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Title: Metal complexes of bis- and tris-dioxolenes and related ligands
Author: Loughrey, Jonathan James
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2013
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This thesis concerns the synthesis and analysis of poly-dioxolene complexes and their related ligands, for the purposes of generating complexes of mixed valence. Work was firstly performed using the tris-dioxolene cavitand species, cyclotricatechylene (ctc), due to its structural rigidity and non-conjugation of the dioxolene rings. A preliminary investigation into the ability of cyclotricatechylene to support electron transfer was performed by addition of selected electron acceptor molecules to solutions of ctc. Two novel donor : acceptor complexes were isolated although displayed a lack of formal electron transfer between the two molecules, and is presented in chapter 2. Ctc was then substituted at the upper-rim to form a number of complexes of general formula [{(L)M}₃(μ₃-ctc)]. It was found that in each synthesised, with the exception of where M = Cu(II) and L = tBu₂Bipy, the dioxolene rings could be independently oxidised as shown by electrochemical analysis and two were capable of supporting mixed valence upon electrochemical oxidation where M = Pt(II) and L = dppb and tBu₂Bipy. These were characterised fully and displayed Robin/Day class II or III character as determined by UV/vis/NIR spectroeletrochemistry, and is presented in chapter 3. Due to challenges faced during the synthesis and analysis of complexes containing the ctc core, a simpler system was investigated containing two dioxolene rings based upon the 2,3,6,7-tetrahydroxy-9,10-dimethyl-9,10-dihydro-9,10- ethanoanthracene (H4thea) unit. Three diplatinum(II) complexes were synthesised of general formula [{(L)Pt}₂(μ₂-thea)] where L = dppb, dppe and tBu₂Bipy which again showed two one-electron redox processes corresponding to the reversible oxidation and reduction of each dioxolene ring. These complexes were chemically oxidised where it was found that the two halves of each were strongly coupled, near the Robin/Day class II/III border by UV/vis/NIR and EPR spectroscopy, and is presented in chapter 4. Finally, attempts were made to synthesise the analogous thiolated ligands to ctc and H4thea, although challenges faced during their synthesis resulted in this remaining incomplete. The progress made towards these compounds is presented in chapter 5.
Supervisor: Halcrow, Malcolm ; Hardie, Michaele Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available