Rate constants of electron attachment to alkyl iodides measured by photoionization electron attachment ion mobility spectrometry (PI-EA-IMS)

Gao, Hui; Niu, Wenqi; Huang, Chaoqun; Yan, Hong; Shen, Chengyin; Wang, Hongmei; Lu, Yan; Chen, Xiaojing; Xia, Lei; Jiang, Haihe; Chu, Yannan

doi:10.1016/j.ijms.2014.11.001

Cited by 6 publications

(3 citation statements)

References 22 publications

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“…Studies on EARs in the literature were mainly focused on the electron attachment dissociation (EAD) reactions. For example, the EAD channels and rate constants of a series of nitrobenzene compounds and halogenated hydrocarbons , were investigated. Inspired by these studies and considering the high electron affinity energy of MGLY (0.87 ± 0.01 eV), we render that the EAR may be used for MGLY detection.…”

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confidence: 99%

Electron Attachment Reaction Ionization of Gas-Phase Methylglyoxal

et al. 2018

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Methylglyoxal (MGLY) plays a significant role in atmospheric chemistry by serving as a key contributor to the formation of active free radicals, ozone, and secondary organic aerosol. Detection of MGLY by traditional chemical ionization such as proton-transfer reaction has several shortcomings such as parent molecule fragmentation. In this study, an electron attachment reaction (EAR) ionization method has been developed for the effective detection of MGLY. Almost no fragmentation was observed during the EAR. The generation of MGLY − anion in the EAR was further confirmed by cryogenic photoelectron imaging spectroscopy. The concentration of MGLY can be calibrated by using dibromomethane (CH 2 Br 2 ) as reference gas. The detection sensitivity of MGLY was estimated to be (100 ± 2) mV/ppbv (parts per billion by volume). The O 2 , H 2 O, CO 2 , and trace gases in ambient air have no obvious effects on the detection of MGLY − anion by the EAR ionization method.

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confidence: 99%

Electron Attachment Reaction Ionization of Gas-Phase Methylglyoxal

et al. 2018

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“…A more complex condition, multiple-collision with variable collision energies, can be realized by utilizing a reactor composed of a drift tube (DT) and an ion funnel (IF). The DT, which has been extensively used as the analyzer in the ion mobility spectrometry 41,42 , as well as the reactor of proton transfer reactions 43,44 and electron attachment reactions 45,46 have been used to study the interactions of Ti + , Co + , and Er + with CH4 23,47,48 . In the DT, ions drift under an adjustable direct current (DC) electric field accompanying multiple collisions with neutral molecules.…”

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confidence: 99%

C―C Coupling of Methane Mediated by Atomic Gold Cations under Multiple-Collision Conditions

Ren¹,

中国科学院化学研究所²,

Liu³

et al. 2020

Acta Physico-Chimica Sinica

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The reactivity of atomic metal cations toward CH4 has been extensively investigated over the past decades. Closed-shell metal cations in electronically ground states are usually inert with CH4 under thermal collision conditions because of the extremely high stability of methane. With the elevation of collision energies, closed-shell atomic gold cations (Au + ) have been reported to react with CH4 under single-collision conditions to produce AuCH2 + , AuH + , and AuCH3+ species. Further investigations found that the ion-source-generated AuCH2 + cations can react with CH4 to synthesize C-C coupling products. These previous studies suggested that new products for the reaction of Au + with CH4 can be identified under multiple-collision conditions with sufficient collision energies. However, the reported ion-molecule reactions involving methane were usually performed under single-or multiple-collision conditions with thermal collision energies. In this study, a new reactor composed of a drift tube and ion funnel is constructed and coupled with a homemade reflectron time-of-flight mass spectrometer. Laser-ablation-generated Au + ions are injected into the reactor and drift 120 mm to react with methane seeded in the helium drift gas. The reaction products and unreacted Au + ions are focused through the ion funnel and accumulate through a linear ion trap and are then detected by a mass spectrometer. In the reactor, the pressure is approximately 100 Pa, and the electric field between the drift tube and ion funnel can regulate the collision energies between ions and molecules. The reaction of the closed-shell atomic Au + cation with CH4 is investigated, and the C-C coupling product AuC2H4 + is observed under multiple-collision conditions with elevated collision energies. Density functional theory calculations are performed to understand the mechanism of the coupling reaction (Au + + 2CH4 → AuC2H4 + + 2H2).Two pathways involving Au-CH2 and Au-CH3 species can separately mediate the C-C coupling process. The activation of the second C-H bond in each process requires additional energy to overcome the relatively high barrier (2.07 and 2.29 eV). Ion-trajectory simulations under multiple-collision conditions are then conducted to determine the collisional energy distribution in the reactor. These simulations confirmed that the electric fields between the drift tube and ion funnel could supply sufficient center-of-mass kinetic energies to facilitate the C-C coupling process to form AuC2H4 +

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“…We have recently paid interest to the electron attachment reaction (EAR). − Low-energy electron attachment to some neutral molecules with high electron affinities generally leads to detectable parent anions . Studies on EARs in the literature were mainly focused on the electron attachment dissociation (EAD) reactions of some organic compounds (nitrobenzene, halogenated hydrocarbons) in condensed-phase materials. , Recently, we reported an exciting discovery that EAR ionization can realize the sensitive detection of gas-phase MGLY without fragmentation . Encouraged by this recent discovery and considering the higher electron affinity of GLY (1.10 ± 0.02 eV) compared to that of MGLY (0.87 ± 0.01 eV), we speculate that the EAR ionization method may also be used to detect GLY with high selectivity and high sensitivity.…”

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confidence: 99%

Sensitive Detection of Gas-Phase Glyoxal by Electron Attachment Reaction Ionization Mass Spectrometry

et al. 2019

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Glyoxal (GLY) acts as a key contributor to tropospheric ozone production and secondary organic aerosol (SOA) formation on local to regional scales. The detection of GLY provides useful indicators of fast photochemistry occurring in the lower troposphere. The fast and sensitive detection of GLY is thus important, while traditional chemical ionization such as the proton-transfer reaction (PTR) is extremely limited by the poor detection limit and extensive fragmentation. To address these limitations, electron attachment reaction (EAR) ionization was applied to detect GLY. The generation of parent anions (GLY–) without fragmentation was observed, and cryogenic photoelectron imaging spectroscopy further characterized the structure of GLY–. The detection limit was estimated to be as low as (52 ± 1) pptv (parts per trillion by volume) with 1 min measurements. Other components in ambient air, such as water, carbon dioxide, and trace gases (acetone, propanal, etc.) have no effect on the detection of GLY. The EAR ionization is more promising than PTR ionization in detecting GLY. The detection of GLY in ambient air by the EAR ionization has been demonstrated.

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Rate constants of electron attachment to alkyl iodides measured by photoionization electron attachment ion mobility spectrometry (PI-EA-IMS)

Cited by 6 publications

References 22 publications

Electron Attachment Reaction Ionization of Gas-Phase Methylglyoxal

Electron Attachment Reaction Ionization of Gas-Phase Methylglyoxal

C―C Coupling of Methane Mediated by Atomic Gold Cations under Multiple-Collision Conditions

Sensitive Detection of Gas-Phase Glyoxal by Electron Attachment Reaction Ionization Mass Spectrometry

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