Fuchsine

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Fuchsine (sometimes spelled fuchsin) or rosaniline hydrochloride is a magenta dye with chemical formula C₂₀H₁₉N₃·HCl.<ref name="nih-basic">"Basic chemical data". Discovery Series online database, Developmental Therapeutics Program, U.S. National Institutes of Health. Retrieved on 2007-10-08.</ref><ref>Goyal, S.K. "Use of rosaniline hydrochloride dye for atmospheric SO₂ determination and method sensitivity analysis". Journal of Environmental Monitoring, 3, 666–670, {{#invoke:doi|main}}. Retrieved on 2007-10-08.</ref> There are other similar chemical formulations of products sold as fuchsine, and several dozen other synonyms of this molecule.<ref name="nih-basic" />

It becomes magenta when dissolved in water; as a solid, it forms dark green crystals. As well as dying textiles, fuchsine is used to stain bacteria and sometimes as a disinfectant. In the literature of biological stains the name of this dye is frequently misspelled, with omission of the terminal -e, which indicates an amine.<ref>Baker JR (1958) Principles of Biological Microtechnique. London: Methuen.</ref> American and English dictionaries (Webster's, Oxford, Chambers, etc.) give the correct spelling, which is also used in the literature of industrial dyeing.<ref>Hunger K (2003) Industrial Dyes. Chemistry, Properties, Applications. Weinheim: wiley-VHC.</ref> It is well established that production of fuchsine results in development of bladder cancers by production workers. Production of magenta is listed as a circumstance known to result in cancer.<ref>Template:Cite book</ref>

HistoryEdit

Fuchsine was first created by Jakub Natanson in 1856 from aniline and 1,2-Dichloroethane.<ref name=":0">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In 1858 August Wilhelm von Hofmann obtained it from aniline and carbon tetrachloride.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> Template:Ill discovered the substance independently of Hofmann the same year and patented it.<ref>Template:Cite journal</ref> Fuchsine was named by its original manufacturer Renard frères et Franc,<ref>Béchamp, M. A. (January–June 1860.) "Comptes rendus hebdomadaires des séances de l'Académie des sciences. 1860. (T. 50)." French Academy of Sciences, Mallet-Bachelier: Paris, tome 50, page 861. Retrieved on 2007-09-25.</ref> is usually cited with one of two etymologies: from the color of the flowers of the plant genus Fuchsia,<ref name="fuchsin2004">(2004.) "Fuchsin" The American Heritage Dictionary of the English Language, Fourth Edition, Houghton Mifflin Company, via dictionary.com. Retrieved on 2007-09-20</ref> named in honor of botanist Leonhart Fuchs, or as the German translation Fuchs of the French name Renard, which means fox.<ref>"Fuchsine." Template:Webarchive (Website.) ARTFL Project: 1913 Webster's Revised Unabridged Dictionary. Retrieved on 2007-09-25</ref> An 1861 article in Répertoire de Pharmacie said that the name was chosen for both reasons.<ref>Chevreul, M. E. (July 1860). [[[:Template:Google books]] "Note sur les étoffes de soie teintes avec la fuchsine, et réflexions sur le commerce des étoffes de couleur."] Répertoire de Pharmacie, tome XVII, p. 62. Retrieved on 2007-09-25.</ref><ref>Template:Cite journal</ref>

UsageEdit

In the 21st century, it remains useful for biological chemistry, particularly for detecting glycogenic material.<ref name=":0" />

Historically, after its discovery it became widely-used in the textile industry in the late 1800s and 1900s for dyeing fabrics pink, and also for dyeing foodstuffs, particularly red wine, despite health concerns.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Acid fuchsineEdit

Acid fuchsine is a mixture of homologues of basic fuchsine, modified by addition of sulfonic groups. While this yields twelve possible isomers, all of them are satisfactory despite slight differences in their properties. Template:Citation needed

Basic fuchsineEdit

Basic fuchsine is a mixture of rosaniline, pararosaniline, new fuchsine and Template:Ill.<ref>Horobin RW & Kiernan JA 20002. Conn's Biological Stains, 10th ed. Oxford: BIOS, p. 184–191</ref> Formulations usable for making of Schiff reagent must have high content of pararosanilin. The actual composition of basic fuchsine tends to somewhat vary by vendor and batch, making the batches differently suitable for different purposes.

In solution with phenol (also called carbolic acid) as an accentuator<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> it is called carbol fuchsin and is used for the Ziehl–Neelsen and other similar acid-fast staining of the mycobacteria which cause tuberculosis, leprosy etc.<ref>Clark G 1973 Staining Procedures Used by the Biological Stain Commission, 3rd ed. Baltimore: Williams & Wilkins, pp. 252–254</ref> Basic fuchsine is widely used in biology to stain the nucleus, and is also a component of Lactofuchsin, used for Lactofuchsin mounting.

PropertiesEdit

File:Basic Fuchsine Crystals.JPG

Basic fuchsine pieces. The two magenta stains on the paper were made by placing one drop of ethanol-water azeotrope, centre, and water, right, on the streaks remaining on the paper after the 'crystals' were removed. The 'crystals' were then replaced and the photograph taken.

The crystals pictured at the right are of basic fuchsine, also known as basic violet 14, basic red 9, pararosanaline or CI 42500. Their structure differs from the structure shown above by the absence of the methyl group on the upper ring, otherwise they are quite similar.

They are soft, with a hardness of less than 1, about the same as or less than talc. They possess a strong metallic lustre and a green yellow color. They leave dark greenish streaks on paper and when these are moistened with a solvent, the strong magenta colour appears.

Chemical structureEdit

Fuchsine is an amine salt and has three amine groups, two primary amines and a secondary amine. If one of these is protonated to form ABCNH⁺, the positive charge is delocalized across the whole symmetrical molecule due to pi cloud electron movement.

The positive charge can be thought of as residing on the central carbon atom and all three "wings" becoming identical aromatic rings terminated by a primary amine group.Template:Clarify Other resonance structures can be conceived, where the positive charge "moves" from one amine group to the next, or one third of the positive charge resides on each amine group. The ability of fuchsine to be protonated by a stronger acid gives it its basic property. The positive charge is neutralized by the negative charge on the chloride ion. The positive "basic fuchsinium ions" and negative chloride ions stack to form the salt "crystals" depicted above.

ReferencesEdit

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