Carbide Dihydrides: Carbonaceous Species Identified in Ta4+‐Mediated Methane Dehydrogenation

• Published in: Angewandte Chemie International Edition Vol. 59; no. 52; pp. 23631 - 23635
• Main Authors: Lengyel, Jozef, Levin, Nikita, Wensink, Frank J., Lushchikova, Olga V., Barnett, Robert N., Landman, Uzi, Heiz, Ueli, Bakker, Joost M., Tschurl, Martin
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 21-12-2020; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: Banded structure; bond activation; Carbides; Carbyne; Cations; Communication; Communications; Dehydrogenation; DFT calculations; Dihydrides; Hydrides; infrared spectroscopy; Intermediates; Metal ions; Metals; Methane; methane conversion; Quantum chemistry; Spectroscopy; Spectrum analysis; tantalum cluster
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202010794

The products of methane dehydrogenation by gas‐phase Ta4+ clusters are structurally characterized using infrared multiple photon dissociation (IRMPD) spectroscopy in conjunction with quantum chemical calculations. The obtained spectra of [4Ta,C,2H]+ reveal a dominance of vibrational bands of a H2Ta4C+ carbide dihydride structure over those indicative for a HTa4CH+ carbyne hydride one, as is unambiguously verified by studies employing various methane isotopologues. Because methane dehydrogenation by metal cations M+ typically leads to the formation of either MCH2+ carbene or HMCH+ carbyne hydride structures, the observation of a H2MC+ carbide dihydride structure implies that it is imperative to consider this often‐neglected class of carbonaceous intermediates in the reaction of metals with hydrocarbons.
Tantalum carbide dihydride cations are identified as products in the reaction of methane with gas‐phase Ta4+ clusters by IR spectroscopy, in conjunction with density‐functional theory calculations.