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Title: Aspects of the chemistry of 1,2,4,5-tetrakis(amino)benzenes
Author: Hood, Matthew Francis
ISNI:       0000 0004 2718 3337
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2011
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This thesis describes the synthesis and properties of a number of novel substituted 1 ,2,4,5-tetrakis(amino )benzenes for which synthetic methods have only recently become available. Similar compounds have previously been observed as very electron rich systems; this thesis therefore explores some of the behaviour of these compounds that stems from this observed property. Chapter 1 details a proposed architecture for using single organic molecules as storage or processing units for single bits of binary data. This involves a bottom-up approach of creating single molecules, which could be used to fulfil the role of components in an integrated circuit. The design criteria that a molecule would need to fulfil in order to perform this task are discussed and substituted 1,2,4,5- tetrakis(amino )benzenes are suggested as possible candidates. Chapter 2 reports the results of a theoretical and computational study into the effects of ion-pairing on the observed electrochemical behaviour of tertiary 1,2,4,5-tetrakis(amino)benzenes. Compounds 1 - 6 are modelled using Density Functional Theory in the gas phase, in solution and as ion-pairs with [PF6] and [CI04] anions. The results of this study provide some insight as to why some of the tertiary tetrakis( amino )benzenes exhibit two-electron oxidation processes under certain conditions. Chapter 3 goes on to explore the synthesis of a selection of novel secondary tetrakis(amino)benzenes 9a - 11a based on recently published methods employing palladium catalysis. These new compounds have aromatic substituents on the nitrogen atoms and methyl or methoxy groups on the 3 and 6 positions of the central benzene ring. The ease with which these compounds can be oxidised to the corresponding benzoquinonediimines 9 - 11 is noted. Chapter 4 reports the discovery that these benzoquinonediimines can be oxidatively cyclised to produce the novel riminophenazines 12 and 13 or tetra(aza)pentacenes 14 and 15. The oxidative synthesis of these compounds is optimised and the tetra(aza)pentacenes are observed to be stable with regard to further oxidation and can form dications. Chapter 5 explores the ability of the benzoquinone diimines to form stable coordination compounds with a variety of rhodium-containing fragments producing a selection of binuclear complexes. These compounds were observed to be redox active. The effect on the redox potentials caused by changes to substituents on the central ring as well as the ancilliary ligands was investigated. Chapter 6 summarises the conclusions drawn in each of the preceding chapters to give an overall picture of the properties and behaviour of the compounds studied. These observations are linked to the electron rich nature of these compounds. Some comments are offered regarding how the compounds studied would meet the specification laid out for 'molecular bits'. A number of interesting observed properties are highlighted. Potential future applications of the compounds detailed herein are explored, and a range of derivative compounds which would be worthy of further study are highlighted.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available