Design, synthesis and application of arylazopyrazole photoswitches
File(s)
Author(s)
Gibson, Rosina
Type
Thesis
Abstract
Photoswitches are molecules that can undergo reversible changes to their physical and chemical properties upon irradiation with light. The arylazopyrazoles are a class of azo-based photoswitch, which show excellent photochemical properties such as efficient switching and long metastable isomer half-lives. When applied effectively, photoswitches can be used to control processes in both time and space using light, a stimulus highly desirable in many applications.
Chapter 1 gives an overall introduction to photoswitching and summarises the progress achieved in improving photoswitches to further their use in application. The azo scaffold is discussed in detail, highlighting the improvements of arylazopyrazoles over azobenzenes, and using examples of arylazopyrazoles in a variety of applications to demonstrate this success. Chapter 2 focuses on synthetic methodologies towards azo-based compounds, discussing known methods and exploring potential reactions that can be added to the chemist’s toolkit for synthesis of the arylazopyrazoles.
Chapters 3 and 4 investigate manipulation of the fundamental properties of photoswitches. An alternative switching stimulus to light is explored with acid catalysed switching, which simultaneously shifts the light absorption of the compounds. Perturbing the thermodynamic equilibrium of a photoswitch system is then attempted using reversible covalent bonding to switch between cyclic and linear forms.
Chapters 5 and 6 investigate application of arylazopyrazoles to key photoswitch fields. The arylazopyrazoles studied in light-thermal energy conversion and storage produced novel results of sub-zero storage and release. Finally, an arylazopyrazole analogue of a highly potent biological inhibitor is investigated as a molecular tool to understand the kinetics of inhibition of a protein.
Chapter 1 gives an overall introduction to photoswitching and summarises the progress achieved in improving photoswitches to further their use in application. The azo scaffold is discussed in detail, highlighting the improvements of arylazopyrazoles over azobenzenes, and using examples of arylazopyrazoles in a variety of applications to demonstrate this success. Chapter 2 focuses on synthetic methodologies towards azo-based compounds, discussing known methods and exploring potential reactions that can be added to the chemist’s toolkit for synthesis of the arylazopyrazoles.
Chapters 3 and 4 investigate manipulation of the fundamental properties of photoswitches. An alternative switching stimulus to light is explored with acid catalysed switching, which simultaneously shifts the light absorption of the compounds. Perturbing the thermodynamic equilibrium of a photoswitch system is then attempted using reversible covalent bonding to switch between cyclic and linear forms.
Chapters 5 and 6 investigate application of arylazopyrazoles to key photoswitch fields. The arylazopyrazoles studied in light-thermal energy conversion and storage produced novel results of sub-zero storage and release. Finally, an arylazopyrazole analogue of a highly potent biological inhibitor is investigated as a molecular tool to understand the kinetics of inhibition of a protein.
Version
Open Access
Date Issued
2022-06
Date Awarded
2022-09
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Fuchter, Matthew
Sponsor
Imperial College London
Publisher Department
Chemistry
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)