Studies on the Photoluminescence of Indoles

Abstract

The literature on the fluorescence of indole, and its application in cone recent studies on the intrinsic fluorescence of proteins, is briefly reviewed. The electronic energy levels of the indole chromophore are described, with a method for analysing the overlapping 1La  and 1Lb transitions, using the differential shifting of these bands caused by methyl substitution. Solvent effects on indole emission are investigated. Non -hydroxylic solvents are found to shift the spectrum in a manner explicable by polarisation interaction. Hydroxylic solvents interact more strongly with the 1La state than with the 1Lb state, causing reversal of these levels in fluorescence from indole or skatole, but not from 5 ~ methylindole. All these indoles form exciplexes with hydroxylic solvents, and the possible structure of the exciplexes is discussed. The interaction of the indole chromophore with the carbonyl group is investigated, and to facilitate this, several indoles were synthesised using the Fischer indole reaction. The ketonic carbonyl quenches by excitation transfer from indole to the ketone, whilst the non - ketonic carbonyl forms a donor - acceptor complex with the excited indole. Quenching is dependent on the electron affinity of the non — ketonic carbonyl group. These studies are compared with reported studies on related benzene derivatives. Comments are made on the determination of quantum yields and lifetimes.

Divisions: College of Health & Life Sciences
Additional Information: Copyright © Geoffrey Lockwood, 1974. Geoffrey Lockwood asserts their moral right to be identified as the author of this thesis. This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without appropriate permission or acknowledgement. If you have discovered material in Aston Publications Explorer which is unlawful e.g. breaches copyright, (either yours or that of a third party) or any other law, including but not limited to those relating to patent, trademark, confidentiality, data protection, obscenity, defamation, libel, then please read our Takedown Policy and contact the service immediately.
Institution: Aston University
Uncontrolled Keywords: photoluminescence,indoles
Last Modified: 21 May 2024 13:04
Date Deposited: 24 Jan 2011 15:28
Completed Date: 1974-10
Authors: Lockwood, Geoffrey

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