The major directions of this thesis involve (1) the synthesis, immobilization, and characterization of tridentate phosphine linkers on silica, (2) the study of unprecedented Si2C bond cleavage in Rh and Ir phosphine complexes, and (3) the study of performance polymers with solid2state NMR techniques. First a brief overview of solid2state NMR and its relevance to the various areas of chemistry covered in this thesis is given. Following the synthesis, immobilization, and characterization of tridentate phosphine ligands, EtOSi[(CH2)nPPh2]3 (n = 4, 7, 11) and [MeP((CH2)nPPh2)3]+I? (n = 4, 7, 11) on silica is detailed. Both, immobilization by electrostatic interactions and by a covalent siloxane bond to the support, is studied and compared. Ligand exchange with Wilkinson?s catalyst affords immobilized Rh complexes. These materials are applied to catalytic olefin hydrogenation. In either case active hydrogenation catalysts are obtained that can easily and efficiently be recycled up to 30 times. Detailed investigations reveal that irrespective of the linkage to the support the catalysts consist initially of well2defined molecular species that form supported Rh nanoparticles with a narrow size distribution in the course of the catalytic reaction. The nanoparticles are active hydrogenation catalysts as well, and no metal leaching into solution is detected. The reaction of the tridentate phosphine ligands EtOSi[(CH2)2PPh2]3 and MeSi[(CH2)2PPh2]3 with Rh and Ir complexes is investigated. This reaction does not lead to the anticipated Wilkinson2type complexes with the metal in the +I oxidation state, but instead to oxidative addition of the C(sp3)2Si bond to Rh or Ir centers to yield octahedral complexes with the metal in the +III oxidation state. These complexes are fully characterized by multinuclear NMR in solution and in the solid state. Preliminary density functional theory (DFT) calculations corroborate the preference for oxidative addition. Subsequently the study of performance thermoplastics which are important materials for the oil and gas industry is presented. The polymer morphology is studied by solid2state NMR techniques. Special attention is devoted to potential decomposition pathways at elevated temperatures for polyetheretherketone (PEEK) and polyphenylene sulfide (PPS) polymers. 13C CP/MAS (cross polarization with magic angle spinning) NMR and IR spectroscopy reveal that PEEK polymers show no detectable chemical change on the molecular level, while PPS polymers display signs of oxidation of the thioether group and branching via formation of ether, thioether, and biphenyl linkages. Furthermore, the water absorption of polybenzimidazole (PBI), polyetherketoneketone (PEKK), and their blend PEKK2PBI is studied. It is demonstrated that steam2treatment even at high temperatures and pressures does not cause chemical decomposition and that the changes, which are morphological in nature, are fully reversible.

A la present tesi doctoral es desenvolupen nous estudis sobre agents de solvatació quiral (CSA) difuncionals. Els CSAs tenen la capacitat d'interaccionar de forma diferencial amb cada un dels enantiòmers d'una mescla d'un substrat quiral, mitjançant la formació d'enllaços no covalents, és a dir, de tipus àcid-base, ponts d'hidrògen, dipolars,... formant complexes d'associació diastereomèrics. Aquest reconeixement quiral produeix un diferent entorn químic i magnètic dels enantiòmers, el que per RMN es podrà observar en una anisocronia dels seus senyals, principalment de protó. Aquesta diferència dels desplaçaments químics ens permetrà determinar la composició de la mescla. Ja que l'observació dels senyals és una mitja d'un sistema dinàmic entre els elements lliures i complexats, la separació dels senyals dependrà tant de la termodinàmica de l'associació com de les característiques estructurals dels complexes.En el nostre grup d'investigació es va abordar la síntesi de CSAs difuncionals. En el primer cas que ens ocupa a la present tesi doctoral, l'?,?'-bis(trifluorometil)-9,10-antracendimetanol (ABTE) va aportar una gran capacitat enantiodiferenciadora. Els estudis per RMN ens permeteren atribuir aquests resultats en la capacitat que té el confórmer Cisoide de l'ABTE en generar complexes bidentats amb els substrats quirals, en els que la major proximitat del CSA a cada una dels enantiòmers del substrat, provoca una major diferenciació en l'entorn magnètic.A la present tesi doctoral s'abordà la síntesi estereoselectiva de l'ABTE. La reducció tipus CBS del 9,10-bis(trifluoroacetil)antracè ens permeté obtenir el CSA desitjat en un 65% de rendiment i amb una proporció estereomèrica de RR/RS/SS= 89:11:0. Aquesta ruta es va dur a escala més gran, per tal de fer la seva fabricació per a la seva comercialització (ACRÔS).Per RMN també s'estudien les associacions entre l'ABTE i l'1,2-benzendimetanol i l'1,3-benzendimetanol, per evidenciar l'existència dels complexes bidentats. S'observen les variacions dels senyals de protó del CSA, també es determinen les estequiometries dels complexos i les seves constants de formació. L'estudi es completa amb un estudi teòric per mecànica molecular. Amb tots els resultats es pot concloure que el CSA forma un complex bidentat amb l'1,2-benzendimetanol i també amb l'1,3-benzendimetanol, però amb aquest últim no de forma exclusiva sinó que també existeixen associacions monodentades.També s'estudien les diferències estructurals i d'estabilitat de la interacció entre l'ABTE i l'1-aminoindà i l'1-amino-2-indanol. L'existència de l'associació bidentada s'evidencià amb la major variació dels desplaçaments químics de cada un dels enantiòmers del substrat en relació a la que es va obtenir en la solvatació amb el CSA homòleg monofuncional. Amb el primer substrat es va poder atribuir en un augment de l'estabilitat de l'associació, degut, segurament a una disminució de l'entropia. En canvi, amb l'1-amino-2-indanol no es van apreciar diferències en l'estabilitat, amb el que podem atribuir una major variació dels desplaçaments químics a efectes estructurals de la complexació, principalment en una associació bidentada més íntima.A la segona part de la tesi es desenvolupa la síntesi estereoselectiva de l'?,?'-bis(trifluorometil)-9,10-antracendimetanamina (ABTA), que s'obté per la doble trifluorometilació de la sulfinimina quiral derivada de la condensació del 9,10-antracendimetanol amb la sulfinamida de Ellman, amb un rendiment global d'ABTA del 57% i de forma enantiopura. També es descriuen les síntesis de la 2,2,2-trifluoro-1-(9-antril)etilamina, la 1-(9-antril)etilamina i l'aproximació de l'?-trifluorometil-9-[10-(2,2,2-trifluoroetanamino)]antracenmetanol (ABTEA).Es fan diversos estudis de solvatació mitjançant RMN, del nou CSA difuncional ABTA. En ells es va observar la separació de les bandes dels protons dels enantiòmers en afegir un elevat nombre d'equivalents de CSA, fins a 15, i l'estudi termodinàmic, que també es va realitzar per RMN, ens va donar constants d'associació molt baixes. Probablement, aquests resultats es deuen a la poca basicitat del grup amino, que no afavoreix la formació de ponts d'hidrògen. / In the current thesis new studies about difunctional chiral solvating agents (CSA) are developed. CSAs have the ability to interact differentially with each of the enantiomers of a chiral substrate, through non covalent bonds, like acid-base interactions, hydrogen bonds, dipolar interactions.giving diastereomeric associative complexes. This chiral recognition produces distinct chemical and magnetic properties to each enantiomer, that will be observed, in RMN, as an anisocrony of its signals, mainly the proton signals. This chemical shift difference will allow us to determine the composition of the mixture. Since the observed chemical shifts are an average of a dynamic system where elements are free or complexate, the chemical shift variation will depend on the thermodynamic of the association and either on the structural properties.In our research group, the synthesis of difunctional CSAs has been developed. The first case which we're dealing with at the current thesis, is the ?,?'-bis(trifluoromethyl)-9,10-anthracenedimethanol (ABTE), that showed, in last studies, an excellent chiral recognition capacity. The NMR studies allowed us to conclude that this attribute is due to the capability of the Cisoid conformer of the ABTE to give bidentate complexes with the chiral substrates, where the greater proximity of the CSA to each one of the enantiomers of the substrate, induces a greater differentiation of their magnetic fields.In the current thesis, the stereoselective synthesis of ABTE has been developed. The CBS reduction of 9,10-bis(trifluoroacetyl)anthracene allowed us to obtain the desired CSA in a 65% yield with an stereomeric ratio of RR/RS/SS=89:11:0. This reaction has been scaled up for the manufacture and commercialization of the product (ACRÔS).With the NMR, we have been studied the association between ABTE and 1,2-benzenedimethanol and 1,3-benzenedimethanol, to demonstrate the existence of the bidentate complexes. We observed the chemical shift of the proton signals of the CSA, and we determined the stequiometry of the complexes and their binding constant. The study is completed with a theoretical estimation by molecular mechanics. With all the results, we could conclude that the CSA generates a bidentate complex with 1,2-benzenedimethanol and also with 1,3-benzenedimethanol, but not as an exclusive form with the last one, which would be in equilibrium with monodentate associations.There has been studied, also, the structural and thermodynamic differences of the interactions of the ABTE with 1-aminoindane and 1-amino-2-indanole. The greater difference of the chemical shifts between enantiomers of each substrate compared to the results obtained when using the comparable monofunctional CSA, gives us evidences of the existence of the bidentate association. With several NMR experiments, we could attribute the greater chiral recognition with the first substrate to a more stable association, due to probably lower entropy. On the other hand, the association with the second substrate didn't improve because of a more stable complex, but for the structural properties, mainly in a more close bidentate association.At the second part of the thesis, the stereoselective synthesis of ?,?'-bis(trifluoromethyl)-9,10-antracenedimethanamine (ABTA) is developed. It consists in a double stereoselective trifluoromethylation of the chiral sulfinimine derived from the condensation of 9,10-anthracendimethanol with the Ellman sulfinamide, with a 56% global yield of the ABTA in its enantiopure form. There are also described the synthesis of 2,2,2-trifluoro-1-(anthryl)ethylamine, 1-(9-anthryl)-ethylamine and the approach to the ?-trifluoromethyl-9-[10-(2,2,2-trifluoroethanamino)]anthracenemethanol (ABTEA).The chiral recognition capability of the new difunctional CSA, ABTA, is studied with several chiral substrates. The registered NMR experiments showed us a generally low capacity, observing the differentiation of the chemical shifts of the enantiomers after adding great amounts of CSA. The thermodynamic study could be done also with the NMR, and it gave us very low binding constants of the diastereomeric complexes. These results could come, probably, of the low basicity of the amino group, that wouldn't favour the formation of hydrogen bonds.

NMR Instrumentation

Solid state ¹H MAS NMR spectroscopy was used to investigate the temperature and hydration dependance of water and hydroxyl proton spectra of hydrated mesoporous MCM-41. The NMR spectra show a complex peak structure, with hydroxyl proton resonances seen in dry MCM-41 disappearing as water is introduced into the pores, and new peaks appearing representing water and hydrated silanol groups. Until now the assignment of these peaks was unclear and the consensus was that magnetization exchange played an important role in the coalescence of the various peaks which appear in the spectra. It was found recently that magnetization exchange is not necessary to produce the spectral featured observed [Niknam, M., M.Sc. Thesis, University of Waterloo (2010)]. In the present study a simplified model, based on chemical shift averaging by the making and breaking of hydrogen bonds as water undergoes rotational motion and translational self-diffusion on the pore surface, has been developed to explain the NMR spectral results. The model is able to reproduce the experimental ¹H MAS NMR spectra for all hydrations and temperatures studied. For the first time, definitive spectral assignments for all hydroxyl and water protons in the sample has been achieved. Spectral features arising due to temperature change have been explained by using the known result that the proton chemical shift of a hydrogen atom involved in hydrogen bonding varies linearly with temperature. Furthermore, it is reported for the first time, that with increasing hydration, water molecules begin to favour forming two hydrogen bonds to the surface. This may represent the first step in the pore filling process.

Design and characterization of tissue engineered substitutes rely on robust monitoring techniques that provide information regarding viability and function when exposed to various environmental conditions. In vitro studies permit the direct monitoring of cellular and construct changes because these substitutes remain accessible. However, upon in vivo implantation, changes in cell viability and function are often detected using indirect or invasive methods that make assessing temporal changes challenging. . Thus, the development of non-invasive monitoring modalities may facilitate improved tissue substitute design and, ultimately, clinical outcome. The overall objective of this thesis was to establish a method to monitor and track cells and the cellular environment within a tissue engineered substitute in vitro and in vivo. This was accomplished via 31P NMR spectroscopy and through the incorporation of perfluorocarbon (PFC) emulsions for the monitoring of DO concentration by 19F NMR spectroscopy. The first aim of this thesis was to develop a method that tracked the state of cells and of the cellular environment within alginate constructs during perfusion studies in which the perfusing medium DO concentrations were changed over time or cells were exposed to a cytotoxic antibiotic. Due to challenges in acquiring DO concentration gradient information within beads, a second aim was to develop a mathematical model that would calculate gradients from experimentally acquired volume averaged DO concentrations; thus, significantly enhancing the robustness of tracking the alginate beads. Lastly, since the PFC emulsions used in the study may affect cell viability and function, a third aim was to characterize, experimentally and via modeling, the effect of several PFC emulsion concentrations on the encapsulated and #946;TC-tet cells.

The dynamical characteristics and the structure of lithium in Nafion were investigated by solid state magic angel spinning nuclear magnetic resonance(MAS NMR). Variable temperature, longitudinal NMR relaxation time(T1), self-diffusion coefficients and rotational activation energy of various concentrations were determined. The distribution of the 7Li MAS NMR spectra of Nafion/Li represent the pore size, and T1 of Nafion/Li is slower than the bulk lithium solution, it implied the lithium were crowed in the pore(exchanged with the proton). Rotational activation energy illustrated the block level of lithium in different pores of Nafion. In the longitudinal NMR relaxation rate of various concentrations, instead, the type of bonding between lithium and water were different. The variable temperature experiments of 7Li MAS NMR spectra also illustrated the temperature about 60~66¢J result in the change of microstructure of Nafion.

Nafion has been the mostly used perfluorosulfonated proton exchange membrane (PEM) in fuel cell. Although a number of problems remain to be resolved on the application of Nafion as a PEM, a less expensive alternative PEM has not been found mainly because of its high proton conductivity. Therefore, much effort has been invested to modify it or find a better and inexpensive material. The exploration of the methods to counter degradation and aging of Nafion is also an important direction of research. In this work, the behavior of PEG in Nafion is investigated with solid state NMR spectroscopy. A series of samples with different PEG sizes and concentrations in Nafion was prepared and the variable temperature proton spectra and longitudinal relaxation times (T1) were measured on two spectrometers. Some interesting findings were made, e.g., the 1H chemical shift of water in concentrated PEG solution decrease while its T1 increase, the higher the concentration of PEG, the larger the increase (of water 1H chemical shift) or decrease (of water 1H T1). These findings provide valuable information on further improving the performance of Nafion in proton conductivity and durability.

Perfluororated proton exchange membrane Nafion is the mostly used type of ion exchange membrane in fuel cells. Over the past decades, various studies have been carried out on their structures at different scales, proton conduction mechanism, electrochemical performance, thermal and mechanical properties etc, but many problems are still open, such as the precise picture of proton conduction, degradation and aging of the membrane, even the distribution of pores and channels etc. Because membrane degradation is crucial for practical operation of fuel cells and its understanding offers insights for developing new generation membranes, more and more attention is paid to this issue. Methanol is used in direct methanol fuel cells (DMFC) and alcohols are sensitive to the structure and dynamics of Nafion. In addition, aqueous solutions of alcohols are known to have special mesoscopic structures. Therefore, this thesis employs the aqueous solution of methanol as a probe and investigate the physicochemical mechanism of the degradation of Nafion 117 by means of solid state NMR spectra, relaxation, exchange, diffusion and micro-imaging. A series of methanol-water binary solution samples covering the entire range of concentration (0% ~ 99%(w/w)) were prepared and the 1H,17O NMR spectra,T1¡BT2, exchange rate, diffusion coefficient of these samples in bulk and in Nafion were measured. In bulk samples, the OH peak of water and that of methanol could be resolved with concentration at or above 40% (w/w). The microscopic and mesoscopic structure and dynamics of methanol solutions (in bulk) were subsequently investigated with variable temperature and diffusion experiments. By measuring the variable temperature 1H and 17O spectra, T1, T2, diffusion and micro-images of the methanol solutions in Nafion 117, the structure and dynamics of methanol solutions in bulk and in Nafion 117 were then compared. Based on these data, the structure an dynamics of Nafion 117 and the correlations between methanol and proton conduction and membrane degradation are discussed. The results of this work provides valuable reference for further understanding the structure, dynamics and degradation of Nafion and their relationship with proton conduction.

Zeolites are microporous crystalline materials, which are widely used in catalysis, adsorption, and ion-exchange processes. However, in most cases, the synthesis of novel zeolites as functional materials still relies on trial-and-error methods, which are time consuming and expensive. Therefore, the motivation for this thesis work is to understand the zeolite synthesis mechanismand further develop knowledge for manipulating zeolite properties and ultimately the rational design of porous materials. This work focused on formation of silicalite-1 (pure-silica ZSM-5) from basic aqueous solutions containing tetraorthosilicate (TEOS) as silica source, and tetrapropylammonium (TPA) cations as the organic structure-directing agent. The presence of silica precursor particles with size of 2-5 nm in these mixtures prior to and during hydrothermal treatments have been observed through dynamic light scattering (DLS), small-angle X-ray (SAXS) and transmission electron microscopy (TEM). However, to quantify composition and the molecular structure transformation of these silica precursor particles during zeolite synthesis is still a technical challenge. Another important yet unresolved question is how organocations interact with these nanoparticles and direct zeolite nuclei. Unlike many studies performed analyzing the inorganic phase (silica) present in synthesis mixtures, this study quantified the organocation-silica particle interaction and its ultimate effect on zeolite growth mainly through probing the behavior of the organocations. Pulsed-field gradient (PFG) NMR was used to capture the mobility change of organocations, and was complemented with scattering measurements (DLS, SAXS) on the silica nanoparticles. On the basis of the measurement results, the thermodynamic and kinetic properties of the organic-inorganic interaction were derived. Upon aging at room temperature, this interaction manifested as binding of TPA onto the silica particles due to electrostatic interactions, and such binding behavior can be well described by the Langmuir adsorption model. Upon hydrothermal treatment, a fraction of TPA adsorbed at room temperature dissociates from the growing silica nanoparticles and the corresponding desorption profiles were fitted well by the pseudo-second order kinetic model. The addition of tetramethylammonium (TMA) as "competitors" promoted TPA desorption kinetics and hindered silica nanoparticle growth due to stronger association of TMA with particles than that of TPA. Finally, the TPA adsorption strength increased via addition of monovalent salts with increasing ionic size whereas that of TMA shows an opposite trend. This suggests one potential route for tuning the organic-silica precursor particle interactions and thus possibly affecting some kinetics steps in the synthesis.

Minor amounts of monomers or homopolymer of poly(butylene succinate) (PBS) were copolymerized or blended with monomers or homopolymer of poly(ethylene succinate) (PES). PEBSA 95/05 represents a copolymer synthesized from a feed ratio of 95 mol% ethylene glycol and 5 mol% 1,4-butanediol with 100 mol% succinic acid. Copolymers PEBSA 90/10 and 50/50 were also synthesized. Blends of PES and PBS were prepared in solution with ratios of PES/PBS: 98/02, 95/05 and 90/10. Molecular weights of homopolymers and copolymers were measured using capillary viscometer and gel permeation chromatography. The results indicate that polyesters used in this study have high molecular weights. The chemical composition and the sequence distribution of co-monomers in copolyesters were determined using 1H NMR and 13C NMR. The distribution of ES and BS units in these copolyesters was found to be random from the evidence of a single Tg and a randomness value close to 1.0 for a random copolymer. Thermal properties of polyesters and blends were characterized using differential scanning calorimeter (DSC), temperature-modulated DSC (TMDSC) and thermogravimeter. For copolymers, melting point of PES significantly decreases from 100.9 to 94.5 to 89.8 oC with an increasing in BS units from 0 to 5 to 10 mol%. Blends keep the intrinsic melting points of PES and PBS homopolymers. There is no significant difference or no trend about the thermal stability of these polyesters and blends. Wide-angle X-ray diffractograms (WAXD) were obtained for specimens after complete isothermal crystallization. Diffraction peaks indicate that the crystal structure of PES is dominated in PES-enriched copolymers. However, PEBSA 50/50 displays weak diffraction peaks of the characteristic peaks of PBS homopolymer. Isothermal crystallization of copolyesters and blends were performed using DSC. Their crystallization kinetics and melting behavior after complete crystallization were analyzed. The n1 values of the Avrami exponent for copolyesters increased from 2.54 to 2.84 as the isothermal temperature (Tc) increased. The Hoffman-Weeks linear plots yielded an equilibrium melting temperature of 111.1 and 107.0 oC, respectively, for PEBSA 95/05 and 90/10. Homopolymer PES has an equilibrium melting temperature of 112.7 oC. For blends, the n1 value has a minimum at Tc of 40 oC then it increases with an increase in Tc or in PBS. At the same Tc, n1 increases slightly and the rate constant (k1) decreases when the ratio of PBS in blends increases. All of these blends gave an equilibrium melting temperature of 113.1 oC. Multiple melting behavior involves melting-recrystallization-remelting and various lamellar crystals. As Tc or BS unit in copolymer increases, the contribution of recrystallization slowly declines. Acetophenone was used a diluent for PES homopolymer. Five concentrations were used to estimate the melting point depression, and the heat of fusion of PES was obtained to have a value of 163.3 J/g according to Flory equation. Spherulitic growth rates of copolymers were measured at Tc between 30 and 80 oC using polarized light microscope (PLM). Maximum growth rates occurred at Tc around 50 oC. It is found that the growth rate of copolymer decreases significantly after randomly incorporating BS units into PES. Non-isothermal method at a cooling rate of 2, 4 or 6 oC/min was used to calculate the isothermal growth rates of copolymers. These continuous data fit very well with the data points measured isothermally. Growth rates data are separately analyzed using the Hoffman-Lauritzen equation. A regime II-III transition is found at 59.4 and 52.4 oC, respectively, for copolyesters PEBSA 95/05 and PEBSA 90/10. The results of DSC and PLM indicate that blend PES/PBS 98/02 not only retains the melting point and the crystallinity of PES homopolymer, but also increases the nucleation rate of this blend. The effect of blending 2 mol% PBS with PES on the biodegradability of PES is deserved to be investigated furthermore.