This dissertation, "Luminescent Cyclometalated Gold (III) Complexes With Ancillary N-heterocyclic Carbene and Alkynyl Ligands: From Design, Synthesis, Photophysics to Supramolecular Assembly and Functions" by Ka-man, Au, 區嘉雯, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: A library of luminescent cyclometalated gold(III) complexes containing various bis-cyclometalating R-C DEGREESN DEGREESC ligands derived from 2,6-diphenylpyridine and ancillary alkynyl ligands, [Au(R-C DEGREESN DEGREESC)(C≡CR')], has been synthesized. Some of the complexes have been structurally determined by X-ray crystallography. These complexes were found to exhibit intense emission in dichloromethane solution at 298 K, originating from metal-perturbed triplet intraligand (IL) excited states of the R-C DEGREESN DEGREESC ligand, with substantial charge transfer character from the aryl moiety to the pyridyl ring. In the presence of electron-rich alkynyl ligands, the emission origin could be switched to an alkynyl-to-cyclometalating ligand ligand-to-ligand charge transfer (LLCT) excited state. This class of complexes was also demonstrated to show rich electroluminescence properties as emitters in organic light-emitting devices. In addition, the supramolecular assembly of this class of complexes has also been revealed in gelation studies. N-Heterocyclic carbenes have been incorporated into the gold(III) metal center to prepare a series of luminescent mononuclear and dinuclear gold(III) complexes, [{Au(C DEGREESN DEGREESC)}n(NHC)](PF6)n and [{Au(tBuC DEGREESN DEGREESCtBu)}n(NHC)]- (PF6)n (n = 1, 2). The X-ray crystal structures of most of the complexes have been determined. The emissions of these complexes were assigned to originate from the metal-perturbed intraligand excited state of the bis-cyclometalating ligand. One of the C2-bridged dinuclear complexes was found to exhibit two distinct reduction couples, tentatively correlated to the presence of significant intramolecular π-π interaction in the complex. Two novel series of luminescent mononuclear alkynylgold(III) complexes, [Au(C DEGREESN)(C≡CR)2] (HC DEGREESN = 2-phenylpyridine (Hppy) and derivatives) and [Au(C DEGREESN DEGREESN)(C≡CR)]PF6 (HC DEGREESN DEGREESN = 6-phenyl-2,2'-bipyridine and derivatives), have been synthesized. Some of the X-ray crystal structures have been determined. The former class of complexes with bidentate C DEGREESN ligands has been observed to show tunable emission spanning across the visible spectrum from 462 to 697 nm. With the exception of [Au(ppy)(C≡C-C6H4-NH2-p)2] which showed a low-energy band originated from a 3LLCT [π(C≡C-C6H4-NH2)→π*(C DEGREESN)] excited state, all complexes exhibited vibronic-structured emission bands originated from the intraligand transition of the cyclometalating C DEGREESN ligand in dichloromethane solution at 298 K. On the other hand, most of the complexes with the tridentate C DEGREESN DEGREESN-type ligand have been observed to exhibit vibronic-structured emission bands attributed to the intraligand transition of the C DEGREESN DEGREESN ligand in low-temperature butyronitrile glass. DOI: 10.5353/th_b4775268 Subjects: Organogold compounds - Synthesis Carbenes (Methylene compounds) Heterocyclic compo