Carbide Dihydrides: Carbonaceous Species Identified in Ta(4) (+)‐Mediated Methane Dehydrogenation

The products of methane dehydrogenation by gas‐phase Ta(4) (+) 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 H(2)Ta(4)C(+) carbide dihydride structure over those indicative for a HTa(4)CH(+) 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 MCH(2) (+) carbene or HMCH(+) carbyne hydride structures, the observation of a H(2)MC(+) carbide dihydride structure implies that it is imperative to consider this often‐neglected class of carbonaceous intermediates in the reaction of metals with hydrocarbons.