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dc.contributor.advisorLucas, Nigel T.
dc.contributor.authorWang, Emily Lei
dc.date.available2012-03-21T20:49:16Z
dc.date.copyright2012
dc.identifier.citationWang, E. L. (2012). Synthesis of alkoxy-substituted hexa-peri-hexabenzocoronenes as molecular hosts (Thesis, Master of Science). University of Otago. Retrieved from http://hdl.handle.net/10523/2151en
dc.identifier.urihttp://hdl.handle.net/10523/2151
dc.description.abstractSupramolecular chemistry has attracted a lot of attention due to a diversity of applications based on the aggregation of molecules through non-covalent interactions. One molecule enveloping another molecule through these non-covalent interactions is defined as host-guest chemistry, an important topic in supramolecular chemistry. Electron-rich polycyclic aromatic hydrocarbons (PAHs) provide attractive hosts to electron-deficient guests such as buckminsterfullerene (C60). Hexabenzocoronenes (HBCs), a type of PAH consisting of 42 carbons in thirteen fused benzenoid rings, can be synthesized using a number of now well-developed synthetic approaches. However, highly substituted, electron-rich and non-planar HBCs have been less studied. Dodecamethoxy-HBC, HBC(OMe)12 has been synthesized by cyclotrimerization of bis(3,5-dimethoxyphenyl)acetylene, followed by a cyclodehydrogenation, but shows low solubility to common organic solvents. Introduction of hexyl chains on the dodecamethoxy-HBC, HBC(OMe2)12(C6H13)6, dramatically improves solubility. It exhibits a highly distorted core conformation with bay region torsion angles of 31.85 - 35.16˚. In the solid state, HBC(OMe2)12(C6H13)6 exhibits a herringbone-type packing with no close face-to-face contacts. Slow evaporation of the solution of HBC(OMe2)12(C6H13)6 and C60 (1:1) in toluene gives black, block crystals which show a columnar packing with alternating HBC and C60 units. The closest intracolumn approach between HBC(OMe2)12(C6H13)6 and C60 is 2.94 Å and the column separation is 16.7 Å. An alternative approach to “double concave” HBC hosts is by the introduction of pendant aryl groups with 2,6-substituents. The six-fold symmetric HBC precursor hexa[4-(2ʹ,6ʹ-dimethoxyphenyl)phenyl]benzene was found to be poorly soluble but the hexaalkoxy-analogue, hexa[4-(2ʹ,6ʹ-(dihexyloxyphenyl)phenyl]benzene, is readily dissolved. Attempted planarisation of this later HPB did not proceed cleanly, nor was the product highly soluble. A related trimethylsilyl-functionalized hexaaryl-HPB was also prepared, and provides entry to hexaryl-HBCs with a plethora of functional groups.
dc.language.isoen
dc.publisherUniversity of Otago
dc.rightsAll items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectHBC
dc.subjecthexabenzocoronenes
dc.subjectbuckministerfullerene
dc.subjectmethoxy substituted
dc.subjectpolycyclic aromatic hydrocarbons
dc.subjectPAH
dc.titleSynthesis of alkoxy-substituted hexa-peri-hexabenzocoronenes as molecular hosts
dc.typeThesis
dc.date.updated2012-03-21T04:20:53Z
dc.language.rfc3066en
thesis.degree.disciplineDepartment of Chemistry
thesis.degree.nameMaster of Science
thesis.degree.grantorUniversity of Otago
thesis.degree.levelMasters
otago.interloanno
otago.openaccessAbstract Only
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