Fermi resonance in substitutedZ-3-methylene phthalides

Perjéssy, A.; Hritzová, Oľga; Šusteková, Zora; Hrnčiar, P.; Bowden, Keith

doi:10.1007/bf00807889

Cited by 9 publications

(6 citation statements)

References 17 publications

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“…The IR absorption bands of the C=O stretching vibrations of compounds 1 in the region of 1870-1710 cm -1 in CHCl 3 exhibit clear splitting. It has been found on the basis of similar behaviour of (Z)-4-(substituted benzylidene)-2-phenyloxazol-5(4H)-ones 3 and other unsaturated lactones 7 that this splitting is caused by two-level Fermi resonance interaction between the C=O stretching mode and the first overtone of an out-ofplane deformation vibration of C-H group. In order to obtain unperturbed wavenumbers for both fundamental (C=O) and the first overtone ω 02 (C-H) absorption bands, the relations based on the method Langseth and Lord and improved by Nyquist et al 8 have been applied.…”

Section: Ir Uv-vis and Nmr Spectroscopymentioning

confidence: 90%

Base-Catalysed Hydrolysis and Reactivity-Spectra Correlations of (Z)-4-Benzylidene-2-(Substituted Phenyl)Oxazol-5(4H)-ones

Palcut

Benko

Müller

et al. 2004

Journal of Chemical Research

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Rate coefficients have been measured for the base-catalysed hydrolysis of a series of (Z)-4-benzylidene-2-(substituted phenyl)-4H-oxazol-5-ones in 70% v/v aqueous dioxan at various temperatures. The enthalpies and entropies of activation, and a Hammett reaction constant for the reaction, have been evaluated. The 1 H and 13 C NMR chemical shifts were assigned, as well as the IR carbonyl stretching frequencies in chloroform, after deconvolution and band separation. Successful correlations between the carbonyl stretching wavenumbers and the 13 C NMR chemical shifts and the rates of the alkaline hydrolysis were found.

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Section: Ir Uv-vis and Nmr Spectroscopymentioning

confidence: 90%

Base-Catalysed Hydrolysis and Reactivity-Spectra Correlations of (Z)-4-Benzylidene-2-(Substituted Phenyl)Oxazol-5(4H)-ones

Palcut

Benko

Müller

et al. 2004

Journal of Chemical Research

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“…16 These CO absorption bands observed in chloroform exhibit significant splitting arising from Fermi resonance. In tetrachloromethane solution, the compounds exhibit more or less single CO absorption bands.…”

Section: Correlation Of Rates and Carbonyl Stretching Frequenciesmentioning

confidence: 98%

Base-catalysed hydrolysis of ?-lactones: reactivity-structure correlations for 3-(aryl- and alkylmethylene)-(Z)-1(3H)-isobenzofuranones

Bowden

Agnihotri

Ranson

et al. 1997

J. Phys. Org. Chem.

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Rate coefficients were measured for the base-catalysed hydrolysis of a series of ␥-lactones, i.e. 39 substituted 3-(aryl-and alkylmethylene)-(Z)-1(3H)-isobenzofuranones (3-aryl-and alkylmethylenephthalides) in 70% (v/v) aqueous dioxane at 30·0°C. A Hammett reaction constant for the 3-or 4-substituted phenyl series is ca 1·5, whereas those for the 2-substituted phenyl and 4-substituted 1-naphthyl series, using para-values, are ca 1·0 and 1·9. These results are related to an electrostatic field effect model. A very successful correlation between the rates of alkaline hydrolysis of all 39 phthalides and the carbonyl stretching frequencies in chloroform was found. Substituent effects in widely different environments give linearly related effects on both reactivity and physical properties. Computational studies using the semi-empirical AM1 method correctly modelled both the details of the mechanistic pathway and the substituent effects.

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“…The Fermi resonance interaction on the carbonyl stretching frequencies has been investigated for a series of 3-(arylmethylene)-(Z)-1(3H)-isobenzofuranones after deconvolution and band separation. 5 It has been shown 5,6 that the unperturbed frequencies of car-bonyl stretching vibrations exhibit excellent linear correlations with Hammett ' constants. The additivity of substituent effects on reactivity has been investigated in several systems.…”

Section: Introductionmentioning

confidence: 97%

“…3 The computed structures for the more stable conformations of the substrate, TS1 and TS2 for the lactone 9 ( Table 2) 11, 467-474 (1998) bands in the carbonyl stretching vibration region resulting from Fermi resonance of the fundamental carbonyl stretching vibration with the first overtone of the out-ofplane carbon-hydrogen deformation vibration in the arylmethylene moiety. 5,6 For the corresponding phenoxy systems, 1a, only the compounds numbered 2, 5, 15, 19 and 20 in Table 2 exhibit a Fermi resonance doublet in the # CO absorption bands. The infrared spectra of the above five compounds were corrected for Fermi resonance after deconvolution and band separation.…”

mentioning

confidence: 99%

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Base-catalysed hydrolysis of ?-lactones: reactivity-structure correlations for 3-(substituted phenoxy- and thiophenoxymethylene)-(Z )-1(3H )-isobenzofuranones

Bowden

Ranson

Perjéssy

et al. 1998

J. Phys. Org. Chem.

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Rate coefficients were measured for the base-catalysed hydrolysis of a series of substituted 3-(phenoxyor thiophenoxymethylene)-(Z)-1(3H)-isobenzfuranones (3-phenoxy-or thiophenoxymethylenephthalides) in 70% (v/v) aqueous dioxane at 30.0°C, in addition to the carbonyl stretching frequencies in chloroform and tetrachloromethane following deconvolution and band separation, when required. The Hammett reaction constants for the alkaline hydrolysis of the 3-/4-substituted phenoxy and thiophenoxy series are ca 0.75 and 1.10, respectively. These results are related to electrostatic field and resonance effects. Successful correlations between the carbonyl stretching frequencies and substituent constants and the rates of alkaline hydrolysis were found. Computational studies using the semi-empirical AM1 method correctly model both the details of the mechanistic pathway and the substituent effects.

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Fermi resonance in substitutedZ-3-methylene phthalides

Cited by 9 publications

References 17 publications

Base-Catalysed Hydrolysis and Reactivity-Spectra Correlations of (Z)-4-Benzylidene-2-(Substituted Phenyl)Oxazol-5(4H)-ones

Base-Catalysed Hydrolysis and Reactivity-Spectra Correlations of (Z)-4-Benzylidene-2-(Substituted Phenyl)Oxazol-5(4H)-ones

Base-catalysed hydrolysis of ?-lactones: reactivity-structure correlations for 3-(aryl- and alkylmethylene)-(Z)-1(3H)-isobenzofuranones

Base-catalysed hydrolysis of ?-lactones: reactivity-structure correlations for 3-(substituted phenoxy- and thiophenoxymethylene)-(Z )-1(3H )-isobenzofuranones

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