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.

Rhodamine 6G Based New Fluorophore Chemosensor Toward Hg 2

Abstract: Rhodamine dyes belong to xanthene family has excellent photostability and photophysical properties. In rhodamine dyes, Rhodamine 6G and its precursors also have xanthene chromophore and it shows high fluorescent quantum yield. Rhodamine 6G derivates are simple to synthesis and its high sensitivity and water solubility are suitable as good chemosensor. In this regard, Rhodamine 6G derivates which have selectivity to specific metal cation can used to detect various heavy metal ions. In this study, rhodamine 6G derivatives were synthesized by reaction of rhodamine 6G hydrazide and glyoxal and 4-phenyl thiosemicarbazide and it showed colorimetric and fluorescence sensing toward Hg2+ ion. This novel chemosensor was analyzed and measured on UV-Vis and fluorescence spectrophotometer. HOMO/LUMO values were also calculated by computational calculation.

Application of Xanthene Derivatives in Analytical Chemistry Part LXV. The Spectrophotometric Determination of Vanadium with O-Hydroxyhydroquinonephthalein in the Presence of Cationic Surfactants

Abstract: The colour reaction between o-hydroxyhydroquinonephthalein and vanadate ion in the presence of hexadecyltri-methylammonium chloride and L-ascorbic acid as a reductant was discussed. And the spectrophotometric determination of vanadium utilizing the colour reaction system in micellar media was proposed at about pH 5.4. Beer's law was obeyed in the concentration range 0-8 μg of vanadium at 540 nm. The apparent molar extinction was 8.7 × 10 4 1 mol−1 cm−1 with Sandell sensitivity of 0.0006 μg/cm2. This proposed method was relatively simple and sensitive, and then its applications for the waste water, river water, rain water, etc. were discussed.

The lactone form of fluorescein: Crystal structure of the 1:1 molecular complex of fluorescein with methanol

Abstract: The structure of the fluorescein molecule in its i:i complex with methanol was determined by x-ray crystallographic analysis with anisotropic refinement to R = 0.043. The molecule has lactone structure. The plane of the lactone ring is perpendicular to the tricyclic xanthene fragment. The methanol molecules are hydrogen bonded to fluorescein and apparently stabilize the lactone form which converts to the zwitterionic form upon storage. IR spectral and x-ray phase analysis of the yellow and red polycrystalline samples of fluorescein obtained from water and methanol shows that the color of the samples does~not correspond unequivocally to the molecular form, The red samples from methanol and water have different structure, which indicates the presence of solvent molecules or the existence of polymorphic modifications of the quinoid form of fluorescein.

Sustainable synthesis of 1,8-dioxooctahydroxanthenes in deep eutectic solvents (DESs)

Abstract: Deep eutectic solvents are obtained by the fusion of two or more compounds: hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs). They are formed by mixing the constituents with moderate heating (via hydrogen bond interactions). In this manuscript, the dual activities (as catalysts and reaction media) of six deep eutectic solvents were compared for the synthesis of 1,8-dioxooctahydroxanthenes at room temperature. Here DES 2, a combination of ZrOCl2·8H2O with ethylene glycol at a 1 : 2 ratio, was found to be the supreme catalyst among the six DESs and was reused for five batches. The photophysical properties of the xanthene derivatives were examined by UV-vis and fluorescence spectroscopy in THF. The synthesised molecules showed absorption maxima around 285–295 nm and emission maxima around 403–404 nm. The ground state dipole moments of all the molecules were calculated by the Debye–Guggenheim method using toluene as the non-polar solvent. All the synthesised molecules showed significant dipole moment values and are in good agreement with theoretical values.

Solvent‐free Synthesis of 1,8‐Dioxo‐octahydroxanthenes and Tetra‐hydrobenzo[a]xanthene‐11‐ones over Poly(N,N′‐dibromo‐N‐ethylnaphtyl‐2,7‐sulfonamide)

Abstract: In this work, poly(N,N′-dibromo-N-ethylnaphtyl-2,7-sulfonamide) (PDNES) as a highly efficient catalyst was applied for the synthesis of 1,8-dioxo-octahydroxanthenes and tetra-hydrobenzo[a]xanthene-11-ones under neutral and solvent-free conditions.