Studies of the Reactions of Group 8 Transition-Metal Ions Fe+, Co+, and Ni+ with Linear Alkanes. Determination of Reaction Mechanisms and MCnH2n+ Ion Structures Using Fourier Transform Mass Spectrometry Collision-Induced Dissociation

Article abstract of DOI:10.1021/ja00354a003

With use of Fourier transform mass spectrometry, the ion products resulting from the reactions of the group 8 transition-metal ions Fe⁺, Co⁺, and Ni⁺ with a variety of hydrocarbons were studied by both collision-induced dissociation and specific ion-molecule reactions.Evidence is provided for four unique MC4H8⁺ structures.All three metal ions dehydrogenate linear alkanes larger than propane via initial insertion into C-C bonds resulting in the formation of bis(olefin)-metal ion complexes.In addition, Fe⁺ also dehydrogenates linear alkanes via initial insertion into C-H bonds, producing an olefin-metal ion complex. β-Hydride transfers are more facile for Co⁺ than either Fe⁺ or Ni⁺.Secondary β-hydride transfers are more facile than primary β-hydride transfers for both Co⁺ and Ni⁺; however, the reverse is observed for Fe⁺.Both Co⁺ and Ni⁺ are highly selective against insertion into terminal C-C bonds, with Fe⁺ showing considerably less selectivity.Formation of MC4H6⁺ ions from linear alkanes larger than butane occurs via initial alkane loss producing a metal ion-butene complex followed by dehydrogenation.