Vibrational Study of the Interaction of 2,4-Dichlorophenoxy Acetic Acid in Acetone Solution

MARÍA V. CASTILLO; MARÍA E. MANZUR; LILIANA DI MARCO; LILIAN DAVIES; VERÓNICA RUNCO; SILVIA A. BRANDÁN

Descriptors, Structural and Spectroscopic Properties of Heterocyclic Derivatives of Importance for Health and the Environment

Publisher Nova Science Publishing Inc.

Año: 2015; p. 158 - 173

In the present chapter, the characterization of the 2,4-dichlorophenoxyacetic acid (2,4-D) in acetone solution was carried out by using the infrared, HATR (Horizontal Attenuated Total Reflectance) and Raman spectroscopies. The structural and vibrational properties of the three conformers more stable of 2,4-D were predicted in acetone solution by using the density functional theory (DFT) with the 6-31G* and 6-311++G** basis sets. The solvent effect was studied at both levels of theory using the self consistent reaction field (SCRF) method with the polarized continuum model (PCM). The calculated geometrical parameters, the atomic charges, bond orders, main delocalization energies, the molecular electrostatic potentials, molar volume, solvation energies and the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gaps corresponding to all the forms of 2,4-D were compared and analyzed among them. HOMO-LUMO calculations predicted for both conformers a low reactivity in acetone solution than in gas phase. The harmonic vibrational wavenumbers calculated for the more stable structures in acetone were performed at the same theory levels. The complete assignments of all the observed bands in the vibrational spectra were performed combining the DFT calculations with the scaled quantum mechanical force field (SQMFF) methodology in order to compare the theoretical and experimental wavenumber values. Vibrational Study of the Interaction of 2,4-Dichlorophenoxy Acetic Acid in Acetone Solution. Available from: http://www.researchgate.net/publication/275040366_Vibrational_Study_of_the_Interaction_of_24-Dichlorophenoxy_Acetic_Acid_in_Acetone_Solution [accessed Sep 30, 2015].