Electron attachment to some naphthoquinone derivatives: long-lived molecular anion formation
Electron attachment to some naphthoquinone derivatives: long-lived molecular anion formation
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DOI：
10.1002/rcm.6934
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发表时间：
2014-07-30
影响因子：
2
通讯作者：
Modelli, A.
中科院分区：
文献类型：
--
作者：
Asfandiarov, N. L.;Pshenichnyuk, S. A.;Modelli, A.
理论基础：电子亲和性（EA）是分子的基本性质之一。EA值可以用各种实验方法测量，尽管它们的可用性仍然相对有限。本文尝试用解离电子吸附光谱（DEAS）方法对12种萘醌（NQ）衍生物的电子吸收光谱进行了研究。利用电子透射光谱（ETS）和DEAS技术，结合密度泛函理论（DFT）的计算，对NQ和胡桃醌的空能级结构进行了研究。结果：研究中的所有分子都形成了与三种共振态相关的极长寿命的分子阴离子（除了NQ，其中仅观察到两个长寿命共振）。NQ的羟基取代导致EA和内部自由度（N）的数量增加，并且，因此，增加分子负离子（NI）的平均电子自脱离寿命。通过一个简单的Arrhenius近似从分子NI的测量寿命的评估EA给出了合理的协议与DFT calculations.CONCLUSIONS：NI寿命测量通过一个修改后的DEAS仪器可以提供定量数据EA的结果。一个简单的阿克里乌斯近似似乎足以描述电子从分子阴离子中脱离的过程。版权所有（C）2014约翰威利父子有限公司
RATIONALE: Electron Affinity (EA) is one of the fundamental properties of a molecule. EA values can be measured with various experimental methods, although their availability is still relatively limited. We make an attempt to use Dissociative Electron Attachment Spectroscopy (DEAS) data for evaluation of the EAs of twelve naphthoquinone (NQ) derivatives.METHODS: Naphthoquinone (NQ) and eleven of its hydroxyl derivatives were investigated by means of DEAS. A combined investigation of NQ and juglone by means of the Electron Transmission Spectroscopy (ETS) and DEAS techniques, with the support of density functional theory (DFT) calculations, allowed us to elucidate the empty-level structures of NQ and its hydroxyl derivatives.RESULTS: All molecules under investigation form extremely long-lived molecular anions associated with three resonant states (except for NQ, where only two long-lived resonances were observed). The hydroxyl substituents of NQ cause an increase in EA and number of internal degrees of freedom (N), and, as a result, an increase in the mean electron autodetachment lifetimes of the molecular negative ions (NIs). Evaluation of the EAs from the measured lifetimes of the molecular NIs through a simple Arrhenius approximation gives results in reasonable agreement with those obtained with DFT calculations.CONCLUSIONS: NI lifetime measurements by means of a modified DEAS instrumentation can provide quantitative data of EA. A simple Arrhenius approximation seems to be adequate to describe the process of electron detachment from molecular anions. Copyright (C) 2014 John Wiley & Sons, Ltd.