Crystal structure, Hirshfeld surface analysis and energy frameworks of 1-[(E)-2-(2-fluoro-phen-yl)diazan-1-yl-idene]naphthalen-2(1H)-one.

The title compound, C16H11N2OF, is a member of the azo dye family. The dihedral angle subtended by the benzene ring and the naphthalene ring system measures 18.75 (7)°, indicating that the compound is not perfectly planar. An intra-molecular N-H⋯O hydrogen bond occurs between the imino and carbonyl groups. In the crystal, the mol-ecules are linked into inversion dimers by C-H⋯O inter-actions. Aromatic π-π stacking between the naphthalene ring systems lead to the formation of chains along [001]. A Hirshfeld surface analysis was undertaken to investigate and qu-antify the inter-molecular inter-actions. In addition, energy frameworks were used to examine the cooperative effect of these inter-molecular inter-actions across the crystal, showing dispersion energy to be the most influential factor in the crystal organization of the compound.

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.

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.

(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-(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 3.765 (2) Å.