Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2038, USA.
J Phys Chem A. 2012 Mar 29;116(12):3089-93. doi: 10.1021/jp2101557. Epub 2012 Mar 15.
Recent studies have shown that the reactivity of the 4-dehydropyridinium cation significantly differs from the reactivities of its isomers toward tetrahydrofuran. While only hydrogen atom abstraction was observed for the 2- and 3-dehydropyridinium cations, nonradical reactions were observed for the 4-isomer. In order to learn more about these reactions, the gas-phase reactivities of the 4-dehydropyridinium cation and several of its derivatives toward tetrahydrofuran were investigated in a Fourier transform ion electron resonance mass spectrometer. Both radical and nonradical reactions were observed for most of these positively charged radicals. The major parameter determining whether nonradical reactions occur was found to be the electron affinity of the radicals--only those with relatively high electron affinities underwent nonradical reactions. The reactivities of the monoradicals are also affected by hydrogen bonding and steric effects.
最近的研究表明，4-二氢吡啶阳离子的反应活性与其异构体对四氢呋喃的反应活性有显著差异。对于 2-和 3-二氢吡啶阳离子，仅观察到氢原子的抽取，而对于 4-异构体，则观察到非自由基反应。为了更深入地了解这些反应，在傅里叶变换离子电子共振质谱仪中研究了 4-二氢吡啶阳离子及其几种衍生物与四氢呋喃的气相反应活性。对于大多数这些带正电荷的自由基，都观察到了自由基和非自由基反应。发现决定是否发生非自由基反应的主要参数是自由基的电子亲合势——只有那些具有相对较高电子亲合势的自由基才会发生非自由基反应。单自由基的反应活性也受到氢键和空间位阻效应的影响。
