RAW Data for Thesis entitled " An investigation of MOFs as Bifunctional Catalysts for Tandem Reactions" (Thesis data)



The chemical versatility of metal organic frameworks (MOFs) has been exploited in the designed synthesis of a bifunctional catalysts containing Lewis acidic and metal phosphine catalytic centres, with the aim of efficient and selective tandem catalysis. First, a wide range of known and novel early transition metal-based MOFs were synthesised and characterised, and their Lewis acidity examined in an imine formation reaction. From among the most promising of these, MOF-808(Hf) was chosen on the basis of its ability to include phosphine groups in a facile manner, and bifunctional MOFs based on this platform were tested for a series of tandem reactions.
A series of scandium MOFs based on tricarboxylate, mixed dicarboxylate and tricarboxylate and tetracarboxylate linkers was synthesised and the materials examined for their Lewis acidity. In addition to STA-27, a novel scandium MOF with an unprecedented scandium 1D building block, scandium versions of previously-reported trivalent metal MOFs were synthesised for the first time by using different tricarboxylate and functionalised dicarboxylate linkers. STA-27 showed the highest catalytic activity among all the scandium MOFs in the imine condensation but did not offer ready functionalisation routes for phosphines. Next, previously-reported zirconium and hafnium-based MOFs were synthesised which were capable of being post-synthetically functionalised with phosphine groups: their Lewis acidity was analysed. These materials include zirconium and hafnium MOFs with different cluster connectivities ranging from twelve to six. Furthermore, novel tricarboxylate and tetracarboxylate MOFs based on zirconium and hafnium were synthesised from the same starting materials by using different monocarboxylic acids as modulators. MOF-808(Hf) was identified as the best Lewis acidic catalyst among all the twenty-five MOFs examined and furthermore offered a straightforward route to functionalisation.
Post-synthetic modification of MOF-808(Hf) to include triarylphosphine ligands was performed. Sulfonated phenylphosphines were incorporated without oxidation to give a �MOF ligand� that can complex platinum group metals such as Ir and Rh to give a bifunctional catalyst containing both metal-phosphine complexes and Lewis acidic framework hafnium (or zirconium) metal sites. The metallated phosphine-bearing MOFs act as fully heterogeneous bifunctional catalysts for tandem reductive amination and hydroaminomethylation reactions.
Date made available14 Mar 2022
PublisherUniversity of St Andrews
Date of data production1 Apr 2015 - 12 Nov 2018

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