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: A design strategy for fluorescence probes with a high off/on activation ratio in the red wavelength region is presented, based on a novel fluorescein analogue in which the O atom at the 10 position of the xanthene chromophore is replaced with a Si atom.
141 citations
TL;DR: In this article, the efficiency, generality and applicability of novel Bronsted acidic ionic liquid triethylamine-bonded sulfonic acid {[Et 3 N−SO 3 H]Cl, N, N -diethyl- N -sulfoethanammonium chloride} as homogeneous and green catalyst for organic transformations under various conditions are studied.
140 citations
TL;DR: An unexpected one-pot synthetic approach toward spiro[fluorene-9,9'-xanthene] (SFX) under excessive MeSO(3)H conditions has been developed and the key step involves a thermodynamically controlled cyclization reaction.
137 citations
TL;DR: Comparative reactivity studies for the catalase-like disproportionation of hydrogen peroxide and the epoxidation of olefins by the HPX and HPD platforms with acid and ester hanging groups reveal that the introduction of a proton-transfer network, properly oriented to a redox-active platform, can orchestrate catalytic O-O bond activation.
Abstract: Porphyrin architectures bearing a hydrogen-bonding scaffold have been synthesized The H-bond pendant allows proton-coupled electron transfer (PCET) to be utilized as a vehicle for effecting catalytic O-O bond activation chemistry Suzuki cross-coupling reactions provide a modular synthetic strategy for the attachment of porphyrins to a rigid xanthene or dibenzofuran pillar bearing the H-bond pendant The resulting HPX (hanging porphyrin xanthene) and HPD (hanging porphyrin dibenzofuran) systems permit both the orientation and acid-base properties of the hanging H-bonding group to be controlled Comparative reactivity studies for the catalase-like disproportionation of hydrogen peroxide and the epoxidation of olefins by the HPX and HPD platforms with acid and ester hanging groups reveal that the introduction of a proton-transfer network, properly oriented to a redox-active platform, can orchestrate catalytic O-O bond activation For the catalase and epoxidation reaction types, a marked reactivity enhancement is observed for the xanthene-bridged platform appended with a pendant carboxylic acid group, establishing that this approach can yield superior catalysts to analogues that do not control both proton and electron inventories
136 citations
TL;DR: In this article, the adsorption of the R6G on the porous surface of the silica gels determined the formation of r6G fluorescent J-dimers as concentration increased, in concordance with the behavior reported for other xanthene molecules.
Abstract: Rhodamine 6G (R6G)-doped silica gels were prepared through the sol−gel process using dye concentrations ranging from 4.00 × 10-6 to 6.40 × 10-4 M. The adsorption of the R6G on the porous surface of the silica gels determined the formation of R6G fluorescent J-dimers as concentration increased, in concordance with the behavior reported for other xanthene molecules as rhodamine B (RB) and rhodamine 110 (R110) also doped in silica gels. The photophysical study of the R6G fluorescent dimers doped in silica gels was done through the recording of the excitation and emission fluorescence spectra as well as the measurement of the lifetime values. The exciton theory was used for the elucidation of the adsorption angle (θ), the angle between the monomer units (α), and the separation distance between the molecules (R) of the R6G fluorescent dimers. The angle between the monomer units (α) and the separation distance between the molecules (R) were also determined for RB and R110 fluorescent dimers doped in silica gels.
133 citations