engleski

Complexation Properties of Phenantridine-Based Calix[4]arene Derivatives

Calixarenes are macrocyclic oligomers consisted of four or more phenolic residues linked by methylene bridges in the ortho position. As such, they can be easily functionalized with ketone, ester, amide, or other functional groups on 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 phenantridinebased calix[4]arene derivatives L1 and L2 towards alkali, alkaline earth and lanthanide cations in various organic solvents (acetonitrile, methanol, ethanol, N, N‐dimethylformamide, dimethyl sulfoxide) were investigated. Stability constants of the corresponding complexes were determined (or in some cases only assessed) by means of UV spectrophotometry, fluorimetry, and isothermal titration calorimetry. The latter technique also provided information on reaction enthalpies and entropies. The obtained thermodynamic parameters were discussed regarding the structural characteristics of the studied compounds and solvation properties of the solvents used.

calix[4]arenes ; ion receptors ; thermodynamics ; solvation ; fluorescence

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