3-Pentanone 2,4-dinitrophenylhydrazone

Crystals of the title compound, C11H14N4O4, were obtained from a condensation reaction of 2,4-dinitrophenylhydrazine and 3-pentanone. In the crystal structure, the molecule, except one methyl group, displays a nearly planar structure. The imino group links to the adjacent nitro group via intramolecular hydrogen bonding. The partially overlapped arrangement and face-to-face separation of 3.410 (9) Å between parallel benzene rings indicate the existence of π–π stacking between adjacent molecules. The crystal structure also contains weak intermolecular C—H⋯O hydrogen bonding.

Crystals of the title compound, C 11 H 14 N 4 O 4 , were obtained from a condensation reaction of 2,4-dinitrophenylhydrazine and 3-pentanone. In the crystal structure, the molecule, except one methyl group, displays a nearly planar structure. The imino group links to the adjacent nitro group via intramolecular hydrogen bonding. The partially overlapped arrangement and face-to-face separation of 3.410 (9) Å between parallel benzene rings indicate the existence ofstacking between adjacent molecules. The crystal structure also contains weak intermolecular C-HÁ Á ÁO hydrogen bonding.

Comment
As some phenylhydrazone derivatives have shown to be potentially DNA damaging and mutagenic agents (Okabe et al., 1993), a series of new phenylhydrazone derivatives have been synthesized in our laboratory (Shan et al., 2003;Shan et al., 2006). As part of the ongoing investigation, the title compound has recently been prepared and its crystal structure is reported here.
A partially overlapped arrangement between parallel benzene rings of the adjacent molecules is illustrated in Fig. 2. The face-to-face separation of 3.410 (9) Å between C1-benzene and C1 i -benzene rings [symmetry code: (i) 1 -x,1 -y,-z] is significantly shorter than van der Waals thickness of the aromatic ring (3.70 Å, Cotton & Wilkinson, 1972) and indicates the existence of π-π stacking in the crystal structure. The crystal structure also contains intermolecular weak C-H···O hydrogen bonding (Table 2).
Experimental 2,4-Dinitrophenylhydrazine (0.4 g, 2 mmol) was dissolved in ethanol (10 ml), and H 2 SO 4 solution (98%, 0.5 ml) was slowly added to the ethanol solution with stirring. The solution was heated at about 333 K for several min until the solution cleared.
3-Pentanone (0.17 g, 2 mmol) was then added to the above solution with continuous stirring. The mixture was refluxed for 30 min. When the solution had cooled to room temperature red powder crystals appeared. The powder crystals were separated and washed with water three times. Recrystallization from absolute ethanol solution yielded well shaped single crystals of the title compound.

Refinement
Imino H atom was located in a difference Fourier map and refined isotropically. Methyl H atoms were placed in calculated positions with C-H = 0.96 Å and torsion angles were refined to fit the electron density, U iso (H) = 1.5U eq (C). Other H atoms were placed in calculated positions with C-H = 0.93 (aromatic) and 0.97 Å (methylene), and refined in riding mode with U iso (H) = 1.2U eq (C). Fig. 1. The molecular structure of the title compound with 30% probability displacement ellipsoids for non-H atoms, dashed line indicates hydrogen bonding.