Polyhedral oligomeric silsesquioxane based precursors as linkers for porous materials
Within this thesis, the organic synthesis and characterisation of various polyhedral oligomeric silsesquioxane (POSS) based compounds has been explored. The target POSS based compounds studied have been chosen because of their eight functionalised organic corners which house the ability to be modified and designed by a variety of organic reactions. Following this, their characteristic stable inorganic core and well defined three dimensional structure determined them to be suitable monomers for the synthesis of ordered frameworks with potential porosity. The first series of reactions involved the synthesis of octaphenylsilsesquioxane (OPS) and discusses the successful functionalisation to produce octa(iodophenyl)silsesquioxane (I8OPS), in addition to subsequent functionalisation attempts to produce a carboxylic acid derivative of I8OPS. Interestingly, this series was found to be highly selective for functionalisation in the para position of the phenyl ring, reinforcing the symmetrical nature of the molecule. An additional reaction series aimed to synthesise an imidazole derivative of an alkyl-POSS compound, following the successful synthesis of octakis(3-chloropropyl)silsesquioxane, through two procedures. Within this thesis, a different direction of study was explored, involving the synthesis of various metal organic frameworks and zeolitic imidazolate frameworks through variations in the experimental conditions and procedures. A systematic approach was also explored, where it was determined that a high number of ligands and metal combinations could be investigated simultaneously. This resulted in the synthesis of various metal organic frameworks from both powder and single crystal X-Ray Diffraction (XRD). From these findings, appropriate synthetic approaches for the eventual synthesis of a POSS based framework were identified.
|Publication Date||Oct 1, 2016|