New Synthetic Strategies for Luminescent Platinum(II) and Iridium(III) Complexes

Luminescent transition metal complexes, specifically platinum and iridium complexes, have been widely employed in optoelectronic applications, as well as phosphorescent labels and sensors because of their favorable photophysical and electrochemical features. For their continued development and implementation in applications, careful control and optimization of photophysical and electrochemical properties of these complexes are a requisite, motivating studies on a more diverse range of structures. This dissertation is mainly focused on development of an unconventional ligand design strategies for Pt(II) and Ir(III) complexes. Chapter 1 introduces the concept that noncovalent Lewis acid-base interactions can modulate the excited-state properties of phosphorescent platinum compounds. Postsynthetic addition of borane Lewis acids to Lewis base decorated organoplatiunum chromophores induces significant changes in the optical and electrochemical properties, providing an approach more rapid and systematic than that offered by traditional covalent substituent modification. In Chapters 2–5, a new class of cyclometalated iridium complexes supported by acyclic diaminocarbene ancillary ligands is described, with a particular focus on improving the efficiency and stability of blue-emitting cyclometalated Ir(III) complexes. In a separate effort, in Chapter 6, a new synthetic approach to assemble Ir(III) and Pt(II) chromophores into Ir-Pt-Ir trimetallic complexes using the highly reactive cyclometalated iridium synthons is described. The supramolecular constructs were synthesized under mild conditions without extensive purification steps and could function as platforms for studying excited-state energy transfer dynamics.