Acid assisted proton transfer in 4‐[(4‐R‐phenylimino)methyl]pyridin‐3‐ols: NMR spectroscopy in solution and solid state,X‐ray and UV studies and DFT calculations |
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| Authors: | Almudena Perona Dionisia Sanz Rosa M Claramunt Elena Pinilla M Rosario Torres José Elguero |
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| Institution: | 1. Departamento de Química Orgánica y Bio‐Orgánica, Facultad de Ciencias, UNED, Senda del Rey 9, E‐28040 Madrid, SpainDepartamento de Química Orgánica y Bio‐Orgánica, Facultad de Ciencias, UNED, Senda del Rey 9, E‐28040 Madrid, Spain.===;2. Departamento de Química Orgánica y Bio‐Orgánica, Facultad de Ciencias, UNED, Senda del Rey 9, E‐28040 Madrid, Spain;3. Departamento de Química Inorgánica, Laboratorio de Difracción de Rayos‐X, Facultad de Ciencias Químicas, UCM, E‐28040 Madrid, Spain;4. Instituto de Química Médica, CSIC, Juan de la Cierva, 3, E‐28006 Madrid, Spain |
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| Abstract: | The behaviour of Schiff bases of 3‐hydroxy‐4‐pyridincarboxaldehyde and 4‐R‐anilines (R?H, CH3, OCH3, Br, Cl, NO2) in acid media has been described. 1H, 13C, 15N‐NMR chemical shifts allow to establish the protonation site and its influence on the hydroxyimino/oxoenamino tautomerism. DFT calculations, electronic spectra and X‐ray diffraction are in agreement with the NMR conclusions. Copyright © 2007 John Wiley & Sons, Ltd. |
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| Keywords: | Schiff bases acid media tautomerism hydrogen bonds NMR spectroscopy density functional calculations X‐ray electronic spectra |
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