Phosphorescent materials derived from charged polypyridine complexes of platinum(II) and platinum(IV)

Photoactive materials have gained widespread interest amongst researchers given their ability to harness and redirect the energy of photons. Photon absorption by the material can enable normally unfeasible chemical reactions, promote electron transfer/flow, or be re-emitted. This versatility makes these compounds indispensible to areas of research such as light-emitting devices, dye-sensitized solar cells, photocatalytic hydrogen production, and optical oxygen sensors. The focus of this dissertation is the development of novel compounds for such purposes.;Synthetic methodologies were developed to produce two new families of phosphorescent platinum compounds. Chapter 2 discusses a family of 16 cyclometalated platinum(II) diimine complexes derived from four cyclometalating ligands and four diimine ligands. The versatility of the synthetic process is demonstrated and the complexes are fully characterized via NMR spectroscopy, mass spectrometry, and elemental analysis. The complexes demonstrate green phosphorescence from a ligand centered state (∼500 nm), while the minimal contribution from the metal-to-ligand charge transfer state did not go unnoticed. The photophysical and electrochemical qualities of the complexes are described, and their excited state dynamics explained.;Chapter 3 accounts the synthesis and characterization of a novel family of 11 bis-cyclometalated platinum(IV) complexes. The synthetic route included utilizing cyclometalated platinum(II) pendant complexes for a second, oxidation-facilitated cyclometalation to arrive at the precursor bis-cyclometalated platinum(IV) dichlorides. These complexes were converted to the heteroleptic diimine complexes via ligand substitution. All complexes exhibited long-lived triplet excited states (1-260mus), and some showed particularly efficient oxygen quenching. Excited state dynamics as predicted by static DFT calculations were proven inaccurate by experimental data, and time-dependent DFT was utilized to account for this discrepancy.;The newly developed synthetic procedures have provided numerous opportunities for continued research. Specifically, the synthesis of mixed-ligand bis-cyclometalated platinum(IV) complexes, and platinum(IV) species with other ancillary ligands such as acetylacetonate, cyanide, and N-heterocyclic carbenes, are routes to new luminescent materials which will be explored.