EQUILIBRIUM STUDIES OF WEAKLY-BOUND FE(L)(-2 AND CH4() COMPLEXES WITHL = XE, CO2, N)

The binding energies of Xe, N-2, CO2 and CH4 to the Fe+ cation have be en studied by equilibrium measurements using Fourier-transform mass sp ectrometry. Reacting mass-selected Fe(CO2)(+) with the mixtures N-2/CH 4, CO2/CH4, CO2/Xe, CO2/N-2 and Xe/N-2 provides an internally consiste nt set of equilibrium constants and free energies Delta Delta G (298 K ). Consideration of B3LYP calculated thermal corrections suggests Fe+- Xe < Fe+-CO2 < Fe+-N-2 < Fe+-CH4 for the 0 K bond dissociation energie s. Using the literature value for D-0(Fe+-CH4) as an anchor point, D-0 (Fe+-Xe) = 11.7 +/- 1.5, D-0(Fe+-CO2) = 13.0 +/- 1.3 and D-0(Fe+-N-2) = 13.4 +/- 1.1 kcal/mol are obtained. (C) 1997 Elsevier Science B.V.