Crystal structure and Hirshfeld surface analysis of 1-[()-2-(3-nitro-phen-yl)diazen-1-yl]naphthalen-2-ol.

The title compound, CHNO, belongs to the family of azo dyes. In the light of a single-crystal X-ray study, it is evident that of the tautomeric forms (azo-hydrazone), the hydrazone form is the predominant form in the solid state, namely, (1)-1-[2-(3-nitro-phen-yl)hydrazin-1-yl-idene]-1,2-di-hydro-naphthalen-2-one. The naphthol and benzene fragments attached to the -N=N- moiety adopt the conformation.

Crystal structure of (E)-5-benz-yloxy-2-{[(4-nitro-phen-yl)imino]-meth-yl}phenol.

In the title compound, C20H16N2O4, the mol-ecule adopts an E conformation about the N=C bond. There is an intra-molecular O-H⋯N hydrogen bond forming an S(6) ring motif. The nitro-benzene and benz-yloxy rings are inclined to the central benzene ring by 4.

Crystal structure of 1-[(Z)-2-phenyl-hydrazin-1-yl-idene]naphthalen-2(1H)-one.

In the title compound, C16H12N2O, the dihedral angle between the planes of the benzene ring and naphthalenone ring system is 1.89 (8)°; an intra-molecular N-H⋯O hydrogen bond occurs between the imino group and the carbonyl group. In the crystal, mol-ecules are linked by weak C-H⋯π inter-actions into supra-molecular chains propagating along the [01-1] direction.

(E)-4-Chloro-2-{[4-(di-methyl-amino)-benzyl-idene]amino}-phenol.

In the title aromatic Schiff base compound, C15H15ClN2O, the mol-ecule exists in a trans conformation with respect to the C=N bond. The dihedral angle between the benzene rings is 14.49 (6)°.

2-(1,3-Benzodioxol-5-yl)-1H-benzimid-azole.

The asymmetric unit of the title compound, C14H10N2O2, contains two independent mol-ecules. In each mol-ecule, the benzodioxole ring system displays an envelope conformation, with the methyl-ene C atom located at the flap deviating by 0.081 (2) and 0.

(E)-1-(3-Formyl-phen-yl)-2-(2-oxidonaphthalen-1-yl)diazen-1-ium.

In the title zwitterion, C17H12N2O2, the dihedral angle between the benzene ring and naphthalene ring system is 11.76 (7)° and an intra-molecular N-H⋯O hydrogen bond exists. In the crystal, molecules are linked via pairs of C-H⋯O hydrogen bonds, forming inversion dimers.

(E)-1-[2-(2-Cyano-phen-yl)diazen-2-ium-1-yl]naphthalen-2-olate.

There are two independent zwitterion mol-ecules (A and B) in the asymmetric unit of the title compound, C17H11N3O, which belongs to the family of azo dyes. The dihedral angle between the benzene ring and the naphthalene ring system is 6.99 (6)° in mol-ecule A and 4.

1-(3-Acetyl-phen-yl)-2-(2-oxidonaph-thalen-1-yl)diazen-1-ium.

The title compound, C18H14N2O2, crystallized with two independent zwitterion mol-ecules (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.

Bis{1-[(E)-(2-chloro-phen-yl)diazen-yl]naphthalen-2-olato}copper(II).

The Cu(II) atom in the title compound, [Cu(C16H10ClN2O)2], is located on an inversion center and is tetra-coordinated by two N and two O atoms from two bidentate 1-[(E)-(2-chloro-phen-yl)diazen-yl]naphthalen-2-olate ligands, forming a square-planar complex. In the crystal, mol-ecules are linked via weak C-H⋯O and C-H⋯Cl hydrogen bonds, forming chains propagating along [010]. There are also π-π inter-actions present involving adjacent naphthalene rings [centroid-centroid distance = 3.

1-(4-Hy-droxy-phen-yl)-2-(2-oxidonaphthalen-1-yl)diazen-1-ium methanol hemisolvate.

In the title compound, C16H12N2O2·0.5CH3OH, the H atom of the -OH group has been transfered to the N atom in the azo group, forming a zwitterion. Hence, there is an intra-molecular N-H⋯O, rather than an O-H⋯N, hydrogen bond in the mol-ecule.