Flowing Afterglow and SIFT-Drift Studies of Gas Phase Ion-Molecule Reactions

在有机动力学计划范围内，这个项目涉及科罗拉多大学C.de Puy和V.Bierbaum的持续工作。它们将在高真空下通过电子撞击产生高度活性的离子物种，并通过质谱学观察这些离子与中性分子碰撞产生的反应。这将通过消除凝聚相反应中存在的溶剂化效应来更好地理解有机离子反应。将在流动余辉选择离子流管装置中研究离子与中性分子之间的反应。离子将通过电子碰撞或包括离子合成反应在内的其他方法产生，在四极滤质器中与其他离子和中性前体分离，并与0.5Torr的氦一起注入流动管中。高活性离子，例如CH-离子，将被允许与各种中性试剂反应，以便将它们的反应速度和产物通道与更传统的反应离子进行比较。同位素标记的离子，特别是那些含有S-34、氯-37、O-18和C-13的离子，将被用作示踪剂，以检查原本被隐藏在例如HS-34阴离子与硫化氢之间的反应的速率(S-32)。预计将出现在星际介质中的带正电的碳氢化合物阳离子将被允许与已知存在于太空中的分子(例如水)反应，以试图了解在不寻常的空间条件下有机分子的起源。将通过硅烷的化学反应来探测极弱酸性分子的酸性，例如胺、杂芳烃和烷烃。总体目标是通过消除溶剂化的遮蔽效应来了解简单的有机离子反应的细节。

This project, within the Organic Dynamics Program, involves the continuing work of C. De Puy and V. Bierbaum of the University of Colorado. They will generate highly reactive, ionic species by electron impact under high vacuum, and observe, by mass spectrometry, reactions resulting from the collision of these ions with neutral molecules. This will lead to a better understanding of organic ionic reactions by removing the effects of solvation which are present in condensed phase reactions. Reactions between ions and neutral molecules in a flowing afterglow selected ion flow tube apparatus will be studied. Ions will be generated by electron impact or by other methods including ion synthesis reactions, separated from other ions and neutral precursors in a quadrupole mass filter and injected into a flow tube together with 0.5 torr of helium. Highly reactive ions, as for example CH anion, will be allowed to react with a variety of neutral reagents in order to compare their reaction rates and product channels with more conventional reactant ions. Isotopically labeled ions, particularly those containing S-34, Cl-37, O-18 and C-13, will be used as tracers to examine rates for reactions which would otherwise be hidden as in, for example, that between HS-34 anion and hydrogen sulfide (S-32). Positively charged hydrocarbon cations which are expected to occur in the interstellar medium will be allowed to react with molecules (e.g., water) known to be present in space in an attempt to understand the origin of organic molecules under the unusual conditions of space. The acidity of very weakly acidic molecules, for example amines, heteroaromatic compounds and alkanes, will be probed by chemical reactions of silanes. The overall goal is to understand the details of simple organic ionic reactions by removing the obscuring effects of solvation.