The Solvent Effect on Spin Exchange in Long-Chain Nitroxide Biradicals |
| |
| Authors: | V A Tran K Rasmussen G Grampp A I Kokorin |
| |
| Institution: | (1) Institute of Physical and Theoretical Chemistry, Graz University of Technology, Graz, Austria;(2) N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, Russian Federation |
| |
| Abstract: | Intramolecular electron spin exchange, as a function of temperature and the solvent viscosity, polarity and relaxation properties
of the solvent molecules, has been studied by X-band electron paramagnetic resonance (EPR) spectroscopy in two long-chain
flexible nitroxide biradicals existing in fluid solutions in three spectroscopically different spatial conformations. Certain
thermodynamic parameters of the conformational rearrangements were calculated from the EPR spectra. Spin exchange in two biradicals
dissolved in five different alcohols was compared with that in a nonpolar solvent (toluene), polar protic (water) and aprotic
(acetonitrile), and with thermodynamic characteristics of the solvents. Distinct correlations were found between macroscopic
(solvent viscosity, polarity) and microscopic (solvent longitudinal relaxation time) characteristics of solvents, and thermodynamic
parameters of the intramolecular conformational transitions.
Authors' address: Van Anh Tran, Institute of Physical and Theoretical Chemistry, Graz University of Technology, Technikerstrasse
4, 8010 Graz, Austria |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
