Luminescent Platinumii Palladiumii And Goldiii Complexes Containing Isocyanide Alkynyl And N Heterocyclic Carbene Ligands PDF Download

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Luminescent Platinum(ii), Palladium(ii) and Gold(iii) Complexes Containing Isocyanide, Alkynyl and N-Heterocyclic Carbene Ligands

Luminescent Platinum(ii), Palladium(ii) and Gold(iii) Complexes Containing Isocyanide, Alkynyl and N-Heterocyclic Carbene Ligands
Author: Faan-Fung Hung
Publisher: Open Dissertation Press
Total Pages:
Release: 2017-01-27
Genre:
ISBN: 9781361385418
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This dissertation, "Luminescent Platinum(II), Palladium(II) and Gold(III) Complexes Containing Isocyanide, Alkynyl and N-heterocyclic Carbene Ligands: Synthesis, Photophysical Properties and Material Applications" by Faan-fung, Hung, 孔繁峰, 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: Several cyclometalated Pt(II) isocyanide complexes containing C-deprotonated C DEGREESN DEGREESC ligands (C DEGREESN DEGREESC = 2,6-diphenylpyridine derivatives) were synthesized. These complexes display orange-red emissions with max at 582-619 nm and quantum yields of up to 26% in CH2Cl2 at room temperature. The incorporation of carbazole/fluorene/thiophene unit(s) to C DEGREESN DEGREESC ligands leads to minimized structural distortion of complexes in their excited states and thereby suppresses non-radiative decay pathways. The high thermal stability (Td >300 C) renders these complexes good candidates as phosphorescent dopants in organic light-emitting diodes (OLEDs). Red-emitting OLEDs with CIE coordinates of (0.650.01, 0.350.01) were fabricated by vacuum deposition, showing a maximum external efficiency of 12%. In addition, well-defined nano/microstructures were obtained from self-assembly of these complexes driven by π∙∙∙π, C-H∙∙∙π and C-H∙∙∙H-C interactions as observed in the crystal structures. Two series of organopalladium(II) alkynyl complexes containing a terpy (terpy = 2,2':6',2''-terpyridine) or C DEGREESN DEGREESC pincer carbene ligand (C DEGREESN DEGREESC = 2,6-bis(1-butylimidazol-2-ylidenyl)pyridine) were prepared. These complexes are non-emissive in solution at room temperature except that the one containing both C DEGREESN DEGREESC and pyrenylacetylide ligands shows phosphorescence (Φ = 0.3%) originating from intraligand state of the acetylide ligand. This could be attributed to the strong -donating N-heterocyclic carbene (NHC) in the pincer ligand that strongly destabilizes d-d state, the population of which provides an efficient non-radiative decay channel. To make comparison between Pd(II) and Pt(II) complexes with the two ligand systems, Pt(II) C DEGREESN DEGREESC alkynyl complexes were also prepared. They are emissive in solution and some display excimer emissions at high concentration (〖10〗 DEGREES(-4)-〖10〗 DEGREES(-3) mol 〖10dm〗 DEGREES(-3)). The X-ray crystal structures of [Pd(L)(CCPh)](〖PF〗_6) (L = terpy and C DEGREESN DEGREESC) revealed one-dimensional chain stacking of complex cations with alternating Pd(II)∙∙∙Pd(II) contacts of about 3.29-3.35 A and π-π interactions of about 3.4 A . Well-defined submicron/nanostructures were obtained from self-assembly of Pd(II) and Pt(II) alkynyl complexes driven by π-π interactions between aromatic moieties and/or metal∙∙∙metal interactions. DFT calculations on the optimized structures of [M(L)(CCPh)]+ (M = Pd(II) and Pt(II)) revealed the existence of metal∙∙∙metal closed-shell interactions. In addition, the complex containing the C DEGREESN DEGREESC ligand exhibits slightly enhanced metal∙∙∙metal interactions and larger "bonding" energy upon dimerization. Furthermore, spin-orbit coupling between singlet and triplet excited states is more effective which promotes rapid intersystem crossing. A new class of cyclometalated Au(III) complexes containing C-deprotonated C DEGREESN ligands (C DEGREESN = 2-phenylpyridine and its derivatives) and cis-chelating bis-NHC ligands was synthesized. These are the first examples of Au(III) complexes supported by cis-chelating bis-NHC ligands. They display emissions in solution under degassed condition at room temperature with &

DESIGN & SYNTHESIS OF LUMINESC

DESIGN & SYNTHESIS OF LUMINESC
Author: Suk-Hang Lam
Publisher: Open Dissertation Press
Total Pages: 292
Release: 2017-01-26
Genre: Science
ISBN: 9781361034019
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This dissertation, "Design and Synthesis of Luminescent Platinum(II) and Gold(III) Complexes With Tridentate Pincer-type Ligands: From Computational Study to Experiments and Application Studies" by Suk-hang, Lam, 林淑恒, 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 DESIGN AND SYNTHESIS OF LUMINESCENT PLATINUM(II) AND GOLD(III) COMPLEXES WITH TRIDENTATE PINCER-TYPE LIGANDS - FROM COMPUTATIONAL STUDY TO EXPERIMENTS AND APPLICATION STUDIES Submitted by LAM Suk Hang for the degree of Doctor of Philosophy at The University of Hong Kong in June 2015 Square planar platinum(II) and gold(III) complexes possess unique spectroscopic and photophysical properties which enable them as promising candidates for many applications such as optoelectronic devices and biological sensors. The understanding of the intrinsic properties of these complexes is therefore essential to optimize their performance as well as provide guidance on the molecular design for specific applications. This thesis aims to provide useful insights for the molecular design strategies with the aid of computational studies to tune the electronic properties of these complexes and electroluminescence studies in the fabrication of organic light-emitting devices (OLEDs). Computational studies have been performed to inspect electronic structures and photophysical properties as well as their correlation with the nature of ancillary ligands in the platinum(II) complexes of 1,3-bis(N-alkylbenzimidazol-2′-yl)benzene, [Pt(bzimb)(C≡C-R)], 1,3-bis-hetero-azolylbenzenes, [Pt(N DEGREESC DEGREESN)(C≡C-R)], and pyridine-based N-heterocyclic carbene, [Pt(NHC)(C≡C-R)] . It was found that the emission of the arylalkynylplatinum(II) complexes with pyridine-based N-heterocyclic carbene ligand was originated from the triplet alkynyl-to-tridentate pincer ligand-to-ligand charge transfer excited state mixed with platinum-to-tridentate pincer metal-to-ligand charge transfer character, and the excited state energy was found to be red-shifted according to the increasing π electron-donating ability of the aryl group attached to the alkynyl ligand. On the other hand, the emission energies of the platinum(II) complexes of 1,3-bis(N-alkylbenzimidazol-2′-yl)benzene and 1,3-bis-hetero-azolylbenzenes were found to be dependent on the different electron-donating substituents on the pincer ligands. Calculations have also been performed on the representative alkynylplatinum(II) + + complexes [Pt(trpy)(C≡C-R)] (trpy = 2,2′ 6′,2′′-terpyridine), [Pt(bzimpy)(C≡C-R)] (bzimpy = 2,6-bis(N-alkylbenzimidazol-2′-yl)pyridine) and [Pt(bzimb)(C≡C-R)] as well as alkynylgold(III) complexes [Au(C DEGREESN DEGREESC)(C≡C-R)] (C DEGREESN DEGREESC = 2,6-diphenylpyridine), [Au{C(Np) DEGREESN DEGREESC(Np)}(C≡C-R)] (C(Np) DEGREESN DEGREESC(Np) = 2,6-di(2-naphthyl)pyridine) and [Au(N DEGREESN DEGREESN)(C≡C-R)] (N DEGREESN DEGREESN = 2,6-bis(1H-benzimidazol-2-yl)pyridine) in order to have a better understanding on their nature of the emissive origins as well as the radiative and nonradiative processes. In particular, factors governing the ordering of the triplet excited states and radiative decay rate constants of the emissive state ( ES) have been examined. Their potential energy profiles for the deactivation process from the ES via triplet metal-centered states have also been explored. This study revealed for the first time the potential energy profiles for the thermal deactivation pathway of square planar platinum(II) and gold(III) complexes. In addition to the computational

LUMINESCENT PALLADIUM(II) & PL

LUMINESCENT PALLADIUM(II) & PL
Author: Pui-Keong Chow
Publisher: Open Dissertation Press
Total Pages: 502
Release: 2017-01-26
Genre: Science
ISBN: 9781361005392
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This dissertation, "Luminescent Palladium(II) and Platinum(II) Complexes With Tridentate Monoanionic and Tetradentate Dianionic Cyclometallated Ligands: Structures, Photophysical Properties and Material Application" by Pui-keong, Chow, 周沛強, 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: Four structural isomers of platinum(II) complexes with C-deprotonated R-C DEGREESN DEGREESN-R' cyclometallated ligands (R-C DEGREESN DEGREESN-R' = -extended 6-aryl-2,2'-bipyridine derivatives containing 2-naphthyl, 3-isoquinolinyl, 1-isoquinolinyl or 2-quinolinyl moieties) have been synthesized with their photophysical properties investigated. The one bearing a 3-isoquinolinyl moiety shows the highest emission quantum yield among the four and hence has been extensively modified to give a series of complexes with different ancillary ligands (chloride, iodide, phenoxide, or acetylide). Most of these complexes show vibronic emission (max = 515-644 nm) with high emission quantum yield (up to unity) in degassed CH2Cl2; one of them has been used for OLED fabrication and shows a maximum EQE of 8.15 % with current efficiency of 25 cd A-1. The photocatalytic properties of these derivative complexes for oxidative tertiary amine functionalization have also been examined. Several highly robust and emissive platinum(II) complexes supported by two types of tetradentate O DEGREESN DEGREESC DEGREESN ligand systems (Φem up to 0.99; Td up to 520 ℃) have been synthesized and show different emission energies (λmax = 482-561 nm). Most of them exhibit excimeric emission in solution state at room temperature which are dependent on the modifications on the tetradentate O DEGREESN DEGREESC DEGREESN ligands. DFT/TDDFT calculations reveal that the metal complex showing the most intense excimeric emission possesses an excimeric excited state with a localized structure, which is unusual for these classes of platinum(II) complexes. Based on this finding, WOLED (ηL(max) = 71.0 cd/A, ηp(max) = 55.8 lm/W, ηExt = 16.5 %, CIE = 0.33, 0.42, CRI = 77) and WPLED (ηL(max) = 17.0 cd/A, ηp(max) = 9.1 lm/W, ηExt = 9.7 %, CIE = 0.43, 0.45, CRI = 78) based on this complex have been fabricated with high efficiency achieved. Palladium(II) complexes containing C-deprotonated R-C DEGREESN DEGREESN-R' cyclometallated and pentafluorophenylacetylide ligands exhibit phosphorescence in both solid state and fluid solutions at room temperature with some of them exhibiting aggregation-induced emission (AIE). These complexes have been applied as photosensitizers in light-induced oxidative functionalization of secondary and tertiary benzylic amines as well as in light-induced hydrogen production, with a maximum of 175 turnovers for hydrogen produced. Palladium(II) complexes containing two types of tetradentate dianionic O DEGREESN DEGREESC DEGREESN ligand systems (Systems 1 and 2) have been prepared and show constrasting photophyical properties. A full scale time-resolved spectroscopic analysis has been done on some of these complexes and a platinum(II) analogue. These complexes are found to have similar excited state decay pathway( 〖S_1〗 DEGREESi→〖S_1〗 DEGREESf→T) with ΦISC of about unity. The emission efficiency of System 2 complexes is superior to that of System 1 complexes, which is ascribed to the suppression of excited state distortion on the basis of the results of DFT calculations. A lower radiative decay rate of System 2 palladium(II) complexes relative to the platinum(II) analogue has been found, which could be due to their lower spin-orbit coupling constant. One of the palladium(II) complexes ha

Luminescent Cyclometalated Gold (III) Complexes with Ancillary N-Heterocyclic Carbene and Alkynyl Ligands

Luminescent Cyclometalated Gold (III) Complexes with Ancillary N-Heterocyclic Carbene and Alkynyl Ligands
Author: Ka-Man Au
Publisher: Open Dissertation Press
Total Pages:
Release: 2017-01-27
Genre:
ISBN: 9781361365533
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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

LIGHT-EMITTING PLATINUM (II) &

LIGHT-EMITTING PLATINUM (II) &
Author: Wei Lu
Publisher: Open Dissertation Press
Total Pages: 324
Release: 2017-01-28
Genre: Science
ISBN: 9781374799653
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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