Anion coordination chemistry

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

Anion coordination chemistry has thus made very significant progress in recent years. The development of other receptor molecules possessing well-defined geometrical and binding features will make it possible to further refine the requirements for anion recognition, so as to yield highly stable and selective anion complexes with characteristic coordination patterns. 

The development of anion coordination chemistry and anion receptor molecules has opened up the possibility to perform molecular catalysis on anionic substrates of chemical and biochemical interest, such as adenosine triphosphate. The catalysis of phosphoryl transfer is of particular interest, namely in view of the crucial role of such processes in biology and of the numerous enzymes that catalyse them. 

Despite the early discovery of the katapinands, non-covalent anion coordination chemistry was relatively slow to develop in comparison with the development of hosts for cations and even neutral molecules. While it is generally true that anion hosts obey the same rules that govern the magnitude of binding constants and host selectivity in cation hosts (primarily based on preorganisation, complementarity, solvation and size and shape effects), their application is made much more difficult because of some of the intrinsic properties of anions, listed below. 

Garcia-Espana, E., Diaz, P., Llinares, J. M. and Bianchi, A., Anion coordination chemistry in aqueous solution of polyammonium receptors , Coord. Chem. Rev. 2006, 250, 2952-2986. 

Dietrich, B. Guilhem, J. Lehn, J.-M., Pascard, C. and Sonveaux, E., Molecular recognition in anion coordination chemistry , Helv. Chim. Acta., 1984, 67, 91-104. 

Bencini, A., Bianchi, A., Garciaespana, E., et al., Anion coordination chemistry. 2. Electrochemical, thermodynamic, and structural studies on supercomplex formation between large polyammonium cycloalkanes and the 2 complex anions hexacyanoferrate(Ii) and hexacyanocobaltate(Iii). Inorg. Chem. 1987, 26, 3902-3907. 

Beer, P. D. Wheeler, J. W. Moore, C. New approaches to anion coordination chemistry. Acyclic quaternary polybipyridinium receptors designed to bind anionic guest species, in Supramolecular Chemistry, Balzani, V. De Cola, L., Eds. Kluwer Academic Publishers Netherlands 1992, 105-118. 

Keywords Anion coordination chemistry Cryptands Ligands Metal coordination chemistry Molecular recognition Receptors Sarcophagines... 

In the evolution of anion coordination chemistry, it was discovered that neutral molecules can also operate as effective receptors for anions provided that they contain polarised N-H fragments (e.g. of amides [53], ureas [54], thioureas [55] or pyrroles [56]), which act as H-bond donors for anions. These receptors cannot compete for hydrogen bonding with water and alcohols and must be studied in aprotic solvents of varying polarity, e.g. CHCI3, MeCN, DMSO. In this vein,... 

Bistren cryptands have been deservedly more successful in anion coordination chemistry than in traditional coordination chemistry. In particular, the bistren framework has provided the basis for the design of a variety of receptors that are suitable for the inclusion of polyatomic anions of varying size and shape. A number... 

Parker, D. (2000) Luminescent lanthanide sensors for pH, p02 and selected anions. Coordination Chemistry... 

B. Dietrich, J. Guilhem, J.M. Lehn, C. Pascard, E. Sonveaux, Molecular Recognition in Anion Coordination Chemistry - Structure, Binding Constants and Receptor-Substrate Complimentarity of a Series of Anion Cryptates of a Macrobicyclic Receptor Molecule , Helv. Chim. Acta, 67,91 (1984)... 

This review covers adsorption, catalysis, and photocatalysis that can be investigated and understood by photoluminescence spectroscopy. Most of the results discussed in this review have been obtained by photoluminescence techniques, but other, complementary techniques, are also discussed to emphasize the originality and potential value of photoluminescence spectroscopy, particularly with regard to anion coordination chemistry, excited states, and reaction dynamics. The latter field is of utmost importance in chemistry (35). Additional applications of photoluminescence spectroscopy to the study of solid surfaces are reviewed in the books Photochemistry on Solid Surfaces"(. 6) and Surface Photochemistry (37). 

Cobaltocenium based systems have therefore proved very versatile in the field of anion coordination chemistry. The role of the cobaltocenium unit is to enhance interaction with the bound anion and to function as a sensing unit. The structure of the receptor can then be controlled by simple organic manipulations of the Cp groups. In this manner, novel anion selectivity can readily be incorporated into these receptors. 

Anion coordination chemistry polyguanidinium salts as anion complexones. 

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