Lauth violet

Fig. 3.12 The dependence on pH of the oxidation-reduction potential for c0x = cRcd (1) 6-dibromphenol indophenol, (2) Lauth s violet, (3) methylene blue, (4) ferricytochrome c/ferrocytochrome c, (5) indigo-carmine... 

Thionine [Lauth s violet] 0.563J 0.064 1-13 Colorless to violet... 

By the sodium mirror technique, Bruin et obtained in dioxan anion radicals from 3,7-diaminophenothiazine (Lauth s violet), from 3,7-bis-dimethylaminophenothiazine (methylene blue), from 7-di-methylaminophenothiazone (methylene violet), and from phenothiazine itself. From the very well resolved ESR spectra of these radicals the value x 7 G was derived. 

In the same year methyl violet, which had already been noticed by Lauth in 1861, was manufactured on a large scale by Poirrier and Chapat. 

Eerntlisen [36] showed later that certain dyestuffs containing sulphur (methylene blue and Lauth s violet) also belong to this class of colouring-matters. 

Lauth s Violet gives a green solution with concentrated sulphuric acid, and on dilution the colour changes through blue to violet. On reduction it yields paradiamidothiodiphenylamine [36]. 

It is certain that methylene blue is the tetramethyl derivative of Lauth s violet, although it cannot be obtained by direct methyl-ation of the latter. Its constitution is analogous to that of tetramethylindamine. Like this, it contains a pentavalent nitrogen atom, which is in combination with two methyl groups and an hydroxyl or acid radical. The hydrochloride has the constitution expressed at the head of the section. The properties of the base of methylene blue are those of an ammonium base, and this agrees with the above conception of its constitution. The base is not easily separated from its salts. It is best obtained by decomposition of the hydrochloride with silver oxide, and has pi obably the formula CieHisNsSOH. It dissolves easily in water with a blue colour. 

As this compound is also formed by methylation of the leuco-compound of Lauth s violet, the relationship between the two dyestuffs is demonstrated. 

This body contains one amido group less than Lauth s violet, and is formed by oxidation of monamidothiodiphenylamine. 

This compound may be obtained by oxidation o paramidophenol in presence of sulphuretted hydrogen or by treating Lauth a violet with an alkali. In the latter case the imido-group is eliminated as ammonia. 

Solution of 2 g FeS04 7 HjO in 500 mL of water (or an equivalent amount of Mohr s salt), 20 % sulfuric acid, 0.02 g of the dyestuff Lauth s violet (thianine). 

Diaminophenthiazine (see structural formula above), which was first prepared in 1876 by Lauth from 1,4-diaminobenzene and hydrogen sulfide, forms a violet cation in acidic solution. 

C.l. 52000 CCRIS 5616 Cyanine 3,7-Diaminophen-azathionium chloride 3,7-Diaminophenothiazin-5-ium chloride EINECS 209-470-3 Katalysin Lauth s Violet Lauthsches violett NSC 9591 NSC 56342 Phenothiazin-5-ium, 3,7-diamino-, chloride Thionin Thionine. Used as a microscopic stain. 

Phenoxazine and phenothiazine dyes are basic dyes which possess a delocalized quinone iminium chromophore analogous to phenoxazone. They are derived from the classical dyes Meldola Blue 40 and Lauth s Violet 41 ... 

Of the triphenylmethane derivatives, gentian violet has been most often used in medical applications. It is a purple dye, so-called because its color resembles that of the gentian flower it has nothing to do with Gentiana species. It is a mixture of crystal violet (hexamethyl-para-rosaniline) 96% and methyl violet (tetramethyl- and pentamethyl-para-rosaniline). Methyl violet was first synthesized by Lauth in 1861 [15 ] after Perkins discovery of aniline dyes [16 ]. 

J-Lactam see azetidin-2-one /J-Lactam antibiotics 54 /i-Lactamase 213 Lactoflavin 491 /i-Lactone see oxetanone Lamotrigin 509 Lapachenol 320 Lauth s Violet 446 Lawesson reagent 1 Leflunomide 190 Lepidine 387 Leucopterin 489 Levetiracetam 160 Levobupivacaine 434 Levosimendan 462 a-Lipoic add 164 Lobeline 432 Loganin 316 Losartan 280 Ludferin 211 Ludgenin 429 Lukianol 570 Lumazine 489 Lumiflavine 491 Luminol 56,498 Lupinine 423 Luteolin 340 Lutidine 345... 

Sulphide is found in anoxic sea water and may be present in small amounts even when there is a low concentration of oxygen. The method described here, depending on the formation of Lauth s violet from p-phenylenediamine, is a simple application to sea water of a well established colorimetric method for sulphide. Other substituted p-phenylenediamines have been used but there is little indication diat one is better than another. A critical study by Kato, Takei and Ogasawara (Technol. Kept., Tohoku Univ., 19 85, 1954) indicates that the unsubstituted amine is probably best. Sulphur is converted quantitatively into a highly coloured dye-stuff and the method is nearly as sensitive as theoretically possible and suitable for all concentrations of sulphide to be expected in the sea. 

The acidified sample is allowed to react with p-phenylenediamine and ferric chloride. A complex oxidation and substitution takes place resulting in the quantitative incorporation of any sulphide-sulphur present into a heterocyclic sulphur-containing dye called Lauth s violet. The extinction of solutions are measured, before or after dilution, using 1- or 10-cm cells. 

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