نتایج جستجو برای: solvatochromic effects
تعداد نتایج: 1544609 فیلتر نتایج به سال:
We study the solvent-induced frequency shifts of the OH-stretching mode of 1-naphthol and 2-naphthol in nonpolar/weakly polar solvents, subject to electronic excitation, with ultrafast UV/mid-infrared pump-probe spectroscopy and theoretical modeling based on Pullin's perturbative treatment of vibrational solvatochromic effects. The model is parametrized at the density functional theory (DFT) le...
In N-(2,5-di-tert-butylphenyl)-9-pyrrolidinoperylene-3,4-dicarboximide (5PI) the absorption and emission spectra display large solvatochromic shifts, but, remarkably, the Stokes shift is practically independent of solvent polarity. This unique behavior is caused by the extraordinarily large ground state dipole moment of 5PI, which further increases upon increasing solvent polarity, while the ex...
INTRODUCTION Previous studies have demonstrated the potential of solvatochromic dyes for investigating the physical chemistry of homeopathic potencies. RESULTS Following examination of this class of dyes in organic solvents, results obtained using the positively solvatochromic dye Bis-dimethylaminofuchsone (BDF) in aqueous solution are now reported. Spectral changes observed with this dye in ...
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(...
Heterogeneous catalytic hydrogenation of cyclohexene, catalyzed by Pt/A1203, was carried out in thirteenvarious solvents (four alcoholic solvents, six aprotic polar solvents and three non polar solvents) at 25 °C.Single-parameter correlations of logk vs. normalized polarity parameter (ETN), hydrogen-bond acceptorbasicity (p), hydrogen-bond donor acidity (a) and dipolarity/polarizibility (it*) d...
The solvation properties of some room-temperature ionic liquids consisting of imidazolium cations and various anions were examined by means of the high-pressure spectroscopy with solvatochromic probes. We measured the pressure dependence of KamletTaft solvatochromic parameters (π∗, β) and microviscosity (η). It was found that π∗ and β were not so sensitive to the types of imidazolium cations an...
of various physicochemical and spectroscopic measurements using various indicator compounds. 1–6 Especially, three parameters, dielectric constant, DC, donor number, DN, and acceptor number, AN serve as fundamental and extensive set for applications. However, it is not easy to directly derive these parameters by means of the original measurement method. It is expected that they can be predicted...
The concentrations of all components in the phases of aqueous two-phase polyethylene glycol-sodium sulfate system of a fixed composition with different concentrations of NaCl additive were determined. Solvatochromic solvent features of aqueous media in the phases of all the systems were characterized in terms of solvent dipolarity/polarizability, solvent hydrogen bond donor acidity and hydrogen...
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