Master of Science
Prof. Joe B. Gilroy
Phosphadiazonium cations capture the essence of phosphorus mononitride (P≡N), an extremely reactive molecule, as these compounds contain a P≡N moiety stabilized by a bulky aryl group. However, since being synthesized in the late 1980s by Niecke et al. their chemistry has remained a relatively niche field. Burford et al. reacted phosphadiazonium cations with nitrogen-centred Lewis bases to create a wide variety of interesting adducts ([L-PNMes*][OTf]). This thesis builds on the previous work and is focused on applying phosphadiazonium cations in nitrogen-based heterocycle materials chemistry. Reacting these compounds with chelating hydrazone ligands provides an interesting avenue for growth in this niche sector of materials chemistry and provides foundational work that can be built on moving forward. The novel pnictogen-rich heterocycles presented in this thesis display an interesting bonding arrangement studied through NMR spectroscopy, UV-Vis spectroscopy and using density-functional theory.
Summary for Lay Audience
Atoms make up all life around us. They are found in various forms, from individual atoms to long chains, sometimes known as polymers and rings, also called cycles. Some of these atoms can combine to form rings more easily than others, depending on how they interact. Nitrogen is commonly applied to heterocycles, rings containing at least one non-carbon atom, to modify the properties of these cycles in desired ways. Phosphorus based heterocycles are far less common. Combining phosphorus and nitrogen in heterocycles is even more rare. Phosphorus mononitride is an unstable molecule consisting of just two atoms, phosphorus and nitrogen. The essence of this molecule can be captured by adding a bulky support group of atoms to prevent unwanted interactions. These species are referred to as phosphadiazonium cations. This thesis uses these rare phosphadiazonium species and inserts it into a supporting structure consisting of nitrogens and carbons to create novel examples of phosphorus containing heterocycles.
Milkovich, Shaun K., "Application of Phosphadiazonium Cations in Nitrogen-based Heterocycle Chemistry" (2023). Electronic Thesis and Dissertation Repository. 9762.
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