A kinetic and photochemical study of some basic dyes

Swarbrick, Elizabeth Anne (1989) A kinetic and photochemical study of some basic dyes. Doctoral thesis, Lancashire Polytechnic.

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Abstract

A series of dyes related to Crystal Violet have been synthesised in addition to a range of substituted oxygenbridged
analogues of Malachite Green. The dye perchiorates have been prepared from the corresponding carbinols or leuco bases.
The influence of the terminal group and the bridging unit together with the effects of substituents on the electronic
absorption spectra of the dyes have been examined.
The rates of hydrolysis of the dyes at various hydroxide ion concentrations and tanperatures have been determined. The
bridged tripherylmethane dyes shcx.z increased stability. Substituent effects in the oxygen bridged Malachite Green
series have been studied and the rate law has been found to differ from that of related dyes. The enhanced stability
observed for the 2-methyl and 2-trifluoranethyl derivatives is discussed. The thermodynamic paraneters Ill * and have been obtained for the dyes studied.
The efficiency with which the dyes generate singlet oxygen has been investigated and their performance ccmpared to that of
Methylene Blue. As canplanentary work, the fluorescence and phosphorescence properties of the dyes have been evalwted. The Vogel.-Rettig model has been applied to explain the differing fluorescence quantun efficiencies of the dyes, particularly the bridged molecules.
Solutions of a nunber of tripherbe'lmethane dyes, all nonbridged, have been found to undergo fading in some ornic solvents. Studies have been carried out to account for this behaviour.


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