THE GAS-PHASE CHEMISTRY OF FE+ WITH NORMAL-PENTANENITRILE - A SEEMINGLY SIMPLE SYSTEM

The reactions of gas-phase Fe+ with n-pentanenitrile and several deuterium-labeled isotopomers have been studied together with low-energy collision-induced dissociation (CID) of Fe(C4H9CN)+ complexes, employing Fourier transform ion cyclotron resonance (FTICR) spectrometry. While loss of H-2 is due to remote functionalization, ethylene is produced from internal positions, generating CH3-Fe+-CH2CN, an isomer of Fe(CH3CH2CN)+. Loss of propene is also observed in low abundance, producing an iron-acetonitrile complex. All three processes are in competition with the formation of the ferracyclobutane complex Fe(CH3)(CN)CH2CH2CH2+, which, upon reopening, brings about equilibration of the alpha and (omega - 1) positions, thus affording a specific, degenerate isomerization of the Fe(C4H9CN)+ collision complex. Collision-induced dissociation experiments with isotopomeric reaction products were performed, which provided structural information and revealed the positions of the deuterium atoms after the degenerate isomerization.