Anion Photoelectron Imaging Spectroscopy of C 6 HF 5 – , C 6 F 6 – , and the Absence of C 6 H 2 F 4 –
Anion Photoelectron Imaging Spectroscopy of C 6 HF 5 – , C 6 F 6 – , and the Absence of C 6 H 2 F 4 –
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C 6 HF 5 α、C 6 F 6 α 和不存在的 C 6 H 2 F 4 α 的阴离子光电子成像光谱
DOI：
10.1021/acs.jpca.3c04016
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Jarrold, Caroline Chick
中科院分区：
文献类型：
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作者：
McGee, Conor J.;McGinnis, Kristen Rose;Jarrold, Caroline Chick
取代基对苯分子的电子结构有深远的影响。在本文中，我们提出了新的C5HF5-分子阴离子的光电子能谱，以验证[Int.J·昆特。化学2017,188，e25504]五氟苯具有正电子亲和力，正如六氟苯已知的那样。由于阴离子和中性离子结构的显著不同，C6HF5-的PE谱显示出一个宽的振动未分辨的带。测得C5HF5-的垂直剥离能(VDE)为1.33±0.05 eV，观察到该信号的最低结合能为0.53±0.05 eV，如果以此作为电子亲和势，则与计算值吻合较好。此外，我们尝试使用1，2，3，4-四氟苯、1，2，3，5-四氟苯和1，2，4，5-四氟苯的前体生成完整的C6H2F4-分子离子，因为四氟苯被预测具有几乎为零的电子亲和力。使用光电负离子源，我们不能产生完整的四氟苯阴离子。密度泛函理论计算支持更详细地讨论氟取代对这些物种的电子结构的影响。
Substituents have a profound effect on the electronic structure of the benzene molecule. In this paper, we present new photoelectron spectra of the C5HF5–molecular anion, to test predictions [Int. J. Quant. Chem.2017, 188, e25504] that pentafluorobenzene has a positive electron affinity, as hexafluorobenzene was already known to have. The PE spectrum of C6HF5–exhibits a broad and vibrationally unresolved band due to significant differences between the structure of the anion and the neutral. The vertical detachment energy (VDE) of C5HF5–is determined to be 1.33 ± 0.05 eV, and the lowest binding energy at which the signal is observed is 0.53 ± 0.05 eV, which, if taken as the electron affinity, is in good agreement with the computed value. In addition, we attempted to generate intact C6H2F4–molecular ions using the 1,2,3,4-tetrafluorobenzene, 1,2,3,5-tetrafluorobenzene, and 1,2,4,5-tetrafluorobenzene precursors, as tetrafluorobenzene was predicted to have a near-zero but marginally positive electron affinity. Using a photoemission anion source, we were not able to produce the intact tetrafluorobenzene anion. Density functional theory calculations support a more detailed discussion of the impact of fluorine substitution on the electronic structure of these species.