engleski

Phenanthridine-based calix[4]arene derivates: synthesis and their complexation with alkali metal cations

Calixarenes are a class of supramolecular hosts that can be easily functionalized with suitable donor groups at the lower and/or upper rim to give efficient receptors for various ionic or neutral species. Due to the prominent sensitivity of fluorescence spectroscopy and high affinity of these macrocyclic ligands towards cations it is possible to prepare highly sensitive ion sensors by introducing fluorescent substituents into the calixarene moiety. In the scope of this work, the binding affinities of tertiary amide and ester phenantridine-based calix[4]arene derivatives L1 and L2 towards alkali metal cations in various organic solvents (acetonitrile, methanol, ethanol, N, N-dimethylformamide and dimethyl sulfoxide) were investigated experimentally (UV spectrophotometry, fluorimetry and isothermal titration calorimetry) as well as by means of classical molecular dynamics simulations which provided an additional insight into the complexation properties and structures of the complex species formed. The results gained by the latter technique indicated the occurrence of inclusion of solvent molecules in the calixarene hydrophobic cavity of the free and complexed ligands, which was found to significantly affect the complexation equilibria. The obtained thermodynamic reaction parameters were discussed regarding the structural characteristics of the studied compounds and solvation properties of the solvents used.

Alkali-metal cations ; calixarenes ; fluorescence ; thermodynamics

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