STRUCTURAL, VIBRATIONAL SPECTRA AND NORMAL COORDINATE ANALYSIS FOR TWO TAUTOMERS OF 4(5)-(2’-FURIL)IMIDAZOL

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 investigated the molecular vibrations of both 4 and 5 tautomeric forms of 4(5)-(2´-furil)-1H-imidazol (1) by infrared and Raman spectroscopies and calculation based on the Density Functional Theory (DFT) approach. Examination of the temperature dependence of IR intensity revealed of bands characteristic of the 4 and 5 tautomers of 1. The comparison of experimental and calculated chemical shifts in Nuclear Magnetic Resonance spectroscopy was carried out for identified the two tautomeric forms. The assignation of vibrational normal modes was performed and the force field obtained reproduces the experimental vibrational wavenumbers with a value of ca. 4.7 cm-1 for the two tautomers. The natural bond orbital (NBO) study reveals the characteristics of the electronic delocalization of the two tautomeric structures.