Exploring the behaviour and catalytic properties of cyclen derived DO3A triamide derivatives

Thesis

Catalysts have played, and will continue to serve, a vital role in an increasing range of processes. While the role of lanthanides in catalysis is well known, the development of homogenous water-soluble lanthanide-containing catalysts is relatively understudied and includes various desirable properties.

Chapter-1 introduces lanthanide chemistry, covering their coordinative abilities, photophysics, definitions of stability and local magnetic fields. Including a description of their current catalytic uses.

Chapter-2 focuses on the study of Ln.p.DO3A (Ln=Eu, Tb) complexes as a prototype system. These systems are shown to catalyse the fluorination of halocarboxylicacid substrates, via a proposed ternary complex.

Chapter-3 details the synthesis of DO3AM derivatives, conceived to favour binding of fluoride and carboxylic acids. A number of synthetic routes to these systems were explored, and it was found that amide coupling of DO3A free acids offered the best combination of yield and synthetic flexibility.

Chapter-4 focuses on luminescence measurements of the eight DO3AM-derived complexes synthesised in chapter-3, and on the binding of fluoride and carboxylate guests.The affinity of these complexes for anionic guests was found to be dependent on the nature of the amide side chains, which provide structural rigidity and influence solubility. Quantification of binding with anionic guests using DynaFit® and measurement of luminescence lifetimes was used to select three complexes which resist self-aggregation and display significant affinity for carboxylates and fluoride.

Chapter-5 explores the use of these three candidate complexes in the fluorination of halocarboxylic acid substrates with fluoride ions. ¹⁹F NMR spectroscopy was used to follow the course of fluorination. All the candidate complexes were shown to accelerate the rate of reaction relative to the control. These results indicate that practical fluorination using these methods is a realistic possibility.

Chapter-6 summarises and draws conclusions from the work covered in this thesis, with comments on potential future work.

Chapter-7 describes the experimental procedures followed in accomplishing the results reported in chapters 2-5.

The appendix includes some spectroscopic data not included in chapters 2-5.

Authors: Lamont, L

• DOI: 10.5287/ora-pde9kw55v
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: lanthanide; catalysis; DO3A
• Subjects: Inorganic chemistry