Generation and Reactivity toward Oxygen of Carbon-Centered Radicals Containing Indane, Indene, and Fluorenyl Moieties
作者:Enrique Font-Sanchis、Carolina Aliaga、Elena V. Bejan、Raecca Cornejo、J. C. Scaiano
DOI:10.1021/jo026666o
日期:2003.4.1
than steric effects in determining the low radical reactivity with oxygen. Scavenging by the nitroxide TEMPO was also examined, and revealed that in this case steric effects are more important than in the case of oxygen. The rate constants for the hydrogen abstraction by cumyloxyl and tert-butoxyl radicals generated thermally and photochemically have been determined in benzene, and were in the range
包含茚满,茚和芴基的共振稳定基团表现出对氧的减弱的反应性。对于最稳定的自由基,观察到大约10(5)M(-1)s(-1)的速率常数。k(OX)(自由基被氧捕获的速率常数)对相应的键离解能的依赖性表明,在确定与氧的低自由基反应性方面,立体电子效应比空间效应更重要。还检查了通过氮氧化物TEMPO的清除作用,结果表明,在这种情况下,空间作用比在氧气作用下更重要。在苯中已经确定了由热和光化学产生的枯基氧基和叔丁氧基从氢中提取氢的速率常数,其范围为约。(1-13)x 10(6)M(-1)s(-1),