Ligands with Extended π-Systems: Synthesis, Coordination Chemistry and Reactivity

Abstract

Well-defined polyaromatic molecules with a large, extended π-system – also known nanographenes – have been widely studied over the last decades. Their unique electronic, photophysical and self-assembly properties have led to various applications, for example in optoelectronic devices. These properties have also attracted the attention of coordination chemists, and several ligands have been developed bearing an extended π-system in recent years. Nonetheless, their complicated synthesis, and properties such as low solubility have hindered further developments in the field. The variety of different ligand binding pockets embedded within an extended π-system that has been reported is consequently low. In this thesis, the synthesis of new nanographene ligands is described, in particular the first examples of π-extended ligands with the ubiquitous β-diketiminate-type binding pocket. The characterisation of these ligands and their coordination chemistry with a variety of transition metals is described. The properties and reactivity of the resulting complexes is scrutinised, highlighting the redox-active properties of these ligands. Furthermore, exploration of the reactivity of newly developed π-extended β-diketiminates led to the discovery of new heterocyclic, organic compounds with unique photoluminescent properties. Together, the results from this thesis add to the growing library of nanographene ligands and our understanding of their properties and reactivity.