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Catalysis in carbon nanoreactors

The work presented in this thesis describes the preparation and application of hollow carbon nanostructures as containers of preparative chemical reactions. The effects of nanoscale confinement in carbon nanoreactors have been shown to dramatically affect the selectivity, activity and stability of catalytic chemical transformations. The optimum structural properties of the nanoreactor have been established by comparing the regioselectivity of molecular catalysts of the hydrosilylation reaction confined in a range of carbon nanostructures. In wide, internally corrugated hollow graphitised nanofibres, the effects of confinement were more prevalent than inside narrower, atomically smooth carbon nanotubes. The specific nature of the interactions induced at the unique reaction environment provided by nanofibres via confinement of nanopartic1e catalytic centres and reactant molecules was elucidated by exploration of the properties of the hydrosilylation reaction using a range of aromatic and aliphatic substrates. The synergy between increased local concentrations of aromatic reactants and the stabilisation of specific reaction intermediate species were critical in determining the regioselectivity of the reaction pathway in nanoreactors. The magnitude of local concentration effects have been quantified for the first time using a competitive hydrosilylation reaction methodology. A greater than three-fold increase in the addition of aromatic hydrosilanes relative to aliphatic analogues has been attributed to maximal1t-1t interactions between the graphitic internal surfaces of nanoreactors and the aromatic reactant molecules. The effects of local concentrations of aromatic molecules were harnessed in the silane oxidation reaction, yielding vital information regarding the critical dimensions of molecules and oligomeric structures that are subject to confinement at the graphitic step-edges of carbon nanoreactors.
Date January 2014
CreatorsSolomonsz, William Arran
PublisherUniversity of Nottingham
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation

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