Transition-Metal Ethene Bonds: Thermochemistry of M+(C2H4)n(M = Ti−Cu,n= 1 and 2) Complexes

Abstract

Complexes of the first-row transition-metal cations (Ti+−Cu+) with one and two ethene molecules are studied by guided ion beam mass spectrometry. Thermalized complexes are formed in a flow tube source and examined by energy-resolved collision-induced dissociation with Xe. The energy dependence of the CID cross sections is analyzed with consideration of multiple collisions, internal energy of the reactants, and lifetime effects. First, D0(M+−C2H4), and second, D0(C2H4M+−C2H4), adiabatic metal ion ethene bond energies, in eV, obtained in this study are 1.51 ± 0.11 for Ti (first bond only), 1.29 ± 0.08 and 1.32 ± 0.14 for V, 0.99 ± 0.11 and 1.12 ± 0.11 for Cr, 0.94 ± 0.12 and 0.91 ± 0.15 for Mn, 1.50 ± 0.11 and 1.57 ± 0.16 for Fe, 1.93 ± 0.09 and 1.58 ± 0.14 for Co, 1.89 ± 0.11 and 1.79 ± 0.15 for Ni, and 1.82 ± 0.14 and 1.80 ± 0.13 for Cu, respectively. These values include corrections for diabatic dissociation in the cases of Fe+(C2H4) and Mn+(C2H4)2, a point that is discussed in detail. Previous work obta...