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This dissertation concerns the syntheses and characterization of supramolecules with quadruply bonded Mo2 4+ units, Mo2(DAniF)3 + (DAniF = N,N'-di-p-anisylformamidinate) or cis- Mo2(DAniF)2 2+, and chiral organometallic Rh2 4+ units, including racemic cis-Rh2(C6H4PPh2)2 2+ and pure enantiomers of cis-Rh2(C6H4PPh2)2 2+. Molecular pairs of dimolybdenum units in which Mo2(DAniF)3 + units are linked by cyclic diamidate anions or dioxolene anions have been investigated. Linkers impact the electronic communication between the dimetal units in various ways. The symmetry and the energy of the frontier orbitals of the linker are among the factors which influence significantly the properties of the molecular pairs. Nature has provided us a great opportunity to study quantitatively the equilibrium between neutral supramolecules with cis-Mo2(DAniF)2 2+ units. Studies of the concentrationdependent and temperature-dependent equilibria between a molecular triangle and square as well as a molecular loop and triangle using 1H and 19F NMR spectra provide quantitative values for the thermodynamic equilibrium constant K, as well as ∆Hº, and ∆Sº for the equilibria. The synthesis and characterization supramolecular compounds containing chiral cis- Rh2(C6H4PPh2)2 2+ units, including three racemic triangles and pure enantiomers of three triangles, a carceplex with T symmetry and two loops are also presented.

Here we report the preparation, structure, and spectroscopic properties of an intriguing copper(I) cyclophane-like dimeric complex [Cu2(dppa)2(bpy)2][BF4]2(2)¡B[Cu2(dppa)2(mbpy)2][BF4]2(3)¡B[Cu2(dpbp)2(bpy)2][BF4]2(7)©M[Cu2(dppb)2(bpy)2] [BF4]2(8), containing phenyl phosphine bridge ligands, such as diphenylphosphino acetylene (dppa), 1,4-bis(diphenylphosphino)benzene (dppb) and 4,4'-bis(diphenyl phosphino)biphenyl (dpbp). As a building unit, the complex [Cu2(dpbp)2(NCMe)4] [BF4]2(9) containing labile acetonitrile molecules those can be easily substituted by anionic ligands, is expected to combine with suitable linkers to synthesize supramolecular arrays with shapes of polygons and polyhedra.

Host-guest interactions have been well studied in the new century to obtain fundamental insights into supramolecular chemistry. Most of the pioneering works have been done using techniques such as NMR, X-ray crystallography, IR spectroscopy and so on. However, none of these techniques is universal for the investigation of all types of supramolecules, and usually they have one or more limiting factors such as relatively large sample consumption, matrix effects from solvents, etc. Electrospray mass spectrometry has been widely used to investigate host-guest interactions in the gas phase. A particular advantage of gas phase host-guest research is that the experimental results can be directly compared to computational results because complicating interferences from solvents are not present. Thus electrospray mass spectrometry coupled with high-level computational methods becomes a powerful tool to elucidate binding behavior in host-guest complexes. With rigid, symmetric structures available in a range of sizes, cucurbiturils have been ideal prototypical host molecules in host-guest chemistry since they were characterized in 1980s. Recent research in my group has shown cucurbiturils can form various complexes with positive ions in the gas phase, such as molecular containers trapping small neutral guest molecules inside or wheel-and-axle architectures with linear molecules threaded through. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is an ideal technique for investigation of host-guest supramolecular complexes due to its ultra-high mass resolving power, ultra-high mass accuracy, and high sensitivity. Moreover it has the capability of trapping ions for ion chemistry, and versatile tandem mass spectrometry capabilities. This dissertation focuses on the characterization of cucurbituril complexes in the gas phase using electrospray ionization FT-ICR mass spectrometry. Chapter 1 describes FTICR mass spectrometry techniques including principles, performance, instrumentation and applications. Electrospray ionization methods are also discussed in this chapter. Chapter 2 introduces structures, properties, synthesis and host-guest chemistry of the cucurbituril family. Chapters 3 investigate cucurbituril complexation behavior with amino acids and peptides. Chapter 4 investigates the alkali metal ions “lids removal” from cucurbit[5]uril molecular box. Chapter 5 characterizes the cucurbit[6]uril pseudorotaxanes in the gas phase. Chapter 6 characterizes the complexes formed by cucurbit[6]uril and α,ω-alkyldiammonium cations in the gas phase, using energy-resolved SORI-CID method. High-level computational methods were also performed to explain the experimental results.

The terminal ligand in [(Ph₂phen)₂Ru(dpp)RhCl₂(TL)](PF₆)₃ (Ph2phen = 4,7-diphenyl1,10-phenanthroline; dpp = 2,3-bis(2-pyridyl)pyrazine; TL = terminal ligand – a 4,4′-disubstituted-2,2′-bipyridine where the substituent was carbomethoxy (dcmbpy), hydrogen (bpy) or methyl (Me₂bpy)). The electron-withdrawing ability of the substituent was shown to increase the rate of chloride loss upon electrochemical reduction, facilitating catalytic water reduction. The electronic properties of the terminal ligand also impact the photophysical properties of the molecule. The excited state lifetime of the complex with a dcmbpy terminal ligand was 93 ns while the excited state lifetimes of the complexes with a bpy or Me₂bpy terminal ligand were 44 ns and 47 ns, respectively. Ligand substitution was shown to influence the photocatalytic water reduction activity of these complexes with the dcmbpy complex producing approximately twice the amount of hydrogen (62 ± 7 turnovers in 20 h) as the other two complexes. / Master of Science

Les complexes de coordination supramoléculaires constitués de briques moléculaires chirales sont bien décrits dans la littérature. En revanche, les systèmes combinant briques moléculaires chirales et chiralité inhérente restent encore très peu explorés. C'est dans ce contexte que s'inscrit ce travail de recherche. Nous avons étudié de nouveaux ensembles supramoléculaires de coordination tridimensionnels chiraux pour des applications potentielles en catalyse. La synthèse a été développée par auto-assemblage de briques moléculaires différentes : ligands azotés bitopiques, ligands tritopiques et complexes de coordination. Neuf auto-assemblages différents ont été réalisés avec les ligands bitopiques dérivés de l'imidazole et de complexes de Pd (II) et de Pt (II). Les auto-assemblées triangulaires T-7, T-9, T-10, T-12, T-13 et T-15 ont été obtenues majoritairement alors que les structures T-11, C-11a et C-11b ou encore T-14 et C-14, ont été obtenues sous la forme d'un mélange triangle-carré dont les proportions dépendent de la concentration et de la nature du solvant. Leur caractérisation et l'étude de leur structure en solution ont permis de mettre en évidence une chiralité inhérente à leur structure. A notre connaissance, l'auto-assemblée T-7 est la première structure triangulaire chirale, composée de briques moléculaires achirales, complètement caractérisée en solution. A partir de l'auto-assemblage ligand tritopique / ligand bitopique / complexe métallique, trois structures prismatiques chirales ont été synthétisées grâce à l'encapsulation d'un invité pyrènecarboxaldéhyde (I-8). La structure Prism-2 a été obtenue avec un excellent rendement et une très bonne pureté. Sa caractérisation par spectroscopie RMN en solution et son analyse en DFT ont permis de déterminer la chiralité inhérente de la structure obtenue comme un racémique P-(Prism-2⊃(I-8)2) et M-(Prism-2⊃(I-8)2). L'analogue énantiopur Prism-3 est obtenu par l'auto-assemblage de L4Me, 4tpt et du complexe énantiopur Pd-5 en présence de I-8. La spectroscopie RMN en solution a permis de déterminer la configuration de l'énantiomère obtenu, (λ,P)-(Prism-3⊃(I-8)2), et confirme la chiralité inhérente de ces structures prismatiques. / Supramolecular coordination complexes, constituted of chiral molecular bricks, are well described in the literature. However, supramolecular complexes combining chiral building blocks and inherent chirality are underexplored. In this context, we have undertaken the synthesis of novel chiral three-dimensional supramolecular coordination complexes for their potential uses in catalysis. Their synthesis have been carried out by self-assembly of different molecular bricks: ditopic and tritopic nitrogen-ligands, and coordination complexes. Nine different self-assemblies have been synthesized with imidazole-based ditopic ligands and palladium(II), or platinum(II), coordination complexes. On the one hand, the triangular self-assemblies T-7, T-9, T-10, T-12, T-13 and T-15 have been obtained as the major component. On the other hand, structures T-11, C-11a-b or T-14 and C-14 have been obtained as a mixture of triangular and square structures in a ratio depending on the concentration and the solvent. The full characterization of these structures in solution has shown their inherent chirality. To our knowledge T-7 is the first triangular supramolecular coordination complex constituted of achiral components shown to be chiral in solution. Self-assembly syntheses of tritopic and ditopic ligands as well as palladium(II) coordination complexes were carried out, in the presence of pyrenecarboxaldehyde (I-8). Three chiral prismatic structures have been obtained. Prism-2 has been characterized by NMR spectroscopy in solution and DFT analysis which supports its inherent chirality. The racemic (P-(Prism-2⊃(I-8)2) / M-(Prism-2⊃(I-8)2)) has been isolated with an excellent yield and a very good purity. Prism-3, an enantiopure analog of Prism-2, was obtained by self-assembly synthesis of L4Me, 4tpt and the enantiopure coordination complex Pd-5 in the presence of I-8. The configuration of the isolated enantiomer was carried out by NMR spectroscopy in solution and assigned to (λ,P)-(Prism-3⊃(I-8)2), confirming the inherent chirality of the different prismatic structures.

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Supramolecular chemistry covers intermolecular interactions where non-covalent bonds are involved, and many of them are based on host-guest interactions. Cyclodextrins (CDs) are cyclic oligosaccharides consisting of 6-, 7- or 8-glucose units, which are called alpha-, beta- or gamma-CDs, respectively. They have hydrophobic interior and hydrophilic exterior, and are widely being used as hosts for various organic molecules. The formation of CD inclusion complexes with a variety of dyes has continuously drawn our interests, since CDs are readily available and have ability to include dye molecules altering their properties. The present thesis covers the study of inclusion complexes of CDs and chromophore dyes, largely in two ways; rotaxane and pseudorotaxane. The stable rotaxane structure is achieved with the synthesis of dye rotaxane. The introduction of CD ring around azo chromophore provides a simple way to improve the solubility and stability of azo dye. We have shown that by incorporating proper compounds as a coupler, azo dye rotaxanes can be used as pH indicators and metal ion sensors. We have described the synthesis of novel acetylene dye rotaxane using the Pd-catalyzed reaction of Heck-Cassar-Sonogashira-Hagihara type. Its fluorescence properties in the solid state as well as in solutions are examined and compared with those of free dye. Free dye, which has tetra-carboxylic groups, is found to be highly sensitive to various metal ions, exhibiting high Stern-Volmer constants, K(SV). On the contrary, acetylene dye rotaxane exhibits much less quenching against various quenchers. The appearance of fluorescent anisotropic structure has been observed by the formation of inclusion complex between acetylene dye and gamma-CD. Its structural nature is studied by various techniques, including fluorescence, fluorescence anisotropy, wide angle X-ray scattering (WAXD) and differential scanning calorimetry (DSC) measurements. Methyl orange, an acid azo dye, forms a dimeric inclusion complex with gamma-CD, resulting in the formation stable anisotropic aggregates. Several other azo dyes are found to form anisotropic supramolecule in the presence of gamma-CD, and their structural characteristic has been discussed in terms of the number and position of solubilizing groups.

No description available.

No description available.