Investigations of the Mechanisms and Energetics for Transition Metal Ion Mediated Reactions

Citation

Hanratty, Maureen Alice (1985) Investigations of the Mechanisms and Energetics for Transition Metal Ion Mediated Reactions. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/6mqm-3w23. https://resolver.caltech.edu/CaltechTHESIS:02012019-115455977

Abstract

Multiphoton infrared activation has been used to probe the potential energy surfaces for the reactions of stable Co(C₅H₁₀)⁺ adducts, formed by ligand exchange reactions in an ion cyclotron resonance spectrometer. These investigations are discussed in Chapter II. Infrared activation effected with a cw CO₂ laser is highly selective, with dissociation occurring only by the lowest energy pathway.

Chapter III describes the use of product translational energy release distributions to investigate the potential energy surfaces for elimination of H₂ and small hydrocarbons from ionic cobalt and nickel complexes with alkanes. The measurements were made using a reverse geometry double focusing mass spectrometer. For dehydrogenation reactions, both the shape of the kinetic energy release distribution and the maximum kinetic energy release appear to be correlated with the reaction mechanism. Statistical RRKM theory is used to model the observed kinetic energy release distributions.

The kinetic energy release distributions associated with loss of H₂ and small hydrocarbons from Co(C₅H₁₀)⁺ complexes are presented in Chapter IV. The results from the ionic cobalt-alkene adducts are compared with the kinetic energy release distributions for the ionic cobalt-alkane complexes discussed in Chapter III. Collision induced dissociation is also employed to characterize the Co(C₅H₁₀)⁺ adducts.

The formation and reactions of iron and nickel clusters containing up to four metal atoms with a varying number of CO ligands are discussed in Chapter V. Ion-molecule condensation reactions result in the rapid formation of polynuclear metal carbonyl clusters which lose CO when exposed to infrared or visible radiation. The reactivity of these ligated species is markedly different from that of the bare metal ion. The potential of this method for generating very specific unsaturated cluster compounds is demonstrated.

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