Modeling vibrational spectra of indole in water

Ten, G. N.; Yakovleva, A. A.; Burova, T. G.; Berezin, V. I.; Баранов, В. И.

doi:10.1007/s10812-010-9360-2

Cited by 10 publications

(20 citation statements)

References 8 publications

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“…(b) can be related to the CO stretching band . A contribution of the CC and CN stretching modes of the pyrrole structure is also possible for the peaks at 1256 and 1263 cm −1 as calculated by Ten et al …”

Section: Resultsmentioning

confidence: 58%

“…(b) and 1509 cm −1 in Fig. (b); in particular, one such pyrrole mode is reported in the 1507–1528 cm −1 spectral range . In fact, other spectral features at wavenumbers lower than those due to CC aromatic ring vibrations can be attributed to the vibration modes of pyrrole ring.…”

Section: Resultsmentioning

confidence: 83%

“…A possible assignment of Raman bands can be based on several works related to vibrational properties of synthetic and natural eumelanins and other aromatic compounds containing indole and pyrrole groups . From an analysis of Figs (b) and (b), the broad band at about 1590 cm −1 results from the contribution of four Raman bands centred at 1771, 1717, 1617 and 1528 cm −1 in synthetic eumelanin and 1781, 1698, 1602 and 1517 cm −1 in natural eumelanin.…”

Section: Resultsmentioning

confidence: 99%

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Vibrational spectroscopy of synthetic and natural eumelanin

Perna

Lasalvia

Capozzi

2016

Polymer International

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We report vibrational spectra of two types of eumelanin samples: a synthetic one, produced by oxidation of tyrosine with hydrogen peroxide, and a natural one, extracted from Sepia officinalis, with the aim to point out the differences between the main vibrational properties of such two pigments. Fourier Transform Infrared (FTIR), Raman and Surface Enhanced Raman Scattering (SERS) spectra allow to identify several vibrational modes involving specific monomeric units. The main differences between the spectra of the two types of eumelanin are related to i) a larger amount of carboxylic acid in synthetic than in natural sample; ii) a shift of spectral position of corresponding peaks; iii) a contribution of residual proteins to the signal from natural sample. Such results suggest that vibrational techniques may be helpful to nondestructively determine the composition of different eumelanin pigments, with potential applications in biomedical, electronic and cultural heritage fields. This article is

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Section: Resultsmentioning

confidence: 58%

Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 99%

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Vibrational spectroscopy of synthetic and natural eumelanin

Perna

Lasalvia

Capozzi

2016

Polymer International

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“…The length and angle of the N 1 H...O H-bond in aqueous solution model V decreased compared with the isolated state from 2.997 to 2.891 A° and from 179.3 to 175.2 o . The changes of the geometric parameters of skatole on going from the isolated state to aqueous solution and the complex with water (1:1) were identical to those of indole although the length of the H-bond between skatole and water was 0.006 A° shorter than for indole [9].…”

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confidence: 81%

Theoretical analysis of the effect of intermolecular interaction on ir spectra of skatole

et al. 2012

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543.42:547.753 The molecular structure and IR vibrational spectra of skatole in the isolated state, in aqueous solution, and in hexane have been calculated in the p) approximation. Characteristic spectral differences associated with the influence of both polar and nonpolar solvents and a hydrogen bond have been defined for the vibrational spectrum of skatole. Calculation of the isolated skatole molecule in the anharmonic approximation enabled the interpretation of the vibrational spectrum to be refined.Introduction. Indole derivatives are extremely physiologically active compounds that are widely used in medical practice. They can exert stimulating and inhibiting action on the nervous system and possess hemorrhagic, sedative, and radioprotective properties in addition to others [1,2]. For example, indole-3-carbinol facilitates detoxification of poisons, including those with carcinogenic properties, and reduces the threat of developing a series of hormone-dependent tumors of epithelial origin [3].Indole and skatole are toxic substances that are formed in the intestines as a result of the destruction of the tryptophan side chain by bacteria. Like phenol and cresol, they are detoxified in the liver where they are oxidized preliminarily into compounds containing a hydroxyl. Subsequent binding of indole and skatole to polar glucuronic acid makes these nonpolar (hydrophobic) compounds highly soluble and more easily eliminated from the organism [4,5]. Vibrational spectra (IR and Raman) of skatole and its radicals were calculated earlier in a harmonic approximation by the DFT method [6]. Results of the theoretical calculation of isolated skatole were analyzed and compared with experimental spectra in CCl 4 solutions.Considering that the properties of molecules in the gas phase and in solutions can differ considerably, the goal of the present work was to determine the effects of intermolecular interactions (IMI) on the structure and vibrational spectra of skatole. Furthermore, skatole exhibits hydrophobic properties and is poorly soluble in water. Therefore, the effects of IMI on the properties of skatole are conveniently studied in various types of solvents (polar and nonpolar).Normal vibrations and geometric parameters were calculated by the DFT method in the B3LYP/6-311++G(d,p) approximation [7]. The explicit and effective effects of IMI were analyzed for a model with a directly formed H-bond, i.e., for an intermolecular complex of indole with water (1:1), and for models of a self-consistent reactive field (SCRF) that enabled the effects of polar (water, dielectric permeability ε = 78.39) and nonpolar (cyclohexane, ε = 2.023) solvents to be considered.

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“…Vibrational and vibronic spectra of nucleic acid bases have been stud ied both theoretically and experimentally [1][2][3][4][5][6][7][8][9]. The results of these studies have made it possible to describe in general the intensity distribution in the spectra and explain their main regular features.…”

Section: Introductionmentioning

confidence: 99%