Further development in solid-state NMR of half-integer quadrupolar nuclei

Sasaki, Akiko (2016) Further development in solid-state NMR of half-integer quadrupolar nuclei. PhD thesis, University of Glasgow.

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Abstract

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.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Solid-state, NMR.
Subjects: Q Science > QD Chemistry
Colleges/Schools: College of Science and Engineering > School of Chemistry
Supervisor's Name: Lennon, Prof. David and Senn, Dr. Hans and Wimperis, Prof. Steve
Date of Award: 2016
Depositing User: Akiko Sasaki
Unique ID: glathesis:2016-7153
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 04 Apr 2016 15:28
Last Modified: 20 Apr 2016 07:35
URI: http://theses.gla.ac.uk/id/eprint/7153

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