Bis{1-[(E)-(2-chloro­phen­yl)diazen­yl]naphthalen-2-olato}copper(II)

The Cu^II atom in the title compound, [Cu(C₁₆H₁₀ClN₂O)₂], is located on an inversion center and is tetra­coordinated by two N and two O atoms from two bidentate 1-[(E)-(2-chloro­phen­yl)diazen­yl]naphthalen-2-olate ligands, forming a square-planar complex. In the crystal, mol­ecules are linked via weak C—H...O and C—H...Cl hydrogen bonds, forming chains propagating along [010]. There are also π–π inter­actions present involving adjacent naphthalene rings [centroid–centroid distance = 3.661 (13) Å].

1-(4-Hy­droxy­phen­yl)-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 intra­molecular N—H...O, rather than an O—H...N, hydrogen bond in the mol­ecule. The mol­ecule is almost planar, the dihedral angle between the benzene ring and the mean plane of the naphthalene ring system being 4.51 (6)°. In the crystal, mol­ecules are linked to and bridged by O—H...O hydrogen bonds involving the methanol mol­ecule, which is located about a twofold rotation axis, and hence half-occupied, forming zigzag chains along [001]. Mol­ecules are also linked via C—H...π and π–π inter­actions, the latter involving adjacent benzene and naphthalene rings and having a centroid–centroid distance of 3.6616 (13) Å, forming a three-dimensional network.

1-(3-Acetyl­phen­yl)-2-(2-oxidonaph­thalen-1-yl)diazen-1-ium

The title compound, C₁₈H₁₄N₂O₂, 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—H...O hydrogen bond forms an S(6) ring motif. In the crystal, mol­ecules are linked via C—H...O hydrogen bonds, forming –A—A—A– and –B—B—B– chains parallel to one another and propagating along the a-axis direction. There are also π–π inter­actions 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].

(E)-1-[2-(2-Cyano­phen­yl)diazen-2-ium-1-yl]naphthalen-2-olate

There are two independent zwitterion mol­ecules (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 mol­ecule A and 4.38 (6)° in mol­ecule B. The azo group adopts an E conformation with respect to the –N=N– bond and each of the independent mol­ecules has an intra­molecular N—H...O hydrogen bond. In the crystal, mol­ecules are linked by C—H...O and C—H...N hydrogen bonds, forming ribbons propagating along [-110]. The ribbons are linked via π–π inter­actions involving the benzene and naphthalene rings of inversion-related A and inversion-related B mol­ecules, forming a three-dimensional structure. The most significant centroid–centroid distances vary from 3.6599 (6) to 3.7538 (9) Å.

(E)-1-(3-Formyl­phen­yl)-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 intra­molecular N—H...O hydrogen bond exists. In the crystal, molecules are linked via pairs of C—H...O hydrogen bonds, forming inversion dimers.