Porphyrin-based nanorings and helices

Thesis

Chapter 1 discusses the background information and key publications relevant to the work described in Chapters 2-5. It first covers the synthesis of porphyrin-based molecular wires and nanorings, along with their properties. It then provides background information on aromaticity and gives examples of how aromaticity can be observed in large molecular systems. Finally, it discusses how chirality effects the properties of organic π-conjugated materials and how this can be investigated experimentally.

Chapter 2 presents the synthesis of a butadiyne-linked 18-porphyrin nanoring (c-P18) and of two snowflake-shaped templates (T18A and T18B). I discuss the computational design of the snowflake-shaped templates, then outline the successful synthetic routes to both versions. The synthesis of various linear butadiyne-linked porphyrin wires is then summarised along with the use of these oligomers in the template-directed synthesis of the 18-porphyrin nanoring. Finally, the characterisation data for the various nanoring·template complexes is presented.

Chapter 3 covers our in-depth study of the c-P18·T18A/B complexes, which includes; our computational analysis of the conformations each complex explores in solution, the binding of each template variant to the c-P18 nanoring, and our computational predictions and experimental evidence for globally aromaticity in c-P18.

Chapter 4 presents the current progress of our collaboration with Natalie Miller and Dr Gordon Hedley at the University of Glasgow, which aims to explore exciton size and motion in the c P18·T18A/B complexes.

Chapter 5 summarises the design, synthesis and purification of a chiral template which is capable of holding a butadiyne-linked porphyrin oligomer in a helical geometry. The binding between this chiral template and the oligomer is quantified and the chiroptical properties of the resulting helices are explored.

Authors: Holmes, J

• DOI: 10.5287/ora-erwrrp6ma
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: supramolecular chemistry; aromaticity; template-directed synthesis; organic chemistry
• Subjects: Chemistry, Organic