首页 | 本学科首页   官方微博 | 高级检索  
     检索      


An NMR,ESR, ENDOR and TRIPLE resonance investigation of a cation radical formed from 1,2,4,5-tetramethoxybenzene
Authors:S A Fairhurst  I M Smith  L H Sutcliffe  S M Taylor
Abstract:Several methods have been established for preparing cation radicals from 1,2,4,5-tetramethoxybenzene that allow highly resolved ESR spectra to be recorded. Precise values of the hyperfine coupling constants for the aromatic and methoxy protons have been obtained; the values are 0.2268±0.0004 and 0.0863±0.0002 mT, respectively, with dichloromethane as solvent. No temperature dependence is evident. TRIPLE resonance experiments showed that both coupling constants have the same sign. NMR experiments provided contact shift and line broadening measurements; these proved that both the above constants are positive and led to a value of 3.1 (±0.3)×108M?1 s?1 at 23°C for the rate constant for electron exchange between the cation radical and the parent compound.
Keywords:
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号