Structural and Vibrational Study of 2-(Quinolin-8-yloxy)-Acetic Acid based on FT-IR-Raman Spectroscopy and DFT Calculations

GERARDO R. ARGAÑARAZ, ELIDA ROMANO, JUAN ZINCZUK SILVIA A. BRANDÁN

Journal of Chemistry and Chemical Engineering

Davidpublishing

Lugar: Libertyville; Año: 2011 vol. 5 p. 747 - 758

1934-7375

Abstract: We have prepared the 2-(quinolin-8-yloxy)-acetic acid and characterized it by infrared and Raman spectroscopies in the solid phase. The Density Functional Theory (DFT) method, together with the 6-31G* and 6-311++G** basis sets, show that three stable molecules, for the anhydrous and monohydrated compounds were theoretically determined in the gas phase, and that probably the two more stable conformations are present in the solid phase of the monohydrated compound. The harmonic vibrational wavenumbers for the optimized geometries were calculated at B3LYP/6-31G*and B3LYP/6-311++G** levels. For a complete assignment of all the observed bands in the vibrational spectra the DFT calculations were combined with Pulay’s scaled quantum mechanical force field (SQMFF) methodology in order to fit the theoretical wavenumber values to the experimental ones. The characteristics of the electronic delocalization of all structures of both forms were performed by using natural bond orbital (NBO), while the corresponding topological properties of electronic charge density are analysed by employing Bader’s atoms in molecules theory (AIM).