High static pressure alters spin trapping rates in solution. Dependence on the structure of nitrone spin traps.
Using a competitive spin trapping method, relative spin trapping rates were quantified for various short-lived radicals (methyl, ethyl, and phenyl radicals). High static pressure was applied to the competitive spin-trapping system by employing high-pressure electron spin resonance (ESR) equipment. Under high pressure (490 bar), spin trapping rate constants for alkyl and phenyl radicals increased by 10 to 40%, and the increase was dependent on the structure of nitrone spin traps. A maximum increase was obtained when tert-butyl(4-pyridinylmethylene)amine N-oxide (4-POBN) was used as a spin trap. Activation volumes (DeltaDeltaV(double dagger)) for the two spin trapping reactions were calculated to be -17-(-9) cm(3) mol(-1) for the 4-POBN system.
Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima Naka, Okayama 700-8530, Japan. ysueishi@cc.okayama-u.ac.jp
Yoshimi
Y
Sueishi
Daisuke
D
Yoshioka
Chiharu
C
Yoshioka
Shunzo
S
Yamamoto
Yashige
Y
Kotake
D003497:Cyclic N-Oxides / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000032:analysis / Q000737:chemistry; D015394:Molecular Structure; D009589:Nitrogen Oxides / Q000737:chemistry*; D011312:Pressure; D011725:Pyridines / Q000737:chemistry; D012996:Solutions; D013113:Spin Labels; D019097:Spin Trapping
D003497:Cyclic N-Oxides; D005609:Free Radicals; D009589:Nitrogen Oxides; D011725:Pyridines; D012996:Solutions; D013113:Spin Labels; C043438:alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone; C015388:nitrones; C029217:phenyl-N-tert-butylnitrone; C017245:5,5-dimethyl-1-pyrroline-1-oxide