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Author ORCID Identifier

https://orcid.org/0000-0001-5680-7995

AccessType

Open Access Dissertation

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Chemistry

Year Degree Awarded

2024

Month Degree Awarded

February

First Advisor

Igor Kaltashov

Subject Categories

Analytical Chemistry | Biochemistry | Inorganic Chemistry

Abstract

Polyoxometalates (POMs) are a class of inorganic molecule of increasing interest to the inorganic, bioinorganic and catalytic communities among many others. While their prevalence in research has increased, tools and methodologies for the analysis of their fundamental characteristics still need further development. Decavanadate (V10) specifically has been postulated to have several unique properties that have not been confirmed independently. Mass spectrometry (MS) and its ability to determine the composition of solution phase species by both mass and charge is uniquely well suited to the analysis of POMs. In this work we utilized high-resolution mass spectrometry to characterize V10 in aqueous solution. We were able to observe a unique loss of water fragmentation pathway and prove the existence of partially reduced V10 species in solution. Due to the high negative charge of the V10 complex, it was also investigated as an analogue to heparin sulfate which has been shown to disrupt the infectivity cycle of SARS-CoV-2. Native mass spectrometry was used to demonstrate the ability of V10 to bind to the receptor binding domain of the spike protein. Additionally, the ability to disrupt the formation of a complex between the receptor binding domain (RBD) of the spike protein and the ectodomain of the angiotensin-converting enzyme 2 (ACE2) receptor was likewise investigated using native MS. This mechanism of action against SARS-CoV-2 was confirmed with cell viability studies. Further investigation of the solution phase dynamics of V10 was carried out by performing an oxygen exchange experiment coupled with high resolution mass spectrometry. The resulting exchange profiles revealed the existence of multiple populations of V10, including novel metastable conformations of V10. Further analysis of the oxygen exchange data yielded kinetic information about these metastable states and their role in the solution phase dynamics of V10. Finally, we also demonstrated the utility of bulk electrolysis in the synthesis of POV nanocages with unique ratios of reduced VIV centers. MS analysis of the species showed that the VO4 centered nanocage V19O46 is a precursor to the more stable chloride centered V15O36Cl which was shown to have unique solution phase dynamics upon subsequent oxygen exchange analysis. The work presented demonstrates the utility of mass spectrometry and isotopic exchange in the analysis of POMs.

DOI

https://doi.org/10.7275/36463505

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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