Structural, vibrational spectra and normal coordinate analysis for two tautomers of 4(5)-(2_-furyl)-imidazole

- A. E. LEDESMA, J. ZINCZUK, J. J. LÓPEZ GONZÁLEZ, A. BEN ALTABEF, S. A. BRANDÁN

JOURNAL OF RAMAN SPECTROSCOPY

JOHN WILEY & SONS LTD

Año: 2010 vol. 41 p. 587 - 597

0377-0486

We have synthesized both the 4 and 5 tautomeric forms of 4(5)-(2
-furyl)-imidazole (1) and investigated their molecularvibrations by infrared and Raman spectroscopies as well as by calculation based on the density functional theory (DFT)approach. Examination of the temperature dependence of IR intensity revealed the band characteristics of the 4 and 5tautomers of (1). Comparison of experimental and calculated chemical shifts in nuclear magnetic resonance (NMR) spectroscopywas made in order to identify the two tautomeric forms. The assignment of vibrational normalmodes was performed, and theforce field obtained reproduced the experimental vibrationalwavenumbers with a root mean-square deviation (RMSD) value ofca. 13 cm−1 for both tautomers. The natural bond orbital (NBO) study reveals the characteristics of the electronic delocalizationof the two tautomeric structures.