title: Infrared spectra of metallacyclopropane, insertion, and dihydrido complex products in reactions of laser-ablated group 6 metal atoms with ethylene molecules.
abstract: Reactions of laser-ablated group 6 metal atoms with ethylene have been investigated. The insertion and dihydrido products (MH-CHCH(2) and MH(2)-C(2)H(2)) are identified from reactions of W and Mo with ethylene isotopomers, whereas products in the Cr spectra are assigned to the insertion and metallacyclopropane (M-C(2)H(4)) complexes. Our experiments with CH(2)CD(2) show that the dihydrido complex is formed by beta-hydrogen transfer in the insertion complex because the MHD-CHCD isotopic product is favored. The present matrix infrared spectra and DFT computational results support the general trend that the higher oxidation-state complexes become more stable on going down the group 6 column. Unlike the cases of group 4 and 5 metals, binary metal hydride (MH(x)) absorptions are not observed in the infrared spectra, suggesting that the H(2)-elimination reactions of ethylene by group 6 metals are relatively slow, consistent with previous gas-phase reaction dynamics studies.
authors.affiliation: Department of Chemistry, University of Incheon, 177 Dohwa-dong, Nam-ku, Incheon 402-749, South Korea.
authors.forename: Han-Gook
authors.initials: HG
authors.lastname: Cho
authors.forename: Lester
authors.initials: L
authors.lastname: Andrews