Bridging the Gap: Synthesis of Bay-Annulated Hexa-peri-hexabenzocoronenes

Abstract

This thesis consists of five chapters describing the bay-annulation of the planar hexa-peri-hexabenzocoronene towards a bowl-shaped hexa-peri-hexabenzocoronene where all six bay sites are annulated.

Chapter one provides an overview of polycyclic aromatic hydrocarbons and their fundamental properties, along with a review on the synthesis of hexa-peri-hexabenzocoronene and the bowl-shaped polycyclic aromatic hydrocarbons corannulene and sumanene.

Chapter two describes the extension of research previously undertaken on synthesising cyclopenta-incorporated hexa-peri-hexabenzocoronene where fluorene is utilised as a pre-formed source of five-membered rings. Improvements made in the synthesis of key precursors, exploration of conditions facilitating the unexpected chlorination previously observed during cyclodehydrogenation, and utilisation of this functionality is discussed.

Chapter three describes the extension of the methodology discussed in chapter two towards multiple annulations of hexa-peri-hexabenzocoronenes where fluorene is utilised as a pre-formed source of five-membered rings. A number of different topologies containing the fluorene moiety were investigated, with the synthesis and subsequent oxidative cyclodehydrogenation reactions outlined.

Chapter four describes bay-annulation of hexa-peri-hexabenzocoronenes post-cyclodehydrogenation, and product reactivity. Due to limited examples of post-cyclodehydrogenative functionalisation of hexa-peri-hexabenzocoronenes, the development of synthetic methods to achieve annulation is discussed.

Chapter five describes an extension of chapter four where alternative annulation reactions at the periphery of hexa-peri-hexabenzocoronene were explored. In particular, annulation from ethynyl or heteroatomic precursors was investigated in a two-step process from a single hexa-peri-hexabenzocoronene precursor.