1,3-Bis[(4-nitro­benzyl­idene)amino­oxy]propane

Wen-Kui Dong; Yin-Xia Sun; Jun-Feng Tong; Hai-Hong Zhao; Li Wang

doi:10.1107/S1600536809031316

. 2009 Aug 12;65(Pt 9):o2141–o2142. doi: 10.1107/S1600536809031316

1,3-Bis[(4-nitrobenzylidene)aminooxy]propane

Wen-Kui Dong ^a,^*, Yin-Xia Sun ^a, Jun-Feng Tong ^a, Hai-Hong Zhao ^a, Li Wang ^a

PMCID: PMC2969883 PMID: 21577551

Abstract

The complete molecule of title compound, C₁₇H₁₆N₄O₆, is generated by a crystallographic twofold axis. Within the molecule, the two benzene units are approximately perpendicular, making a dihedral angle of 85.91 (4)°. In the crystal, molecules are linked into a three-dimensional network by C—H⋯O hydrogen bonds and short O⋯O and N⋯O interactions, with distances of 2.998 (2) and 2.968 (3) Å, respectively.

Related literature

For general background to Schiff base complexes and their applications, see: Niederhoffer et al. (1984 ▶); Zhang et al. (1990 ▶); Tisato et al. (1994 ▶); Lacroix (2001 ▶); Sundari et al. (1997 ▶); Koehler et al. (1964 ▶); Cordes & Jencks (1962 ▶); Akine et al. (2006 ▶). For related structures, see: Fun et al. (2008a ▶,b ▶); Kia et al. (2009 ▶); Shi et al. (2007 ▶); Ren et al. (2008 ▶); Ding et al. (2009 ▶); Dong et al. (2008a ▶). For a related Schiff base bisoxime compound synthesized using a similar route, see: Dong et al. (2008b ▶).

Experimental

Crystal data

C₁₇H₁₆N₄O₆
M _r = 372.34
Monoclinic,
a = 29.005 (3) Å
b = 4.7878 (5) Å
c = 6.3579 (7) Å
β = 99.144 (1)°
V = 871.71 (16) Å³
Z = 2
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 298 K
0.45 × 0.17 × 0.06 mm

Data collection

Siemens SMART 1000 CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.952, T _max = 0.993
2321 measured reflections
872 independent reflections
675 reflections with I > 2σ(I)
R _int = 0.049

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.094
S = 0.96
872 reflections
123 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.13 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: SMART (Siemens, 1996 ▶); cell refinement: SAINT (Siemens, 1996 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809031316/fl2256sup1.cif

e-65-o2141-sup1.cif^{(15.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809031316/fl2256Isup2.hkl

e-65-o2141-Isup2.hkl^{(43.3KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O3ⁱ	0.93	2.40	3.206 (4)	145
C9—H9⋯O3ⁱ	0.93	2.63	3.395 (4)	139
C9—H9⋯O2ⁱⁱ	0.93	2.71	3.374 (4)	129

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

This work was supported by the Foundation of the Education Department of Gansu Province (No. 0904-11) and the ‘Jing Lan’ Talent Engineering Funds of Lanzhou Jiaotong University, which are gratefully acknowledged.

supplementary crystallographic information

Comment

Schiff bases are among the most prevalent mixed-donor ligands in the field of coordination chemistry in which there has been growing interest, mainly because of their wide application in areas such as biochemistry (Niederhoffer et al., 1984), catalysis (Zhang et al., 1990), medical imaging (Tisato et al., 1994), optical materials (Lacroix, 2001) and thin films (Sundari et al., 1997). Although most Schiff bases are stable in both solution and the solid state, C=N bonds often suffer exchange reactions (Koehler et al., 1964) as well as hydrolysis (Cordes & Jencks, 1962). Rate constants of oxime formation are smaller than those of imine formation and the equilibrium constants are larger by several orders (Akine et al., 2006). Hence, the title compound should be stable enough to resist the metathesis of the C=N bonds. Many bisdentate Schiff base compounds have been structurally characterized (Fun et al., 2008a; Fun et al., 2008b; Kia et al., 2009), but only a relatively small number of bisoxime compounds have had their X-ray structures reported (Shi et al., 2007; Ren et al., 2008). As an extension of our work (Ding et al., 2009; Dong et al., 2008a) on the structural characterization of bisoxime compounds, the title compound, is reported here (Fig. 1).

In the title compound all bond lengths are in normal ranges. The molecule sits on a crystallographic twofold passing through the central CH₂ group (symmetry code: -x, y, -z) such that there is 1/2 molecule per asymmetric unit. Within the molecule, the dihedral angle between the plane of oxime functional group and benzene ring is about 0.54 (3)° for O1—N1—C3 and the C4—C9 ring, and the two benzene rings are approximately perpendicular with a dihedral angle of 85.91 (4)°. In the crystal intermolecular C—H···O hydrogen bonds link the molecules into an infinite three-dimensional supramolecular network. The molecules are held together by intermolecular hydrogen bonds (Table 1) to form infinite zigzag chains along the a axis and wave-like layers parallel to the ac plane (Fig. 2). In addition, the interesting features of the crystal structure are short intermolecular O···O and N···O interactions that form infinite helical chains along the b axis as depicted in Fig. 3. The O···O and N···O distances of 2.998 (2) and 2.968 (3) Å, respectively, are significantly shorter than the sum of the van der Waals radii of the relevant atoms. Thus, the zigzag and helical chains form a three-dimensional supramolecular structure through the crosslinked hydrogen-bonded and short intermolecular O···O and N···O interactions (Fig. 4).

Experimental

The title compound was synthesized according to an analogous method reported earlier (Dong et al., 2008b). To an ethanol solution (2 ml) of p-nitrobenzene (186.6 mg, 1.235 mmol) was added dropwise an ethanol solution (3 ml) of 1,3-bis(aminooxy)propane (51.3 mg, 0.473 mmol). The mixture was stirred at 328 K for 3 h. After cooling to room temperature, the precipitate was filtered off, and washed successively with ethanol and n-hexane, respectively. The product was dried in vacuo and purified by recrystallization from ethanol to yield 127.8 mg of (1); Yield, 71.8%. m. p. 427–429 K. Anal. Calcd. for C₁₇H₁₆N₄O₆: C, 54.84; H, 4.33; N, 15.05; Found: C, 55.06; H, 4.29; N, 15.04.

Colorless needle-like single crystals suitable for X-ray diffraction studies were obtained after about two weeks by slow evaporation from a chloroform-N,N-dimethylformamide of mixed solution of the title compound at room temperature.