Dissertations / Theses: 'Resolution (Chemistry)'

1

Parkin, Richard M. "Kinetic resolution strategies." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343475.

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2

Stevens, Anne Theresa. "The optical resolution of albuterol." Master's thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/19648.

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The acetonide derivative of (rac)-albuterol has been prepared and used as a substrate in cocrystallisation experiments with several acidic resolving agents~ Successful resolution of the acetonide was achieved with both di-0-benzoyl- and di-0-toluoyltartaric acid, with the (2S,3S)enantiomer of the acid selectively co-crystallising with the desired (R)-albuterol acetonide. High performance liquid chromatography on a chiral stationary phase, and 1H NMR experiments using a chiral shift reagent were used to assess the optical purity of the resolved material. Acid hydrolysis of the resolved acetonide gave rise to the target, (R)-albuterol, which was isolated as an acetate salt. The inferred absolute configuration of the resolved acetonide was assessed by 1H NMR analysis of its (R)-Mosher ester, and confirmed by an X-ray structural determination of its (R)-phenylethylurea derivative. The acetonide derivative of (rac)-albuterol has been prepared and used as a substrate in cocrystallisation experiments with several acidic resolving agents~ Successful resolution of the acetonide was achieved with both di-0-benzoyl- and di-0-toluoyltartaric acid, with the (2S,3S)enantiomer of the acid selectively co-crystallising with the desired (R)-albuterol acetonide. High performance liquid chromatography on a chiral stationary phase, and 1H NMR experiments using a chiral shift reagent were used to assess the optical purity of the resolved material. Acid hydrolysis of the resolved acetonide gave rise to the target, (R)-albuterol, which was isolated as an acetate salt. The inferred absolute configuration of the resolved acetonide was assessed by 1H NMR analysis of its (R)-Mosher ester, and confirmed by an X-ray structural determination of its (R)-phenylethylurea derivative.

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3

Waterman, Naomi Ariane. "Super-resolution imaging with metamaterials." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8151/.

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The key area of investigation of this research project was the application of metamaterials to super-resolution optical imaging. Specifically, an optical microscope was proposed to emulate a TIRF-SIM microscope, but using metamaterials to create a structured evanescent field. A metamaterial unit cell design of two ‘H’ shape nano-holes at ±45° to the normal in a gold film, with 50nm feature size was developed and simulated in CST Microwave Studio, able to produce structured evanescent illumination patterns. Although this original design proved unsuccessful, both in terms of fabrication and image reconstruction, an alternative design was developed. Alongside this, in MATLAB an algorithm for SIM image reconstruction using the typical sinusoidal masks was created successfully. Then to accommodate atypical SIM masks, such as those produced by the metamaterials, new approaches to SIM image reconstruction were also developed. These approaches modelled the masks as the sum of sinusoids and as the product of sinusoids. These reconstruction approaches were unsuccessful when using the original metamaterial masks, but were successfully able to reconstruct image with improved resolution, compared to standard SIM, using the alternative metamaterial masks. Moreover, resolution enhancement was demonstrated using six masks instead of the nine or more typically used.

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4

Grange, Andrew H. "Medium resolution atmospheric pressure ionization mass spectrometry /." Full text open access at:, 1988. http://content.ohsu.edu/u?/etd,158.

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5

Potente, Nina M. "High Resolution Structural Studies of vc-ASADH." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1271384044.

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6

Nelson, Keegan Gregory. "Enantioselective hydrolysis of 1-arylpropargylic esters by enzymatic kinetic resolution and dynamic kinetic resolution of 1-arylallylic esters." Thesis, University of Missouri - Kansas City, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1538847.

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Chiral 1-arylprop-2-en-1-ols and 1-arylprop-2-yn-1-ols are useful building blocks for modern pharmaceuticals. Previous work has found that enzyme catalysis is a potential new enantioselective synthetic route to the former. We found that Candida antarctica lipase is also an effective catalyst for kinetic resolution of various substituted 1 arylpropargylic acetates and haloacetates, affording the respective (R) -1 arylproargylic alcohols with high enantioselectivity (99-100% ee). By varying the substituents on both sides of the ester bond, we discovered that the deacylation of lipase is likely the rate-determining step for our catalytic system. A greater challenge is designing a dynamic kinetic resolution (DKR) system for such substrates, which combines a resolving catalyst (lipase) with a racemizing catalyst, and can potentially lead to quantitative conversion of a racemic substrate into an enantiopure product. We studied the efficacy of various transition-metal complexes for substrate racemization and will report our results for In and Cu compounds.

While kinetic resolution has been performed on the 1-arylallylic acetates with excellent yield and enantioselectivity and the DKR regime has been designed, the resulting site-isolation system has required further testing and fine tuning. We have herein investigated the utilization of macroscale site-isolation as well as various factors including solvent, and acyl donor effects in order to optimize conditions of the system.

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7

Fowkes, Amelia Jane. "High resolution powder neutron diffraction in solid state inorganic chemistry." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299525.

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8

Bell, W. "High resolution spectroscopy of stratospheric trace species." Thesis, University of Strathclyde, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325275.

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9

Panov, Sergey I. "Moderate and high resolution spectroscopy of transient molecular ions /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487945015618952.

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10

Pushkarsky, Michael B. "High resolution spectroscopy and photochemistry of the free radicals /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488202678773409.

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11

Pauley, Deanne Josephine. "High-resolution microwave spectroscopy of several weakly bound complexes." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185187.

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High resolution rotational spectra were obtained for a several weakly-bound complexes (WBC) and one transition metal organometallic molecule, cyclopentadienylnickel nitrosyl (CpNiNO), using pulsed-beam, Fourier transform microwave spectroscopy. The weakly-bound complexes included the two structural isomers of N₂O-HF, the planar bent asymmetric N₂O-HCN complex, the planar bent asymmetric N₂O-HCl complex, and the "stacked" H₂S-SO₂, and H₂S-CO₂ complexes. In all of the cases with the exclusion of the CpNiNO molecule, additional isotopic measurements were obtained to aid in the spectral and structural analyses of the weakly-bound complexes. Analysis of rotational spectra was used to determine several spectroscopic constants. For each WBC and CpNiNO rotational constants and some quartic distortion parameters were determined. In the experimental studies performed on N₂O-HCN and N₂O-HCl additional quadrupole coupling components were determined from the data analysis. Structural analyses were performed on all of the WBC's. Isotopic Kraitchman analysis was used as a comparative guideline in helping to select the lowest energy vibrationally-averaged structure. High resolution (0.005 cm⁻¹) infrared spectra for CpNiNO were obtained with the Fourier transform spectrometer in the Kitt Peak McMath Solar Telescope. Absorption spectra were measured in the 1750-1880 cm⁻¹ and 2500-3700⁻¹ regions. A program written by Dr. Clive Jarman, a postdoc in Dr. Peter Bernath's laboratory, was used to perform Loomis-Wood analysis of 2 significant patterns in the 2500-3700 cm⁻¹ range. The series determined from the Loomis-Wood analysis are given in the dissertation.

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12

Ng, Youn Chen Marie Christine. "Kinetic resolution of carboxylic acids by microbial lipases." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60723.

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Four microbial lipases were examined to test a proposed substrate model based on the relative size of the substituents on the stereogenic carbon of $ alpha$-substituted carboxylic acids (Fig. 5). Literature and our results for the kinetic resolution of carboxylic acids with the lipases from Candida rugosa, Aspergillus niger, Mucor meihei and Pseudomonas cepacia showed that sterics alone do not account for enzymatic enantioselectivity.
In the course of this work, it was found that the lipase from Aspergillus niger showed appreciable enantioselectivity (E = 19 $ pm$ 3 at pH 7/10 mM phosphate buffer) in the hydrolysis of methyl pipecolinate. Given that there are limited ways to obtain optically pure pipecolinic acid, our results offered a viable alternative. Consequently, three strategies were used to improve this enantioselectivity. Altering reaction conditions (pH, concentration and type of buffer) and substrate modifications did not improve enantioselectivity significantly. Partial purification of the crude lipase from Aspergillus niger improved the enantiomeric ratio from ca. 20 to greater than 100 for the hydrolysis of octyl pipecolinate.

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13

Milner, Christian Rigby. "High spectral resolution remote sensing of foliar chemistry in forest ecosystems." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621793.

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14

Caulkins, Bethany Gayle. "Enzymatic Intermediates of Tryptophan Synthase at Atomic Resolution Using Solid-State NMR." Thesis, University of California, Riverside, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10286555.

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The acid-base chemistry that drives catalysis in pyridoxal-5'-phosphate (PLP)-dependent enzymes has been the subject of intense interest and investigation since the initial identification of its role as cofactor in this extensive class of enzymes. X-ray crystallography, optical spectroscopy, and physical-organic studies point to the importance of protonation/deprotonation at ionizable sites on the coenzyme, substrates, and sidechains to activate key steps in the catalytic process. Yet direct characterization remains elusive as these techniques cannot specifically identify proton locations or report unambiguously on local chemical environment. The chemical shift in nuclear magnetic resonance (NMR), however, is an extremely sensitive probe of chemical environment, but a large complex like a protein will give an enormous amount of data that can be inscrutable without guidelines for specific structure determination. The use of computational chemistry aids in the creation of models that rely on specific chemical-level details and predicts detailed information like chemical shift. We employ NMR crystallography – the synergistic combination of X-ray diffraction, solid-state NMR spectroscopy, and computational chemistry - to define three-dimensional, chemically-detailed structures of the intermediates in the tryptophan synthase cycle under conditions of active catalysis. Together these methods can provide consistent and testable models for structure and function of enzyme active sites. Our results from studies on tryptophan synthase confirm some long-held mechanistic hypotheses, but also point to several novel structural hypotheses.

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15

Kline, Neal. "Moderate Resolution Cavity Ringdown Spectroscopy of Reactive Intermediates Relevant to Hydrocarbon Oxidation." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405979077.

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16

Cullin, David W. "High resolution laser spectroscopy of jet-cooled substituted cyclopentadienyl radicals /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu148768795996825.

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17

Ashworth, Stephen Hugh. "The high resolution electronic spectroscopy of nickel dichloride." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302831.

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18

Schubert, J. E. "High-resolution spectroscopy of small gas-phase radicals." Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354301.

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19

Dunn, James. "High resolution X-ray spectroscopy of laboratory sources." Thesis, University of Leicester, 1990. http://hdl.handle.net/2381/35870.

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A detailed programme of research is presented to design, build and operate a high resolution h?hz5000 curved crystal Johann-type x-ray spectrometer for the waveband below 13A. The spectrometer is used to observe line emission features from different laboratory x-ray sources. Characteristics of the Johann geometry are described with emphasis given to the properties of sensitivity, dispersion, resolving power and waveband. The tolerance of the instrumental parameters is defined for successful high spectral resolution operation. The key feature of the spectrometer is the unique crystal bending device which can generate a high quality cylindrical curvature of radius R=150?5000mm. The crystal focusing alignment and testing procedures are evaluated. Choice of crystals suitable for the observation programme is discussed together with analysis techniques for interpretation of the x-ray spectral line profiles. The instrument is optimised for time-integrated and time-resolved ion temperature measurements of UKAELA DITE Tokamak at the Culham Fusion Laboratory. X-ray line emission results from medium Z He-like and H-like impurity ions are presented for different plasma conditions. Density sensitive He-like and Li-like Aluminium ion satellite emission features are studied for intense transient laser produced plasmas at the Central Laser Facility, SERC Rutherford Appleton Laboratory. The peak plasma electron density of 0.1 time solid density is estimated from these line intensity ratios and is in good agreement with Stark line width measurements. X-ray emission from beam-foil interactions is observed on the Folded Tandem accelerator of the Nuclear Physics Department, Oxford University. The proposed improvement in the intrinsic spectral line broadening due to the accelerator is investigated by high resolution axial beam measurements of the He-like Silicon and H-like Neon n=2 transitions. The Lyman-a intensity ?-ratio and wavelength separation ?hFS is studied for the fine-structure of Hydrogenic Neon, Magnesium, Aluminium and Silicon. The fine-structure separation is compared with the Dirac theory and other experimental data, while the possible mechanisms giving rise to the non-statistical value of the ?-ratio are analysed.

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20

Dinh, Phi Manh. "Dynamic kinetic resolution of secondary alcohols and esters." Thesis, University of Bath, 1999. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285289.

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21

Lam, Wai Hung. "Chiral resolution by diastereomeric salt crystallization /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?BIEN%202005%20LAM.

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22

Ahmed, Sharmin Nayela. "Kinetic resolution of carboxylic acids by Candida rugosa lipase." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68151.

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A substrate structure rule to predict the enantioselectivity of Candida rugosa lipase (CRL) towards $ alpha$-substituted carboxylic acids is proposed. Lipase from Candida rugosa resolved methyl $ alpha$-substituted phenylacetates -5. These substrates were examined to understand the influence of steric and the electronic nature of the substituents at the chiral center on the enantioselectivity. Crude CRL was partially enantioselective towards substrates -3, and highly selective towards and, E $>$ 100. Partial purification of crude CRL by 2-propanol extraction and separation by an ion exchange chromatography, dramatically improved the enantioselectivity towards -3, E $>$ 100. One main lipase fraction, F$ sb{ rm C}$ was obtained with 58 fold purification and 62% yield. This improvement in enantioselectivity was achieved with a simple dialysis against deionized water or 50% 2-propanol extraction. Lauric acid (10 mM), partially reversed the increase in the enantioselectivity. The absolute configuration of the favored enantiomer for crude and partially purified lipase preparations, was S. Other lipases with opposite stereoselectivities were not identified.
Based on literature and our results, it is believed that the size of the substituents at the stereogenic carbon center can account for the enantioselectivity of CRL catalyzed hydrolysis. The opposite configuration is not preferred when the electronic nature of the medium size substituent is varied. The rule can predict the selectivity data for partially purified CRL preparations. We believe that the accuracy of the rule can be improved if more examples of partially purified CRL reactions are examined.

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23

梁韻詩 and Wan-sze Leung. "High resolution spectroscopy of free radicals." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31237319.

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24

Leung, Wan-sze. "High resolution spectroscopy of free radicals /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19737610.

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25

Gardner, Amy A. S. "Experiments toward high resolution spectroscopy of N+2." Thesis, University of Sussex, 2016. http://sro.sussex.ac.uk/id/eprint/61452/.

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26

Genshaft, Alexander S. "Methods to interrogate cells and their interactions with single-cell resolution." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127892.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, May, 2020
Cataloged from the PDF of thesis.
Includes bibliographical references.
Only recently have molecular methods achieved high-quality and unbiased representations of diverse intracellular molecules at the single-cell level. With this technological advancement, researchers have begun deconvolving population-level measurements to understand whether prior observations were homo- or heterogeneous across the sample. In order to make multi-omics workflows compatible with low input samples comprising a few to single cells, new methods are required. Here, we devise a scalable, integrated strategy for coupled protein and RNA detection in single cells. This method and other similar protocols enable researchers to dive deeper into cellular phenotypes while retaining single-cell resolution, critical for determining what transcriptional programs arise and in which cells with what other programs.
However, cellular phenotypes are not solely determined by the products of transcription and translation - cells are constantly receiving information from their environment including direct contact with other cells, secreted biomacromolecules and small molecules. To explicitly examine how a cell's spatiotemporal activity impacts its behavior, we developed and validated SPACECAT: a strategy to annotate, track, and isolate specific cells in a non-destructive, viability-preserving manner. To accomplish this goal, we created a novel photocaged viability dye and incorporated other photoactivatable fluorophores that we can combine to create five distinct fluorescence signatures. We show that the SPACECAT protocol is a powerful tool for targeting specific microenvironments to reveal phenotypes that would otherwise be obscured by bulk signatures. However, SPACECAT does not capture precise interaction history with defined cell types and cannot track secreted molecules.
To exert more control over cellular interactions, we created a protocol that confines interacting cliques of cells to microwells, preventing cells or secreted molecules from leaving their well of origin, and isolating them from the many other cliques interrogated in parallel. By examining cliques under biological, chemical, and null control stimuli, we see distinct transcriptional programs that underly immunological interaction between CD4+ T cells and antigen presenting cells. Through these novel methods and their proof-of-principle applications, we enable researchers & clinicians to delve further into their systems of interest.
by Alex S Genshaft.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Chemistry

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27

Cochrane, Heather Dunlop. "Surface studies of catalytic cerias using atomic resolution TEM." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276508.

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28

Sheridan, Phillip Michael. "High-resolution millimeter-wave spectroscopy of metal-containing species: Examining fundamental ligand interactions." Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/284335.

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Millimeter-wave spectroscopy has been used in this thesis to accomplish two main goals: (1) to study bonding, structural, and electronic properties of small, metal-bearing molecules in their ground electronic states, in particular how individual metal atoms bond to small ligands, and (2) to provide rest frequencies for radio astronomical searches of metal containing species in the interstellar medium. The types of molecules studied in this thesis can be broadly classified into three groups: (1) alkali and alkaline-earth amides (MNH₂), (2) diatomic molecules in high electron spin or high orbital angular momentum electronic ground states (MX), and (3) transition metal cyanides (MCN). In this first category, the pure rotational spectra of LiNH₂ (X¹A₁), LiND₂ (X¹A₁), NaND₂ (X¹A₁), MgNH₂ (X²A₁), and MgND₂ (X²A₁), were recorded and analyzed. For each, the first experimental monomer r₀ structures were determined. These species were found to be planar and not invert, in contrast to ammonia. In addition, for the alkaline-earth amides, the M-N bond appears to become less ionic from Sr to Ca to Mg. The second class of molecules investigated, high-spin diatomcs, includes: NaC(X⁴Σ⁻), CrN(X⁴Σ⁻), CrO(X⁵Πᵣ), MnF(X⁷Σ⁺), FeN(X²Δᵢ), FeC(X³Δᵢ), and TiF(X⁴Φᵣ). These species represent examples of electronic states that have never or seldom been observed by high-resolution millimeter-wave spectroscopy, due to their high values of electron spin and orbital angular momenta. The analysis of their spectra has been used to test the adequacy of the effective Hamiltonians developed to model their rotational spectra; in particular the use of theoretically predicted higher order parameters. The final group studied includes the transition metal cyanides CoCN (X3Φᵢ ) and NiCN (X2Δᵢ). Unlike their alkali, alkaline-earth, and group 13 counterparts, these species were determined to be linear cyanides with the metal atom bonded to carbon, similar to both CuCN (X1Σ⁺) and ZnCN (X2Σ⁺). For both molecules, complications in the rotational spectra due to the Renner-Teller effect were observed and analyzed.

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29

Odedra, Smita. "Some novel developments in high-resolution NMR spectroscopy." Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5772/.

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The radiofrequency (rf) pulses used in NMR are subject to a number of imperfections, such as those resulting from the inhomogeneity of the rf field or an offset of the transmitter frequency from exact resonance. In spin-echo experiments, these imperfections yield spectra with reduced signal intensity and distorted phase. Composite pulses, which have tailored bandwidth properties with respect to experimental frequency parameters such as the rf field strength or resonance offset, offer a route to improving the amplitude of the spin-echo signal. However, the symmetry of the pulse sequence must be carefully considered to prevent the introduction of phase errors into the spin-echo signal. Here, composite pulses will be studied as a means to improving one of the most common techniques for 1H background suppression in MAS NMR, the ”Depth” sequence. Novel composite 180° pulses will be presented for this application and verified experimentally. The composite pulse Depth experiment yields spectra with improved amplitude of the 1H signals of interest, while successfully maintaining good suppression of background signals. Novel families of dual-compensated 180° composite pulses for I = 1/2 will also be designed for use in NMR spin-echo experiments. These pulses are capable of simultaneously compensating for resonance offset and rf inhomogeneity problems. Crucially, unlike many composite pulses that have been presented before, these new pulses have the correct symmetry properties to form a spin echo without phase distortion. Composite pulses have found wide usage in solution-state NMR, and although in principle the same pulses can be applied in solid-state NMR experiments, complications can arise under magic angle spinning (MAS). The effects of MAS on composite pulse performance will be explored both through computer simulations and 31P experiments. Finally, on a different theme, we will investigate spin-locking of half-integer quadrupolar nuclei in solids. Spin-locking is an important feature of many NMR experiments, yet the complex behaviour observed for quadrupolar nuclei is not fully understood. Using the theoretical model introduced by Ashbrook and Wimperis, we will investigate the far off-resonance case of spinlocking for I = 3/2 and I = 5/2 nuclei.

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30

Son, Ea-Ji-Ru. "Studies on Resolution of Enantiomeric Dialkylaryl Sulfonium Ions with NMR Shift Reagents." TopSCHOLAR®, 1997. http://digitalcommons.wku.edu/theses/358.

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Praseodymium(III) NMR shift reagent, which is an upfield shift reagent, is focused on for assessment of enantiomeric excess and resolution of methyl sulfonium ions. A series of alkylmethylphenylsulfonium ions were analyzed, where alkyl is ethyl (I), butyl(H), octyl (III), and benzyl(IY). The praseodymium agent gives base-lined resolution of the ortho hydrogens resonance for I and IH. All spectra are strongly temperature-dependent. I is shifted more than ED, consistent with a steric effect. Assignments for I were made by gradually increasing the concentration of the shift reagent and by analyzing R-enriched I. Racemization of R-enriched isomer of I by pyramidal inversion was observed at 50 °C.

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Barnes, Alexander B. (Alexander Benjamin). "High-resolution high-frequency dynamic nuclear polarization for biomolecular solid state NMR." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/65263.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, June 2011.
Vita. Cataloged from PDF version of thesis.
Includes bibliographical references.
Dynamic Nuclear Polarization (DNP) has exploded in popularity over the last few years, finally realizing its potential to overcome the detrimental lack of sensitivity that has plagued performing NMR experiments. Applied to magic angle spinning (MAS) experiments, this renaissance of DNP has been primarily driven by the development of instrumentation; namely gyrotron oscillators as high-power stable microwave power sources and the NMR probes and associated equipment required to spin samples routinely below 100 Kelvin. The first three chapters of this thesis provide an overview of the theory, instrumentation, and applications of DNP. Chapter 1 introduces the magnetic resonance Hamiltonian with a focus on interactions that are necessary to control in order to obtain high-resolution DNP spectra. Chapters 2 and 3 are published reviews of DNP. Whereas Chapter 2 targets magnetic resonance spectroscopists, Chapter 3 is intended for an electric engineering audience. Both reviews are included as the associated depth and coverage of the topics are complementary and lead to a better understanding of DNP. The later chapters describe in detail advancements in probe, cryogenics, and gyrotron technology required to perform DNP MAS experiments, as well as the gains in sensitivity and resolution such instrumentation has permitted. Of particular importance is the development of a cryogenic sample ejection system that resulted in exquisite resolution of spectra recorded <100 K, both of crystalline peptide and the active site of membrane proteins. Such developments in instrumentation and demonstrations of resolution go towards overturning a long-held stance in the field that DNP would always suffer from broadened, unresolved spectra. Such techniques also allow us to investigate site specific dynamics of a crystalline peptide, the high resolution SSNMR structure of which is discussed in Chapter 3. DNP and the developed instrumentation is also leveraged to measure inter-atomic distances in the active site of a membrane protein with sub-angstrom precision. Chapters 7 describes the calculation of the microwave field strength across the sample in a MAS DNP probe and introduces strategies to increase it. Finally Chapter 8 introduces a major advance in the microwave source technology associated with DNP experiments. Detailed designs of a novel 250 GHz gyrotron oscillator are shown and experiments demonstrate a continuous broad 3 GHz bandwidth with >10 W across the band, which results in substantially improved DNP performance.
by Alexander B. Barnes.
Ph.D.

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32

Lin, Mei-Huey. "Yttrium-catalyzed reactions : transacylation, secondary alcohol resolution, cyanosilylation of ketones and epoxides /." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486457871786632.

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33

Kim, Hyun Sik. "High performance fourier transform mass spectrometry : soft ionization methods and resolution enhancement /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487859879937953.

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34

Boulineau, Rémi Louis Jean. "Super-resolution of photodynamic emitters by fluorescence fluctuation analysis." Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/47640/.

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A range of fluorescence fluctuation analysis methods were developed and applied to labels commonly used in biological samples. Various super-resolution techniques were demonstrated in vitro and in vivo using objective-type Total Internal Reflection Fluorescence Microscopy (TIRFM). An experimental Fluorescence Correlation Spectroscopy (FCS) setup was developed along with associated post-acquisition data algorithms. The technique was applied to investigate the stoichiometry of a protein subunit of ribonucleotide reductase (RNR). FCS method was adapted with an Electron Multiplying Charge Coupled Device (EMMCD) detection scheme and applied to inorganic Quantum Dots (QDs) diffusing in solutions of different viscosities. Super-resolution Optical Fluctuation Imaging (SOFI) algorithm was implemented in ImageJ software and conclusive results obtained on reference samples of QDs and combed DNA. Potential applications of temporal correlation analysis to the study of diffusive processes and single particle tracking were also discussed. A new super-resolution technique applicable to multiple adjacent fluorescent molecules called Direct Object Resolution by Image Subtraction (DORIS) was developed and tested with QD complexes. The method enables one to accurately map the position of two emitters displaying intermittency in their fluorescence emission and separated by a distance below the diffraction limit, without the need of complex instrumentation or analysis. The technique relies on the subtraction of the Point Spread Function (PSF) of each single fluorescent probe, and is in theory applicable to any blinking or flickering dye. The principle was first demonstrated on simulated data and experimentally on QDs coupled by 100-basepair double-stranded DNA constructs. Super-resolution by image subtraction was further applied in vivo in S. pombe cells, where distances between clustered fluorescent fusion proteins were accurately determined. The selective activation of photoswitchable probes mEos3 was exploited to optimise the DORIS subtraction process and provided a simple method to determine the relative positions of closely spaced emitters within an aggregate, as encountered in association sites or multimeric complexes.

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35

Thompsen, Jeffrey Matthew. "High-resolution millimeter-wave spectroscopy of 3d-block transition-metal sulfides." Thesis, The University of Arizona, 2001. http://hdl.handle.net/10150/278773.

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The first pure-rotational spectra of two transition-metal sulfides, copper sulfide (CuS) and manganese sulfide (MnS) have been determined. In addition, the millimeter/sub-millimeter spectra of SrS, SrNH₂ and SrND₂ have been determined for the first time. Electronic ground states have been confirmed with experimental evidence. Results indicate that the bonding trends of the transition-metals sulfides are slightly different than their isovalent analogs, the transition-metal oxides. Furthermore, the study of MnS has allowed for experimental testing of current high spin-state quantum theory, by analysing the spectra using third and fourth-order corrections to the effective Hamiltonian. Highly accurate spectroscopic constants and rotational transition frequencies have been determined for all species.

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36

Henderson, Christine Mary. "Applications of biocatalysts in the resolution of chiral organometallic compounds." Thesis, University of Warwick, 1988. http://wrap.warwick.ac.uk/99598/.

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The aim of this thesis was to resolve fully a racemic organometallic complex, using a hydrolytic enzyme as the resolving agent. This was to demonstrate the vast range of substrates that biocatalysts will react with in a specific fashion and to provide a unique example of an enzyme recognising and differentiating between the two enantiomers of a molecule showing planar chirality. Irontricarbonyl-protected 2.4-dienes were chosen as the initial target molecules. Methyl sorbate irontricarbonyl was found not to be a substrate for PLE, neither in aqueous nor in organic media. Irontricarbonyl (2,4-hexadien-1-ol) acetate was shown to be a substrate for both esterases and lipases. The biocatalyst most effectively catalysing this hydrolysis in terms of rate and enantioselectivity was PPL, which gave a maximum of 43% e.e. when the reaction was conducted in an aqueous environment of pH 7 containing 10% MeOH. 2-Carboethoxy-1,3-butadiene irontricarbonyl and its corresponding acetate derivative were both found to be suitable enzyme substrates. 2-Acetoxy-methyl-butadiene irontricarbonyl was selectively hydrolysed to give the deprotected alcohol in a maximum of 40% e.e. This was achieved using the lipase Aspergillus niger as the biocatalyst in an aqueous media of pH 7. The e.e. was determined by 31P nmr spectroscopy of a phospholane derivative of the optically active alcohol. 2-Carboethoxy-1,3- butadiene irontricarbonyl was selectively hydrolysed by PLE in aqueous media of pH 7 containing 20% MeOH to give the corresponding acid in 85% e.e. Optically active 2-carboxy-1,3-butadiene irontricarbonyl was upon one recrystallisation gained in 100% e.e. The e.e. was verified by 1H mnr spectroscopy of an amide derivative of the optically pure acid, and its absolute configuration was determined by X-Ray structure analysis and by comparison of its cd. The second type of organometallic complexes screened for enzyme-substrate feasibility were the ferrocenes. 1,1’-Ferrocenedicarboxylic acid dimethyl ester was shown to be a very non-ideal substrate, giving a mixture of mono- and di-acids as the reaction products. α-Methylferrocenecarboxylic acid methyl ester was not an enzyme substrate in either aqueous nor organic media. α -Methylferrocenemethyl acetate decomposed in aqueous conditions to give the corresponding α-methylferrocenemethyl cation, yet in organic media was proved to be an adequate lipase substrate. Studies of the comparative rates and selectivities of lipases either free in reaction media or immobilised on Biofix were carried out for the lipase- catalysed transesterification of α-methylferrocenemethyl butyrate with 1-heptanol in iso-octane at 40°C. This showed that the rate of reaction and selectivity of the lipase varied dramatically as to which condition was used. In the case of both A. niger and R. javanicus, the lipase free in solution remained inactive whereas the lipase immobilised on Biofix catalysed the reaction rapidly and non-selectively. For PPL, the act of immobilising the lipase on Biofix reversed its enantioselectivity. The exception to this was CCL, which free in solution gave the highest e.e. of 50%. The e.e. was determined by 1H nmr spectroscopy of α-methylferrocenemethyl aldehyde in the presence of chiral solvating agent 2,2,2-trifluoro-1-(9-anthryl) ethanol.

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37

Saeed, Mansoor. "Novel achiral and chiral derivatising reagents for indirect chiral resolution." Thesis, University of Sunderland, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260828.

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38

Suckley, Andrew Paul. "High resolution rotational and vibrational spectroscopy of weakly bound dimers." Thesis, University of Exeter, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293989.

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39

Aaronson, Barak D. B. "High resolution electrochemical imaging for energy conversion and storage applications." Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/78415/.

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The work presented herein involves the development of the scanning electrochemical cell microscopy (SECCM) platform for visualizing electrochemical and (photo)electrochemical activity of processes at electrode surfaces relevant to energy applications. The use of complementary microscopy characterization techniques such as: field emission-scanning electron microscopy (FE-SEM), electron backscatter diffraction (EBSD), atomic force microscopy (AFM) and Raman microscopy provides a correlation between the localized (photo)electrochemical activity (obtained by SECCM) and physical properties of the investigated surfaces. SECCM studies of a polycrystalline platinum surface highlight the significant variations in electrochemical activity that can be measured at electrode surfaces due to variations in localized crystallographic orientation and the presence of grain boundaries. An ostensibly simple redox couple (Fe2+/3+) in two different acidic media on a polycrystalline platinum foil is utilized as a model system and the localized crystallographic orientation of the surface is determined by EBSD analysis. The approach is then extended to room temperature ionic liquids (RTILs) to study the reduction of triiodide (I3-) to iodide (I-) on polycrystalline platinum for the application of dye sensitized solar cells (DSSCs) as a counter electrode. The coupling of illumination with high sensitivity current followers and external lock-in amplifiers to the SECCM setup is described and the resulting platform is demonstrated to allow investigation of (photo)electrochemical systems. Two examples are provided: imaging photo-anodes in DSSCs and electrodeposition and characterization of conjugated polymers on a transparent electrode for organic photovoltaic devices. Finally, photo-SECCM is used for determining structure-activity relationships for (photo)electrocatalysts of conjugated organic polymers by coupling the technique with AFM and Raman spectroscopy, suggesting the technique as a potential high throughput screening platform. The approach is exemplified by investigating poly(3-hexylthiophene) and provides not only a correlation of film morphology and photo-activity but also extracts important information on film growth and aging.

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40

Pyle, Joseph R. "YOYO and POPO Dye Photophysics for Super-Resolution Optical Nanoscopy." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1560261722202949.

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41

Burkhart, Brian M. "Structure of Recombinant Flavodoxin from Cyanobacteria Anabaena 7120 determined at 1.40 Å Resolution /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487858417984339.

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42

Wright, Rossana Rubino. "High resolution, rotationally resolved, electronic spectroscopy of free radicals : MgCH3, MgNC and HCCs /." The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487949508372479.

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43

Garcia, Menendez Fernando. "High-resolution three-dimensional plume modeling with Eulerian atmospheric chemistry and transport models." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50264.

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Eulerian chemical transport models are extensively used to steer environmental policy, forecast air quality and study atmospheric processes. However, the ability of these models to simulate concentrated atmospheric plumes, including fire-related smoke, may be limited. Wildland fires are important sources of air pollutants and can significantly affect air quality. Emissions released in wildfires and prescribed burns have been known to substantially increase the air pollution burden at urban locations across large regions. Air quality forecasts generated with numerical models can provide valuable information to environmental regulators and land managers about the potential impacts of fires. Eulerian models present an attractive framework to simulate the transport and transformation of fire emissions. Still, the limitations inherent to chemical transport models when applied to replicate smoke plumes must be identified and well understood to adequately interpret results and further improve the models' predictive skills. Here, a modeling framework centered on the Community Multiscale Air Quality modeling system (CMAQ) is used to simulate several fire episodes that occurred in the Southeastern U.S. and investigate the sensitivity of fine particulate matter concentration predictions to various model inputs and parameters. Significant sources of uncertainty in the model are identified and discussed, including the spatiotemporal allocation of fire emissions and meteorological drivers. In addition, special attention is given to model grid resolution. Adaptive grid modeling is explored as a strategy to simulate fire-related plumes. An adaptive version of CMAQ, capable of dynamically restructuring the grid on which solution fields are estimated and providing refinement at the regions where accuracy is most dependent on resolution, is presented. The fully adaptive three-dimensional modeling technique can be applied to reach unprecedented levels of grid resolution and provide insight into plume dynamics unattainable with static grid models. Through this work the capability of current chemical transport models to replicate fire-related air quality impacts is evaluated, key research needs to achieve effective simulations are identified, and numerical tools designed to improve model performance are developed.

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44

Del, Alamo Aurora. "Studies of hexahelicene bonded phases for the HPLC resolution of enantiomers." Thesis, University of Warwick, 1995. http://wrap.warwick.ac.uk/3994/.

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The thesis presents a review of the literature on the HPLC resolution of enantiomers using chiral stationary phases and discusses the mechanisms of separation and the utility of these phases. The synthesis and chemical, chiroptical and spectroscopic properties of helicenes are also reviewed and the potential utility of helicene-based for the HPLC resolution of enantiomers is discussed. The work carried out involved the preparation of a hexahelicene-based chiral stationary phase and demonstrations of its utility for the resolution of chiral analytes. This phase was chemically bonded rather than physically coated, in order to make it stable to hydrolysis and solvent stripping, and therefore to permit its employment with a wide range of mobile phases. This thesis describes the synthesis of hexahelicen-7-ylacetic acid methyl ester, including confirmation of the structure of the key synthetic intermediates by spectroscopic analysis, and the investigation of several proceduresfor the resolution of hexahelicen-7-ylacetic acid methyl ester into its enantiomers, one of which enabled around 100 mg amounts of each of (+) and (-) enantiomers of hexahelicen-7-ylacetic acid to be obtained in highly chemically and optically pure form. The thesis also gives an account of several synthetic approaches to covalently bonding of the chiral selector (hexahelicen-7-ylacetic acid) to a modified silica stationary phase. Chiral stationary phases were prepared from each of the enantiomers in sufficient amount to permit the packing of analytical columns of these phases. Chiral solutes containing nitroaryl functionalities were synthesised to investigate the chiral resolving power of these novel phases. Adequate separations were obtained with both chiral stationary phases and, as anticipated, the eluting order of chiral analytes was reversed between the (+) and (-) stationary phases. The work demonstrated the utility of these columns for the resolution of nitroaryl-containing chiral analytes.

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45

Treweeke, Nigel R. "Preparation of #alpha#-substituted amino acid derivatives by dynamic kinetic resolution." Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390818.

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46

Squibb, Adrian D. "The resolution and reactivity of phosphine-substituted diene complexes of iron." Thesis, Keele University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293968.

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47

Cook, Daniel W. "Chemometric Curve Resolution for Quantitative Liquid Chromatographic Analysis." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4362.

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In chemical analyses, it is crucial to distinguish between chemical species. This is often accomplished via chromatographic separations. These separations are often pushed to their limits in terms of the number of analytes that can be sufficiently resolved from one another, particularly when a quantitative analysis of these compounds is needed. Very often, complicated methods or new technology is required to provide adequate separation of samples arising from a variety of fields such as metabolomics, environmental science, food analysis, etc. An often overlooked means for improving analysis is the use of chemometric data analysis techniques. Particularly, the use of chemometric curve resolution techniques can mathematically resolve analyte signals that may be overlapped in the instrumental data. The use of chemometric techniques facilitates quantitation, pattern recognition, or any other desired analyses. Unfortunately, these methods have seen little use outside of traditionally chemometrics focused research groups. In this dissertation, we attempt to show the utility of one of these methods, multivariate curve resolution-alternating least squares (MCR-ALS), to liquid chromatography as well as its application to more advanced separation techniques. First, a general characterization of the performance of MCR-ALS for the analysis of liquid chromatography-diode array detection (LC-DAD) data is accomplished. It is shown that under a wide range of conditions (low chromatographic resolution, low signal-to-noise, and high similarity between analyte spectra), MCR-ALS is able to increase the number of quantitatively analyzable peaks. This increase is up to five-fold in many cases. Second, a novel methodology for MCR-ALS analysis of comprehensive two-dimensional liquid chromatography (LC x LC) is described. This method, called two dimensional assisted liquid chromatography (2DALC), aims to improve quantitation in LC x LC by combining the advantages of both one-dimensional and two dimensional chromatographic data. We show that 2DALC can provide superior quantitation to both LC x LC and one dimensional LC under certain conditions. Finally, we apply MCR-ALS to an LC x LC analysis of fourteen furanocoumarins in three apiaceous vegetables. The optimal implementation of MCR-ALS and subsequent integration was determined. For these data, simply performing MCR-ALS on the two dimensional chromatogram and manually integrating the results proved to be the superior method. These results demonstrate the usefulness of these curve resolution techniques as a compliment to advanced chromatographic techniques.

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48

Lewandowski, Józef Romuald. "Methodology and applications of high resolution solid-state NMR to structure determination of proteins." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45640.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2008.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Vita.
Includes bibliographical references.
A number of methodological developments and applications of solid-state NMR for assignment and high resolution structure determination of microcrystalline proteins and amyloid fibrils are presented. Magic angle spinning spectroscopy on uniformly and selectively "C and '5N labeled samples is performed at magnetic fields from 11.7 to 21.1 T and spinning frequencies from 9 to 65 kHz.Dynamic Nuclear Polarization on nanocrystals of amyloidogenic peptide GNNQQNY is presented demonstrating that 'H-'H spin diffusion can efficiently transfer the enhanced polarization across the solute that is not in an intimate contact with the polarizing agent.An improved theoretical treatment of Rotational Resonance Width (R2W) experiments and its application to determination of precise 13C-13C distance is presented. A general theory of second averaging in modulation frame for designing solid-state NMR experiments is introduced and discussed in the context of two methods: Cosine Modulated Rotary Resonance (CMpRR) for performing a broadband double-quantum 13C-13C recoupling without the need for additional 'H decoupling and Cosine Modulated recoupling with Chemical Shift reintroduction (COMICS) that provides a general frequency selective method for measuring precise 13C-13C distances in uniformly labeled solids. Cosine Modulated Adiabatic Recoupling (CMAR) - an adiabatic extension of the CMpRR, that is particularly robust with respect to rf inhomogeneity, is also introduced. A number of applications CMpRR at 21.1 T to proteins with varying degrees of macroscopic order are presented. A second order Third Spin Assisted Recoupling (TSAR) mechanism is introduced and discussed in detail. The heteronuclear TSAR - Proton Assisted Insensitive Nuclei Cross-Polarization (PAIN-CP) and homonuclear Proton Assisted Recoupling (PAR) yield long distance 13C_1-N, 3C-_13C and 15N- 5N restraints in uniformly labeled systems with spinning frequencies up to 65 kHz that are used for protein structure calculation. Structure, dynamics and polymorphism of amyloidogenic peptide GNNQQNY from the yeast protein sup35p are investigated. Finally, PAIN-CP and '3C-13C PAR are used for high resolution de novo structure determination of 10.4 kDa Crh protein dimer.
by Józef Romuald Lewandowski.
Ph.D.

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49

Barkhuysen, Shani. "High resolution 195Pt and 119Sn NMR characterization of platinum(II)-tin(II) complexes." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17841.

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50

Kennedy, Matthew R. "Non-covalent interactions and their role in biological and catalytic chemistry." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53044.

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The focus of this thesis is the question of how non-covalent interactions affect chemical systems' electronic and structural properties. Non-covalent interactions can exhibit a range of binding strengths, from strong electrostatically-bound salt bridges or multiple hydrogen bonds to weak dispersion-bound complexes such as rare gas dimers or the benzene dimer. To determine the interaction energies (IE) of non-covalent interactions one generally takes the supermolecular approach as described by the equation \begin{equation} E_{IE} = E_{AB} - E_{A} - E_{B}, \end{equation} where subscripts A and B refer to two monomers and AB indicates the dimer. This interaction energy is the difference in energy between two monomers interacting at a single configuration compared to the completely non-interacting monomers at infinite separation. In this framework, positive interaction energies are repulsive or unfavorable while negative interaction energies signify a favorable interaction. We use prototype systems to understand systems with complex interactions such as π-π stacking in curved aromatic systems, three-body dispersion contributions to lattice energies and transition metal catalysts affect on transition state barrier heights. The current "gold standard" of computational chemistry is coupled-cluster theory with iterative single and double excitation and perturbative triple excitations [CCSD(T)].\cite{Lee:1995:47} Using CCSD(T) with large basis sets usually yields results that are in good agreement with experimental data.\cite{Shibasaki:2006:4397} CCSD(T) being very computational expensive forces us to use methods of a lower overall quality, but also much more tractable for some interesting problems. We must use the available CCSD(T) or experimental data available to benchmark lower quality methods in order to ensure that the low quality methods are providing and accurate description of the problem of interest. To investigate the effect of curvature on the nature of π-π interactions, we studied concave-convex dimers of corannulene and coronene in nested configurations. By imposing artificial curvature/planarity we were able to learn about the fundamental physics of π-π stacking in curved systems. To investigate these effects, it was necessary to benchmark low level methods for the interaction of large aromatic hydrocarbons. With the coronene and corannulene dimers being 60 and 72 atoms, respectively, they are outside the limits of tractability for a large number of computations at the level of CCSD(T). Therefore we must determine the most efficient and accurate method of describing the physics of these systems with a few benchmark computations. Using a few benchmark computations published by Janowski et al. (Ref. \cite{Janowski:2011:155}) we were able to benchmark four functionals (B3LYP, B97, M05-2X and M06-2X) as well as four dispersion corrections (-D2, -D3, -D3(BJ), and -XDM) and we found that B3LYP-D3(BJ) performed best. Using B3LYP-D3(BJ) we found that both corannulene and coronene exhibit stronger interaction energies as more curvature is introduced, except at unnaturally close intermolecular distances or high degrees of curvature. Using symmetry adapted perturbation theory (SAPT)\cite{Jeziorski:1994:1887, Szalewicz:2012:254}, we were able to determine that this stronger interaction comes from stabilizing dispersion, induction and charge penetration interactions with smaller destabilizing interactions from exchange interactions. For accurate computations on lattice energies one needs to go beyond two-body effects to three-body effects if the cluster expansion is being used. Three-body dispersion is normally a smaller fraction of the lattice energy of a crystal when compared to three-body induction. We investigated the three-body contribution using the counterpoise corrected formula of Hankins \textit{et al.}.\cite{Hankins:1970:4544} \begin{equation} \Delta ^{3} E^{ABC}_{ABC} = E^{ABC}_{ABC} - \sum_{i} E^{ABC}_{i} - \sum_{ij} \Delta ^{2} E^{ABC}_{ij}, \end{equation} where the superscript ABC represents the trimer basis and the E(subscript i) denotes the energy of each monomer, where {\em i} counts over the individual molecule of the trimer. The last term is defined as \begin{equation} \Delta ^{2} E^{ABC}_{ij} = E^{ABC}_{ij} - E^{ABC}_{i} - E^{ABC}_{j}, \end{equation} where the energies of all dimers and monomers are determined in the trimer basis. Using these formulae we investigated the three-body contribution to the lattice energy of crystalline benzene with CCSD(T). By using CCSD(T) computations we resolved a debate in the literature about the magnitude of the non-additive three-body dispersion contribution to the lattice energy of the benzene crystal. Based on CCSD(T) computations, we report a three-body dispersion contribution of 0.89 kcal mol⁻¹, or 7.2\% of the total lattice energy. This estimate is smaller than many previous computational estimates\cite{Tkatchenko:2012:236402,Grimme:2010:154104,Wen:2011:3733,vonlilienfeld:2010:234109} of the three-body dispersion contribution, which fell between 0.92 and 1.67 kcal mol⁻¹. The benchmark data we provide confirm that three-body dispersion effects cannot be neglected in accurate computations of the lattice energy of benzene. Although this study focused on benzene, three-body dispersion effects may also contribute substantially to the lattice energy of other aromatic hydrocarbon materials. Finally, density functional theory (DFT) was applied to the rate-limiting step of the hydrolytic kinetic resolution (HKR) of terminal epoxides to resolve questions surrounding the mechanism. We find that the catalytic mechanism is cooperative because the barrier height reduction for the bimetallic reaction is greater than the sum of the barrier height reductions for the two monometallic reactions. We were also able to compute barrier heights for multiple counter-ions which react at different rates. Based on experimental reaction profiles, we saw a good correlation between our barrier heights for chloride, acetate, and tosylate with the peak reaction rates reported. We also saw that hydroxide, which is inactive experimentally is inactve because when hydroxide is the only counter-ion present in the system it has a barrier height that is 11-14 kJ mol⁻¹ higher than the other three counter-ions which are extremely active.

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Dissertations / Theses on the topic 'Resolution (Chemistry)'

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