Spectroscopic, Structural, and Conformational Properties of ( Z )-4,4,4-Trifluoro-3-(2-hydroxyethylamino)-1-(2-hydroxyphenyl)-2-buten-1-one, C 12 H 12 F 3 NO 3 : A Trifluoromethyl-Substituted β-Aminoenone

Abstract

The (Z)-4,4,4-trifluoro-3-(2-hydroxyethylamino)-1-(2-hydroxyphenyl)-2- buten-1-one (C 12H 12F 3NO 3) compound was thoroughly studied by IR, Raman, UV-visible, and 13C and 19F NMR spectroscopies. The solid-state molecular structure was determined by X-ray diffraction methods. It crystallizes in the P2 1/c space group with a = 12.1420(4) Å, b = 7.8210(3) Å, c = 13.8970(5) Å, β = 116.162(2)°, and Z = 4 molecules per unit cell. The molecule shows a nearly planar molecular skeleton, favored by intramolecular OH???O and NH???O bonds, which are arranged in the lattice as an OH???O bonded polymer coiled around crystallographic 2-fold screw-axes. The three postulated tautomers were evaluated using quantum chemical calculations. The lowest energy tautomer (I) calculated with density functional theory methods agrees with the observed crystal structure. The structural and conformational properties are discussed considering the effect of the intra- and intermolecular hydrogen bond interactions.