Victoria University

Capture and Activation of Carbon Dioxide Using Guanidine Superbases

ResearchArchive/Manakin Repository

Show simple item record

dc.contributor.advisor Coles, Martyn Bomann, Grace 2017-09-13T22:37:34Z 2017-09-13T22:37:34Z 2017 2017
dc.description.abstract Due to its abundance and low-cost, carbon dioxide is a desirable C₁-building block within organic transformations. However, the thermodynamic and kinetic stability of CO₂ often necessitates preliminary activation before it can be inserted into organic molecules. This prompts the need for compounds that can effectively promote the activation of CO₂. This research investigates the capture and activation of carbon dioxide using a class of superbases that incorporate the bicyclic guanidine unit, 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]-pyrimidine (hppH, 1). A series of compounds containing multiple hpp-units assembled around a phenyl ring scaffold were synthesized and investigated in the functionalization of CO₂. The work presented in this study has demonstrated the ability of protonated superbasic hppH derivatives to efficiently and effectively capture and activate carbon dioxide from ambient air to form the corresponding guanidinium bicarbonate salts. A series of optimization reactions was carried out, and showed that addition of substoichiometric concentrations of a proton source activates these guanidine compounds to their fully protonated cationic forms, and results in CO₂ capture through bicarbonate formation. A series of protonation studies were employed to fully characterize the cationic species. The tetraphenylborate and hydrochloride guanidinium salts were synthesized, isolated, and characterized by ¹H NMR and ¹³C NMR spectroscopic analysis. Molecular structures of relevant crystals were obtained through single crystal X-ray diffraction. These structures revealed a complex hydrogen-bonding network within these ionic species, and showed efficient delocalization of the formal positive charge within the protonated guanidinium units. The guanidine superbases were implemented in a series of reactions attempting the functionalization of CO₂ and an alcohol to form corresponding alkylcarbonate products. However, the synthesis of these carbonate products was not achieved under the reaction conditions employed. This lack of success has been attributed to the hygroscopic nature of this class of compounds, resulting in the preferential capture of ambient water. en_NZ
dc.language.iso en
dc.publisher Victoria University of Wellington en_NZ
dc.subject Carbon dioxide en_NZ
dc.subject Superbase en_NZ
dc.subject Crystallography en_NZ
dc.subject Carbon Capture en_NZ
dc.title Capture and Activation of Carbon Dioxide Using Guanidine Superbases en_NZ
dc.type text en_NZ
vuwschema.contributor.unit School of Chemical and Physical Sciences en_NZ
vuwschema.type.vuw Awarded Research Masters Thesis en_NZ Chemistry en_NZ Victoria University of Wellington en_NZ Masters en_NZ Master of Science en_NZ
dc.rights.license Creative Commons GNU GPL en_NZ 2017-06-15T05:04:15Z
vuwschema.subject.anzsrcfor 030599 Organic Chemistry not elsewhere classified en_NZ
vuwschema.subject.anzsrcfor 030199 Analytical Chemistry not elsewhere classified en_NZ
vuwschema.subject.anzsrctoa 4 EXPERIMENTAL DEVELOPMENT en_NZ

Files in this item

This item appears in the following Collection(s)

Show simple item record Except where otherwise noted, this item's license is described as

Search ResearchArchive

Advanced Search


My Account