Showing papers on "Xanthene published in 1983"

Quantum yield of singlet oxygen production by xanthene derivatives

Abstract: The singlet oxygen quantum yield (ϕ1o2) of 11 purified fluorescein derivatives was determined by reaction with singlet oxygen acceptors in aqueous and ethanolic solutions; in both solvents ϕ1o2 was enhanced with increasing halogenation. Tryptophan and 2,2,6,6-tetramethylpiperidone were found to be unadapted for the determination of ϕ1o2, in our systems; however, the use of 9.10-dipropionic anthracene acid andp-nitrosodimethylaniline in conjunction with imidazole derivatives was suitable for 1O2 detection in water. Both methods lead to results in excellent agreement. As in ethanol. ϕ1o2, was equal to the triplet state quantum yield (ϕT), the comparison between the two solvents showed that ϕT in water was greater than in ethanol. The comparison between our values obtained with polychromatic light with published data obtained with monochromatic light suggests that the triplet quantum yield of fluorescein derivatives is wavelength independent.

Mechanisms of photosensitization

Abstract: This review discusses important developments in the area of photosensitization from approximately June, 1982, through June, 1983. For the most part the articles cited will represent in vitro work, including studies with animal and human cells in culture. The review is divided into three sections dealing with the following classes of photosensitizing dyes and pigments: (1) porphyrins; (2) furocoumarins; (3) miscellaneous (including, e.g. flavins, xanthenes, and thiazines).

Photopolymerization initiator composition having high sensitivity

Abstract: PURPOSE:To attain satisfactory photopolymn initiating power by combining an org peroxide with an org dye compound having a specified structure CONSTITUTION:This photopolymn initiator composition contains one or more kinds of org peroxides (PO) and one or more kinds of org dye compounds (DY) as effective components in (1-99):(99-1) weight ratio of PO:DY Most of unsatd compounds can be photopolymerized under ultraviolet light or visible light in a vary short time by using the initiator composition Org compounds each having one or more oxygen-oxygen bonds in the molecule such as methyl ethyl ketone peroxide, cyclohexanone peroxide and 3,3,5-trimethylcyclohexanone peroxide are used as the org peroxides, and the org dye compounds include cyanine, merocyanine, xanthene and thiazole dyes each having a specified structure and assuming a color in the range of yellow-red-purple

Process for dyeing or printing cellulose-containing fibrous material with reactive dyes

Abstract: It comprises using reactive dyes of the formula where D is the radical of a sulpho-containing dye of the monoazo, polyazo, metal complex azo, anthraquinone, phthalocyanine, formazan, azomethine, dioxazine, phenazine, stilbene, triphenylmethane, xanthene, thioxanthone, nitroaryl, naphthoquinone, pyrenequinone or perylenetetracarbimide series, R is hydrogen or the radical of a substituted or unsubstituted hydrocarbon, Y is a radical or and X is chlorine or bromine, in an aqueous medium at pH >7, and gives dyeings and prints having good fastness properties.

Electronic Structure and Spectra of Organic Dye Anions of Uranine and Eosin Y

Abstract: The excited states of the organic dye anions of Uranine and Eosin Y are invesitigated by the semi-empirical SCF-MO-CI calculations. The two-center core integral values of the C–Br bond (−0.20 eV) were determined. Agreement between the calculated and observed spectra was satisfactory. The first intense bands of these dye anions can be assigned to the HOMO→LUMO transition band arising from the local excitation of xanthene ring. The second bands are interpreted as the overlap of the two transition bands for the xanthene ring and for the residual π-systems.

Novel xanthene compound

Abstract: NEW MATERIAL:The compound of formula I (R 1 WR 4 are alkyl, aryl or cycloalkyl wherein the aryl may be substituted with halogen or lower alkyl or the alkyl may together form a ring; R 5 WR 10 are H, alkylhalogen, alkoxy, etc.; the adjacent R's may together form a ring). EXAMPLE: 3-Diethylamino-6-chloro-7-methyl-9-( 2-methylphenylcarboxamide )phenylxanthene. USE: Extremely useful as a chromogen of pressure-sensitive recording paper, heat- sensitive recording paper, etc. It exists as a stable colored substance without causing the cyclization to a fluorane compound, and has extremely excellent stability to water, plasticizer, etc. PREPARATION: The compound of formula I can be produced by reducing the fluoran compound of formula IV, drying the obtained leuco compound of formula V, treating with a chlorination reagent in an inert solvent, and reacting with an amine. COPYRIGHT: (C)1985,JPO&Japio

Novel xanthene compounds and their photographic use

Abstract: In one embodiment, the present invention is concerned with novel xanthene compounds of the formula ##STR1## wherein each R1 is the same and is selected from ##STR2## R2 is alkyl, R3 is an electron-withdrawing group positioned ortho, meta or para to said N atom, R4 is hydrogen, alkyl or an electron-withdrawing group positioned ortho, meta or para to said N atom; R5 is alkyl; X is hydrogen, an electron-withdrawing group or an electron-donating group; and A is an anion In another embodiment, the present invention is concerned with photographic products and processes employing these xanthene compounds, eg, as photographic light-screening dyes

Photochemische Primärprozesse von Xanthenfarbstoffen. III. Blitzlichtspektroskopische Untersuchungen zum Einfluß von kationischen Mizellen auf die Photoredoxprozesse von Selenopyronin

Abstract: Photochemical Primary Processes of Xanthene Dyes. II. Investigations of the Influence of Anionic Micelles on the Primary Processes of Selenopyronine by Flash Excitation In aqueous solutions containing anionic micelles, the dye cations of selenopyronine are present at the micellar surface. If the concentration of the dye ions is much lower than the concentration of micelles, only monomolecular triplet decay (k1aM = 2 · 10−3s−1) is observed. Under these conditions, the half-oxidized and half-reduced form of selenopyronin is not formed. If the concentration of the dye ions is much higher than the concentration of micelles, two or more dye ions are present at every micelle, and a fast bimolecular decay of the triplet state during the flash is observed. The quenching of the triplet state with p-benzoquinone (k7aM = 1,9 · 109 l/mol s), DABCO (k10aM = 1,6 · 107 l/mol s) and EDTA (k11aM = 1,3 · 105 l/mol s) and the decay processes of the half-reduced and half-oxidized form in the micellar solution are investigated.

Thermo-sensitive recording material

Abstract: PURPOSE:To obtain thermo-sensitive recording material, the density of color formation thereof and the sensitivity of color formation thereof are sufficient and the fastness of the color former contained therein is enough, by adding a naphthoic acid derivative to a thermo-sensitive recording material containing an electron-donating leuco dye and an electron accepting compound. CONSTITUTION:An electron-donating leuco dye, such as a triarylmethane compound, a diphenylmethane compound, a xanthene compound, a thiazine compound, or a spiro-pyrane compound, an electron-accepting compound, such as a phenol compound, and a naphthoate ester of the formula (wherein R is an alkoxy group, an aralkyloxy group, an arylamino group, etc., and a naphthalene ring may have a substituent such as a halogen atom or an alkyl group) or naphthoamide are dispersed separately in water-soluble polymer solutions and mixed, and an inorganic pigment, such as kaoline, and other additives are added to prepare a coating liquid. The liquid is applied onto thick paper.

CC‐Doppelbindungen mit extremer Reaktivität, III. Versuche mit 9‐(9‐Fluorenyliden)xanthen

Abstract: CC Double Bonds with Extreme Reactivity, III. Reactions of 9-(9-Fluorenylidene)xanthene According to equations (1) to (4), 9-(9-fluorenylidene)xanthene (2) reacts with sulfur, malonodinitrile, aniline, or thiophenol to give the compounds 3, 5, 7–11, and diphenyl disulfide.

SPIROLACTONE OF XANTHENE (I) A NOVEL PRODUCT FROM THE REACTION OF α-NAPHTHOL WITH OXALIC ACID

Abstract: The condensation of α-naphthol with oxalic and sulfuric acids gives the novel compound, spiro [7H-dibenzo [c, h] xanthene-7, 1'(2'H)-naphtho [1, 2-b] furan]-2'-one, whose molecular structure was determined by X-ray diffraction methods.

Heat-sensitive recording meterial

Abstract: PURPOSE:To enhance developed color density and sensitivity, reduce fogging and enhance fastness of developed color material, by adding a specified aminophenol derivative into a heat-sensitive recording material comprising an electron-donative colorless dye and an electron-acceptive compound. CONSTITUTION:At least one aminophenol derivative represented by the formula (wherein R1 and R2 may be the same or different and are a substd. or unsubsted. alkyl group, preferably a 1-20C alkyl group or a 7-20C aralkyl group; -R1COO and -NHCOR2 are preferably para-substd.) and preferably having a melting point of 40-200 deg.C is incorporated into the heat-sensitive recording material comprising an electron-donative colorless dye such as a triarylmethane base compound, diphenylmethane base compound or a xanthene base compound and an electron-acceptive compound such as a phenol compound or an organic acid or a metallic salt thereof. In addition to the above components, an inorganic pigment and a binder and the like are appropriately added.

Spectrum on aqualuminescence from γ-irradiated NaCl in the presence of xanthene dyes

Abstract: Etude de l'augmentation de la luminescence en fonction de la concentration de colorants xantheniques (fluoresceine, eosine Y, pyronine G)

Influence of solvent deuteration on the spectral-luminescent and generational properties of xanthene and oxazine dyes

Abstract: Solving the problem of realizing the energetic potential of laser devices based on dye solutions involves making deliberate changes in such characteristics of the active medium as the magnitude of the induced pumping loss, the quantum yield of fluorescence, and the degree of photostability of the laser solutions. This approach presumes either the synthesis of new highly effective compounds or the improvement in the laser characteristics of already existing materials by the selection of the appropriate solvents or chemical additives [1-3]. In a series of works, an increase in the fluorescence quantum yield of certain dyes has been observed on passing from ordinary to deuterated solvents [4, 5]. Unfortunately, the literature includes no information on the attendant changes in laser characteristics of the active media, and also the question of the mechanisms suppressing the nonradiative transfer of the excitation energy in the isotropic substitution of deuterium for hydrogen ions in the solvent molecules remains quite unclear. In the present work, it is established that the use of deuterated ethyl and methyl alcohols leads to improvement in the laser efficiency of xanthene and oxazine dyes; especially favorable effects of solvent deuteration are seen in oxazine-9 (cresyl violet). It is shown that the change in spectroscopic constants controlling the processes of triplet-molecule formation and deactivation in the given materials is not much expressed, and the increase in generational characteristics of the dye solutions is due to slowing of the nonradiational internal-conversion processes S~ § So. Deuterated ethyl and methyl alcohols of analytical grade were used as the solvents; the hydrogen-containing alcohols were doubly distilled. The absorption and luminescence spectra of the dyes, preliminarily purified by the methods of recrystallizatio n and chromatography,