Intrinsic Gas-Phase Behavior of Uranium Species: A Comprehensive Reactivity Study of [O=U≡CH]+ and [UH]+

Author

Justin TerhorstFollow

Defense Date

11-20-2024

Graduation Date

Fall 12-20-2024

Availability

Immediate Access

Submission Type

dissertation

Degree Name

PhD

Department

Chemistry and Biochemistry

School

School of Science and Engineering

Committee Chair

Michael van Stipdonk, PhD

Committee Member

Paul Lummis, PhD

Committee Member

Stephanie Wetzel, PhD

Committee Member

Victor Ryzhov, PhD

Keywords

Mass spectrometry, Ion trap, Organometallics, Organouranium, Uranium Halide, Hydride

Abstract

The intrinsic chemistry of actinide elements, particularly uranium, remains a key challenge in understanding f-block reactivity due to the complexity introduced by solvent interactions, counter-ions, and complex equilibria in the condensed phase. In this dissertation, a systematic gas-phase study utilizing preparative tandem ion-trap mass spectrometry (PTMSⁿ) is presented, focusing on the reactivity of uranium-centered species, specifically [OUCH]⁺, an oxy uranium methylidyne species, and [UH]⁺ ions. By stripping away solvent effects and isolating the ions, PTMSⁿ provides a powerful platform to probe the fundamental chemical behavior of uranium species in their intrinsic state.

The use of ion-trap technology allows for controlled interaction of trapped ions with neutral molecules, enabling the observation of both exergonic and endergonic reactions. The controlled environment of the ion trap affords the opportunity to carefully study uranium chemistry in the absence of competing influences. [OUCH]⁺ and [UH]⁺ ions are explored in depth, where their ability to activate neutral reagents like halogenated alkanes and nitriles are tested. This work features the gas-phase formation of novel species such as [OUX]⁺, [UX_n]⁺, [UHX]⁺ (X = Cl, Br, I), [OUR]⁺, and [UR]⁺ (R = CH, CH₂, CH₃, CH₂CH₃, CH₂CH₂CH₃, CHCH₂, C₆H₅) through reactions with a variety of molecules. This suite of experiments provides insights into periodic trends, uranium halide and alkyl bonding, and the factors that govern uranium-ligand interactions like the inverse trans influence in the gas phase.

In addition to experimental efforts, computational methods, including Density Functional Theory (DFT), complement the findings, providing detailed mechanistic insights into the observed products. The combination of experimental and theoretical approaches not only validates the results but also elucidates the pathways by which uranium ions interact with neutral reagents.

This dissertation details an array of methodologies applied to interrogate the structure, composition, and reactivity of uranium species. Techniques such as isotopic substitution for compositional insight, reaction monitoring to observe spontaneous ion molecule reactions, and collisional activation are employed. These tools allow for the dissection of uranium's chemical behavior in the gas phase, providing clarity on its fundamental properties.

The findings from this research contribute to advancing our understanding of uranium’s role in periodic trends, ion-molecule reactions, and actinide-ligand chemistry. Furthermore, this work lays the foundation for future studies involving more complex uranium-containing systems and expands the utility of PTMSⁿ for probing the chemistry of other heavy elements. By bridging experimental and computational chemistry, this dissertation offers a robust framework for studying gas-phase actinide chemistry, helping to demystify the intrinsic properties of uranium ions.

Language

English

Recommended Citation

Terhorst, J. (2024). Intrinsic Gas-Phase Behavior of Uranium Species: A Comprehensive Reactivity Study of [O=U≡CH]+ and [UH]+ (Doctoral dissertation, Duquesne University). Retrieved from https://dsc.duq.edu/etd/2280

Additional Citations

Terhorst, J. G.; Corcovilos, T. A.; van Stipdonk, M. J. Conversion of a UO22+ Precursor to UH+ and U+ Using Tandem Mass Spectrometry to Remove Both “yl” Oxo Ligands. Journal of the American Society for Mass Spectrometry 2023, 34 (11), 2439–2442. https://doi.org/10.1021/jasms.3c00260.

Terhorst, J.; Lenze, S.; Metzler, L.; Fry, A. N.; Ihabi, A.; Corcovilos, T. A.; van Stipdonk, M. J. Gas-Phase Synthesis of [O=U-X]+ (X = Cl, Br and I) from a UO22+ Precursor Using Ion-Molecule Reactions and an [OUCH]+ Intermediate. Dalton Transactions 2024, 53 (12), 5478–5483. https://doi.org/10.1039/d3dt02811a.

Terhorst, J. G.; Corcovilos, T. A.; Lenze, S. J.; van Stipdonk, M. J. Synthesis of Organo-Uranium(II) Species in the Gas-Phase Using Reactions between [UH]+ and Nitriles. Dalton Transactions 2024. https://doi.org/10.1039/d4dt02508c.