Reactions of Fe+ and Fe(olefin)+ Complexes with Alkenes in the Gas Phase Using Fourier Transform Mass Spectrometry

Article abstract of DOI:10.1021/ja00364a002

Fourier transform mass spectrometry (FTMS) is used to study the reactions of laser desorbed Fe⁺ ions with 21 olefins ranging from C2H4 to C6H12 isomers.Ethene, propene, and isobutene only undergo a slow condensation reaction with Fe⁺, while all of the other olefins studied react rapidly with Fe⁺ eliminating H2, small alkanes, or small olefins generating alkene and alkadiene metal ion products.In addition to primary reactions, secondary, tertiary and quaternary reactions were studied using swept double resonance ejection techniques.Metal-alkadiene products were observed to abstract carbene from olefins, probably via a metallacyclobutane intermediate, with facile incorporation of the abstracted carbene into the alkadiene framework.With the larger olefins, C-C bond cleavage products dominate the primary reactions while dehydrogenation products are dominant in subsequent reactions.Structures of selected product ions are probed by using collision-induced dissociation (CID).A comparison is made between the CID products of stable Fe(olefin)⁺ complexes and products resulting from the ion-molecule reactions of Fe⁺ with the corresponding olefin.Striking differences are observed and discussed.