Calixarene-based supramolecular photocatalysis

Abstract

This thesis presents the synthesis of BODIPY appended calix[4]arenes for use in photocatalysis, building on the foundational ideas of Gutsche to utilise calixarene molecular recognition capabilities for reaction enhancement. It was shown that host-guest interactions within calixarene molecules increased the effective concentration of starting materials and the efficiency of the 1O2 [4+2] cycloaddition with α-terpinene. The first chapter provides necessary background of calixarenes and reactive dyes. The second presents the synthesis of three BODIPY-appended calix[4]arenes theorised to be strong photocatalysts based on previous work at Heriot-Watt University. Through reaction monitoring using 1H NMR spectroscopy it was determined that the presence of a cavity improved the conversion time of α-terpinene to ascaridole. Chapter three examined what modifications to the initial photocatalysts had on the speed of α-terpinene conversion. By introducing a phenolic spacer between the calix[4]arene and BODIPY units, a deeper cavity was created. Under the same reaction conditions as chapter two, reactions using these catalysts were seen to be distinctly slower. Chapter four departs from the initial aim, examining in-situ 1H NMR spectroscopy to track the conversion of 1O2 mediated reactions more accurately. This proved highly successful producing data of good quality, although development of experimental procedure is still required.