Hydrogen bonding interactions in fluorinated 1,2,3-triazole derivatives

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 Inorgánic

Revista Temas Agrarios Volumen 26; Suplemento 1 de 2021

1st International and 2nd National Symposium of Agronomic Sciences: The rebirth of the scientific discussion space for the Colombian Agro.1 Simposio Intenacional y 2 Nacional de Ciencias Agronómicas: El renacer del espacio de discusión científica para el Agro colombiano