نتایج جستجو برای: solvatochromism
تعداد نتایج: 266 فیلتر نتایج به سال:
A novel solvatochromic betaine dye has been synthesized from xanthosine and characterized spectroscopically by UV-vis in a broad range of solvents. The dye 9-(2',3',5'-tri-O-acetyl-beta-d-ribofuranosyl)-2-(pyridinium-1-yl)-9H-purin-6-olate, 1a, exhibits solvent-induced spectral band shifts that are (2)/(3) as large as that of the betaine known as Reichardt's dye, which forms the basis of the E(...
The solvatochromic responses of uric acid (Ua), 6-amino-2-thiouracil (ATU) and a series of their complexes dissolved in ten solvents of different polarity have been measured. The solvent-dependent UV/Vis spectroscopic absorption maxima, λ(max), are assigned to the corresponding electronic transitions and analyzed using SPSS program, regression analysis and Kamlet and Taft methods. The observed ...
The electronic absorption profiles of 3-cyano-1,5-diarylformazans were recorded in different organic solvents having different polarities. Both macroscopic and microscopic aspects were contemplated to determine the influence of various solute-solvent interactions upon absorption spectral shifts. The effects of solvent polarity on the absorbance profiles of the compounds were evaluated. The mult...
1,3-Disubstituted 2-azidoimidazolium salts (substituents = methyl, methoxy; anion = PF6) reacted with N-heterocyclic carbenes to yield yellow 2-(1-(azolinylidene)triazen-3-yl)-1,3-R2imidazolium salts (azole = 1,3-dimethylimidazole, 1,3-dimethoxyimidazole, 4-dimethylamino-1methyl-1,2,4-triazole; R = methyl, methoxy; anion = PF6). Crystal structures of three cationic triazenes were determined. Nu...
The IR absorption and time-resolved IR spectroscopy of the OD stretch mode of HDO in water was successfully used to study osmolyte effects on water H-bonding network. Protecting osmolytes such as sorbitol and trimethylglycine (TMG) make the vibrational OD stretch band red-shifted, whereas urea affects the OD band marginally. Furthermore, we recently showed that, even though sorbitol and TMG cau...
In this investigation, influences on solution behavior and solvatochromism caused by the attachment of a 1H,1H,2H,2H-perfluorooctyl side chain onto derivatives well-known Brooker's Merocyanine (BM) chromophore are explored. Starting from either 4-picoline or 2-picoline, corresponding polyfluoroalkylated o- p-BM have been synthesized in three steps. For all dyes, UV–Vis measurements were conduct...
Two novel, water-soluble, merocyanine fluorophores were readily prepared by microwave-assisted synthesis. Full optical characterization was performed in a series of protic and aprotic solvents, the dyes displayed fluorescence red region with up to 20-fold decrease brightness water, demonstrating strong environmental sensitivity hereby termed as solvato-fluorogenicity (to distinguish from solvat...
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