engleski

Fluorescent Phenanthridine-Based Calix[4]arene Derivatives: Synthesis and Complexation Properties

Calixarenes are macrocyclic oligomers consisted of four or more phenolic residues linked by methylene groups in the ortho position and can be easily functionalized to give receptors for vast number of ionic or neutral species. Calixarenes bearing fluorescent moieties can be considered as potentially very sensitive fluorimetric ion sensors due to the high sensitivity of fluorescence spectroscopy and high affinity of these macrocyclic ligands towards cations. In the scope of this work, two novel fluorescent phenathridine-based calix[4]arene derivatives were designed and prepared. The binding affinities of these compounds towards metal cations in several solvents (acetonitrile, methanol, ethanol, N, N-dimethylformamide, dimethylsufoxide) were investigated. Phenanthridine moities were introduced at a lower calix[4]arene rim and served both as fluorescent probes and parts of cation-binding site. Stability constants of the corresponding complexes were determined by means of UV spectrophotometry, fluorimetry and isothermal microcalorimetry. The latter technique also provided information on reaction enthalpies and entropies. The obtained results were discussed regarding the structural characteristics of the calixarene derivatives and differences in solvation abilities of the solvents used.

calix[4]arenes ; phenantridine ; metal cations ; fluorescence ; complexation ; thermodynamics

Special Issue of Bulletin of the Chemists and Technologists of Bosnia and Herzegovina