Light Emitting Platinum Ii And Gold I Complexes Containing Alkynyl And Isocyanide Ligands PDF Download

This dissertation, "Light-emitting Platinum (II) and Gold (I) Complexes Containing Cyclometalated and Alkynyl Ligands" by Wei, Lu, 陸為, 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: Abstract of thesis entitled LIGHT-EMITTING PLATINUM(II) AND GOLD(I) COMPLEXES CONTAINING CYCLOMETALATED AND ALKYNYL LIGANDS Submitted by Lu Wei for the degree of Doctor of Philosophy at The University of Hong Kong in July 2003 The syntheses, characterizations, spectroscopic properties and applications of light-emitting platinum(II) and gold(I) complexes containing cyclometalated and alkynyl ligands are described and five systems are explored in detail. The tuning of the photoluminescent properties of tridentate cyclometalated platinum(II) complexes bearing σ-alkynyl auxiliaries, namely [(C DEGREESN DEGREESN)Pt(C≡C) R] [H(C DEGREESN DEGREESN) = 6-aryl- 2,2'-bipyridine; n = 1-4; R = aryl, alkyl or trimethylsilyl], through modifications of both the cyclometalating and acetylide ligands, is presented. These neutral Pt(II) materials exhibit enhanced stability during vacuum deposition. Organic light-emitting devices (OLEDs) based on these emitters display orange to red electrophosphorescence with low turn-on voltages ( 4 V), maximum luminance -2 -1 approaching 10,000 cd m and efficiencies up to 4.2 cd A . The crystal structures and photoluminescence of tethered trinuclear cyclometalated platinum(II) complexes, 3+ namely [{R(C DEGREESN DEGREESN)} Pt ( -dpmp)] (R denotes substituent(s) on the (C DEGREESN DEGREESN) 3 3 3 ligand, dpmp = bis(diphenylphosphinomethyl)phenylphosphine), were investigated and compared with their mono- and binuclear analogues to yield insight into the nature of their respective excited states. The emission energies were found to be dependent on the substituents on the cyclometalating ligands and the oligophosphine 8 8 ligands, and sensitive to d -d and π-π interactions. Intermolecular π-stacking interactions were found to affect the crystal packing, solid-state emission energy and vapochromic behavior of mono- and multinuclear dicyclometalated Pt(II) complexes, 1 1 namely [Pt(C DEGREESN DEGREESC)L ] [HC DEGREESN DEGREESCH = 2,6-diphenylpyridine; L = pyridine, isocyanide, 2 2 phosphine], [Pt (C DEGREESN DEGREESC) (-L )] [L = pyrazine, bidentate phosphine] and 2 2 [Pt (C DEGREESN DEGREESC) ( -dpmp)], and aromatic α-diimine Pt(II) complexes bearing 3 3 3 t t functionalized σ-alkynyl auxiliaries, namely [( Bu bpy)Pt(C≡CAr) ] ( Bu bpy = 4,4'- 2 2 2 bis-tert-butyl-2,2'-bipyridine, Ar = 4-pyridyl, 3-pyridyl, 2-pyridyl, 4-ethynylpyridyl, 2-thienyl and pentafluorophenyl). The weak non-covalent interactions observed in the solvated crystal structures, such as π-π, C-H---π(C≡C), C-H---N(py), C-H---F-C and Cl---Cl contacts, were invoked to rationalize the reversible VOC (volatile organic compound) sensing and signaling capabilities of these materials. The syntheses, crystal structures and spectroscopic properties of several π-conjugated carbon-rich scaffolds bearing [Au(PCy )] (Cy = cyclohexyl) termini are described. The ν of the 3 0-0 acetylenic (ππ*) emission for [(Cy P)Au(C≡C) Au(PCy )] (n = ∞) was estimated to 3 n 3 -1 1 occur at 11000 cm by extrapolation of the plot of ν versus 1/n. Prompt (ππ*) 0-0 fluorescence only was detected from the cross-conjugated species [TEE][Au(PCy )] 3 4 ([TEE]H = tetraethynylethene). A correlation between the solid-state emissions and crystal structures of the phosphorescent polymorphic complex [4-NO - C H C≡CAu(PCy )] and their related complexes was observed, and a rationale based 6 4 3 on excitonic coupling is proposed. DOI: 10.5353/th_b