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 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.

Crystal structure of (Z)-3-benz-yloxy-6-[(2-hy-droxy-5-methyl-anilino)methyl-idene]cyclo-hexa-2,4-dien-1-one.

In the title Schiff base compound, C21H19NO3, the conformation about the C=C bond is Z. The N-H group and carbonyl O atom form an intra-molecular N-H⋯O hydrogen bond with an S(6) ring motif. The benz-yloxy ring and the 2-hy-droxy-5-methyl-phenyl ring are inclined to the central six-membered ring by 13.

(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)°.

1-[(E)-2-(5-tert-Butyl-2-hy-droxy-phen-yl)diazen-1-yl]naphthalen-2-ol.

The non-H atoms of the title compound, C20H20N2O2, is located on a mirror plane except two methyl groups of the tert-butyl group. Intra-molecular N-H⋯O hydrogen bonds exist between the hy-droxy and diazenyl groups. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds into supra-molecular chains running along the a-axis direction.

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.

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.

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

The title zwitterion,, C16H11ClN2O, is approximately planar, the dihedral angle between the benzene ring and naphthalene ring system is 1.55 (13)°; an intra-molecular N-H⋯O hydrogen bond stabilizes the planar conformation. In the crystal, π-π stacking between the benzene ring and the naphthalene ring system of adjacent mol-ecules links the mol-ecules into supra-molecular chains running along the b axis, the centroid-centroid distance being 3.

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.