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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TL;DR: Partition coefficients for 39 low-molecular-mass compounds between water and micelles of an ethylene oxide-propylene oxide block copolymer (Pluronic P85) and the monolauryl ether of poly(ethylene oxide) (Brij 35) have been measured by the methods of fluorescence spectroscopy, fluorescence anisotropy, and dialysis kinetics as mentioned in this paper.
Abstract: Partition coefficients for 39 low-molecular-mass compounds between water and micelles of an ethylene oxide-propylene oxide block copolymer (Pluronic P85) and the monolauryl ether of poly(ethylene oxide) (Brij 35) have been measured by the methods of fluorescence spectroscopy, fluorescence anisotropy, and dialysis kinetics. The tested compounds include aromatic hydrocarbons, phenols, naphthols, xanthene dyes, anthracycline antibiotics, and porphyrins. The multifactor analysis of the partition coefficients in terms of the linear free-energy relationships has been performed. It has been shown that the H-donating ability of compounds facilitates their solubilization in Pluronic micelles and has no effect on solubilization in micelles of monolauryl ether of poly(ethylene oxide). This difference indicates that, when solubilization occurs in Pluronic micelles, the compounds under study appear in a hydrophobic core composed of poly(propylene oxide) blocks.
13 citations
TL;DR: In this article, an efficient and environmentally adapted synthesis of xanthene derivatives by condensation of a wide range of aryl aldehydes and cyclohexane-1,3-diones in the presence of catalytic amounts of yttrium(III) nitrate hexahydrate and tin(II) chloride dihydrate is demonstrated.
Abstract: An efficient and environmentally adapted synthesis of xanthene derivatives by condensation of a wide range of aryl aldehydes and cyclohexane-1,3-diones in the presence of catalytic amounts of yttrium(III) nitrate hexahydrate and tin(II) chloride dihydrate is demonstrated.
13 citations
TL;DR: Ytterbium perfluorooctanoate [Yb(PFO)3] was found to be an efficient catalyst for the microwave assisted synthesis of tetrahydrobenzo[a]xanthene-11-ones by the one-pot condensation of 2-naphthol, aldehydes and 1,3-dicarbonyl compound under solvent-free conditions.
13 citations
TL;DR: In this paper, the NaHSO4·H2O has been used as an efficient catalyst for the one-pot preparation of 14H-[(un)substituted phenyl]-dibenzo[a,j]xanthene leuco-dye derivatives by condensation of β-naphthol with substituted benzaldehydes under microwave and thermal conditions.
Abstract: NaHSO4·H2O has been used as an efficient catalyst for the one-pot preparation of 14H-[(un)substituted phenyl]-dibenzo[a,j]xanthene leuco-dye derivatives by condensation of β-naphthol with substituted benzaldehydes under microwave and thermal conditions. This method has the advantages of high yields, a green reaction, an efficient and cost-effective method, simple procedures, short reaction time, and easy workup.
13 citations
TL;DR: In this article, the electronic properties of the xanthene skeleton with different N-substitution patterns were investigated as a function of the molecular conformation by semi-empirical calculations according to the extended Huckel molecular orbitals and the Pariser-Parr-Pople methods.
Abstract: Time-resolved fluorescence measurements were carried out on rhodamine 3B, pyronine B and rhodamine 101 ethylester in protic solvents of different viscosity but of similar dielectric properties by dual-beam multiple frequency phase fluorometry. Emission wavelength dependent biexponential fluorescence decay is reported for all combinations. The electronic nature of the xanthene skeleton with different N-substitution patterns was investigated as a function of the molecular conformation by semi-empirical calculations according to the extended Huckel molecular orbitals and the Pariser-Parr-Pople methods. No evidence in support of the twisted intramolecular charge transfer state model for the S1 state is found in the correlation of experimental and computational results, but a qualitative interpretation for the viscosity dependence of the fluorescence quantum yields of dialkylamino-substituted xanthene dyes is given. The key factor determining the quantum yield was found to be the rigidity of the amino groups and their substitution pattern. The variation of the decay law with emission wavelength is discussed in terms of structural relaxation of the solute, dielectric relaxation of the solvent and specific solute-solvent interactions.
13 citations