Research Theses
Type: Theses
Title: Incorporation of N-heterocyclic carbenes and their precursors into metal-organic frameworks
Author: Capon, Patrick
School/Discipline: School of Physical Sciences
Abstract: Metal-organic Frameworks (MOFs) are a class of porous materials with excellent potential for application in catalysis, gas storage or molecular separations. MOFs are synthesised by combination of an organic linker unit and metal node precursor to yield an overall network structure that typically extends in two or three dimensions. Often the network contains void space, which is the origin of the large surface areas and high porosity observed for many MOFs. N-Heterocyclic Carbenes (NHCs) were originally applied as ligands for metal complexes, and are commonly used as supporting ligands for organometallic catalysis. For example, an NHC is incorporated into Grubbs' second generation catalyst. NHC precursors have been incorporated into MOFs, leading to properties that make them applicable to catalysis and gas sorption. Metalation of the NHC precursor to yield a MOF bound NHC-metal complex provides an opportunity to further enhance a MOF's capacity for gas sorption or to provide a site for catalysis to be performed. The main aim of this thesis was to incorporate NHCs into MOFs to yield materials with applications in catalysis (via NHC metalation) or gas sorption. In Chapter 2 five new azolium or NHC containing 1-D MOFs are presented (1-Cu, 2, 3, 4, and 5), with 1-Cu and 2 showing strong enthalpy of adsorption values for H2 gas. An NHC-Cu(I) complex was generated concomitantly with MOF synthesis to yield 1-Cu, however this metal site was not viable for catalysis due to the low porosity of 1-Cu. These studies were extended to the highly stable DUT-5 MOF in Chapter 3 with two new DUT-5 analogues and two new mixed linker DUT-5 analogues generated. All four materials showed improved porosity compared to the MOFs in Chapter 2. In Chapter 4, the DUT-5 analogues were investigated for CO₂ and CH₄ gas sorption properties at high pressure in order to provide increased industrial relevance. Furthermore, ionic liquids (ILs) were included within the DUT-5 analogues in an attempt to improve CO₂ uptake. However, excessive loading of the IL resulted in a loss of MOF porosity and minimal uptake of CO₂ or CH₄. Finally, early metalation outcomes of the NHC precursor containing DUT-5 analogues are discussed in Chapter 4, with an aim toward NHC-metal based catalysis in further experiments.
Advisor: Sumby, Christopher James
Doonan, Christian
Dissertation Note: Thesis (M.Phil.) -- University of Adelaide, School of Physical Sciences, 2017.
Keywords: metal-organic framework
N-Heterocyclic Carbene
metalation
Provenance: This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legals
DOI: 10.4225/55/59262d5a50cd9
Appears in Collections: Research Theses
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