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Title: Synthesis and electrochemistry of pyrrole derivatives
Author: Millán Barrios, Enrique José
ISNI:       0000 0001 3398 7348
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 1996
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The growing application of conducting polymers in the different areas of chemistry require the use and development of improved starting materials for the electropolymerisation of conducting films. In this thesis the synthesis of a new class of β- and N-pyrrole derivatives has been investigated. The use of a N-phenylsulfonyl group as protecting group and the subsequent Friedel-Crafts acylation have proved to be an efficient and reliable route for the synthesis of (3-pyrrolyl)alkylcarboxylic acids in high yield. The electrochemical studies on ω-(β-(pyrrolyl)alkylcarboxylic acids showed that the electropolymerisation of these derivatives is affected by the length of the spacer between the carboxylic acid group and the pyrrole ring. Films obtained from the electropolymerisation of (pyrrolyl)-3-carboxylic acid and 4-(β-pyrrolyl)-butyric acid showed a pH dependence of the oxidation potential when evaluated in buffer solutions. FT-IR of the oxidised films have been used to identify the changes in the chemical structure of the film when cycled in buffered solutions, a self-doped state having been observed from these studies at basic pH. The length of the spacer tends to decrease the pH response of the film and it has been found that the use of more than four methylene units inhibits any pH response of the film. A macroscopic characterisation of these films has been carried out by the use of contact angle measurements, the results of which suggest that increasing the length favour the deprotonation of the carboxylic acid groups exposed to the surface of the film. A new series of liquid crystalline pyrrole derivatives have been synthesised. Derivatives with long alkyl chains produce nematic monotropic phases. The electropolymerisation of these derivatives is not inhibited by the presence of the bulky cyanobiphenyl groups. However, no liquid crystal phases could be observed in the electropolymerised films.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Conducting polymers; Liquid crystals