Showing papers on "Xanthene published in 1981"
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16 Dec 1981
TL;DR: In this article, a magnetic recording medium which excels in the adhesive strength between the base material and the ferromagnetic thin metallic film was obtained by using an organic high molecular material with the reducing deposition control function provided on the surface for the base materials.
Abstract: PURPOSE:To obtain a magnetic recording medium which excels in the adhesive strength between the base material and the ferromagnetic thin metallic film, by using an organic high molecular material with the reducing deposition control function provided on the surface for the base material. CONSTITUTION:An organic compound having the oxidation-reduction potential in a range from -1.0V to +0.5V such as the azo compound, anthraquinone compound, xanthene compound, azine compound, tiazine compound, oxazine compound, indigo compound, thioindigo compound, triphenylmethane compound and the like is provided on a thermosetting or thermoplastic synthetic high molecular material. Then, a ferromagnetic thin metallic film is provided by an electroless plating method to obtain a magnetic recording medium.
124 citations
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15 Oct 1981TL;DR: In this paper, the viscosity dependent radiationless relaxation of several cyanine dyes has been studied by picosecond laser spectroscopy and it was found that the relaxation rate is proportional to η−α.
Abstract: The viscosity dependent radiationless relaxation of several cyanine dyes has been studied by picosecond laser spectroscopy. It was found that the relaxation rate is proportional to η−α. The value of α, however, is not constant for a certain dye molecule, but is strongly dependent on the kind of solvent used. In n-alcohols for instance α is typically about 1. In glycerol/methanol or glycerol/water mixtures on the other hand α ≈ 0.5. A comparison is made with literature data on orientational relaxation lifetimes of some dyes in similar solvents. It is shown that the radiationless relaxation of cyanine dyes and the orientational relaxation of for instance xanthene dyes changes in roughly the same way as the solvent is changed. This is taken as proof of the proposal that a torsional motion of the heterocyclic quinolyl rings is the main course of the viscosity dependent relaxation of the cyanine dyes studied.
89 citations
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39 citations
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TL;DR: In this article, the photocurrents in zinc oxide and titanium dioxide electrodes sensitized by anionic xanthene dyes (Eosine Y, Phloxine B, Erythrosine, and Rose Bengal) and metal tetraphenylporphines were studied in aqueous solutions.
Abstract: The photocurrents in zinc oxide and titanium dioxide electrodes sensitized by anionic xanthene dyes (Eosine Y, Phloxine B, Erythrosine, and Rose Bengal) and metal tetraphenylporphines were studied in aqueous solutions. The quantum efficiencies of the photocurrents sensitized by anionic xanthene dyes were unaffected by substitution of the dye with various halogen atoms, while those sensitized by the tetraphenylporphines were affected by changing the central metal. It is concluded from these results that the electron injection from the excited xanthene dyes to the semiconductor electrodes is a process so rapid (<<0.1 ns) that no internal quenching processes can compete with it, while that from the tetraphynelporphines is relatively slow competing with the internal deactivation processes. It is also concluded that the electron back transfer from the semiconductor conduction band to the oxdized dye decreases the sensitization efficiency.
36 citations
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TL;DR: In this paper, the authors used Co-Mo catalysts to study the hydrogenolysis behavior of 28 compounds with structures as found in coal and residual oil, including diphenylmethane, indane, tetralin, anthracene and xanthene.
16 citations
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TL;DR: In this paper, a method for the separation of fluorescein dyes from their impurities was developed using high performance liquid chromatography and involved a μBondapak C18 reverse phase column and mixtures of methanol and ammonium acetate buffer.
Abstract: A reliable method for the separation of fluorescein dyes from their impurities was developed using high performance liquid chromatography and involved a μBondapak C18 reverse phase column and mixtures of methanol and ammonium acetate buffer. This technique was used to verify the purity of commercial products as well as to aid in the development of an empirical theory related to retention of halogenated fluorescein dyes by reverse phase columns.
8 citations
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20 Jan 1981
TL;DR: The starting novel compound of formula II was obtained by heating one mole of 3,6-dichloropyridazine with 2 moles or more of the corresponding 2-alkenyl substituted phenol in the presence of a base.
Abstract: NEW MATERIAL:A compound of formula I (R1, R2, R3, R4 and R5 are H or lower alkyl groups; X is lowr alkyl, halogen, lower alkyenyl, lower alkoxy group, etc; n is 0, 1 or 2) EXAMPLE:5a,12a-Etheno-6H,6aH,7H,13H,13aH,14H-[ 1 ]benzopyrano[ 2,3-b ] xanthene USE:A medicine having an analgesic and an anti-inflammatory actions or an intermediate for the synthesis of other medicines or agricultural chemicals PROCESS:A 3,6-bis(2-alkenylphenoxy)pyridazine derivative of formula II is heated with preferably an inert solvent, eg N,N-dimethylaniline, or an inert solid carrier, eg anhydrous sodium carbonate, at 150 degC or above to give the compound of formula I The starting novel compound of formula II is obtained by heating one mole of 3,6-dichloropyridazine with 2 moles or more of the corresponding 2-alkenyl substituted phenol in the presence of a base
7 citations
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10 Jul 1981
TL;DR: Anionic water-insoluble dyes which are easily dispersed in cold water, are at least partially in the form of a salt of a water soluble cationic resin comprising a condensn prod of formaldehyde with a guanidinium salt.
Abstract: Anionic water-insoluble dyes which are easily dispersed in cold water, are at least partially in the form of a salt of a water soluble cationic resin comprising a condensn prod of formaldehyde with a guanidinium salt The resins are made by condensing 05-5 moles, esp 08-2 moles formaldehyde with 1 mole of guanidine salt in an aq medium at 50-90 deg C and a pH of 4-12, esp 7-10 Generally the dye salt is composed of 01-3 moles guanidine per molar equiv anionic dye, esp 1 mole guanidine condensed with 1 mole formaldehyde per molar equiv anionic dye The dyes used are eg those contg sulphonic, phosphonic or carboxylic acid gps, and may be eg of the phthalocyanine, nitro, di- or triphenylmethane, oxazine, thiazine, dioxazine, xanthene, or (esp) anthraquinone or azo series The dyes disperse easily in cold water in the formation of dye baths or printing pastes which have no tendency to recrystallisation, gelling or reagglomeration The dyes are esp useful for colouring natural or synthetic polyamides and/or cellulosic fibres
5 citations
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TL;DR: In this article, the hydride transfer from xanthene to stable carbenium salts with different cation electrophilities is investigated and the reaction is controlled by the absorption of the ions in the visible region of their electronic spectra.
Abstract: The hydride transfer from xanthene to stable carbenium salts with different cation electrophilities: 2,4′,4′'-trichlorotriphenylmethylhexachloroantimonate, triphenylmethylhexafluoroarsenate, triphenylmethylhexachloroantimonate, 4,4′,4′'-trimethyltriphenylmethylhexachloroantimonate and tropylium hexachloroantimonate is investigated. The reaction is controlled by the absorption of the carbenium ions in the visible region of their electronic spectra. The formation of the product of the reaction — triphenylmethane — is detected by gas chromatography and NMR spectroscopy. The rate constants and the reaction order are determined. The acceleration of the hydride transfer on UV-irradiation of the reaction mixture is shown.
5 citations
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5 citations
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20 Feb 1981
TL;DR: In this paper, an unprecendent excited state pathway for the photodegradation of Kiton Red S, a sulforhodamine laser dye, in which the reactive, lowest energy excited triplet state of the molecule is populated by preferential intersystem crossing from upper singlet excited states, not from the singlet state nearest in energy to the triplet.
Abstract: : The primary objective of this research program has been the detailed elucidation of the principal photochemical mechanisms which lead to the degradation of xanthene laser dyes. The research performed in the course of this program has led to the discovery of an unprecendent excited state pathway for the photodegradation of Kiton Red S, a sulforhodamine laser dye, in which the reactive, lowest energy excited triplet state of the molecule is populated by preferential intersystem crossing from upper singlet excited states, not from the singlet state nearest in energy to the triplet. The results obtained have also led to a tentative chronology of the first several stages in the photodegradation process, and have revealed the existence of a previously unknown contact charge transfer (CCT) complex between oxygen and methanol. While much remains to be learned about the details of the chemical reactions involved in the photodegradation of kiton Red S and other xanthene dyes under various conditions, the research performed during this program has achieved significant progress toward this goal. In particular, enough has been learned about the degradation of these dyes that it is now possible to suggest new strategies for slowing their degradation under lasing conditions. These include, in particular, the removal of excitation wavelengths below 240 nm by selective filtering, and the use of improved triplet quenchers.
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TL;DR: In this article, a thermal cycloaddition of p-benzoquinone (2) to 9-vinylidenexanthene(or thioxanthene) derivatives is described.
Abstract: 13-Substituted naphthene(K 1)xanthene(or thioxanthene)-1,4-dione (4a, b) have been obtained by thermal cycloaddition of p-benzoquinone (2) to 9-vinylidenexanthene(or thioxanthene) derivatives (1 a, b). Reductive acetylation of 4 gives the diacetoxy derivatives. Compound 4 acting as dienophile, react with 1 or with 1,1-di(p-methoxyphenyl) ethylene (6) to give diadducts. 1,4-Naphthoquinone (10) reacts similarly with 1 to give 14-substituted anthracene(K 1)xanthene(or thioxanthene) 5,15-diones (11a, b). Compounds 1 a, b also react with N-phenylmaleimide (12) to give the diadducts (3a, 3b, 4, 6a, 12, 12a) hexahydro-12-phenyl-N-phenylphthalimido(K 1)xanthene (or thioxanthene) 4-6a-N-phenylpyrrolidine-r,3'-diones (13) or aromatized monoadducts 12-substituted-N- phenylphthalimide (K1) -xanthene (15 a, b).
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TL;DR: The structure 9-(4-hydroxyphenyl)xanthene is proposed for A274, an extensively conjugated phenol recently shown to be present as a common trace constituent in randomly selected batches of commercial tissue culture media.
Abstract: An extensively conjugated phenol (A274), recently shown to be present as a common trace constituent in randomly selected batches of commercial tissue culture media, was diazomethylated; the monomethyl derivative so prepared was shown to exhibit gas chromatographic and mass spectrometric properties identical to those observed for synthetically prepared 9-(4-methoxyphenyl)xanthene, but different from those of several isomeric compounds. The structure 9-(4-hydroxyphenyl)xanthene is thus proposed for A274.