Doctor of Philosophy
Blacquiere, Johanna M.
Ragogna, Paul J.
The purification of contaminated wastewater effluent is an increasingly important aspect of sustainable chemistry. Several types of materials have been generated that can aid in the purification or removal of contaminants from aqueous or organic systems. By exploiting the chemistry of primary phosphines in the hydrophosphorylation reaction, we generated novel bis-α-aminophosphine chalcogenides as nitrogen, phosphorus, and chalcogen (O, S) -rich molecules. This novel methodology was investigated in-depth through mechanistic studies that included kinetic isotope effect (KIE), Hammett analysis, and trapping experiments. The functional group tolerance of the reaction was also investigated, and subsequently resulted in the formation of a small family of bis-α-aminophosphine chalcogenides, which were comprehensively characterized including the solid-state structure. Applying the reaction methodology to diimine containing compounds results in the formation of linear poly(α-aminophosphine) chalcogenides as heteroatom-rich polymers. Comprehensive characterization was conducted using various spectroscopic and thermal methods. The depolymerization of the afforded poly(α-aminophosphine) chalcogenides was investigated using reducing conditions and gratifyingly the quantitative depolymerization was observed. Addition of a cross-linker in the form of a tri-imine resulted in the formation of poly(α-aminophosphine) chalcogenide networks that showed swelling characteristics. The networks were probed in UO22+ sequestration studies and ultimately displayed promising uptake of UO22+ cations.
Summary for Lay Audience
Polymers are all around us, most often in the form of plastics. We aimed to design a special polymer that can bind to toxic metals present in water. Having a polymer that binds to a metal allows small amounts of highly toxic elements to be more easily filtered from solution. In order to better understand how to develop the polymer, small molecule models were built and tested for metal binding capacity. Insight of the reaction mechanism used to make the polymer was gained by tracking the model reaction in real time, which in turn allowed for easier testing when forming the material. After showing that we were able to conduct the reaction to make small molecule models, we applied the reaction to form both 2-dimensional (2D) and 3-dimensional (3D) polymers. Both the 2D and 3D polymers have very different physical features. Considering the impact of plastics on the environment, we then sought to develop a way to de-polymerize the new polymers. This was used as a method for retrieving some of the materials originally used to make the polymer. Following the polymerization process, we began exploring how well the polymers can remove toxic metals from solutions. We were able to successfully remove uranium from an organic solution.
Lamberink, Jan-Willem, "Hydrophosphorylation of Imines: Synthetic Methodology for the Synthesis of Small Molecules and Materials." (2023). Electronic Thesis and Dissertation Repository. 9670.
Available for download on Tuesday, December 31, 2024