Spectroscopic Identification of the Carbyne Hydride Structure of the Dehydrogenation Product of Methane Activation by Osmium Cations

• Published in: Journal of the American Society for Mass Spectrometry 2018-09, Vol.29 (9), p.1781-1790
• Main Authors: Armentrout, P. B., Kuijpers, Stach E. J., Lushchikova, Olga V., Hightower, Randy L., Boles, Georgia C., Bakker, Joost M.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Banded structure; Bioinformatics; Biotechnology; Carbyne; Cations; Chemistry; Chemistry and Materials Science; Dehydrogenation; Density functional theory; Deuterium; Focus: Application of Photons and Radicals for MS: Research Article; Hydrides; Laser ablation; Mass spectrometry; Metal ions; Methane; Organic Chemistry; Osmium; Proteomics; Rotational spectra; Spectrum analysis; Tantalum
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1007/s13361-018-1929-7

The present work explores the structures of species formed by dehydrogenation of methane (CH 4 ) and perdeuterated methane (CD 4 ) 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′). Graphical Abstract ᅟ