Munn, Alexis S. (2013) Synthesis and characterisation of metal-organic framework materials with carboxylate ligands. PhD thesis, University of Warwick.

Preview

Text WRAP_THESIS_Munn_2013.pdf - Submitted Version Download (23Mb) | Preview

Request Changes to record.

Abstract

The adsorption of various guest molecules by the flexible 1,4-benzenedicarboxylate
metal-organic framework (MOF), MIL-53, has been followed using in situ diffraction
techniques. This crystalline MOF displays a structural expansion upon the adsorption of
guest molecules, evident by a change in unit cell parameters, which allows adsorption to
be followed using diffraction techniques.
Adsorption studies were performed with the Fe(III) form of MIL-53 using both liquidand
gas-phase guest molecules. The results from in situ X-ray diffraction (XRD) studies
show that small aliphatic-alcohols give rise to a two-step expansion whereas branchedalcohols
and larger aromatic molecules result in only a one-step expansion. The solvent
used for liquid phase studies was shown to affect guest adsorption; benzothiophene and
benzothiazole were adsorbed more quickly from a solution of heptane than from a
solution of isopropanol. Gas phase studies were used to investigate the effect of
occluded water molecules inside the pores of the framework upon the adsorption of
methanol. A combination of XRD, thermogravimetry and inelastic neutron scattering
studies were used to show that methanol does not displace water when hydrated MIL-
53(Fe) is used as an adsorbent. Two equivalents of methanol can be packed inside the
pores of the framework, irrespective of the adsorbent being hydrated or dehydrated.
Eight linker-modified MIL-53(Al) materials were supplied by research partners and in
situ XRD studies were performed to reveal the effect of the modifications upon the
adsorption of gas-phase molecules. The results show that the linkers change the
behaviour of the material towards certain guest molecules and the most dramatic effect
was seen when the benzene ring of the linker was replaced by cyclohexane.
A series of cobalt (II) MOFs synthesised with carboxylate and pyridine-N-oxide linkers
is presented. The effect of functionalising the pyridine ring upon the topology of the
resulting framework was studied. Resonance and steric effects were found to influence
the structure of the final product. One of the new materials has the potential to be used
as an adsorbent due to a 3D porous structure.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	Organometallic compounds -- Synthesis, Adsorption, Carboxylic acids, X-rays -- Diffraction, Ligands
Official Date:	July 2013
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Walton, Richard I.
Sponsors:	Seventh Framework Programme (European Commission) (FP7)
Extent:	ix, 353 leaves : illustrations.
Language:	eng

Request changes or add full text files to a record

Repository staff actions (login required)

View Item

Downloads