Sequential bond energies of Fe+(CO2)n, n=1-5, determined by threshold collision-induced dissociation and ab initio theory

Collision-induced dissociation of the Fe+(CO2), complexes for n = 1-5 is studied using kinetic energy dependent guided ion beam mass spectrometry. In all cases, the primary products are endothermic loss of an intact neutral ligand from the complex. The cross section thresholds are interpreted to yield 0 K bond energies after accounting for the effects of multiple ion-molecule collisions, internal energy of the complexes, and unimolecular decay rates. These values are compared with density functional theoretical values for all five complexes. Theory provides bond energies in reasonable agreement with experiment for n = 1-4 and predictions for the infrared spectroscopy of these complexes that agree nicely with experimental results of Gregoire and Duncan (J. Chem. Phys. 2002, 117, 2120). Our thermochemical results are also compared with the Fe+(CO)(n) and Fe+(N-2)(n) complexes, previously studied.