Control of molecular motion is an important step towards the envisaged development of molecular scale devices and machines. A large amount of research has been documented regarding the control of molecular rotation and shuttling processes, but relatively few examples of control over nitrogen pyramidal inversion exist and so far no examples that require solely physical inputs such as light and heat have been reported. The first part of this thesis describes attempts to control nitrogen pyramidal inversion in aziridines and azetidines, using only light and heat to switch between two states with differing rates of inversion. Three avenues of research utilising anthracene photochemistry are discussed. The strategies employed include modifying ring strain by fused macrocycle formation; introduction of ring strain via small ring formation; and disruption of transition state stabilising hydrogen bonds through macrocycle formation. Finally, and more successfully, azobenzene photochemistry was used to modify a π-system adjacent to an aziridine nitrogen centre resulting in different inversion rates in the cis and trans azobenzene isomers. The experimentally derived inversion rates were supported by ab initio calculations. The second part of this thesis outlines attempts to develop photoactivated β-lactam antimicrobial agents. Two families of compounds were synthesised, based on amine linked bis-anthracene, and 2-pyridone isomerisations. Their antimicrobial activity was evaluated against B. Subtilis and E. Coli using the Kirby-Bauer disk diffusion method. One β-lactam produced by anthracene photodimerisation displayed modest activity against B. Subtilis. However, control experiments suggested the acyclic precursor possessed higher levels of antimicrobial activity.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:582402 |
| Date | January 2013 |
| Creators | Hough, Alexander J. |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/57507/ |
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