Kinetics of nitroxide radical trapping. 2. Structural effects
作者:V. W. Bowry、K. U. Ingold
DOI:10.1021/ja00039a006
日期:1992.6
Laser flash photolysis and kinetic competition product studies have demonstrated that in isooctane at ambient temperatures the rate constant for coupling of carbon-centered radicals with persistent nitroxides, k T , depends upon the degree of steric hindrance to coupling and upon the extent of resonance stabilization of the carbon radical. Sterically induced reductions in the magnitude of k T are observed
激光闪光光解和动力学竞争产物研究表明,在环境温度下,在异辛烷中,以碳为中心的自由基与持久性氮氧化合物的偶联速率常数 k T 取决于偶联的空间位阻程度和共振稳定的程度。碳自由基。对于氮氧化合物结构和碳自由基结构的变化,观察到 k T 大小的空间诱导减少。因此,对于任何特定的碳基,k T 对于 Bredt 规则保护的氮氧化物、9-氮杂双环 [3.3.1] 壬烷-N-氧基 (ABNO) 和去甲托烷-N-氧基而言是最大的,而对于通常的'二叔-烷基氮氧化物 k T 沿系列递减,1,1,3,3-四甲基异碘啉-2-氧基≥2,2,5,5-四甲基哌啶-1-氧基(Tempo)>二叔丁基氮氧化物,i.