The objective of this thesis is to examine the photophysical and structural properties of Cu(I) complexes of 2-(2’-pyridyl)benzimidazolyl based ligands and Cu(I), Pd(II) and Pt(II) complexes of 2-(2’-pyridyl)indolyl based ligands, for possible use as phosphorescent emitters in OLEDs. The discovery of the atropisomeric 3,3’-bis(2-(2’-pyridyl)indolyl based ligands led to the examination of C-C coupling reactions and the investigation of the new chiral ligands with transition metal ions. Cu(I) complexes of 2-(2’pyridyl)benzimidazolyl-benzene with varying phosphine ligands were prepared. The structures were studied with X-ray crystallography and NMR. Experimental and computational results established that steric and electronic properties of the phosphine ligands influence the photophysical properties of the Cu(I) complexes. Polynuclear Cu(I) complexes with 2-(2’-pyridyl)benzimidazolyl based ligands and two PPh3 ancillary ligands were synthesized, the photoluminescent and electroluminescent properties were examined. A series of 2-(2’-pyridyl)indolyl based ligands; 2-(2’-pyridyl)indolyl-benzene (pib), 1,4-bis[2-(2’-pyridyl)indolyl]benzene (bib) and 1,3,5-tris[2-(2’-pyridyl)indolyl]benzene) (tib) and the corresponding C-C coupled dimers bis[3,3’(2-(2’-pyridyl)indolyl-benzene)] (bpib), bis[3,3’(1,4-bis[2-(2’-pyridyl)indolyl]benzene (bbib) and bis[3,3’(1,3,5-tris[2-(2’-pyridyl)indolyl]benzene)] (btib) were synthesized in a one-pot reaction with the formation of both C-N and C-C bonds. The photophysical properties of these new molecules were investigated. The dimers display intramolecular exciplex formation. The rotation barrier around the C-C bond in the 3 position of the bis-indole was calculated using DFT which support that bpib is an atropisomeric ligand. Cu(I), Pd(II) and Pt(II) complexes were synthesized with pib and bpib. [Cu(pib)(PPh3)2]+ contains a three-coordinate Cu(I) ion and doesn’t display MLCT but rather 3π-1π phosphorescence. In Pd(pib)(acac) and Pt(pib)(DMSO)Cl the pib ligand forms C,N chelated neutral complexes that display red emission in frozen solution and in solid state. The X-ray crystal structure for [Cu(bpib)2]+ revealed a homo-chiral crystal and for Pd(bpib)Cl2 and Pt(bpib)Cl¬2 show a trans-chelating geometry around the metal centre. Frozen solutions of [Cu(bpib)2]+ and Pd(bpib)Cl2 display MCLT phosphorescence. Finally the atropisomeric ligands bpib and bbib were examined as sensors to determine the enantiomeric excess of Zn(2-bromo-3-methylbutyrate)2 by CD spectroscopy. CD and fluorescent titration experiments verified that these ligands have selective interactions with different Zn(II) carboxylates. DFT computations showed that diastereomeric excess caused by chiral discrimination leads to the CD spectral-response of the atropisomeric ligands toward chiral Zn(II) carboxylates. / Thesis (Ph.D, Chemistry) -- Queen's University, 2008-09-25 09:54:21.464

L'objectif de cette thèse est la synthèse, la caractérisation et l'étude de complexes métalliquesluminescents, en particulier de Pt (II), leurs propriétés d'agrégation en solution, mais également dansun espace confiné ainsi qu’en surface. L'incorporation de complexes de métaux de transition dans lastructure poreuse, et ainsi que leur dépôt à la surface de nanoparticules et dans un cadre métalloorganique(MOF), par greffage post-synthétique, ont été étudiés. Sont également étudiés lacorrélation entre les propriétés de films d’une série de complexes de Pt(II) avec leur morphologie,leur mobilité électronique et la simulation de leur structure auto-assemblée par diffraction auxrayons-X. Les propriétés de luminescence de complexes amphiphiles de Pt(II) sont améliorées àl’intérieur de nanoparticules de silice mesoporeuse par la création d’un d’espace confiné. Un effetsimilaire est observé par le dépôt de complexes de Pt(II) fonctionnalisés sur une surface denanoparticules d’or. La luminescence d’un cadre organométallique a été modifiée par greffage postsynthétiquede complexes d’Ir(III) et de Pt(II). / The aim of this thesis is the synthesis, characterization and investigation of luminescent metalcomplexes, and in particular of Pt(II) compounds, their aggregation properties in solution but inconfined space as well. The incorporation of transition metal complexes in porous structure, and inparticular in a metal-organic framework (MOF), by post-synthesis grafting, have been investigated.Luminescence properties of amphiphilic Pt(II) complexes were enhanced inside mesoporous silicananoparticles by the creation of a confined space. Similar effect is observed by deposition offunctionalized Pt(II) complexes on gold nanoparticles surface. Luminescence of metal organicframework was tuned by post-synthetic grafting of Ir(III) and Pt(II) complexes.

Cette thèse se concentre sur la synthèse et l’analyse photophysique de complexes de Pt(II) luminescents and leur assemblage après agrégation. Multiples motifs supramoléculaires ont été utilisé pour acquérir un contrôle sur l’assemblage de ces complexes plan-carrés.Des ossatures de type couronne-éther furent attachés à des complexes métalliques phosphorescents pour donner un bouton supramoléculaire qui peut être actionné par des cations potassium. De plus, l’altération de l’arrangement de l’empilage des Pt(II) après coordination d’un ligand fut exploité pour la réalisation d’un senseur chimique qui peut être utilisé pour la détection différentielle d’aza-hétérocylces. Par ailleurs, l’installation d’un motif pont hydrogène à un complexe de Pt(II) luminescent fut établie, donnant un composé ayant un organisation 2D sur graphène. Finalement, des complexes de Pt(II) amphiphiles qui s’auto-assemblent en solution aqueuse dans des agrégats hautement luminescents furent synthétisés. La série de complexes soluble dans l’eau, chargés négativement ou neutres furent caractérisés par rapport à leurs paramètres photophysiques et leurs interactions avec des protéines capsides virales. / The presented thesis focused on the synthesis and photophysical investigation of luminescent Pt(II) complexes and their resulting assemblies that form upon aggregation. Multiple supramolecular motifs were utilized in order to gain control over the assembling behavior of the square-planar complexes. Crown-ether scaffolds were tethered with the phosphorescent metal complexes rendering a supramolecular switch that can be triggered by potassium cations. Moreover, alteration of the Pt(II)-stacking arrangement upon ligand coordination was exploited to realize a chemosensor that can be employed for of differential detection of aza-heterocycles. Furthermore, the installation of a H-bond motif to a luminescent Pt(II) complex was established, which resulted in a compound forming a two-dimensional organization on graphene. Finally, amphiphilic Pt(II) complexes were synthesized that self-assemble into highly luminescent aggregates in aqueous solutions. The series of water soluble neutral and negatively charged metal complexes were characterized with respect to their photophysical parameters and their interactions with virus coat proteins.

A series of 24 new photoluminescent symmetric and unsymmetric -NHC pincer Pt complexes was synthesized and characterized, including collection of their 195Pt NMR chemical shifts. In total 18 new X-ray crystal structures, and photophysical studies of these photoluminescent -NHC pincer Pt complexes are reported. -NHC pincer Pt complexes were synthesized and characterized using new -NHC pincer based proligands [(RChetChetCRH3)X2, X = Cl, Br, or BPh4, where het represents imidazolyl, benzimidazolyl, and 1,2,4-triazolyl moieties; R = n-butyl, 3,3-dimethylbutyl, n-hexyl] as starting materials. A new method to synthesize Pt-Cl complexes to prevent halogen mixing was developed using tetraphenylborate salts as proligands. -NHC pincer complexes Pt(II) were oxidized to Pt(IV) complexes by reaction with Br2, I2, or iodobenzene dichloride. Photophysical studies showed emission of blue to red-orange color range for the Pt(II) complexes when irradiated with long wavelength UV light (360 nm). No visible emission for Pt(IV) complexes was observed upon irradiation at 360 nm. The tunable photoluminescence of the synthesized -NHC pincer Pt(II) complexes can be used as the materials for OLEDs. Parameters and scales that provide understanding of steric and electronic effects are essential to predicting properties, and, therefore, to systematically designing new ligands. Meridional tridentate pincer ligands are neither conveniently nor accurately described by existing options. A scale has been developed based on 195Pt NMR chemical shift that is reflective of the total donor ability of a multi-dentate ligand in a square planar complex and that does not suffer from cis/trans stereochemical issues. This scale, Platinum Electronic Parameter (PtEP) and defined as PtEP = -(195Pt NMR shift) in CDCl3 revealed significant deviations of -NHC pincer ligands, PCP and POCOP donor abilities from predicted extrapolations using existing TEP parameters. This initial data set demonstrates the applicability and broad potential of the PtEP scale.

Since C^C* cyclometalated Pt(II) complexes with N-heterocyclic carbene (NHC) ligands have been identified as potential emitter materials in organic light-emitting devices (OLEDs), very promising results regarding quantum yields, colour and stability have been presented. Herein, we report on four nitrile substituted complexes with a chelating NHC ligand (1-(4-cyanophenyl)-3-isopropyl-1H-benzo[d]imidazole or 4-(tert-butyl)-1-(4-cyanophenyl)-3-methyl-1H-imidazole) and a bidentate monoanionic auxiliary ligand (acetylacetone or dimesitoylmethane). The complexes have been fully characterized including extensive 2D NMR studies (COSY, HSQC, HMBC, NOESY, 195Pt NMR), three of them also by solid-state structures. Photophysical measurements in amorphous PMMA films and pure emitter films at room temperature reveal the impact of the mesityl groups in the auxiliary ligand, which led to a significant increase of the quantum yield, while the decay lifetimes decreased. The electron withdrawing nitrile groups shift the emission towards blue colour coordinates.

Le contrôle du mouvement à l’échelle d’une simple molécule est un sujet actuellement florissant et intensément exploré par des chimistes de tous horizons. Le travail présenté dans ce manuscrit s’inscrit dans ce cadre. La conception ainsi que l’étude en solution et à l’état cristallin de tourniquets moléculaires, espèces composées d’un rotor et d’un stator comportant plusieurs sites d’interaction, y sont décrites.Dans une première partie, la synthèse ainsi que le fonctionnement de tourniquets à charnière de Pt(II) sont décrits. La fermeture et l’ouverture de ces systèmes ainsi que les essais de passage d’une station à une autre y sont étudiés. Les sites d’interactions ont été variés sur le rotor et le stator, pour aboutir à des systèmes variant par la dynamique de leur comportement.Dans une seconde partie, une synthèse optimisée de tourniquets à charnière organique est décrite. Les états ouverts et fermés de ces tourniquets ont été caractérisés.Tous les processus décrits pour les tourniquets ont été étudiés par des études RMN mono- et bi-dimensionnelles en solution.Dans un dernier chapitre, des MM’OFs basés sur un tecton comportant un centre Pt(II) et deux sites coordinant de type pyridine sont exposés. Leur utilisation en tant que tecton organométallique avec divers centres métalliques conduit à la formation de réseaux hétérobimétalliques. Un ligand incluant deux centres Pt(II) et un centre Fe(II) entouré par deux terpyridines est décrit. / The control of intramolecular movements has been a topic of high interest for chemists over two decades. Investigations described in this PhD manuscript aim at the design and study, both in solution and in the crystalline state, of molecular turnstiles. These entities are composed of a rotor and a stator, each of these constituents equipped with recognition sites.In the first part, the synthesis and behavior of Pt(II)-based molecular turnstiles are described. The switching between their open and closed states and the migration process between stations are discussed. The recognition sites on both the stator and rotor have been varied, leading to different behaviors, particularly in terms of their dynamics.In solution, 1- and 2-D NMR have been used for the characterization of the dynamic processes.In the last chapter, the use of a Pt(II)-bispyridyl based tecton for the synthesis of MM’OFs is reported. The use of various metal salts as secondary center has led to the construction of networks varying by their geometry and dimensionality. A ligand including two Pt(II) and one Fe(II) complexed by two terpyridyl units is described.