Structure and Dynamics of Ternary Complexes of Cucurbit[8]uril with Spin-Labeled Indicators and Biologically Active Analytes
| Autor: | M. V. Alfimov, R. F. Gabidinova, V. A. Livshits, Vitaly G. Avakyan, B. B. Meshkov |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010405 organic chemistry
Chemistry Supramolecular chemistry Nitroxyl 010402 general chemistry 01 natural sciences 0104 chemical sciences Spin probe symbols.namesake Crystallography chemistry.chemical_compound Unpaired electron Cucurbituril symbols Molecule Physical and Theoretical Chemistry van der Waals force Ternary operation |
| Zdroj: | High Energy Chemistry. 52:157-166 |
| ISSN: | 1608-3148 0018-1439 |
| DOI: | 10.1134/s001814391802011x |
| Popis: | Ternary host–guest complexes have been first obtained from cucurbituril CB[8] as a host molecule and two guest molecules: nitroxyl probes of different structures and biologically important amino acids (AA) and aromatic compounds. To characterize the binding of the guests, parameters of the polarity of the environment and the rotational mobility of the spin probes have been used. These parameters have been shown to depend on the nature of the analytes. For the ternary complexes, in addition to the usual triplet ESR spectra from nitroxyl probes (S3), supramolecular ensembles consisting of three equivalent ternary complexes (“triads”) have been found, whose ESR spectra have a seven-component hyperfine structure (S7) due to delocalization of the unpaired electron over three nitrogen nuclei. The relative intensity of the S7 spectra increases with increasing NaCl concentration in the solution, and also depends significantly on the nature of the analyte and the spin probe. Quantum chemical calculations have shown that (1) to determine the stability of the complexes, it is necessary to allow for the van der Waals interaction, and (2) the complexes involving the zwitterionic form of AA are much more stable than those with the neutral form of AA. |
| Databáze: | OpenAIRE |
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