Armentrout P B, Kuijpers Stach E J, Lushchikova Olga V, Hightower Randy L, Boles Georgia C, Bakker Joost M
Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, UT, 84112, USA.
Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED, Nijmegen, The Netherlands.
J Am Soc Mass Spectrom. 2018 Sep;29(9):1781-1790. doi: 10.1007/s13361-018-1929-7. Epub 2018 Apr 9.
The present work explores the structures of species formed by dehydrogenation of methane (CH) and perdeuterated methane (CD) 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 range. Photofragmentation was monitored by the loss of H/D. Comparison of the experimental spectra and DFT calculated spectra leads to identification of the ground state carbyne hydride, HOsCH (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 (A'). Graphical Abstract ᅟ.
本工作探索了由5d过渡金属阳离子锇（Os）使甲烷（CH）和全氘代甲烷（CD）脱氢形成的物种的结构。利用红外多光子解离（IRMPD）作用光谱和密度泛函理论（DFT），对[Os,C,2H]和[Os,C,2D]产物的结构进行了探索。本研究补充了先前关于由其他四种5d过渡金属阳离子（M = Ta、W、Ir和Pt）使甲烷脱氢形成的相关物种的工作。锇阳离子在激光烧蚀源中形成，与脉冲注入下游反应通道的甲烷发生反应，然后使用腔内实验自由电子激光（FELICE）在300 - 1800 cm范围内通过光解离对所得产物进行光谱表征。通过H/D的损失监测光解离。实验光谱与DFT计算光谱的比较导致确定基态卡宾氢化物HOsCH（A'）为所形成的物种，正如先前理论推测的那样。此外，还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体系。完整的转动轮廓分析解释了观察到的线宽以及几个谱带中双重峰结构的观测结果，这与先前对HIrCH（A'）的观测结果一致。图形摘要ᅟ。
