engleski

Anion-cylopeptide complexes in solution

The anion interactions with various natural and synthetic receptors are subject of an intensive and quickly-developing research in the field of supramolecular chemistry.[1] In the corresponding studies, a special accent is put on the design of molecules that recognize and efficiently react with anions, as well as on the description of intermolecular forces, structure, properties and functions of a receptor molecule and complex species formed upon complexation.[2] Modern research on anionic receptors often uses the basic coordination and recognition principles taken from the receptor observed in natural systems.[1–4] A class of macrocyclic compounds that contains amide groups in their backbone and can be used as selective receptors of anionic species are cyclopeptides.[2–4] rather good complexation properties of these compounds can be attributed to the remarkable hydrogen-bonding donor properties of the amide groups. In addition, the well- structured, yet sufficiently flexible structure of the cyclopeptides, as well as the presence of multiple functional groups oriented in the appropriate direction, with the additional possibility of modifying the peptide backbone and/or the side chains, contribute to the high efficiency and selectivity for anion binding of these receptors.[2–4] In this talk the studies of halides and oxoanions binding with several homocyclopeptide ligands in acetonitrile and dymethylsulfoxide carried out by NMR and microcalorimetric titrations and molecular dynamics simulations will be described. The aim of the investigation was to obtain as detailed as possible insight into the thermodynamic and structural characteristics of the receptors and to rationalize the relation between structure and reactivity of the investigated cyclopeptides. The solvent effect on equilibria of the studied reaction will be addressed as well.

cyclopeptides, anions, complexation

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