The local information provided by nuclear magnetic resonance (NMR) makes it an ideal method for the structural investigations of materials lacking extended long-range ordering. This work focuses on investigations of two types of materials possessing very different types of disorder. The first section involves investigations of alkali borate glasses and the application of solid-state NMR techniques to probe short- and medium-range ordering in such glasses. Differences between the various alkali borates over a wide compositional range are probed using one and two-dimensional techniques. The use of double-resonance dipolar recoupling techniques to investigate cesium-boron distances is investigated. The second section probes a series of transition-metal cyanide coordination polymers. The bidentate nature of the cyanide ligand allows for the possibility of forming numerous isomers. Information about the isomer(s) present is gained via the various NMR parameters available, such as the chemical shifts, shift anisotropies and J-couplings. This is then extended to the characterization of paramagnetic transition-metal cyanides, where strong electron-nuclear interactions are shown to significantly increase spin-lattice relaxation rates allowing the acquisition of spectra without the need of typically employed enhancement techniques, yet often yielding spectra of better quality. Variable-temperature experiments allow a measure of the electron-nuclear interaction, which can be related to spatial proximity, and provide “diamagnetic” chemical shifts allowing comparison with other cyanides. J-couplings and chemical shift anisotropies are shown to be applicable in much the same fashion as with diamagnetic systems.

No description available.

The objective of this dissertation is to demonstrate different applications of ssNMR, with particular emphasis on uses in polymeric and biosciences. First, dynamics investigations on two polymers will be discussed: (1) disulfonated poly(arylene ether sulfone)s /poly(ethylene glycol) blends (BPS-20_PEG), which are under development as chlorine-resistant reverse osmosis (RO) membrane alternatives to aromatic polyamide (PA) technology, and (2) poly(arylene ether sulfone)s modified with 1,4-cyclohexyl ring units to improve processability. Simple cross-polarization magic-angle-spinning (CPMAS) experiments compared the chlorine tolerance of BPS-20_PEG and PA. Techniques capable of detecting motional geometries and rates on timescales from nanoseconds to seconds, including relaxation time measurements, were applied. Correlations were established between relaxation time and water permeability for the RO membranes, and between relaxation time and polydispersity in the 1,4- cyclohexyl ring modified polymer. Next, 31P and 2H static ssNMR experiments evidencing the formation of toroidal pores and thinned bilayers in oriented zwitterionic and anionic phospholipid bilayers, (biomembrane mimetic systems), by the antimicrobial peptides (AMPs) magainin-2 and aurein-3.3, will be mentioned. The toroidal pore geometries induced by magainin-2 were different than those produced by aurien-3.3. The most prominent features were observed in 2H spectra, implying greater interaction of the peptides with hydrophobic lipid acyl chains. Following this, a new two-dimensional homonuclear dipolar recoupling MAS experiment, capable of correlating long range 13C-13C spin pairs in a uniformly/ extensively 13C-labeled biomolecule, will be introduced. This technique was demonstrated on 13C-labeled versions of Glutamine and Glycine-Alanine-Leucine. Experiments involving the recoupling of all 13C-13C spin pairs, and experiments with selective recoupling using Gaussian or cosine-modulated Gaussian pulses, were demonstrated. Finally, work using static 1H- 13C CP ssNMR to selectively detect interfacial water around hydrophobic C60 will be recounted. This project exploited the distance limitation of CP, and 1H spin-lattice relaxation times, to separate the influence of bulk and interfacial water on the spectra. Results indicated that the tumbling of interfacial water is slowed by a factor of 105 compared to bulk water, providing it with a solid-like character, and allowing the hydration shell to be stable at temperatures above the freezing point of water. / Ph. D.

In der hier vorgestellten Arbeit werden neuartige Festkörper-NMR (Nuclear Magnetic Resonance) Experimente vorgestellt, die eine direkte Detektion von Protonen einbeziehen. Die Technik basiert auf einer weitgehenden Verdünnung der Protonen durch Deuteronen in vollständig isotopenmarkierten, rekombinant exprimierten Proteinen und ermöglicht Festkörper-NMR mit sehr schmalen Linienbreiten aller standardmäßig erfassbaren Kerne (Protonen, Stickstoff, Kohlenstoff) ohne Hochleistungsentkopplung. Zusätzlich werden Methoden für ein besonders hohes Signal-zu-Rausch durch Paramagnetic Relaxation Enhancement (PRE) entwickelt. Die so präparierten Proteine erweisen sich tauglich für eine stark verbesserte NMR-Charakterisierung durch eine Vielzahl neuer Struktur- und Zuordnungsexperimente, in denen Techniken aus Festkörper- und Lösungs-NMR vereint werden. Dabei können hier erstmals auch Bereiche im Protein mit einbezogen werden, die langsame Dynamik vollziehen. Die Experimente finden Anwendung auf die SH3-Domäne von alpha-Spektrin, das Alzheimer-Peptid Abeta1-40 und das Membranprotein Omp G. / In this work, novel solid-state NMR (Nuclear Magnetic Resonance) experiments are presented that imply direct detection of protons. The technique is based on extensive dilution of protons with deuterons in uniformly labelled, recombinantly expressed proteins and allows for solid-state NMR providing very narrow lines of all commonly accessible nuclei (protons, nitrogen, carbon) without high-power decoupling. In addition, methods are developed that yield a particularly high signal-to-noise through Paramagnetic Relaxation Enhancement (PRE). The accordingly prepared proteins are shown to be applicable for a significantly improved NMR-characterization by manifold new experiments for assignment and structure elucidation, in which techniques from solid-state and solution NMR are united. For the first time, also those regions in a protein can be accessed that undergo slow dynamics. The experiments are employed on the SH3-domain of alpha-spectrin, Alzheimer’s peptide Abeta1‑40, and the membrane protein Omp G.

L’utilisation intensive des produits phytosanitaires, en particulier les insecticides, provoque des effets indésirables sur les organismes vivants et leur environnement. Mon travail de thèse a consisté à évaluer l’effet de deux insecticides chez un insecte modèle la drosophile. Une première étude concernait l’effet d’un néonicotinoïde, l’imidaclopride. Nous avons pu montrer que l’exposition chronique à des doses sublétales de cet insecticide perturbe la fonction de reproduction chez la drosophile. D’autre part, une exposition aiguë à l’imidaclopride a mis en évidence une résistance chez les femelles d’une souche de drosophile dite ``des champs´´. Deux mécanismes différents ont été mis en évidence dans la résistance à l’imidaclopride de cette souche. Le premier concerne la sous expression d’une sous-unité (D1) du récepteur nicotinique à l’acétylcholine, cible de l’imidaclopride. Le deuxième concerne l’implication des glutathion S-transférases, enzymes de détoxification, dans le métabolisme de l’imidaclopride. Ces études montrent que les insecticides peuvent avoir en plus des effets sur les insectes ravageurs, des effets néfastes sur des organismes non cibles. La deuxième étude avait pour but de modéliser chez la drosophile, l’impact d’un organochloré, la dieldrine, potentiellement impliquée dans la maladie de Parkinson chez l’homme. L’exposition à cet insecticide conduit à une dégénérescence des neurones dopaminergiques ainsi qu’une perturbation de la structure de régions particulières du cerveau. Nous avons également montré des altérations du métabolisme et l’implication de processus épigénétiques dans la neurodégénérescence induite par la dieldrine. Au cours de ce travail, nous avons pu montrer l’intérêt de nouvelles méthodes comme l’Imagerie par Résonance Magnétique (IRM) ou le High Resolution Magic Angle Spinning (HRMAS) dans ce type d’étude. / Pesticides have been used extensively and induce harmful effects on organisms and their environment. The aim of my PhD work was to investigate the effects of two insecticides by using Drosophila as a model. The first study concerns the effect of a neonicotinoid, imidacloprid. The results obtained have shown that a chronic exposure at sublethal doses of this insecticide affects reproduction in flies. Moreover, acute exposure at high doses has pointed out a resistance phenomenon in females of a field strain. We have shown that two mechanisms are implicated: (i) low expression of a subunit of a nicotinic acetylcholine receptor that is the target of imidaclopride and (ii) role of glutathione S-transférases, detoxication enzymes, in imidaclopride metabolism. These results highlight impact of insecticides, in particular imidaclopride, on non target organisms. The aim of the second study was to characterize in Drosophila, effects of an organochlorine, dieldrin, potentially implicated in the etiology of Parkinson’s disease in humans. Dieldrin exposure at low doses promotes neurodegeneration of dopaminergic neurons and alters structures of particular regions of the brain. Disruption of metabolism is also induced after exposition to dieldrin. In addition, we have shown that epigenetic processes are implicated in neurodegenration induced by dieldrin. This work show advantages of new techniques such as Magnetic Resonance Imaging (MRI) and High Reslution Magic Angle Spinning in this kind of study.

Liquid chromatography is an essential technique in manufacturing biopharmaceuticals where it is used on all scales from analytical applications in R&amp;D to full-scale production. In chromatography the target molecule, typically a protein, is separated and purified from other components and contaminants. Separation is based on different affinities of different molecules for the chromatographic medium and the physical and chemical properties of the latter determine the outcome. Controlling and designing those properties demand efficient analytical techniques. In this thesis the approach was to develop characterization methods based on nuclear magnetic resonance (NMR) spectroscopy for the assessment of various important physico-chemical properties. The rationale behind this strategy was that the versatility of NMR – with its chemical and isotopic specificity, high dynamic range, and direct proportionality between the integral intensity of the NMR signal and the concentration of spin-bearing atomic nuclei (e.g., 1H, 13C, 31P and 15N) – often renders it a very good choice for both qualitative and quantitative evaluations. These characteristics of NMR enabled us to develop two quantification methods for chromatography-media ligands, the functional groups that provide the specific interactions for the molecules being separated. Furthermore, a new method for measuring the distribution of macromolecules between the porous chromatographic beads and the surrounding liquid was established. The method, which we have named size-exclusion quantification (SEQ) NMR, utilizes the fact that it is possible to assess molecular size distribution from corresponding distribution of the molecular self-diffusion coefficient where the latter is accessible by NMR. SEQ-NMR results can also be interpreted in terms of pore-size distribution within suitable models. Finally, we studied self-diffusion of small molecules inside the pores of chromatographic beads. The results provided new insights into what affects the mass transport in such systems. The methods presented in this thesis are accurate, precise, and in many aspects better than conventional ones in terms of speed, sample consumption, and potential for automation. They are thus important tools that can assist a better understanding of the structure and function of chromatography media. In the long run, the results in this project may lead, via better chromatographic products, to better drugs and improved health. / Vätskekromatografi är en viktig teknik för tillverkning av biologiska läkemedel och används för alltifrån småskaliga analytiska applikationer till fullskalig produktion. I kromatografi separeras och renas målmolekylen (oftast ett protein), från andra komponenter och föroreningar genom att utnyttja molekylernas olika affinitet för det kromatografiska mediumet, vars fysikaliska och kemiska egenskaper har stor betydelse för hur separationen fungerar. För att kunna kontrollera och designa dessa egenskaper krävs effektiva analysmetoder. Strategin i den här avhandlingen var att utveckla metoder baserade på kärnmagnetisk resonans (NMR) spektroskopi för att karaktärisera flera viktiga fysikalisk-kemiska egenskaper. Anledningen till denna strategi är att mångsidigheten hos NMR – med dess kemiska och isotopiska specificitet, stora dynamiska omfång och direkta proportionalitet mellan NMR-signalens integralintensitet och koncentrationen av spinnbärande atomkärnor (t.ex. 1H, 13C, 31P och 15N) - ofta gör den till det bästa valet för både kvalitativa och kvantitativa tillämpningar. Dessa egenskaper hos NMR gjorde att vi kunde utveckla två kvantifieringsmetoder för kromatografimedia-ligander, dvs de funktionella grupperna som ger de specifika interaktioner som gör att molekylerna kan separeras. Dessutom har en ny metod för att mäta fördelningen av makromolekyler mellan de porösa kromatografiska pärlorna och den omgivande vätskan tagits fram. Metoden, som vi har valt att kalla size-exclusion quantification (SEQ) NMR, utnyttjar det faktum att det är möjligt att mäta molekylstorleksfördelningen genom att mäta motsvarande fördelning av självdiffusionskoefficienter, där den sistnämnda kan bestämmas med NMR. Resultaten från SEQ-NMR kan tolkas i termer av porstorleksfördelningar genom att använda lämpliga modeller. Slutligen studerade vi självdiffusion av små molekyler inuti porerna i kromatografiska pärlor. Resultaten gav nya insikter om vad som påverkar masstransporten i sådana system. De metoder som presenteras i denna avhandling är noggranna, precisa och på många sätt bättre än konventionella metoder när det gäller hastighet, låg provförbrukning och automatiseringspotential. De nya metoderna är därför viktiga verktyg som kan hjälpa till att ge en bättre förståelse av struktur och funktion hos kromatografimedia. I det långa loppet kan resultat från det här projektet kunna bidra till effektivare kromatografiska produkter, vilket i slutändan kan leda till bättre läkemedel och hälsa. / <p>QC 20170403</p>

Em experimentos de Ressonância Magnética Nuclear (RMN) com Rotação da Amostra em Tomo do Ângulo Mágico (MAS), as bandas laterais são um problema comum na obtenção de espectros de alta resolução em sólidos. Em espectrômetros de alto campo magnético ou então, em sistemas que não dispõem de rotores de amostra de freqüência elevada, este problema é mais grave. Para facilitar a interpretação do espectro de alta resolução torna-se necessário suprimir estas bandas laterais. Nesta dissertação descrevemos um método simples de supressão das bandas laterais que consiste em variar a freqüência de rotação da amostra durante a aquisição do sinal, assim como, a instrumentação necessária para realizar esse experimento. Este método, que denominamos de Supressão das Bandas Laterais utilizando-se Freqüência de Rotação Baixa e Variável, baseia-se na dependência da posição das bandas laterais com a freqüência de rotação, reduzindo as coincidências entre suas posições durante a promediação, enquanto o sinal isotrópico permanece estável sempre no mesmo ponto do espectro. Para ilustrar a utilização dessa nova técnica, realizamos experimentos de RMN com o núcleo de 13C em amostras de hexametilbenzeno, tirosina, lignina e ácido húmico, e com o núcleo quadrupolar 79Br em amostras de KBr e NaBr + KBr / Sidebands in Magic-Angle-Spinning Nuclear Magnetic Resonance (MAS-NMR) experiments are a common problem for high field spectrometers or low spinning frequency systems. Although these sidebands may be used to gain information after they have been identified, it is necessary to eliminate then to simplify the interpretation of the spectra; we have recently succeeded in suppressing spinning sidebands by continuously varying the speed during the signal acquisition. This method, that we called variable low speed sideband suppression, relies on the speed dependent of the sideband positions. The purpose of this work is to describe a simple method and apparatus to suppress spinning sidebands in MAS-NMR experiments. The method allows a quick acquisition of the isotropic chemical shift spectra and works well even when the highest available spinning cannot clearly resolve the spinning sidebands. To illustrate the method, we present the 13C MAS-NMR spectra of a variety of sample acquired using cross-polarization and high power proton decoupling. Among the samples studied were: hexamethylbenzene, tyrosine, lignin and humic acid. And quadrupolar nuclei 79Br in the samples Kbr and NaBr + KBr

Une compréhension précise de la géométrie de coordination et de la structure électronique autour d’un ion métallique à l’intérieur des catalyseurs et des matériaux de batteries est essentielle pour contrôler ces systèmes complexes, modifier leur fonctionnement, et permettre la conception logique de sites améliorés. Cependant, la structure de ces systèmes n’est pas toujours accessible par des techniques de diffraction, et même si elle l’est, la structure électronique ne peut alors être déduite qu’indirectement des coordonnées atomiques. De ce fait, il est essentiel d’avoir une sonde directe de la structure électronique. L’objectif de cette thèse est l’étude des propriétés structurales et électroniques des sites mé- talliques de catalyseurs et de matériaux de batteries par Résonance Magnétique Nucléaire en rotation à l’angle magique (MAS NMR). La MAS NMR est une technique très performante pour l’étude des effets locaux dans les matériaux à l’état solide et permet de sonder directement la structure électronique des matériaux paramagnétiques à haute résolution. Néanmoins, cette ap- proche souffre d’une pauvre résolution et d’une sensibilité limitée pour les noyaux proches d’un site paramagnétique. Pour dépasser ces limitations, nous avons levé des verrous dans l’acquisition et l’interprétation de la MAS NMR en développant et appliquant de nouvelles méthodes pour l’étude de solides paramagnétiques basées sur des hautes fréquences de rotation (60-111 kHz MAS). Pour ce faire, un répertoire de séquences d’impulsion a été développé pour la détection et l’interprétation des effets paramagnétiques dans des solides cristallins et non cristallins. Le potentiel de cette méthodologie a été examiné pour l’élucidation de la géométrie locale et de la structure électronique autour des sites paramagnétiques de catalyseurs homogènes ou hétérogènes, et des matériaux de cathodes en phase mixte pour des batteries au Lithium. Nous voyons dans les méthodes présentées ici, un ensemble d’outils indispensables pour l’élucidation de nombreuses questions de la chimie moderne relatives à la structure et la fonction des sites métalliques. / A precise understanding of the coordination geometry and electronic structure around metal cen- ters in catalysts and battery materials is crucial in order to control these complex systems, modify their behavior, and allow rational design of improved sites. However, such systems are not al- ways amenable for diffraction-based structural determination, and even if they are, obtaining atom-specific electronic structure can only be inferred indirectly from the atomic coordinates. As such, a direct probe of the electronic structure is highly desired. The aim of the present thesis is the investigation of structural and electronic properties of metal sites in catalysts and battery materials by magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. MAS NMR is a powerful technique for the investigation of local effects in solid materials, and offers a direct probe of highly resolved electronic structures in paramagnetic solids. However, it suffers from limited sensitivity and resolution for nuclei lying close to a paramagnetic center in general. We address these limitations by first tackling some of the bottlenecks in the acquisition and interpretation of MAS NMR by developing and applying new methodologies to paramagnetic solids using ultra-fast (60-111) kHz MAS rates. A "toolkit" of suitably designed pulse sequences is assembled for broadband detection and interpretation of paramagnetic shifts in crystalline and non-crystalline solids. The potential of this methodology is explored for the elucidation of local geometry and electronic structure around paramagnetic metal sites in homogeneous and heterogeneous catalysts, and a set of mixed-phase Li-ion battery cathode materials. We anticipate that the approaches described herein form an essential tool to elucidate many outstanding questions about the structure and function of metal sites in modern chemistry.

This study investigated the critical behaviour of ternary mixtures of DOPC and DPPC, with cholesterol. The properties of model membranes such as these are studied in order to provide insight into aspects of complex biological systems. Experiments were performed using the Jeener echo, a static solid-state NMR technique, however no information about the critical phenomena was obtained. Conversely, the sideband linewidths measured from 2H MAS NMR are sensitive to temperature and dependent upon the phase behaviour. By fitting the linewidth data to an equation from Suwelack et al. (J. Chem. Phys., 1980; 73(6):2559-2569), the critical temperature and the critical exponent for the correlation length of the system were calculated. The critical exponent values obtained from these samples ranged between νc = 0.65 and νc = 1.2, which encompasses the critical exponents for both the 2D and 3D Ising models within error. The universality class for these model membranes cannot be unambiguously assigned yet.

Em experimentos de Ressonância Magnética Nuclear (RMN) com Rotação da Amostra em Tomo do Ângulo Mágico (MAS), as bandas laterais são um problema comum na obtenção de espectros de alta resolução em sólidos. Em espectrômetros de alto campo magnético ou então, em sistemas que não dispõem de rotores de amostra de freqüência elevada, este problema é mais grave. Para facilitar a interpretação do espectro de alta resolução torna-se necessário suprimir estas bandas laterais. Nesta dissertação descrevemos um método simples de supressão das bandas laterais que consiste em variar a freqüência de rotação da amostra durante a aquisição do sinal, assim como, a instrumentação necessária para realizar esse experimento. Este método, que denominamos de Supressão das Bandas Laterais utilizando-se Freqüência de Rotação Baixa e Variável, baseia-se na dependência da posição das bandas laterais com a freqüência de rotação, reduzindo as coincidências entre suas posições durante a promediação, enquanto o sinal isotrópico permanece estável sempre no mesmo ponto do espectro. Para ilustrar a utilização dessa nova técnica, realizamos experimentos de RMN com o núcleo de 13C em amostras de hexametilbenzeno, tirosina, lignina e ácido húmico, e com o núcleo quadrupolar 79Br em amostras de KBr e NaBr + KBr / Sidebands in Magic-Angle-Spinning Nuclear Magnetic Resonance (MAS-NMR) experiments are a common problem for high field spectrometers or low spinning frequency systems. Although these sidebands may be used to gain information after they have been identified, it is necessary to eliminate then to simplify the interpretation of the spectra; we have recently succeeded in suppressing spinning sidebands by continuously varying the speed during the signal acquisition. This method, that we called variable low speed sideband suppression, relies on the speed dependent of the sideband positions. The purpose of this work is to describe a simple method and apparatus to suppress spinning sidebands in MAS-NMR experiments. The method allows a quick acquisition of the isotropic chemical shift spectra and works well even when the highest available spinning cannot clearly resolve the spinning sidebands. To illustrate the method, we present the 13C MAS-NMR spectra of a variety of sample acquired using cross-polarization and high power proton decoupling. Among the samples studied were: hexamethylbenzene, tyrosine, lignin and humic acid. And quadrupolar nuclei 79Br in the samples Kbr and NaBr + KBr