Articulo
Hydrogen bonding interactions in fluorinated 1,2,3-triazole derivatives
Registro en:
issn:1144-0546
issn:1369-9261
Autor
Espitia Cogollo, Edeimis
Piro, Oscar Enrique
Echeverría, Gustavo Alberto
Tuttolomondo, M. E.
Pérez, Hiram
Jios, Jorge Luis
Ulic, Sonia Elizabeth
Institución
Resumen
The study of the intra- and intermolecular interactions in the solid state of four related fluorine-containing 1,2,3-triazole derivatives (1: R = –H, 2: R = –NO2, 3: R = –CH3, 4: R = –Cl) was carried out using quantum chemical calculations, vibrational (IR and Raman) and solid phase UV-vis spectroscopy, and single-crystal X-ray diffraction methods. The enol–keto/keto–enol tautomerism on the o-hydroxyacetophenone moiety was analyzed in terms of the synergy between O–H⋯O intramolecular hydrogen bond strengthening and the enhancement of π delocalization within the pseudo ring. The preference of the enol–keto form was attributed to the aromatic stabilization energy. The proton in the triazole ring was located on the intermediate nitrogen atom, with no evidence of prototropy in the studied series. Compounds 1 and 4 have similar structural motifs with N–H⋯O hydrogen bonds connecting amino and carbonyl groups of neighboring molecules in a chain along the a-axis. For 2, it was found that both oxygen atoms of the nitro substituent participate as acceptors, connecting adjacent molecules by hydrogen bonds through the N–H and O–H groups. In compound 3, the crystallization water molecule dominates the hydrogen bonding interactions, which associates three molecules of 3, giving rise to a three-dimensional H-bonding network. These intra and intermolecular interactions, which affect the absorption band locations of the involved groups, were also detected in the vibrational spectra of the studied triazoles. Centro de Química Inorgánica