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Turchaninov, V. K.; Вокин, А. И.; Aksamentova, T. N.; Krivoruchka, I. G.; Шулунова, А. М.; Andriyankova, L. V.

doi:10.1023/a:1026134903372

Cited by 3 publications

(2 citation statements)

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“…The 1 H and 13 C NMR spectra were obtained on a Varian VXR-500S spectrometer (working frequency 500 MHz), pulse 90o, relaxation delay 4 s. ÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄ a In carbon tetrachloride (inert medium) and 1,4-dioxane (protophilic medium), see Table 4 and [44]. b For experimental solvatochromic parameters, see Table 5 and [44]. c Correlation with the parameters b (32380 +120 cm 31 ) and x (3370 +260 cm 31 ) is observed.…”

Section: Methodsmentioning

confidence: 99%

“…There is no doubt that the latter result is explained by the increase in the groundstate dipole moment (m g ) of the solvatochromic indicator, produced by this transition [44,47,48]. On the specific solvation via two-center hydrogen bonding between indicator and medium (compound XXI), the electronic absorption band is shifted red by about 200 cm 31 and the nonspecific solvatochromic effect decreases (Dnpp * = s a p * ) in spite of increasing m g .…”

Section: State Of Intramolecular Ohbr Bond In Solvation Complexesmentioning

confidence: 99%

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Solvatochromism of Heteroaromatic Compounds: XXV. Effect of Bifurcate Hydrogen Bond with a Weak Intramolecular Component on the IR, NMR, and UV Spectra of 2,6-Dibromo-4-nitrophenol

et al. 2005

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Dissolution of 2,6-dibromo-4-nitrophenol in aprotic protophilic solvents forms a three-center solvation H-complex with a sharply weakened intramolecular hydrogen bond. This weakening is associated with a deformation of the bond angle of the hydroxy group. It is only on interaction with weak p-bases that the intramolecular component of the bifurcate hydrogen bond appreciably affects the spectral position of the OH stretching vibration band; this results in a nonlinear dependence between vOH and the Kamlet3Taft solvatochromic parameter.In work [2], based on a phenomenological notion of complexes with a bifurcate (three-center) hydrogen bond comprising both an intra-and an intermolecular components, has predicted the effect of the formation energy of such complexes on their n XH vibration frequency. For compounds with a weak intramolecular hydrogen bond, two possibilities have been predicted: a monotonic nonlinear or nearly linear dependence of n XH on the H-bond affinity the subunit of the complex.To test this hypothesis, in the present work we have studied 2,6-dibromo-4-nitrophenol, a compound with a weak intramolecular OH...Br bond [3315], by means of IR, NMR, and UV spectroscopy and quantum chemistry.

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Section: Methodsmentioning

confidence: 99%

Section: State Of Intramolecular Ohbr Bond In Solvation Complexesmentioning

confidence: 99%

Solvatochromism of Heteroaromatic Compounds: XXV. Effect of Bifurcate Hydrogen Bond with a Weak Intramolecular Component on the IR, NMR, and UV Spectra of 2,6-Dibromo-4-nitrophenol

et al. 2005

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Nitroanilines as Quenchers of Pyrene Fluorescence

et al. 2012

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The quenching of pyrene and 1-methylpyrene fluorescence by nitroanilines (NAs), such as 2-, 3-, and 4-nitroaniline (2-NA, 3-NA, and 4-NA, respectively), 4-methyl-3-nitroaniline (4-M-3-NA), 2-methyl-4-nitroaniline (2-M-4-NA), and 4-methyl-3,5-dinitroaniline (4-M-3,5-DNA), are studied in toluene and 1,4-dioxane. Steady-state fluorescence data show the higher efficiency of the 4-NAs as quenchers and fit with a sphere-of-action model. This suggests a 4-NA tendency of being in close proximity to the fluorophore, which could be connected with their high polarity/hyperpolarizability. In addition, emission and excitation spectra evidence the formation of emissive pyrene-NA ground-state complexes in the case of the 4-NAs and, in a minor degree, in the 2-NA. Moreover, time-resolved fluorescence experiments show that increasing amounts of NA decrease the pyrene fluorescence lifetime to a degree that depends on the NA nature and is larger in the less viscous solvent (toluene). Although the NA absorption and the pyrene (Py) emission overlap, we found no evidence of dipole-dipole energy transfer from the pyrene singlet excited state ((1)Py) to the NAs; this could be due to the low NA concentration used in these experiments. Transient absorption spectra show that the formation of the pyrene triplet excited state ((3)Py) is barely affected by the presence of the NAs in spite of their efficiency in (1)Py quenching, suggesting the involvement of (1)Py-NA exciplexes which--after intersystem crossing--decay efficiently into (3)Py.

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