Extended Aromatic Materials Centred Around Tropylium

Polycyclic aromatic materials have garnered a significant amount of interest since the discovery of graphene, due to their desirable properties and potential applications in optoelectronic materials. While defect-free graphene is entirely planar, the inclusion of non-hexagonal rings can often cause it to deviate from planarity, resulting in geodesic fragments (with positive Gaussian curvature) or saddle-shaped fragments (with negative Gaussian curvature). Typically, the former is accomplished by inclusion of five-membered ring defects, while the latter is accomplished through larger ring defects (heptagons, octagons, etc.). Specifically, the strategic inclusion of cycloheptatrienes allows for oxidation to tropyliums, which gives rise to a novel class of charged polycyclic aromatics. However, little is known about the steric and electronic impacts of including tropyliums in extended aromatic materials. This PhD project investigates the synthesis, modelling and properties of a series of highly substituted tropyliums, which can be considered intermediates towards a tropylium-embedded warped nanographene.