Spectroscopic Identification of the Carbyne Hydride Structure of the Dehydrogenation Product of Methane Activation by Osmium Cations
Spectroscopic Identification of the Carbyne Hydride Structure of the Dehydrogenation Product of Methane Activation by Osmium Cations
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DOI：
10.1007/s13361-018-1929-7
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发表时间：
2018-09-01
影响因子：
3.2
通讯作者：
Bakker, Joost M.
中科院分区：
文献类型：
--
作者：
Armentrout, P. B.;Kuijpers, Stach E. J.;Bakker, Joost M.
本研究探讨了5d过渡金属阳离子锇（Os+）对甲烷（CH4）和过氘甲烷（CD4）脱氢形成的物质结构。利用红外多光子解离（IRMPD）作用光谱和密度泛函理论（DFT），研究了[Os，C,2H]（+）和[Os，C,2D]（+）产物的结构。该研究补充了先前关于甲烷脱氢后由其他四种5d过渡金属阳离子（M+ = Ta+, W+， Ir+和Pt+）形成的相关物种的研究。锇阳离子在激光烧蚀源中形成，与脉冲进入下游反应通道的甲烷反应，并通过使用腔内实验自由电子激光器（FELICE）在300-1800 cm（-1）范围内的光破碎对所得产物进行光谱表征。通过H-2/D-2的损失监测光碎裂。将实验光谱与DFT计算光谱进行比较，可以确定基态碳氢化物HOsCH+ （(2)A’）为形成的物质，这与先前的理论假设一致。此外，对这些配合物的氘标记所观察到的系统光谱位移进行了全面描述，这些配合物是使用IRMPD作用光谱研究的一些最小的系统。完整的旋转轮廓分析解释了观测到的线宽以及在几个波段观测到的双重结构，与先前对HIrCH+ ((2)A')的观测结果一致。
The present work explores the structures of species formed by dehydrogenation of methane (CH4) and perdeuterated methane (CD4) by the 5d transition metal cation osmium (Os+). Using infrared multiple photon dissociation (IRMPD) action spectroscopy and density functional theory (DFT), the structures of the [Os,C,2H](+) and [Os,C,2D](+) products are explored. This study complements previous work on the related species formed by dehydrogenation of methane by four other 5d transition metal cations (M+ = Ta+, W+, Ir+, and Pt+). Osmium cations are formed in a laser ablation source, react with methane pulsed into a reaction channel downstream, and the resulting products spectroscopically characterized through photofragmentation using the Free-Electron Laser for IntraCavity Experiments (FELICE) in the 300-1800 cm(-1) range. Photofragmentation was monitored by the loss of H-2/D-2. Comparison of the experimental spectra and DFT calculated spectra leads to identification of the ground state carbyne hydride, HOsCH+ ((2)A') as the species formed, as previously postulated theoretically. Further, a full description of the systematic spectroscopic shifts observed for deuterium labeling of these complexes, some of the smallest systems to be studied using IRMPD action spectroscopy, is achieved. A full rotational contour analysis explains the observed linewidths as well as the observation of doublet structures in several bands, consistent with previous observations for HIrCH+ ((2)A').