Estimation of σ- and π-donor properties of heterocyclic thioamides by spectroscopic and magnetic resonance methods
| Autor: | Igor V. Burykin, Gennadiy I. Bondarenko, Evgeniy V. Khohlov, M. S. Chernov’yants |
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| Rok vydání: | 2010 |
| Předmět: |
Magnetic Resonance Spectroscopy
Static Electricity Electron donor Electrons Tetracyanoethylene Models Biological Analytical Chemistry law.invention Electron Transport chemistry.chemical_compound law Heterocyclic Compounds Nitriles Organic chemistry Benzothiazoles Electron paramagnetic resonance Instrumentation Spectroscopy Equilibrium constant Thioamide chemistry.chemical_classification Spectrum Analysis Nuclear magnetic resonance spectroscopy Ethylenes Atomic and Molecular Physics and Optics Thioamides chemistry Stability constants of complexes Proton NMR Solvents Physical chemistry Chloroform |
| Zdroj: | Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy. 81(1) |
| ISSN: | 1873-3557 |
| Popis: | The charge-transfer complexes (CTC) of few thioamide: 1-methylimidazoline-2-thione (MMI), 3-methyl-1-ethoxycarbonilimidazoline-2-thione (Carb), 5-methylbenzimidazoline-2-thione (BIZ), benzothiazoline-2-thione (BTZ), benzoxazoline-2-thione (BOZ) as σ-donors and diiodine as σ-acceptor were studied by spectroscopic methods (UV/Vis, (1)H NMR). CTC formation constants of thioamides with diiodine were determined using the function of the average-iodine number. The charge-transfer complexes of thioamides as π-donors with tetracyanoethylene (TCNE) as π-electron acceptor, were studied by UV-spectroscopy in dichloromethane and chloroform solutions. The mechanism of interaction MMI and Carb with TCNE have been studied by EPR spectroscopy. Spectral characteristics and formation constants are discussed in the terms of electron donor affinity of thioamides and the nature of the organic solvent used. The ionization potentials of donors were estimated from the CT transition energies of their complexes. The photolytic equilibrium constants of five thioamides are determined using pH-metric titrations. |
| Databáze: | OpenAIRE |
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