Huan-Xia Zhang

Diisopropyl anthracene-1,8-dicarboxyl­ate

The photodimerization of anthracene and its derivatives has been extensively investigated in the fields of photochromic materials and the preservation of photoenergy (Grimme et al., 1999; Sasaki et al., 1992). The means of achieving controlled derivatives of anthracene has been described earlier (Tamaki et al., 1987; Ueno et al., 1991; Ueno et al., 1989). We present here the crystal structure of the title anthracene derivative, (I).

2,2′-(9,10-Dioxo-9,10-dihydro­anthracene-1,8-diyldi­oxy)bis­(N,N-diethyl­acetamide)

In the title compound, C26H30N2O6, the anthraquinone ring system is not planar, the dihedral angle between the two benzene rings being 11.18 (13)°. The crystal structure is stabilized by C—H⋯O hydrogen bonds.

Di-n-propyl anthracene-1,8-dicarboxyl­ate

The bond lengths and angles in (I) are normal. The anthracene ring system is not strictly planar; the C1–C4/C11/ C12 and C5–C8/C13/C14 benzene rings form dihedral angles of 2.18 (7) and 2.56 (9) , respectively, with the central C9–C14 benzene ring. As a result of steric effects, the groups at atoms C1 and C8 are twisted away from the mean plane of the anthracene ring system (Fig. 1). The dihedral angles formed between various planes are as follows: O1/O2/C15/C16 and C5–C8/C13/C14 = 21.92 (6) , O3/O4/C19/C20 and C1–C4/C11/ C12 = 27.81 (8) , and O1/O2/C15/C16 and O3/O4/C19/C20 = 15.42 (10) . The crystal packing is stabilized by C—H O hydrogen bonds (Table 1).

7‐(Hydroxy­meth­yl)‐1a,7b‐dihydro‐1H‐cyclo­propa[a]naphthalene

In the title compound, C12H12O, the cyclopropane ring makes a dihedral angle of 73.1 (2)° with the naphthalene ring system.

N,N'-bis(2-methoxyphenyl)naphthalene-1,4-dicarboxamide.

The title compound, C26H22N2O4, crystallizes in an anti-C=O orientation, with the two N-substituted benzene rings in different conformations relative to the naphthalene ring. These conformations allow two strong N-H...O hydrogen bonds and one C-H...pi interaction to generate molecular chains in the cell.

3,3′-(1,4-Naphthalene­dimethyl­ene)bis­(1-methyl­imidazolium) diiodide monohydrate

In the title compound, C20H22N42+·2I−·H2O, the two imidazolium rings are twisted away from the central naphthalene plane by 76.6 (1) and 74.5 (1)°. The crystal packing is stabilized by O—H⋯I, C—H⋯O and C—H⋯I hydrogen bonds.

1,4‐Bis(imidazol‐1‐ylmeth­yl)naphthalene

In the title compound, C18H16N4, the two imidazole rings are twisted away from the central naphthalene ring system by 81.4 (1) and 88.4 (1)°. The crystal packing is stabilized by C—H⋯N hydrogen bonds