Location of guest species in zeolites by solid-state NMR
department or school: Science, Faculty of
department or school: Chemistry, Department of
data provider: DSpace
degree campus: UBCV
creator: Lewis, Andrew Ross
issued: 2009-06-22T22:22:07Z
issued: 1998
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Zeolites and related microporous materials are exploited in many commercial applications because of the size and shape selectivity conferred by the molecular dimensions of their channel and cage systems. However, at present there is little direct information regarding the exact location of guest species within these materials; it is difficult to determine the structures of the host-guest complexes by X-ray diffraction techniques due to the limited availability of suitable crystals, and theoretical calculations are not always in agreement with one another. This thesis describes the application and evaluation of cross polarization (CP), rotational echo double resonance (REDOR), and transferred echo double resonance (TEDOR) solid-state N M R experiments for determining the complete three-dimensional structures of zeolite frameworks containing guests such as ions or sorbed organic molecules. In principle, these techniques permit accurate internuclear distances between spin-1/2 nuclei to be determined from measurements of the heteronuclear dipolar coupling. The viability and reliability of ¹⁹F-²⁹Si CP, REDOR and TEDOR N M R experiments was demonstrated by locating the fluoride ions within the octadecasil framework. The experimental methods were optimized and appropriate mathematical data analysis strategies developed. A comprehensive description of the mathematical methods is included. Accurate Si-F distances were determined which were in excellent agreement with those known from the single crystal structure. A series of calculations provided insight into the likelihood of being able to obtain reliable distances from REDOR and TEDOR data in cases where information regarding the number of spins, and the geometrical arrangement of these, is not known a priori. Preliminary investigations to locatep-difluorobenzene molecules within the channels of purely siliceous ZSM-5 were undertaken using these techniques. Apparatus which permitted the extended low temperature operation w…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/9527
extent: 19257353 bytes
format: application/pdf
note: LOCATION OF GUEST SPECIES IN ZEOLITES BY SOLID-STATE NMR by ANDREW ROSS LEWIS M.Sc. (Honours) The University of Auckland, 1991 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF CHEMISTRY We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA July 1998 © Andrew Ross Lewis, 1998 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of C H E M l S T f t y The University of British Columbia Vancouver, Canada Date OcJU>a- { , H*T8 DE-6 (2/88) ABSTRACT Zeolites and related microporous materials are exploited in many commercial applications because of the size and shape selectivity conferred by the molecular dimensions of their channel and cage systems. However, at present there is little direct information regarding the exact location of guest species within these materials; it is difficult to determine the structures of the host-guest complexes by X-ray diffraction techniques due to the limited availability o f suitable crystals, and theoretical calculations are not always in agreement with one another. This thesis describes the application and evaluation of cross polarization (CP), rotational echo double resonance ( R E D O R ) , and transferred echo double resonance ( T E D O R ) solid-state N M R experiments for determining the complete three-dimensional structures of zeolite frameworks containing guests such as ions or sorbed organic molecules. In principle, these tech…
has type: Thesis/Dissertation
date issued: 1998-11
is shown at: 10.14288/1.0061528
language: eng
degree discipline: Chemistry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/9527