Studies in Organic Free Radical and Excited State Chemistry

这个有机动力学项目的奖项为莱斯大学的保罗·恩格尔博士的持续研究提供了支持。本研究的主要目的是研究偶氮烷烃的化学性质及其在热和光化学分解过程中形成的瞬态中间体。我们将从广泛的角度来探讨这种化学反应。将采用几种不同的方法来理解瞬态中间体的行为。通过纳秒瞬态吸收实验研究偶氮烷烃的断键机理。本文将利用缺电子敏化剂对偶氮烷烃进行闪光光解，研究偶氮烷烃结构对单电子氧化形成的阳离子自由基的影响。热裂解动力学和质谱测量将用于确定一系列含有α -氮官能团的碳中心自由基的稳定能。双自由基的寿命将被环丙基中心的生成和重排所“计时”。期望这些不同的研究将导致新的实验方法来观察化学反应中的激发态。

This award in the Organic Dynamics Program provides support for the continuing research of Dr. Paul Engel of Rice University. The main thrust of the research is a study of the chemistry of azoalkanes and the transient intermediates formed in their thermal and photochemical decomposition. This chemistry will be approached on a broad front. Several different approaches to understanding the behavior of transient intermediates will be undertaken. The mechanism of bond-breaking in azoalkanes will be investigated by nanosecond transient absorption experiments. The effect of azoalkane structure on the cation-radicals formed by one-electron oxidation will be studied by flash photolysis of azoalkanes with electron-deficient sensitizers. Thermolysis kinetics and mass spectroscopic measurements will be used to determine the stabilization energies of a series of carbon-centered free radicals containing alpha-nitrogen functionality. Biradical lifetimes will be "clocked" by generation and rearrangement of cyclopropylcarbinyl radical centers. It is expected that these varied studies will lead to new experimental approaches to observing excited states in chemical reactions.