Influence of Pressure on Intramolecular Dynamics in a Long-Chain Flexible Nitroxide Biradical
| Autor: | Boryana Mladenova-Kattnig, Guenter Grampp, Alexander I. Kokorin |
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| Rok vydání: | 2015 |
| Předmět: |
Arrhenius equation
Imagination Nitroxide mediated radical polymerization Chemical substance Solid-state physics Chemistry media_common.quotation_subject Thermodynamics Activation energy Atomic and Molecular Physics and Optics symbols.namesake Computational chemistry Intramolecular force symbols Equilibrium constant media_common |
| Zdroj: | Applied Magnetic Resonance. 46:1359-1366 |
| ISSN: | 1613-7507 0937-9347 |
| DOI: | 10.1007/s00723-015-0721-0 |
| Popis: | A flexible long-chain nitroxide biradical of the structure R6–(CH2)2OOC–(CH2)8–COO–(CH2)2–R6, 1, where –R6 is the 1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl residue, has been investigated by X-band electron paramagnetic resonance spectroscopy in CH3CN solutions at variable temperature and pressure. The effect of changes of the solution viscosity on the intramolecular electron spin exchange in 1 has been characterized in terms of dynamic and thermodynamic parameters such as the equilibrium constant describing the transition of the elongated and coiled effective configuration, τ c/τ, and the characteristic spin-exchange time τ eff and its associated Arrhenius activation energy. It was revealed that the intramolecular dynamics in 1 do not follow the Debye-Stokes–Einstein law. |
| Databáze: | OpenAIRE |
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