Bimolecular Reactions of the Chromium-Benzyne Ion Cr+-C6H4 in the Gas Phase

An FT-ICR Study

verfasst von
Doris Wittneben, Hans Friedrich Grützmacher, Holger Butenschön, Hans Günther Wey
Abstract

The chromium-benzyne ion Cr+-C6H4 was generated in the gas phase by electron-impact-induced loss of 5 CO from (η6-1,2-dioxocyclobutabenzene)tricarbonylchromium(0). The gas-phase reactions of the Cr+-C6H4 ions with methanol, ammonia, several alkanes, alkadienes, and aromatic species were studied by Fourier transform ion cyclotron resonance spectrometry (FT-ICR) using an external ion source. The results show that the bimolecular reactivity of the Cr+-C6H4 cations is determined by the C6H4 ligand, exhibiting the high reactivity of benzyne. No reactions due to a primary reaction at Cr+ are discovered. In most of the reactions, the main product observed for the bimolecular reaction is Cr+ released from the complex by the great exothermicity of the reaction at the C6H4 ligand. However, in the case of less exothermic reactions and if the excess energy is removed from the reaction complex by “evaporating” a neutral leaving group, Cr+ complexes are observed whose ligands arise from addition reactions of the reactants to C6H4. This is the case for cycloadditions of benzene-d5 and naphthalene-d8 to Cr+-C6H4, where the adducts still containing Cr+ as well as ions formed by loss of acetylene-d2 from the adducts are observed. Thus, in the family of transition-metal-cation-benzyne complexes, the Cr+-C6H4 cation is extraordinary in exhibiting reactivity exclusively at the benzyne ligand.

Externe Organisation(en)
Max-Planck-Institut für Kohlenforschung
Universität Bielefeld
Typ
Artikel
Journal
ORGANOMETALLICS
Band
11
Seiten
3111-3116
Anzahl der Seiten
6
ISSN
0276-7333
Publikationsdatum
01.09.1992
Publikationsstatus
Veröffentlicht
Peer-reviewed
Ja
ASJC Scopus Sachgebiete
Physikalische und Theoretische Chemie, Organische Chemie, Anorganische Chemie
Elektronische Version(en)
https://doi.org/10.1021/om00045a028 (Zugang: Unbekannt)