Relaxation rates for spirocyclohexyl nitroxyl radicals are suitable for interspin distance measurements at temperatures up to about 125 K.
Between 65 and 175 K, nitroxyl radicals with spirocyclohexyl groups at the 2- and 6-positions of the piperidine ring exhibit spin echo dephasing rates that are slower than for nitroxyl radicals with 2,5-gem-dimethyl or 2,6-gem-dimethyl substituents that are currently used as spin labels, and are slow enough to permit DEER measurements at temperatures up to about 125 K for spin labels with analogous ring structures.
Kathirvelu
Velavan
V
Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado, 80208, USA.
Smith
Christopher
C
Parks
Christopher
C
Mannan
Md Abdul
MA
Miura
Yozo
Y
Takeshita
Keizo
K
Eaton
Sandra S
SS
Eaton
Gareth R
GR
D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry*; D009589:Nitrogen Oxides / Q000737:chemistry*; D013696:Temperature
D005609:Free Radicals; D009589:Nitrogen Oxides; C039900:nitroxyl