An EPR analysis of nitroxide spin probes in ethyl alcohol and tetrahydrofuran

The solutions of 2,2,6,6-tetramethylpiperidinyloxy (TEMPO), 4-hydroxy-TEMPO (TEMPOL) in ethyl alcohol and tetrahydrofurane (THF), 4-amino-TEMPO (TEMPAMINE) in THF were prepared in a concentration range of 0.1 - 10 mM. The EPR (0.3 T) spectra of these samples were recorded at room temperature. Experimental spectra were simulated using high field approximation. For this purpose a FORTRAN program was written and by the use of this program hyperfine coupling constants and intrinsic line widths were determined. Electronic correlation times of the samples were calculated from the line widths and their dependence on the solvent was discussed.The solutions of 2,2,6,6-tetramethylpiperidinyloxy (TEMPO), 4-hydroxy-TEMPO (TEMPOL) in ethyl alcohol and tetrahydrofurane (THF), 4-amino-TEMPO (TEMPA-MINE) in THF were prepared in a concentration range of 0.1-10 mM. The EPR (0.3 T) spectra of these samples were recorded at room temperature. Experimental spectra were simulated using high field approximation. For this purpose a FORTRAN program was written and by the use of this program hyperfine coupling constants and intrinsic line widths were determined. Electronic correlation times of the samples were calculated from the line widths and their dependence on the solvent was discussed.We would like to thank Prof. Dr. Fevzi Koksal from Ondokuz Mayts University-Samsun for permission to use their laboratories for some measurements. We also wish to thank TUBITAK for the financial support of the project