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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Aminoalkyl Radicals: Direct Observation and Reactivity toward Oxygen, 2,2,6,6-Tetramethylpiperidine-N-oxyl, and Methyl Acrylate
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Aminoalkyl Radicals: Direct Observation and Reactivity toward Oxygen, 2,2,6,6-Tetramethylpiperidine-N-oxyl, and Methyl Acrylate

机译：氨基烷基自由基：对氧气，2,2,6,6-四甲基哌啶-N-氧基和丙烯酸甲酯的直接观察和反应性

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摘要

The reactivity of 11 aminoalkyl radicals toward different additives [oxygen, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), and methyl acrylate (MA)] has been investigated through laser flash photolysis and quantum mechanical calculations. The transient absorption spectra of the radicals were recorded: good agreement was found with the spectra calculated by using quantum mechanical calculations. All the interaction rate constants were measured. A large range of values are obtained: (0.04-3) × 10~9 M~(-1) s~(-1) for O_2, (0.002-5) × 10~8 M~(-1) s~(-1) for TEMPO, and (<0.004-2) × 10~7 M~(-1) s~(-1) for MA. Generation of the decarboxylated aminoalkyl radical derived from N-phenylglycine was unambiguously demonstrated. It was clearly found that both the addition to oxygen and the recombination with TEMPO were strongly governed by the reaction exothermicity. On the other hand, both polar and enthalpy factors have a large influence on the rate constants of the addition reaction to the acrylate unit, which were ranging over at least 4 orders of magnitude. This paper provides a set of new data to characterize the structure/reactivity relationships of aminoalkyl radicals.
机译：通过激光闪光光解和量子力学计算研究了11个氨基烷基对不同添加剂的反应性[氧，2,2,6,6-四甲基哌啶-N-氧基（TEMPO）和丙烯酸甲酯（MA）]。记录了自由基的瞬态吸收光谱：发现与通过量子力学计算所计算的光谱具有良好的一致性。测量所有相互作用速率常数。获得的值范围很大：对于O_2为（0.04-3）×10〜9 M〜（-1）s〜（-1），（0.002-5）×10〜8 M〜（-1）s〜（ TEMPO为-1），MA为（<0.004-2）×10〜7 M〜（-1）s〜（-1）。清楚地证明了衍生自N-苯基甘氨酸的脱羧氨基烷基的产生。清楚地发现，向氧的添加和与TEMPO的重组均受反应放热的强烈控制。另一方面，极性和焓因子都对丙烯酸酯单元加成反应的速率常数有很大的影响，其范围至少在4个数量级上。本文提供了一组新数据来表征氨基烷基自由基的结构/反应性关系。

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