dendrimers 3 and 4 that contain multiple N-H linkages capable of participating in H-bonding, as well as characteristic internal cavities,... 

Currently, the only other monoprotonated sapphyrin-monoanion complex to be solved by X-ray diffraction analysis is that of 3-HN,. As expected, in this complex the azide counteranion is bound above the sapphyrin plane by a combination of anisotropic electrostatic interactions and oriented hydrogen bonds (Figure 4). As such, this structure supports the conclusion, reached in the case of 3-HCl, that a single positive charge on the sapphyrin is enough to effect anion recognition of anionic substrates, at least in the solid state. 

Three stages of ethylene glycol overdose occur. Within the first few hours after ingestion, there is transient excitation followed by CNS depression. After a delay of 4-12 hours, severe metabolic acidosis develops from accumulation of acid metabolites and lactate. Finally, delayed renal insufficiency follows deposition of oxalate in renal tubules. The key to the diagnosis of ethylene glycol poisoning is recognition of anion gap acidosis, osmolar gap, and oxalate crystals in the urine in a patient without visual symptoms. 

Anion Coordination Chemistry and the Recognition of Anionic Substrates... 

Linear recognition is displayed by the hexaprotonated form of the ellipsoidal cryptand bis-tren 33, which binds various monoatomic and polyatomic anions and extends the recognition of anionic substrates beyond the spherical halides [3.11, 3.12]. The crystal structures of four such anion cryptates [3.11b] provide a unique series of anion coordination patterns (Fig. 4). The strong and selective binding of the linear, triatomic anion N3" results from its size, shape and site complementarity to the receptor 33-6H+. In the [N3 pyramidal arrays of +N-H "N- hydrogen bonds, each of which binds one of the two terminal nitrogens of N3-. 

Calix[4]pyrroles offer an alternative receptor site for the recognition of anions. Miyaji et al. [400] prepared a series of calixpyrrole-anthracene receptors that possess conjugated (73) and unconjugated bond pathways of different lengths (74 and 75). The stability constants (103—105 M-1 determined by NMR titration) for the anion complexes of each member of the series follows the trend... 

Eiichi Kimura is retired from the Department of Medicinal Chemistry at Hiroshima University in Japan. His recent research interests have included the supramolecular chemistry of macrocyclic polyamines and their use in molecular recognition and as zinc-enzyme models. These interests have led to the development of fluorophore sensors for Zn(II) [8] use of macrocycles to effect selective recognition of anions [9], nucleobases in polynucleotides [10], thymidine mono- and diphosphate nucleotides (11), carbonic anhydrase and carboxypeptidase [12], and development of Zn(II)-macrocycle anti-HIV agents [13], In May 2004, he received a Purple Ribbon Award from the Emperor of Japan. 

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