There is currently a great interest in the field of porous organosilica
materials because of the high surface areas (> 1000 m²/g) and narrow pore size
distributions which are beneficial for applications such as chromatography, chiral
catalysis, sensing or selective adsorption. Periodic mesoporous organosilicas
(PMOs) represent an interesting class of hybrid silica materials because of the
wide variety of bridging organic groups which can be incorporated within the
precursors [(OR)3Si-R-Si(OR)3] giving rise to materials with exceptional
properties.
We have synthesized and characterized various aromatic PMOs
composed of supporting structural monomers (phenylene- or biphenylenebridged)
and functional stilbene monomers (cis and trans) (1, 2). The effect of
the different synthetic procedures and varying amounts of functional stilbene
monomer on the properties of the materials was examined. The functional transstilbene
component was determined to be well distributed in a phenylene-bridged
PMO using P123 as a pore template from TEM techniques with Os staining. The
trans-stilbene linkers were completely transformed to aryl aldehydes through
ozonolysis with dimethylsulfide workup. Further transformation of the carbonyl
functionality to an aryl imine showed a moderate level of success.
Enantiomeric forms of a novel, chiral PMO precursor (CM) were
synthesized and incorporated into biphenylene-bridged PMOs. Under basic pH
conditions templated with C18TMACl, although very low levels of CM are incorporated, enantiomeric forms of chiral, porous materials are obtained as was
verified by distinct mirror-image circular dichroism spectra. Powder XRD patterns
suggest that a tightly packed asymmetric biphenylene arrangement may be
necessary for the optical activity. Preliminary results using these materials as a
chiral chromatographic phase are promising.
Finally, a thin film morphology of an ethane-bridged PMO incorporating a
thiol ligand, (3-mercaptopropyl)trimethoxysilane, was prepared on a fibre optic
cable and used as a component in a heavy-metal sensing application. / Thesis (Ph.D, Chemistry) -- Queen's University, 2011-03-11 17:24:48.997
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/6338 |
| Date | 14 March 2011 |
| Creators | DICKSON, STEVEN E |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian theses |
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