D. Romani, S. Brandán
Jun 1, 2015
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0
Influential Citations
35
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Journal
Computational and Theoretical Chemistry
Abstract
Abstract In this work, the structural, electronic and vibrational properties of 6-Nitro-1,3-benzothiazole-2(3 H )-thione and their 2-thiol tautomer were studied by using density functional theory (DFT) and self consistent reaction force (SCRF) calculations in gas phase and, in formamide, aqueous, DMSO and acetone solutions. The solvation energies were computed taking into account the solvent effects by using the polarized continuum (PCM) and solvation (SM) models. The atomic charges, electrostatic potentials, bond order, energy stabilizations, topological properties were calculated together with the gap energies and some descriptors in order to predict the reactivities and behaviour of both tautomers in the different media. The dipole moment and solvation energy values for both forms show different behaviours with the permittivity values of the solvents. The studies by infrared spectroscopy reveal the presence of both tautomers and of the two dimers of thione in the solid phase, as supported by the weak IR bands at 1702, 1525, 1303 and 1292 cm −1 and the shoulder at 915 cm −1 . Moreover, the strong IR band at 3062 cm −1 , the bands of the media intensities at 680 and 466 cm −1 and, the very weak band at 499 cm −1 support the presence of the thione form. The higher electrostatic potentials on the NO 2 group of the thiol tautomer and their low electrophilic index show that thiol is better electron donor than thione while, thione has the highest reactivities in all the solvents and in gas phase than thiol. Here, the complete assignments of the normal vibration modes of thione and thiol in gas phase and in the four solvents are reported for the first time.