Triarylmethane dye: Difference between revisions
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'''Triarylmethane dyes''' are synthetic [[organic compound]]s containing [[triphenylmethane]] backbones. As |
'''Triarylmethane dyes''' are synthetic [[organic compound]]s containing [[triphenylmethane]] backbones. As [[dye]]s, these compounds are intensely colored. Many of these dyes undergo reactions in response to acid and base, and thus serve as [[pH indicator]]s.<ref>{{Ullmann's | last1 = Gessner | first1 = Thomas | last2 = Mayer | first2 = Udo | title = Triarylmethane and Diarylmethane Dyes | year = 2000 | doi = 10.1002/14356007.a27_179}}</ref> |
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:[[File:Bromocresol green ionic equilibrium.png|500px|Bromocresol green reacts with acids and bases to give differently colored compounds]] |
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As a consequence of their structure, the [[ |
As a consequence of their structure, the [[Friedel–Crafts alkylation]] reaction is a popular method to prepare many of these compounds: |
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:[[File:ThymolphthaleinSynthesis.png|350px| |
:[[File:ThymolphthaleinSynthesis.png|350px|Friedel–Crafts synthesis of thymolphthalein]] |
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==Families== |
==Families== |
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Revision as of 03:35, 4 July 2014
Triarylmethane dyes are synthetic organic compounds containing triphenylmethane backbones. As dyes, these compounds are intensely colored. Many of these dyes undergo reactions in response to acid and base, and thus serve as pH indicators.[1]
As a consequence of their structure, the Friedel–Crafts alkylation reaction is a popular method to prepare many of these compounds:
Families
Triarylmethane dyes can be grouped into families according to the nature of the substituents on the aryl groups. In some cases, the anions associated with the cationic dyes (say crystal violet) vary even though the name of the dye does not. Often it is shown as chloride.
Methyl violet dyes
Methyl violet dyes have dimethylamino groups at the p-positions of two aryl groups, since they are prepared from Mischler's ketone.
- Methyl violet dyes
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Fuchsine dyes
Fuchsine dyes have amine (NH2 or NHMe) functional groups at the p-positions of each aryl group.
- Fuchsine dyes
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Fuchsine (hydrochloride salt) -
New fuchsine (cation) -
Phenol dyes
Phenol dyes have hydroxyl groups at the p positions of each aryl group.
- Phenol dyes
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Malachite green dyes
Malachite green dyes are related to the methyl violet dyes, except that they contain one phenyl (C6H5) group.
- Malachite green dyes
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Bridged arenes
Where two of the aryl groups are bridged by a heteroatom, these triarylmethane compounds may be further categorized into acridines (nitrogen-bridged), xanthenes (oxygen-bridged), and thioxanthenes (sulfur-bridged).
References
- ^ Gessner, Thomas; Mayer, Udo (2000). "Triarylmethane and Diarylmethane Dyes". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a27_179. ISBN 978-3527306732.