GAS-PHASE CHEMISTRY OF BARE TRANSITION-METAL IONS IN COMPARISON

Some basic principles of gas-phase organometallic chemistry are demonstrated, exemplified for the model compound 2-methylbutanenitrile (5). The reactions of first-row transition-metal ions with 5 and its deuterated isotopomers 5a-5c reveal a distinct influence of the individual metal ion on the chemistry in these systems. While “early” transition-metal ions (Ti+, V+) mainly give rise to dehydrogenations, the activation of C-C bonds dominates for Fe+. Closed d-shell ions (Cu+, Zn+) react under intermediate formation of ion/dipole complexes, and Co+ and Ni+ show inasmuch a “mixed” behavior, as many similarities to Fe+ are noticed. However, part of the products are already formed via ion/dipole complexes. A clear trend is observed, going from Fe+ to Cu+ in that respect. Cr+ is found to be unreactive as reported before in many other cases. The results were obtained by the combined use of ion/molecule reactions performed in a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer and metastable ion decompositions of adduct complexes, generated in the ion source of a triple-sector instrument. © 1990, American Chemical Society. All rights reserved.