Dye eosin

FIG. 4 SHG intensity from the dye eosin B adsorbed at the air-water interface as a function of the pH of the bulk aqueous solution. The aqueous dye concentration is 30 /xM and the fundamental wavelength is 532 nm. 

Macrae and Wright (96) demonstrated that visible light irradiation of xanthene dyes (eosin, erythrosin, rhodamine B, or RB) in ethanolic solutions of 4-(N,N-diethylamino)benzene-diazonium chloride (as the zinc chloride double salt) resulted in decomposition of the diazonium salt. Electron transfer from the dye excited state(s) to the diazonium salt was postulated and dye-diazonium salt ion pair formation in the ground state was shown to be important. Similar dyes and diazonium salts were claimed by Cerwonka (97) in a photopolymerization process in which vinyl monomers (vinylpyrrolidone, bis(acrylamide)) were crosslinked by visible light. Initiation occurs by the sequence of reactions in eqs. 40-42 ... 

The first example of an 1,4-endoperoxide by photo-oxygenation was reported in 1928 by Windaus and Brunken [1] who obtained the peroxide of ergosterol by irradiation in the presence of oxygen and a dye (eosin) (Sch. 1). 

Eosinophils are leukocytes that contain characteristic cationic proteins in their granules that bind the acidic dye eosin. In contrast to neutrophils, eosinophils are minority cells in the blood and are predominantly tissue-dwelling cells found at sites in contact with the environment the mucosal surfaces of the lung, gastrointestinal tract, and genitourinary tract. Selective accumulation of eosinophils, as opposed to neutrophils, is one of the major pathological features of the inflammatory response to infection with parasitic helminths, and in several diseases such as asthma, allergic rhinitis, and atopic dermatitis. A key step in leukocyte recruitment is the local production of chemoattractant molecules that orchestrate the adhesive interactions between leukocytes and the vascular endothelium. 

Why do the vesicles of some mast cells, which contain large quantities of histamine, stain red with the dye eosin ... 

The first picosecond time-resolved observations of a photosensitised charge-injection process in semiconductor particles were carried out by Moser et at. (1985). The rate of electron injection from the excited singlet state of the surface-adsorbed dye eosin, EO(Si), to the conduction band of colloidal Ti02 particles... 

The cationic complexes of lead with 1,10-phenanthroline [25,67], cryptand(2.2.2) [68], and 18-crown-6 [69] form extractable ion-associates with the acid dyes eosin (e = 1.1-10 ) [25,68], Erythrosin, Rose Bengal [25,70], Metanilic Yellow (e = 4.5-10 ) [69], and Bromophenol Blue [67]. The Pb complex with Bathophenanthrolin, associated with Bromophenol Blue (e = 4.0-10 ), has also been applied [67]. 

REE ions with 1,10-phenanthroline form cationic complexes such as [La(phen)3 which give ion-associates with xanthene acid dyes, eosin or Erythrosin [117,118]. Molar absorptivities are of the order of 1-10. Europium(II) has been determined by an indirect method, after reduction of Fe(III) and reaction of the resulting Fe(II) with 1,10-phenanthroline [119]. 

A number of derivatives of fluorescein are useful dyes. Uranin is the disodium salt of fluorescein. ChrysoUn is a salt of benzyl-fluorescein, which is formed from phthalic anhydride and benzyl-resorcinol. It dyes silk and wool a fast yellow, and is used in cotton dyeing. Eosin is the disodium salt of tetrabromo-fluorescein, which is prepared by the action of bromine on fluorescein. Its dilute alkaline solution is rose-colored, and exhibits an intense yellow-green fluorescence. Other dyes related to fluorescein are tetrabromo-dichlorofluorescein and various ethers of fluorescein and its substitution-products. The dyes of this class produce on silk and wool shades from yellow to reddish yellow, cherry-red, and purple. 

Lead azide exists as four polymorphic forms [287] of which the orthorhombic oc-lead azide is the most stable [276]. In fact, a-lead azide is the only acceptable form for technological applications. Presently, the state of the art of making the polymorphs can be summarized as follows a-lead azide is the main product of precipitation, with traces of the other forms present [288]. The monoclinic [276] /3-form is stable when dry, but re crystallizes as the a-form [276,289]. The presence of organic dyes (eosin, neutral red) at the precipitation enhances formation of /3-lead azide [276] the presence of hydrophile colloids inhibits it [276,287]. The monoclinic [287] 7-form, apparently less stable than a and /3 [289], is obtained from pure reagents at a pH of 3.5-7 [287] or in the presence of polyvinyl alcohol [289]. The triclinic 6-form precipitates from pure reagents between pH 3.5 and 5.5 [287]. No method is presently available to yield a single polymorph exclusively, but the crystals differ sufficiently in shape to allow hand selection under the microscope [287,288]. 

Figure 8.4. SD study of the dye eosin in water by third-order photon echo spectroscopy. The peak shift data of eosin in water (sohd circles) and lysozyme complex in water (open triangles) are shown. The inset shows the lysozyme data (open triangles) with fits (solid line). Adapted with permission from J. Phys. Chem. B, 103 (1999), 7995. Copyright (1999) American Chemical Society.

Recently, Zeitler and co-workers [107] have demonstrated the viability of an asymmetric organocatalytic cycle using the organic dye eosin Y as photoredox... 

Figure 19.8 Grid structure obtained by photopolymerization. A grid with a spacing of 1 mm and wall thickness of 250 pm was fabricated inside a wet gel. The gel had a thickness of 6 mm and the grid penetrated throughout the gel. A luminescent dye (eosin Y) was incorporated in the polymerized regions for visualization. From [41].

Human skin Dyes (eosin, methylviolet, oil red 0) 16 BCs Various % protection effects Treffel et al. [87]... 

Dye = benzophenone, isopropyl thioxanthone, merocyanine, etc. Dye/amine/maleimide widi Dye = benzophenone, etc. Dye/amine/diphenyl iodonium salt with Dye = eosin, ketocoumarin, methylene blue, thioxanthene dye, fluorone dye, etc. Dye orate salt/triazine derivative with Dye = cyanine dye, styiylquinolinium dye, etc. Dye/borate salt/alkoxypyridinium salt with Dye = carbocyanine dye, etc. Pl/amine/triazine derivative with Dye = pyrromethene dye. Rose Bengal, etc. Dye/hexabisimidazole derivative (e.g. Cl-HABI)/thiol with PI = styiylnaphtothiazole dye, diethylamino benzophenone, julolidine dye, etc. Dye/amine (or... 

Using a combination of internal reflection spectroscopy and laser flash photolysis, Ryan et al. [66] recently observed the electron exchange with a single crystal Ti02 electrode for the singlet state, the triplet state and the cation radical of the dye Eosin Y. With a temporal resolution of 100 ns, the kinetics of the charge transfer are compared with those of the dye in solution and used to interpret the photoelectrochemistry of the dye at the electrode. Spectroscopic evidence revealed photocurrent production by the triplet state and a reduction of the eosin radical cation by electrons from the Ti02 conduction band and by hydroquinone. 

Structure modifiers was tested for modification of the crystal form of precipitated LA. The most commonly noted ones include dextrin, carboxymethyl cellulose, and PVA. The presence of dextrin promotes formation of the ot-form [16] while the presence of organic dyes (eosin, erythrosin, or neutral red) at precipitation time enhances the formation of the p-form [15]. The crystals of p lead azide are formed in the shape of long needles (Fig. 4.1). 

The photochemical generation of singlet oxygen has suffered from the insolubility of those anionic dyes which are commonly used as sensitizers (see Fig. 11.1). It has recently been found that the photosensitizing dyes eosin and rose bengal can be solu-... 

Desiderio et al. (1998) reported a quantitative method of analyzing dyes in lipstick using micellar electrokinetic capillary chromatography (MEKC) with diode array UV detection. This electrophoretic method was optimized for the separation of seven cosmetic dyes Eosin Y (Cl 45380), certifiable as D C Red No. 22 erythrosine (Cl 45430) cyanosine (Cl 45410), certifiable as D C Red No. 28 Rhodamine B (Cl 45170) Orange II (Cl 15510), certifiable as D C Orange No. 4 Chromotrope FB (Cl 14720) and tartrazine (Cl 19140), certifiable as FD C Yellow No. 5. The process was fast (3 min per separation). 

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