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Title: Heterodinuclear cooperativity in oxygenated polymer catalysis
Author: Deacy, Arron
ISNI:       0000 0004 8503 5770
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2019
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The following thesis describes the synthesis and characterisation of a series of heterodinuclear complexes derived from either a diphenolate macrocycle, or an ovanillin derived dinucleating ligand. Their application as catalysts for the ringopening copolymerisation of CO2/epoxide, or anhydride/epoxide are investigated. Chapter 2: Explores the role of ionic Lewis acids, where a series of Group 1 and 2 metals with zinc (II) complexes are synthesised. All heterocomplexes are less active in the ROCOP of CO2/CHO compared to the di-zinc analogue, with the exception of Mg(II)Zn(II). The chain-shuttling mechanistic hypothesis is advanced with the assignment of Mg(II) as the epoxide binder and Zn(II) as the carbonate donor. Chapter 3: Explores the role of covalent Lewis acids, where a series of Group 13 metals with zinc (II) complexes are synthesised. Activity and CO2 uptake increases down the Group 13 homologues. All complexes are less active than the dizinc counterpart Chapter 4: A Mg(II)Co(II) catalyst is synthesised and shows excellent activity, better than either di-Mg or di-Co analogues. Mg(II)Co(II) has a lower transition state Gibbs free energy vs. the homodinuclear analogues. Its superior performance arises from a combination of favourable entropy, provided by Mg(II) and reduced enthalpy, provided by Co(II). The experimental data supports a chain-shuttling mechanism, with epoxide coordination at Mg(II) and Co(II) accelerating carbonate attack. Chapter 5: A series of Zn(II) and Mg(II) dinucleating o-vanillin complexes with Na(I), Ca(II) and Cd(II) are reported. All zinc heterodinuclear catalysts are less active compared to the homodinuclear complex, where the converse is true for the magnesium complexes.
Supervisor: Williams, Charlotte Sponsor: Econic Technologies ; Engineering and Physical Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available