Mechanistic and Thermochemical Studies of the Reactions of Transition Metal Ions and Uranium Ions with Small Molecules in the Gas Phase

Citation

Armentrout, Peter Bruce (1980) Mechanistic and Thermochemical Studies of the Reactions of Transition Metal Ions and Uranium Ions with Small Molecules in the Gas Phase. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/bcv3-5t71. https://resolver.caltech.edu/CaltechTHESIS:11192024-230500054

Abstract

An ion beam apparatus is employed to study the reactions of metal ions with small molecules. The experiments yield reaction cross sections as a function of ion kinetic energy. Simple models are developed in Chapters IV and VI to interpret the energy dependent cross sections for endothermic reactions. Analysis of reaction thresholds using these models yields thermochemical data of interest. Chapter I is a brief introduction to these topics.

Chapter II describes the reactions of U⁺ and UO⁺ with O₂, CO, CO₂, COS, CS₂ and D₂O. Results are in good accord with literature thermochemistry except for the exothermic reactions of UO⁺ with CO₂ and COS to yield UO⁺₂ where an energy barrier is observed. In Chapter III, the collision induced dissociation of UO⁺ and UO⁺₂ impacting on Ar is studied.

Chapters IV, V and VIII report experiments of metal ions, Ba⁺ Ni⁺ and Co⁺, respectively, reacting with hydrogen. Interpretation of reaction thresholds for production of the metal hydride yields metal hydrogen bond energies. A large energy dependent isotope effect is observed in the reaction of Ni⁺ with HD (Chapter V).

In Chapters VI-VIII, results for reactions of Co⁺ with organic molecules are presented. Chapter VI concerns the formation of CoCH⁺₂ by reaction of Co⁺ with ethene, cyclopropane and ethylene oxide. The bond energy of the cobalt carbene ion is derived. Chapters VII and VIII discuss the reactions of Co⁺ with alkanes. The emphasis in Chapter VII is the ion beam instrument as a probe of the potential energy surface of complex organometallic reactions. Chapter VIII is a comprehensive thermochemical and mechanistic study of the interactions of Co⁺ with saturated hydrocarbons. Several bond energies between Co⁺ and hydrocarbons are derived and a general mechanism for the reactions proposed.

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