Triarylmethane dyes

Anthraquinone dyes have not been widely used in photography. However, Polaroid s initial color film released in 1963 used the anthraquinone cyan 53. This dye illustrates the dye-developer concept in which the control group for diffusion-transfer imaging is a pair of hydroquinone moieties. The branching of the side chain linking the control group to the chromophore is important for light stability [69], 

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ANHBIOHCS - BETA-LACTAMS - PENICILLINS AND OTHERS] (Vol 3) Assaying triarylmethane dyes... 

A useful classification of sensitizing dyes is the one adopted to describe patents in image technology. In Table 1, the Image Technology Patent Information System (ITPAIS), dye classes and representative patent citations from the ITPAIS file are Hsted as a function of significant dye class. From these citations it is clear that preferred sensitizers for silver haUdes are polymethine dyes (cyanine, merocyanine, etc), whereas other semiconductors have more evenly distributed citations. Zinc oxide, for example, is frequendy sensitized by xanthene dyes (qv) or triarylmethane dyes (see Triphenylmethane and related dyes) as well as cyanines and merocyanines (see Cyanine dyes). 

Dyes. Vital dyes have been used for many years in a variety of clinical situations. Patent blue V (also called E131, Acid blue 3, Disulfine blue) and Isosulfan blue (also called Patent blue violet or Lymphazurine), belong to the group of triarylmethane dyes and are the most commonly used [24]. Reports of IgE-dependent anaphylaxis arise. Anaphylactic reactions involving methylene blue seems to be very rare, however, several reports of sensitization to both Patent blue and methylene blue have previously been reported. 

Briliant Blue FCF (E 133, FD C Blue No. 1, Cl Food Blue 2) is a triarylmethane dye disodium 3-[N-ethyl-N-[4-[[4-[N-ethyl-N-(3-sulfonatobenzyl)-amino] phenyl] (2-sulfonatophenyl)methylene]-2,5-cyclohexadiene-l-ylidene]ammoniome-thyl] benzenesulfonate (or disodium (4-(N-ethyl-3-sulfonato-benzylamino) phenyl)-a-(4-N-ethyl-3-sulfonatobenzylamino)cyclohexa-2,5-dienylidene)-toluene-2-sul-... 

Fast Green FCF (FD C Green No. 3, Cl Food Green 3) is a triarylmethane dye related to Brilliant Blue, the disodinm 3-[N-ethyl-N-[4-[[4-[N-ethyl-N-(3-snl-fonatobenzyl)amino] -phenyl] (4-hydroxy-2-snlfonatophenyl)methylene] -2,5-cyclo-hexadien-l-ylidene]ammonio-methyl]-benzenesnlfonate. Fast green is a red to brown-violet powder or crystals, solnble in water, sparingly solnble in ethanol, with a maximnm absorption in water at 625 nm. It is not permitted as food colorant in the EU. -"... 

Green S (E 142, Cl Food Green 4, Brilliant Green BS) is a triarylmethane dye, with the chemical name sodinm N-[4-[[4-(dimethylamino)phenyl](2-hydroxy-3,6-disnlfo-l-naphthalenyl)-methylene]-2,5-cyclohexadien-l-ylidene]-N-methylmetha-naminium. The calcium and potassinm salts are also permitted. Green S is a dark bine or green powder or grannies, solnble in water, slightly solnble in ethanol, with a maximum absorption in water at 632 nm = 1720). It is not permitted as a... 

Patent Blue V (E 131, Cl Food Blue 5, Patent Blue 5) is a triarylmethane dye, the calcium or sodium salt of 2-[(4-diethylaminophenyl)(4-diethylimino-2,5-cyclo-hexadien-l-ylidene)methyl]-4-hydroxy-l,5-benzenedisulfonate. It is a dark-blue powder, soluble in water, slightly soluble in ethanol. The absorption maximum is 638 nm in water, pH 5, with = 2000. Patent blue is not permitted for use as... 

Arylmethane leuco dyes are converted into di- or triarylmethane dyes on oxidation. This class of dye precursors sometimes is referred to as leuco di- or triphenylmethane dyes, or di- or triphenylmethane leuco dyes. The use of the term di- or triarylmethane dyes can be misleading as the central carbon atom is a carbonium ion. Instead, the term di- and triarylmethine dye is recommended for this class as it correlates with the well-known polymethine dyes. Nevertheless, it has not been commonly used. 

Unlike triarylmethane dyes, comparatively little work has been done with diaryl heteryl-, and aryl diheteryl methane compounds. Analogous to triarylmethanes, triheterylmethane dyes are also prepared using POCl3 and a ketone. The intermediate leuco compounds (similar to 65, see Scheme 8) are not isolated40 in the case of triheterylmethane leuco dyes. 

Although treated as separate classes in the Colour Index, these structural types are closely related and the few diphenylmethane dyes such as auramine (1.28 Cl Basic Yellow 2) are now of little practical interest. Commercial usage of the triarylmethane dyes and pigments has also declined considerably in favour of the major chemical classes. They were formerly noteworthy contributors to the acid, basic, mordant and solvent ranges, primarily in the violet, blue and green sectors. Numerous structural examples are recorded in the Colour Index. The terminal groupings can be amine/quinonimine, as in auramine and crystal violet (1.29 Cl Basic Violet 3), hydroxy/quinone, or both. The aryl nuclei are not always benzenoid (section 6.5). 

Several examples of typical triarylmethane dyes have already been mentioned, in particular, pararosaniline (6.161), malachite green (6.162) its o-chloro derivative (6.169), crystal violet (6.164), rosaniline (6.165) and diphenylamine blue (6.173). Cl Basic Green 1 (6.168 R = C2H5), the ethyl analogue of malachite green, is prepared by the aldehyde route and is isolated as the sulphate. The ethyl analogue of crystal violet is Cl Basic Violet 4 (6.167 R = C2H5) and is obtained by the ketone route. 

Anthraquinone acid, disperse, basic and reactive dyes 280 Polycyclic vat dyes 294 Indigoid and thioindigoid dyes 316 Sulphur and thiazole dyes 321 Diarylmethane and triarylmethane dyes 327 Miscellaneous colorants 344 References 353... 

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