Xanthene dye

To improve the light stability of the original Polacolor film, Polaroid introduced a metallized set of image dyes in 1972. This set included a chromed azomethine yellow 44, a chromed azo magenta 45, and a highly solubilized derivative of copper phthalocyanine 46 [60], 

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Xanthene dyes are those containing the xanthylhim [261-23-4] (la) or diben2o-y-pryan nucleus [92-83-1] (xanthene) (lb) as the chromophore with amino or hydroxy groups meta to the oxygen as the usual auxochromes. They are... 

For uniformity with the stmctures given in the Colourindex the ammonium radical (9) is used for the amino-substituted xanthenes and the keto form for the hydroxy derivatives. The xanthene dyes may be classified into two main groups diphenylmethane derivatives, called pyronines, and triphenylmethane derivatives (eg, (4)), which are mainly phthaleins made from phthaUc anhydride condensations. A third much smaller group of rosamines (9-phenylxanthenes) is prepared from substituted ben2aldehydes. The phthaleins may be further subdivided into the following fluoresceins (hydroxy-substituted) rhodamines (amino-substituted), eg, (6) and mixed hydroxy/amino-substituted. 

Most xanthene dyes are classified as basic dyes by their method of appHcation acid dyes can be produced by introduction of sulfonic acid groups. The fluoresceins, which contain carboxy and hydroxy substituents, are also acid dyes for coloration of silk. Some of the fluoresceins in which the carboxy group has been esterified, are soluble in alcohol or other organic solvents and can be classified as solvent dyes. Mordant dyes can be produced by introducing o-dihydroxy or sahcyhc acid groups (2), which when metallised can have very good lightfastness. 

The physical properties of the xanthene type dye stmcture in general have been considered. For example, the aggregation phenomena of xanthene dyes has been reviewed (3), as has then photochemistry (4), electron transfer (5), triplet absorption spectra (6), and photodegradation (7). For the fluoresceins in particular, spectral properties and photochemistry have been reviewed (8), and the photochemistry of rhodamines has been investigated (9). 

Reactive xanthene dyes with P-hydroxyethylsulfonyl groups, as exemplified by stmcture (29), provide brilliant shades and excellent washfastness on cotton (40). The sulfutein derivative (29) is synthesized by condensing 3-aminophenol-P-hydroxyethylsulfone with... 

A series of water-soluble fiber-reactive xanthene dyes has been prepared from the reaction of ben2oxanthenedicatboxylic acid anhydride disulfonic acid with, for example, 3-aminophenyl-P-hydtoxyethyl sulfone to yield dyes, with high brilliance and good fastness properties for dyeing of or printing on leather, wool, sHk, or ceUulosic fibers (53). 

Table 2. Toxicological Properties of Selected Xanthene Dyes ...

See Analgesics, antipyretics, AND antiinflammatory agents Xanthene dyes. 

Xanthene dyes (qv) can be either acidic or basic. Acid xanthenes are known to exist in two tautomeric forms. The phenoHc type, or fluorans, are free-acid stmctures such as D C Orange No. 10 (17b) and D C Red No. 21 (17c). Most have poor water solubHity. In contrast to these, the quinoids or xanthenes are usuaHy the highly water-soluble sodium salt counterparts of the fluorans such as D C Orange No. 11 (18) and D C Red No. 22 (21a). Presendy, there are no certifiable basic xanthene colorants. 

Xanthene Dyes. This class is best represented by Rhodamine B. It has high fluorescent brilliance but poor light and heat stabihty it may be used in phenohcs. Sulfo Rhodamine is stable and is useflil in nylon-6,6. Other xanthenes used in acryhcs, polystyrene, and rigid poly(vinyl chloride) are Solvent Green 4, Acid Red 52, Basic Red 1, and Solvent Orange 63 (see Xanthene dyes). 

Polacolor. The first instant color film, Polacolot, was introduced by Polaroid Corporation in 1963. Polacolot was replaced in 1975 by Polacolot 2, a film with improved light stabiUty, which utilizes the metallized dye developers shown in Eigute 4. An extended range version, Polacolot ER, introduced in 1980, utilizes the cyan and yeUow metallized dye developers together with a magenta dye developer that incorporates a xanthene dye having reduced blue absorption (see Eig. 5). 

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). 

Neady every significant class of dyes and pigments has some members that function as sensitizers. Toxicological data are often included in surveys of dyes (84), reviews of toxic substance identification programs (85), and in material safety data sheets provided by manufacturers of dyes. More specific data about toxicological properties of sensitizing dyes are contained in the Engchpedia under the specific dye classes (see Cyanine dyes Polymethine dyes Xanthene dyes). 

SENSORS WITH RESPONSE ON SOME XANTHENE DYES BASED ON MOLECULARLY IMPRINTED ELECTROSYNTHESIZED POLYMERS... 

In the present work, the synthesis of two MIEPs is described and their application for sensing and separation two xanthene dyes - rhodamine and fluorescein - has been reported. 

Combes, R.D. and Haveland-Smith, R.B., A review of the genotoxicity of food, drug and cosmetic colours and other azo, triphenyhnethane and xanthene dyes, Mutation Res., 98, 101, 1982. 

Quinophthalon dyes Quinoline yellow Xanthene dyes Erythrosine (see below)... 

Erythrosine (E 127, FD C Red No. 3, Cl Food Red 14) is a xanthene dye named disodium salt of 2-(2,4,5,7-tetraiodo-3-oxido-6-oxoxanthen-9-yl)benzoate monohydrate (or disodium salt of 9-(o-carboxyphenyl)-6-hydroxy-2,4,5,7-tetraiodo-... 

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