AN EXAMINATION OF THE EFFECTS OF EXTENDED CONJUGATION THROUGH POLYCYCLIC SYSTEMS INCORPORATED INTO MONOAZO DYES

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dc.contributor.authorWADA, BONIFACE TYOTSUWE
dc.date.accessioned2014-07-11T07:22:06Z
dc.date.available2014-07-11T07:22:06Z
dc.date.issued1987-01
dc.descriptionThesis Submitted in fulfilment of the requirements for the degree of DOCTOR OF PHILOSOPHY by BONIFACE TYOTSUWE WADA Department of Colour Chemistry, University of Leeds, January, 1978.en_US
dc.description.abstractA systematic investigation has been carried out into the spectroscopic behaviour of some monoazo dyes derived from polycyclic systems. Hallas and his students have previously examined various phenylazo dyes derived from terminally bridged systems, viz. kairoline (N-methyl- 1,2,3,4-tetrahydroquinoline), N-2-cyanoethyl-l,2,3,4- tetrahydroquinoline, lilolidine(1,2,5,6-tetrahydro-4HpyrroloC3 ,2,1-i ] Iquinoline) and julolidine (2,3,6,7- tetrahydro-lH,5H-benzo[i j ]quinolizine). The present work is a continuation of these researches and includes dyes derived from more complex molecules based on naphthalene and phenanthrene. Novel azo dyes have also been prepared by coupling polyclic systems to N,N-diethylaniline in order to compare their characteristics with the well-documented properties of simple dialkylamino compounds. Several useful intermediates have been prepared for the first time and improved routes to others have been developed. Thus, l~amino-2-nitronaphthalene was obtained by direct amination of 2-nitronaphthalene and was found to be identical with samples obtained by other routes. A pure sample of 7-nitrotetral-l-one has been prepared and its oxime has been shown to melt at 170°C in contrast to the reported value of 150°C. A useful route has been devised for the preparation of several unsymmetrically disubstituted 9,10-dihydrophenanthrene derivatives and the corresponding phenanthrene analogues. The dinitration of 9,10-dihydrophenanthrene affords largely 2,7-dinitro-9,10-dihydrophenanthrene from which 2-amino-7-nitro-9,10-dihydrophenanthrene is obtained through selective reduction. The analogous phenanthrene compound is best obtained by aromatisation of the dinitro-9,10-dihydro compound followed by selective reduction. The electron-donating abilities of four different couplers have been examined by monitoring the spectral changes of appropriate dyes in ethanol and in ethanolic hydrogen chloride. The terminally bridged systems are in general better electron donors than a simple dialkylamino group, although dyes derived from N-2-cyanoethyl-l,2,3,4- tetrahydroquinoline show hypsochromic shifts in ethanol with respect to the corresponding dialkylamino dyes owing to the strong electron withdrawing influence of the cyano group. Spectral data have also shed light on the complex question of colour chemical constitution relationships as well as establishing the halochromism of some of the dyes in various solvents. The Pariser-Parr-Pople Molecular Orbital method with limited configuration interaction (PPP-MO CI) has been applied to most of the intermediates and the corresponding dyes for the prediction of molecular properties in the ground state and in the first singly excited stateen_US
dc.identifier.urihttp://hdl.handle.net/123456789/5090
dc.language.isoenen_US
dc.subjectEXAMINATION,en_US
dc.subjectCONJUGATION,en_US
dc.subjectPOLYCYCLIC SYSTEMS,en_US
dc.subjectINCORPORATED,en_US
dc.subjectMONOAZO DYESen_US
dc.titleAN EXAMINATION OF THE EFFECTS OF EXTENDED CONJUGATION THROUGH POLYCYCLIC SYSTEMS INCORPORATED INTO MONOAZO DYESen_US
dc.typeThesisen_US
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