Topic
Xanthene
About: Xanthene is a research topic. Over the lifetime, 2132 publications have been published within this topic receiving 34803 citations. The topic is also known as: Xanthene & dibenzo[a,e]pyran.
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Patent•
09 Dec 1989
TL;DR: The solubility of Xanthan is improved by the addition of water-soluble carboxylic acids or hydrogen phosphates as mentioned in this paper, which can be used to improve the stability of the Xanthan.
Abstract: The solubility of Xanthan is improved by the addition of water-soluble carboxylic acids or hydrogen phosphates.
4 citations
TL;DR: The photochemical reaction of 3,3-dimethyl-1,2-indanedione (DMID) with xanthene was investigated in detail in this paper, where the reaction proceeds via hydrogen abstraction by 3(nπ) of DMID leading to triplet radical pair composed of its semidione radical and 9-xanthenyl radical.
Abstract: The photochemical reaction of 3,3-dimethyl-1,2-indanedione (DMID) with xanthene was investigated in detail. The products are 1-hydroxy-3,3-dimethyl-1-(9-xanthenyl)-2-indanone (3a) (49%), 2-hydroxy-3,3-dimethyl-1-indanone (13%), 1,1′-dihydroxy-3,3,3′,3′-tetramethyl-1,1′-biindan-2,2′-dione (5a) (23%), and 9,9′-bixanthenyl (6) (49%). The reaction proceeds via hydrogen abstraction by 3(nπ)* of DMID leading to triplet radical pair composed of its semidione radical and 9-xanthenyl radical. The product 3a is a combination product from the radical pair, while 5a and 6 are escaping products from it. The hydrogen abstraction occurs at C-1 carbonyl group of DMID in a fairly efficient quantum yield (Φ=0.71). Behavior of the DMID semidione radical is rather resemble those of open-chain semidione radicals than those of sterically hindered semidione radicals.
4 citations
TL;DR: The title compound, C36H36N4O4, was prepared as a spirolactam ring formation of the rhodamine dye for comparison with a ring-opened form of the xanthene ring system.
Abstract: The title compound, C36H36N4O4, was prepared as a spirolactam ring formation of the rhodamine dye for comparison with a ring-opened form. The xanthene ring system is approximately planar [r.m.s. deviations from planarity = 0.023 (9) A for the xanthene ring]. The dihedral angles formed by the spirolactam and 1,3-benzodioxole rings with the xanthene ring system are 86.8 (1) and 74.3 (1)°, respectively.
4 citations
TL;DR: A series of new polyarylates bearing cardo xanthene groups were synthesized by phase-transfer-catalyzed interfacial polycondensation of 9,9-bis[4-(4-chloroformylphenoxy)phenyl]xanthene with various...
Abstract: A series of new polyarylates bearing cardo xanthene groups were synthesized by phase-transfer-catalyzed interfacial polycondensation of 9,9-bis[4-(4-chloroformylphenoxy)phenyl]xanthene with various...
4 citations
TL;DR: In this paper, a reaction scheme was proposed for the chemiluminescent reaction, which is based on the results shown in the previous papers, and most of the experimental results can be explained reasonably.
Abstract: On the basis of the results shown in the previous papers, the following reaction scheme was proposed for the chemiluminescent reaction. Hydrogen peroxide decomposes spontaneously to the radical (R·). A portion of the radical then reacts with the dye molecule (E) to produce an energy-rich intermediate (ME*): E+R·→ME* The energy-transfer takes place from ME* to an unoxidized dye, so the dye is excited electronically: ME*+E→E*+··· However, most of the ME* is decomposed by non-radiative processes. E* is deactivated by fluorescence emission processes (E*→E+hν) or quenching processes (E*+E→E+E). According to this reaction scheme, most of the experimental results can be explained reasonably. It is expected that further experimental evidence, such as the detection of an intermediate, will verify the theory.
4 citations