In the title zwitterion, C 16 H 11 FN 2 O, which belongs to the family of azo dyes, the dihedral angle between the benzene ring and the naphthalene ring system is 15.33 (7) and an intramolecular N-HÁ Á ÁO hydrogen bond closes an S(6) ring. In the crystal, inversion dimers linked by weak C-HÁ Á ÁO hydrogen bonds generate R 2 2 (16) loops. Aromatic -stacking [centroid-centroid distance = 3.585 (11) Å ] is also observed. Structure descriptionThe structures and properties of azo dyes (solubility, habit, stability, colour) are dependent on their solid-state structures (Kennedy et al., 2004). As part of our studies in this area, we now describe the structure of the title compound, which shows zwitterionic behaviour (i.e. proton transfer from the naphthol group to the azo group) in the solid state.The dihedral angle between the benzene ring and the naphthalene ring system is 15.33 (7) and an intramolecular N-HÁ Á ÁO hydrogen bond ( Fig. 1 and Table 1) closes an S(6) ring. In the crystal, inversion dimers linked by weak C-HÁ Á ÁO hydrogen bonds generate R 2 2 (16) loops. The dimers are linked through -stacking between the benzene ring and naphthalene ring systems of adjacent molecules, the centroid-centroid distance between the C1-ring and C9-ring being 3.585 (11) Å . Synthesis and crystallizationThe title compound was obtained through the diazotization of 4-fluoroaniline followed by a coupling reaction with 2-naphthol according to the established procedure (Wang et
Key indicators: single-crystal X-ray study; T = 150 K; mean (C-C) = 0.004 Å; R factor = 0.043; wR factor = 0.120; data-to-parameter ratio = 12.8.The title compound, C 18 H 14 N 2 O 2 , crystallized with two independent zwitterion molecules (A and B) in the asymmetric unit. They are both close to planar, the dihedral angle between the benzene ring and naphthalene ring system being 4.30 (9) in A and 4.69 (9) in B. Each molecule has an E conformation with respect to the azo double bond. In each of the independent molecules, an intramolecular N-HÁ Á ÁO hydrogen bond forms an S(6) ring motif. In the crystal, molecules are linked via C-HÁ Á ÁO hydrogen bonds, forming -A-A-A-and -B-B-B-chains parallel to one another and propagating along the a-axis direction. There are alsointeractions between adjacent molecules involving benzene and naphthalene rings [centroid-centroid distance of 3.626 (3) Å for adjacent A molecules and 3.652 (3) Å for adjacent B molecules]. Related literature
The title compound, C16H11ClN2O2, was obtained by diazotization of 2-amino-4-chlorophenol followed by a coupling reaction with β-naphthol. There are two molecules (A and B) in the asymmetric unit. The crystal structure features only one type of intermolecular interaction, that is strong hydrogen bonds involving the hydroxyl group. The naphthol and phenol fragments attached to the C=N—N— moiety exhibit an s-trans conformation. In addition, those fragments are almost coplanar, subtending a dihedral angle of 13.11 (2)° in molecule A and 10.35 (2)° in molecule B. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H...H (32.1%), C...H/H...C (23.1%), Cl...H/H...Cl (15.2%), O...H/H...O (12.8%) and C...C (9%) contacts.
The non-H atoms of the title compound, C20H20N2O2, is located on a mirror plane except two methyl groups of the tert-butyl group. Intramolecular N—H⋯O hydrogen bonds exist between the hydroxy and diazenyl groups. In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds into supramolecular chains running along the a-axis direction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.