Thesis (M.S.)--University of North Carolina at Greensboro, 2007. / Title from PDF title page screen. Advisor: Gregory M. Raner; submitted to the Dept. of Chemistry. Includes bibliographical references (p. 78-80).

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 178-190).

The discovery of nuclear magnetic resonance in bulk matter in 1945 has led to advances in several branches of physics. One of the most interesting applications of these new techniques has been to problems of the solid state, where information about molecular motion and thermal relaxation effects can be obtained. It is with this field of research that the nuclear magnetic resonance absorption experiments reported in this thesis are concerned. The general theory of nuclear magnetic absorption is developed first and the relevant apparatus and experiment methods are then described. The design and performance of a large permanent magnet made especially for nuclear resonance work is considered and experiments on suitable solids are reported and discussed in the final section.

The behaviour of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP, H4L) was studied in the aqueous medium and at the hydroxyapatite interface as a model of bone. In solution, the pH-dependency of the various protonated forms of HEDP was studied using nuclear magnetic resonance (NMR) spectroscopy of various nuclei and from this comparable pKa values could be obtained from the 31P chemical shift curve. The Raman spectra of the aqueous samples were measured and each protonated form was identified by unique vibrational bands. Multivariate curve resolution analysis was used to redetermine the species distribution diagram, as well as pure component spectra of each protonated form. Molecular modelling was employed to determine the most probable conformer present in solution and also to calculate the theoretical vibrational spectrum of each conformer. Comparison of the theoretical and experimental data allowed the assignment of the different Raman bands observed. The species present at low pH were the most problematic to analyse due to the strong inter- and intramolecular hydrogen bonding indirectly observed in the data. The interaction of HEDP at low and high concentrations with hydroxyapatite, bovine bone and CaHPO4 was investigated in situ by means of Raman spectroscopy and it was found that two Ca-HEDP complexes are sequentially formed at both concentrations, and that the order of formation of these two complexes can be explained from the species distribution diagrams of Ca-HEDP complexes. One complex, CaHEDP•2H2O, was successfully isolated and characterised by means of single-crystal X-ray Diffraction (XRD) methods and Raman spectroscopy. Theoretically generated Raman spectra were used to assist in the assignment of the solid-state Raman spectrum of CaHEDP•2H2O. It is postulated that the unknown complex is the monoprotonated Ca-HEDP complex. Using the Raman spectra of the complexes and HEDP as references, it was determined that HEDP(aq) interacts similarly with hydroxyapatite, bovine bone and CaHPO4 and thus hydroxyapatite can be substituted for bone in the Raman spectroscopic study of HEDP with bone. HEDP interaction was also studied at pH values of 5.0 and 7.4 to understand the nature of the interaction at the pH values at which the diprotonated (H2L2-) form is predominantly present, as well as at the pH of human blood plasma, which is slightly basic. HEDP exists as a monohydrate at room temperature and the single-crystal structure was redetermined, during which the hydrogen positions were experimentally obtained for the first time by means of X-ray diffraction methods. The anhydrous form of HEDP exists above 70°C and Rietveld refinement of the powder X-ray pattern of anhydrous HEDP was used to solve its crystal structure. The complexity of contributory factors allowed only for the non-hydrogen atom positions to be determined. Fourier-transform infrared (FTIR) and Raman spectroscopy were performed on both phases and there is evidence in the Raman spectrum that hydrogen bonding still plays a predominant role in the anhydrous solid state. All these studies led to a better understanding of the nature of bisphosphonate interaction with bone and the results can therefore be applied in future medical studies for drug screening regarding bone cancer research. / Thesis (PhD)--University of Pretoria, 2010. / Chemistry / unrestricted

No description available.

No description available.

A He³ cryostat was designed for steady state nuclear magnetic resonance measurements. The cryostat required about one liter of He³ at NTP. This amount of He³ was liquified at 1.2°K, which was the temperature of the surrounding liquid He⁴ bath, and then pumped on by means of a four-stage mercury diffusion pump. By this procedure, a liquid He³ temperature of 0.35 K was achieved and maintained for four hours. The r-f coil and sample were in direct contact with the liquid He³ to ensure sufficient heat transfer between the two. The temperature of the liquid He³ was measured by means of vapour pressure measurements of the evaporating He³ and by means of resistance measurements of a carbon resistance in contact with the liquid He³. The system was non-recirculating, since a total, uninterrupted run of four hours was considered long enough for most experiments. The He³ could also be retransferred within 20 minutes after such a run, and this process could be continued until in-sufficient quantities of liquid He⁴remained to cool the surroundings. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Relaxation properties of the deuteron spin system in CD₄ and CD₃H were studied in the temperature range from 105°K - 57°K. These results show that the intra-molecular quadrupole interactions dominate and the relaxation occurs through the molecular reorientations of the molecule. The deuteron spin-lattice relaxation times are approximately temperature independent, except for a small contribution from the magnetic dipolar interactions near the melting point in CD₃H. From this data it is concluded that the reorientatlonal correlation time is temperature independent. The deuteron T₂ shows the same temperature dependence as the proton T₂; the deuteron T₂ can be accounted for on the basis of magnetic dipolar interactions alone. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Proton magnetic resonance has been measured in the temperature range -196° to 295°C for potassium caprylate, from -196° to 230°C for lithium stearate, and at -196° and 27°C for potassium caproate. Theoretical second moments for potassium caproate, caprylate and caprate at -196°C were computed using various molecular parameters and were compared with experimental values. Unfortunately the theoretical values were sufficiently alike for any one soap so that it could not be decided which of the parameters were applicable. The results do show, however, that the end methyl group rotates in potassium caproate at -196°C and probably does so in potassium caprylate and caprate. A sharp decrease in line width and second moment takes place in potassium caprylate between 50° and 55°C and between 283° and 286°C. The first transition corresponds to a known crystal phase change at 55°C. The second moment results suggest that some torsional oscillation about the longitudinal axes of the hydrocarbon chain portion of the potassium caprylate molecules takes place below 50° C. Above 55°C torsional oscillation of large amplitude or possibly even rotation of the hydrocarbon chain occurs. The transition between 283° and 286°C corresponds to onset of motion in the hydrocarbon chain restricted only by continued ordering of the polar end groups in the ionic layer of the soap. The proton magnetic resonance results in lithium stearate indicate transitions at 115°, 171+°, and 225°C. These pmr transitions correspond to known phase transitions. The second moment results suggest that the methyl group of the hydrocarbon chain in lithium stearate begins to rotate between-183° and -136°C. The second moment above 115°C is approximately equivalent to that estimated for rotation of the hydrocarbon chain about its long axis. Above 171°C very extensive motion of the chains occurs, although they are still held in position by the ionic layer. The ionic layer begins to break up in the region 215° to 218°C, with the compound becoming an isotropic liquid at about 225°C. / Science, Faculty of / Chemistry, Department of / Graduate

Nuclear magnetic resonance studies in single crystals of aluminum and tin have been done at liquid helium temperatures. The Knight shift in tin has been studied as a function of crystal orientation in a constant magnetic field for different values of field and temperature. The anisotropic Knight shift in tin was observed directly for the first time. The line width of the tin resonance was also studied and found to depend on the crystal orientation in the magnetic field. The second moment of the line has been calculated in terms of dipole-dipole interactions and indirect exchange interactions between nuclei of different magnetic moments and compared with the experimental results. The Knight shift was studied as a function of external field for both tin and aluminum in a search for de Haas-van Alphen type oscillations. No indication of these was found. An upper limit for this effect was determined for each sample. / Science, Faculty of / Physics and Astronomy, Department of / Graduate