1-[(E)-Anthracen-9-ylmethylidene]-2-(2,4-dinitrophenyl)hydrazine

In the title Schiff base, C21H14N4O4, the dihedral angle between the two nitro groups and the central benzene ring are 83.6 (5) and 2.6 (6)°. The anthracene ring system and the benzene ring make a dihedral angle of 0.7 (2)°. Intramolecular N—H⋯O and C—H⋯N hydrogen bonds occur. In the crystal, C—H⋯O hydrogen bonds link the molecules, forming chains along the b-axis direction.


Related literature
For general background to hydrazone derivatives, see: Kahwa et al. (1986). For the structures of 2,4-dinitrophenylhydrazine and 9-anthraldehyde, see: Okabe et al. (1993) and Trotter (1959) Table 1 Hydrogen-bond geometry (Å , ). The title compound was synthesized as part of an investigation of the coordination properties of Schiff bases functioning as ligands. Metal complexes based on Schiff bases have been developed in biology and macromolecular chemistry in the last years (Kahwa et al., 1986).
The three dimensional arrangement of the molecules is held together by weak hydrogen bonds interactions between C-H and nitro-oxygen atoms.
Each unit is almost planar with a maximum deviation of 0.179 (6) A for O2, bond lengths varying in the ranges of The angle between the two nitro groups and the central benzene ring by 83.6 (5) and 2.6 (6)°, and the angle between these two nitro groups is 11.1 (7)°. Dihedral angle between the two aromatic parts of the molecule are 179.7 (6) and -171.7 (6)°, for C8-C7-N4-N3 and C7-N4-N3-C1 respectively.

Experimental
All reagents were obtained from commercial sources and used wirh no further purifications.
The compound was obtained when 1 g of (2,4-dinitrophenyl) hydrazine was dissolved in 5 mL of concentrated H 2 SO 4 .7.5 mL of water where added very slowly to the solution, after this were also added 25 mL of ethanol. In other flask, 4 mL of ethanol 0.05 g of anthracene-9-carbaldehyde where dissolved, and then, 1.80 mL of (2,4-dinitrophenyl)hydrazine was added to the solution. The two solutions were mixed and left to stand, at room temperature, for 24 h and then the solid compound was filtered., 049 g (52,7%)of the final product were obtained.

Refinement
All H atoms could be located in a difference Fourier synthesis but were placed in calculated positions and refined as riding on their parent atoms, using SHELXL97 (Sheldrick, 2008) defaults. Due to the absence of anomalous scatterers, the absolute structure could not be determined.

1-[(E)-Anthracen-9-ylmethylidene]-2-(2,4-dinitrophenyl)hydrazine
Crystal data Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.