HeI photoelectron spectra and structure of 4-hydroxycoumarin

Traven, V. F.; Manaev, A. V.; Safronova, O. B.; Чибисова, Т. А.

doi:10.1016/s0368-2048(01)00320-6

Cited by 13 publications

(6 citation statements)

References 13 publications

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“…In a study of the synthesis and structural transformations of 4-hydroxycoumarin derivatives, [1][2][3][4] we found that 4-hydroxy-3-pyrazolinylcoumarin 1 was photooxidised to 4-hydroxy-3-pyrazolylcoumarin 2 under very mild conditions (Scheme 1). † We found that compound 1 (dissolved in CCl 4 ) changed its electronic absorption spectrum under illumination with visible light for 1 h (Figure 1).…”

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confidence: 99%

Quantitative photooxidation of 4-hydroxy-3-pyrazolinylcoumarins to pyrazolyl derivatives

Traven

Иванов

Pavlov

et al. 2007

Mendeleev Communications

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confidence: 99%

Quantitative photooxidation of 4-hydroxy-3-pyrazolinylcoumarins to pyrazolyl derivatives

Traven

Иванов

Pavlov

et al. 2007

Mendeleev Communications

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“…The present calculations predict that the enol form 4HCa of 4hydroxycoumarin is the most stable tautomer, the diketo form 4HCBb is slightly less stable (by 5.5 kJ•mol −1 ), and the enol form 4HCc has the lowest stability (by 45 kJ•mol −1 ), Table 1, in agreement with the MINDO calculations. 17,18 We therefore expect to observe two tautomers spectroscopically.…”

Section: Resultsmentioning

confidence: 97%

“…16 The diketo form (4HCb) has not been observed by structural methods. Redchenko et al 17 and Traven et al 18 measured the gas phase valence photoelectron spectra of 4HC and a number of other coumarins, as well as performing semiempirical (MNDO, AM1, PM3) and unspecified nonempirical quantum chemical calculations (carried out employing the Gaussian 94 software package with 6-31G* basis set). They interpreted the experimental valence spectra of 4-hydroxycoumarin as evidence of tautomerism.…”

Section: Introductionmentioning

confidence: 99%

X-ray Photoemission Spectra and Electronic Structure of Coumarin and its Derivatives

et al. 2016

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The electronic structures of coumarin and three of its derivatives (7-amino-4-methylcoumarin, 7-amino-4-(trifluoro)methylcoumarin, and 4-hydroxycoumarin) have been studied by theoretical calculations, and compared with experimental valence and core photoelectron spectra to benchmark the predicted spectra. The outer valence band spectra of the first three compounds showed good agreement with theoretical calculations for a single isomer, whereas the spectrum of 4-hydroxycoumarin indicated the presence of more than one tautomer, consistent with published results. Calculations of core level spectra of carbon, nitrogen, oxygen, and fluorine of the first three compounds are also in satisfactory agreement with our measurements. The carbon and oxygen 1s spectra of 4-hydroxycoumarin allow us to identify and quantify the populations of the principle tautomers present. The 4-hydroxy enol form is the most stable isomer at 348 K, followed by the diketo form, with 1.3 kJ·mol(-1) lower energy.

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“…1) namely, 4-hydroxy-2-chromenone (A), 2,4-chromandione (B), and 2-hydroxy-4-chromenone (C). These three possible prototropic transformations have been intensively examined by various chemical reactivity, spectral, thermochemical, and computational methods (Aguirre-Pranzoni et al, 2011;Jacquot et al, 2001;Sousa et al, 2010;Traven et al, 2002). A glance at these standard reference works, the involvement of the tautomeric forms of 4-hydroxycoumarin, that is, 2,4-chromanedione (B) or 2-hydroxy-4-chromenone (A), seems likely.…”

Section: Tautomeric Structure(s)mentioning

confidence: 97%