Abstract
Intramolecular spin exchange in four flexible PEG-based bis-nitroxides was studied by X-band electron paramagnetic resonance (EPR) spectroscopy as a function of temperature and solvent viscosity. A series of biradicals with different lengths of the ethylene glycol bridge connecting the two nitroxide groups was investigated in aqueous and mixed 1:1 i-propanol:water solutions. Conformational transitions in liquid solutions of the biradicals were analyzed, and thermodynamic parameters of the conformational reorganization were calculated from the EPR spectra. Intramolecular distances r between paramagnetic >N–O• fragments in biradicals in frozen solutions were calculated and compared with dynamic properties of the biradicals.
| Original language | English |
|---|---|
| Pages (from-to) | 251-260 |
| Number of pages | 10 |
| Journal | APPLIED MAGNETIC RESONANCE |
| Volume | 46 |
| Issue number | 3 |
| Early online date | 10 Jan 2015 |
| DOIs | |
| Publication status | Published - Mar 2015 |