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Title: Further development in solid-state NMR of half-integer quadrupolar nuclei
Author: Sasaki, Akiko
ISNI:       0000 0004 5922 093X
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 2016
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Half-integer quadrupolar nuclei constitute more than 70% of the NMRactive nuclei in the Periodic Table. Owing to the presence of anisotropic quadrupolar broadening, high-resolution methods are often required for complete spectral analysis of solid-state NMR spectra of half-integer quadrupolar nuclei. The DOR and DAS techniques require specialist probes whilst the MQMAS and STMAS methods are two-dimensional correlation experiments performed under MAS conditions. The MQMAS experiment has been widely used in materials investigations, whereas the STMAS counterpart is ideal for the study of NMR-insensitive nuclei. This thesis is mainly concerned with the satellite transitions of halfinteger quadrupolar nuclei. Firstly, sensitivity enhancement schemes for the STMAS method are proposed and investigated both theoretically and experimentally using 23Na and 87Rb NMR of simple inorganic compounds, and the applicability and limiting factors of the novel methods are discussed. A recent addition to the aforementioned high-resolution techniques is the STARTMAS experiment. Further development of the STARTMAS approach is described, with respect to the spectral analysis, sensitivity enhancement, and implementation under fast MAS conditions, using 23Na, 87Rb and 69/71Ga NMR at B0 = 9.4 and 20.0 T. A potential area of interest in which the intrinsic sensitivity advantage of the STMAS method can be exploited is the natural abundance 33S solid-state NMR. In the latter half of this thesis, ettringite, a cementitious mineral, is employed to demonstrate the feasibility of high-resolution 33S STMAS NMR at B0 = 9.4 and 20.0 T, with particular emphasis on the implementation of 33S STMAS experiments all performed at the natural abundance levels of the 33S nucleus. Additional investigations are then proposed and performed using 1H- 33S CP-MAS NMR experiments to probe the presence of dynamics in ettringite. Recently, quantum mechanical calculations of solid-state NMR parameters have gained popularity, aiding experimentalists to predict and interpret solid-state NMR spectra. Further investigations of first-principles calculations of solidstate 33S NMR parameters are also presented in this thesis, to support the presence of dynamics around the S nuclei in ettringite.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QD Chemistry