Fluorogenic and chromogenic chemosensors and reagents for anions.

Anion receptor chemistry: highlights from 1999

Artificial Receptors for the Recognition of Phosphorylated Molecules Amanda E. Hargrove, Sonia Nieto, Tianzhi Zhang, Jonathan L. Sessler,* and Eric V. Anslyn* Department of Chemistry and Biochemistry, University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712-0165, United States Universidad de Zaragoza, Zaragoza, Spain Henkel Corporation, Rocky Hill, Connecticut 06067 Department of Chemistry, Yonsei University, Seoul, 120-749 Korea

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Artificial receptors for the recognition of phosphorylated molecules

On the basis of many literature measurements, a critical overview is given on essential noncovalent interactions in synthetic supramolecular complexes, accompanied by analyses with selected proteins. The methods, which can be applied to derive binding increments for single noncovalent interactions, start with the evaluation of consistency and additivity with a sufficiently large number of different host–guest complexes by applying linear free energy relations. Other strategies involve the use of double mutant cycles, of molecular balances, of dynamic combinatorial libraries, and of crystal structures. Promises and limitations of these strategies are discussed. Most of the analyses stem from solution studies, but a few also from gas phase. The empirically derived interactions are then presented on the basis of selected complexes with respect to ion pairing, hydrogen bonding, electrostatic contributions, halogen bonding, π–π-stacking, dispersive forces, cation−π and anion−π interactions, and contributions f...

Experimental Binding Energies in Supramolecular Complexes

Anion recognition and anion sensing are of interest because anions play many important roles in living organisms. Most currently known anion sensors work only in organic solution, but sensors for biological applications are required to function in neutral aqueous solution. We have designed and synthesized a novel fluorescent sensor for anions. The sensor molecule 1-CdII contains 7-amino-4-trifluoromethylcoumarin as a fluorescent reporter and CdII-cyclen (1,4,7,10-tetraazacyclododecane) as an anion host. In neutral aqueous solution, CdII of 1-CdII is coordinated by the four nitrogen atoms of cyclen and the aromatic amino group of coumarin. When various anions are added to 100 mM HEPES buffer solution (pH 7.4) containing 1-CdII, the aromatic amino group of coumarin is displaced from CdII, causing a change of the excitation spectrum. While pyrophosphate and citrate were detected with high sensitivity, fluoride and perchlorate produced no response. Among organic anions, ATP and ADP gave strong signals, while ...

A fluorescent anion sensor that works in neutral aqueous solution for bioanalytical application.

The interactions of phosphate and pyrophosphate anions with polyammonium cations deriving from 14 polyamines (five polyazacycloalkanes, four polyazacyclophanes, and five acyclic polyamines) in aqueous solution have been studied by means of potentiometric, microcalorimetric, and NMR measurements in solution. Very stable 1:1 receptor-to-anion complexes are formed. The stability trends of such complexes are not strictly determined by electrostatic forces, hydrogen bond interactions being of considerable importance in the complex formation, the thermodynamic data being consistent with different hydrogen bonding modes. ΔH°−TΔS° compensatory relationships hold for such complexation reactions. The crystal structures of (H4L1)(H2P2O7)2·2H2O and (H4L2)(H2P2O7)2·6H2O (L1 = 1,4,7,10,13,16-hexaazacyclooctadecane, L2 = 1,10-dimethyl-1,4,7,10,13,16-hexaazacyclooctadecane) have been solved by X-ray analysis, evidencing different substrate/anion binding characteristics.

Gianluca Maccagni

Papers

Thermodynamics of phosphate and pyrophosphate anions binding by polyammonium receptors