化学
激进的
印丹
位阻效应
光化学
反应性(心理学)
茚
氧气
反应速率常数
氢原子萃取
烷氧基
药物化学
立体化学
有机化学
烷基
动力学
病理
量子力学
医学
替代医学
物理
作者
Enrique Font‐Sanchis,Carolina Aliaga,Elena Bejan,Raecca Cornejo,J. C. Scaiano
摘要
Resonance-stabilized radicals containing indane, indene, and fluorenyl moieties exhibit attenuated reactivity toward oxygen. Rate constants of approximately 10(5) M(-1) s(-1) were observed for the most stabilized radicals. The dependence of k(OX) (rate constant for radical trapping by oxygen) on the corresponding bond dissociation energies revealed that stereoelectronic effects are more important 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 of ca. (1-13) x 10(6) M(-1) s(-1), showing that benzylic stabilization has a modest effect on substrate reactivity as a hydrogen donor toward alkoxyl radicals.
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