Light Absorption Studies: Part Xiv. The Ultraviolet Absorption Spectra of Phenols

Dearden, John C.; Forbes, W. F.

doi:10.1139/v59-193

Cited by 70 publications

(45 citation statements)

References 21 publications

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“…The absorption spectra of guaiacol, veratrole, codeine and morphine hydrochloride were recorded at room temperature and are in accordance with those of the literature Forbes, 1959a and1959b;Sennikov et al, 1980;Kracmarova, 1982a and1982b;Bowd and Turnbull, 1977;Pinyazhko, 1964). The phosphorescence spec- n-hexane at T = 1.4 K. trum of veratrole in n-hexane is shown in Fig.…”

Section: Resultssupporting

confidence: 87%

The Lowest Excited Triplet States of Codeine and Morphine and of Their Molecular Subunits Veratrole and Guaiacol

Slama

Basché

Bräuchle

et al. 1988

Photochem & Photobiology

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Abstract— The lowest excited triplet T1 states of the two alkaloids, morphine and codeine, have been investigated by ODMR and emission spectroscopy. The electronic character of their T1 states could be determined by comparing the T1 properties with those of the constituent parts guaiacol and veratrole. The T1 properties, e.g. phosphorescence spectra, zero‐field splitting parameters and triplet sublevel selective decay rates are very similar for the constituent parts and the alkaloids. Thus, in analogy to veratrole and guaiacol, the T1 state of codeine and morphine is assigned to a ππ* state mainly localized on the benzene ring and the attached alkoxy and hydroxy groups. There is no evidence for a contribution from the other subunits, trialkylamine and unsaturated alcohol, to the T1 state of codeine and morphine.

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Section: Resultssupporting

confidence: 87%

The Lowest Excited Triplet States of Codeine and Morphine and of Their Molecular Subunits Veratrole and Guaiacol

Slama

Basché

Bräuchle

et al. 1988

Photochem & Photobiology

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“…The phenolic group in a specific compound shows different types of resonance interactions in the exited state of the molecule because of the replacement of the phenoxide or the phenolate (only in basic media) ion that reflected in the maximal wavelength (Dearden et al, 1959). It may be noted that, the acidified methanolic extract contained higher number of constituent phenolics.…”

Section: Spectrophotometric Analysis Of Phenolics In Different Extractsmentioning

confidence: 99%

Finger millet (Eleusine coracana) polyphenols: Investigation of their antioxidant capacity and antimicrobial activity

Banerjee¹

2012

Afr. J. Food Sci.

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Finger millet (Eleusine coracana) or ragi, one of the important minor cereals is a rich source of several phytochemicals and among them polyphenols are the most important because of their nutraceutical potentials. The seed coat-rich fraction (SCF) of the millet contains over 70% of polyphenols of the millet. Treated with different polar and non-polar solvents as such and after acidification with HCl for the extraction, it was observed that the polar solvents extracted more (1.7 to 7.4%) than the non-polar solvents (0.28 to 1.54%) while the 1% HCl-methanol extracted the highest proportion of polyphenols (13%). Fractionation of extracted polyphenols by HPLC revealed the presence of a large number of constituent phenolics. The inhibitory concentration (IC 50 ) values for the antioxidant activity of the polyphenols determined in terms of 1, 1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and 2, 2'-azinobis -3 -ethylbenzothiazoline -6 -sulfonate (ABTS) radicals scavenging activities of acidified methanolic extract, were 63, 109, and 114 µg/mL phenolic, respectively. The polyphenols extracted from finger millet seed coat using 1% HCl -methanol was fractionated by reverse phase-high performance liquid chromatography (RP-HPLC) and the constituent phenolics were characterized by electrospray ionization mass spectrometry (ESI-MS) and NMR. The phenolics identified were the benzoic acid derivatives (gallic, protocatechuic, p-hydroxybenzoic, vanillic, and ferulic acids) and cinnamic acid derivatives (syringic, trans-cinnamic and p-coumaric acids); and also a flavonoid compound namely, quercetin. The millet polyphenols showed proliferation inhibitory activities on Escherichia coli, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Streptococcus pyogenes, Proteus mirabilis, Pseudomonas aeruginosa, Serratia marcescens, Klebsiella pneumonia, and Yersinia enterocolitica. Quercetin exhibited substantial inhibition of the growth of these pathogenic bacteria revealing the potential nutraceutical properties of the millet polyphenols. From the observation, it could be inferred that finger millet polyphenols could be used as natural source of antioxidants especially for minimizing the risk of diseases arising from oxidative deterioration.

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“…Although this latter spectrum has not been isolated, it probably corresponds closely to that of phenol in water. Evidence for this coines frorn the 1 mp hypsochromic shift of the phenol spectrum on going from cyclohexane to water solution (26), and from the almost complete absence of K-band absorption corresponding to proton donating molecules, in water solution (4). The shift caused by self-association (1-2 mp) is thus, as predicted above, similar to that caused by phenol's acting as proton acceptor.…”

Section: T H E Nature O F T H E Hypsochromic S H I F Tmentioning

confidence: 99%

Investigation of the Self-Association of Phenols and Anilines by Ultraviolet Spectroscopy

Dearden¹

1963

Can. J. Chem.

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Light Absorption Studies: Part Xiv. The Ultraviolet Absorption Spectra of Phenols

Abstract: A spectral analysis of benzene derivatives is extended to substituted phenols. The discussion emphasizes hydrogen bonding and steric effects which occur in phenols. Some of the phenolic absorption bands are ascribed to locally excited states.

Cited by 70 publications

References 21 publications

The Lowest Excited Triplet States of Codeine and Morphine and of Their Molecular Subunits Veratrole and Guaiacol

The Lowest Excited Triplet States of Codeine and Morphine and of Their Molecular Subunits Veratrole and Guaiacol

Finger millet (Eleusine coracana) polyphenols: Investigation of their antioxidant capacity and antimicrobial activity

Investigation of the Self-Association of Phenols and Anilines by Ultraviolet Spectroscopy

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