Ferrocenyl derivatives of dithizone : photochromic properties and potential as electrochemical sensors
type: CreativeWork
description: New ferrocenyl derivatives of dithizone were successfully prepared and characterised by various analytical techniques. In the first part of this project interactions between photochromic and redox properties were investigated for the new ferrocenylmercury dithizonate complexes (N,S-dithizonato )(ferrocenyl)mercury(II) (11) and (ferrocene-l, 1'- diyl)bis[(N,S-dithizonato)mercury(II)] (12). UV-Vis spectroscopy showed that these complexes exhibited similar photochromic behaviour to related compounds known in the literature, i.e., a change in colour from orange to blue upon irradiation of organic solutions with visible light. The molar extinction coefficient of compound (12) was almost double that of compound (11), indicating that there are two chromophores absorbing in compound (12) compared to one in compound (11). Cyclic voltammetry on acetonitrile solutions of these photochromic compounds showed no noticeable differences in the voltammograms for the activated blue form compared to the normal orange form when irradiated with sunlight. This suggests that the interactions between the redoxactive group and the changes in the conformation of the photochromic group were not significant enough to make any noticeable changes to the voltammetric behaviour. In the second part of this project the electrochemical recognition of various metal ions by the new ligands S-ferrocenyldithizone (13) and S-ferrocenylmethyldithizone (14) was investigated. In both compounds the transducer is the ferrocenyl substituent and the binding site is the formazan group. These receptors showed a reversible redox wave in acetonitrile assigned to the ferrocene/ferrocenium couple: for receptor (13), E1I2 = 203 mV and for receptor (14), E1I2 = 136 mV relative to ferrocene as a standard reference. Addition of Cu2 + ions to ligand solutions in acetonitrile showed contrasting behaviour: ligand (13) produced a new wave with shift in E1I2 from 203 to 387 mV (M1I2 = 184 mY). For receptor (14), titration with…
abstract: New ferrocenyl derivatives of dithizone were successfully prepared and characterised by various analytical techniques. In the first part of this project interactions between photochromic and redox properties were investigated for the new ferrocenylmercury dithizonate complexes (N,S-dithizonato )(ferrocenyl)mercury(II) (11) and (ferrocene-l, 1'- diyl)bis[(N,S-dithizonato)mercury(II)] (12). UV-Vis spectroscopy showed that these complexes exhibited similar photochromic behaviour to related compounds known in the literature, i.e., a change in colour from orange to blue upon irradiation of organic solutions with visible light. The molar extinction coefficient of compound (12) was almost double that of compound (11), indicating that there are two chromophores absorbing in compound (12) compared to one in compound (11). Cyclic voltammetry on acetonitrile solutions of these photochromic compounds showed no noticeable differences in the voltammograms for the activated blue form compared to the normal orange form when irradiated with sunlight. This suggests that the interactions between the redoxactive group and the changes in the conformation of the photochromic group were not significant enough to make any noticeable changes to the voltammetric behaviour. In the second part of this project the electrochemical recognition of various metal ions by the new ligands S-ferrocenyldithizone (13) and S-ferrocenylmethyldithizone (14) was investigated. In both compounds the transducer is the ferrocenyl substituent and the binding site is the formazan group. These receptors showed a reversible redox wave in acetonitrile assigned to the ferrocene/ferrocenium couple: for receptor (13), E1I2 = 203 mV and for receptor (14), E1I2 = 136 mV relative to ferrocene as a standard reference. Addition of Cu2 + ions to ligand solutions in acetonitrile showed contrasting behaviour: ligand (13) produced a new wave with shift in E1I2 from 203 to 387 mV (M1I2 = 184 mY). For receptor (14), titration with…
author: Malatji, Peter
keywords: Chemistry
date published: 2008
date modified: 2026-07-22T22:23:24Z
provider: University of Cape Town
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Department of Chemistry

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property ID: Handle
value: http://hdl.handle.net/11427/39393