Hydrogen Elimination from Ethylene by Laser-Ablated Zr Atoms: An Infrared Spectroscopic Investigation of the Reaction Intermediates in a Solid Argon Matrix

Intermediates of the hydrogen elimination reaction of ethylene by laser-ablated Zr atoms have been isolated in an argon matrix and investigated by means of infrared spectroscopy. The strong absorptions in the region of 1500−1660 cm -1 are due to the Zr−H stretching modes of several intermediates. There are at least three different groups of product absorptions based on the behaviors upon broad-band photolysis and annealing. Among them, the insertion and dihydrido complexes, presumed in previous studies of the hydrogen elimination of ethylene by Zr atoms, are identified. In addition, the remaining Zr−H stretching absorptions, along with absorptions in the C⋮C stretching and other regions, suggest that ethynyl zirconium trihydride is also formed in the hydrogen elimination reaction. Formation of this compound is consistent with the fact that C 2 H 2 and C 2 D 2 as well as CHCD are produced in the reaction of Zr + CH 2 CD 2 . Density functional theory calculations for the reaction intermediates are also carried out, and the molecular properties and vibrational characteristics are compared with the experimental values.