Crystal structure of 4-({5-[(E)-(3,5-difluorophenyl)diazenyl]-2-hydroxybenzylidene}amino)-2,2,6,6-tetramethylpiperidin-1-oxyl

Abstract

The asymmetric unit of the title compound, C22H25F2N4O2, contains two crystallographically independent molecules. In one molecule, the two benzene rings are oriented at a dihedral angle of 1.93 (10)° and in the other molecule the corresponding dihedral angle is 7.19 (9)°. The piperidine rings in the two molecules adopt a similar distorted chair conformation, and both have pseudo-mirror planes passing through the N—O bonds. An intramolecular O—H...N hydrogen bond between the hydroxy group and the imine N atom is observed in both molecules. In the crystal, weak C—H...O and C—H...F hydrogen bonds, enclosing R22(6) ring motifs, and weak π–π stacking interactions link the molecules into a three-dimensional supramolecular network, with centroid-to-centroid distances between the nearly parallel phenyl and benzene rings of adjacent molecules of 3.975 (2) and 3.782 (2) Å.

Keywords

• crystal structure
• spin-labeled compounds
• Schiff base compounds
• hydrogen bonding
• π–π stacking