Which Electronic State Is Involved in the Activation of CH- and CC-Bonds of 4-Octyne by Bare Chromium Ions?

Abstract

In previous work we reported the unexpectedly rich gas-phase chemistry of complexes of Cr^⊕ with 4-octyne. Results, based on high-resolution translational energy loss spectroscopy (HRTELS) and charge stripping mass spectrometry (CSMS), are now presented which prove that Cr^⊕ generated by electron impact ionization of [Cr(CH₃COCH₂COCH₃)₃] corresponds to the ground state of Cr^⊕(3d⁵, a⁶S). It is also demonstrated that Cr^⊕-induced CH- and CC-bond activations, followed by reductive eliminations of H₂, CH₄ and C₂H₄, are truly unimolecular reactions with practically no collision-induced contributions.