Isobutyr­aldehyde 2,4-di­nitro­phenyl­hydrazone

Crystals of the title compound, C₁₀H₁₂N₄O₄, were obtained from a condensation reaction of isobutyr­aldehyde and 2,4-di­nitro­phenyl­hydrazine. The mol­ecule exists in an E configuration. In the di­nitro­phenyl moiety, the average distance of 1.419 (3) Å for the aromatic C—C bonds adjacent to the imino group is appreciably longer than the average distance of 1.375 (3) Å for the other aromatic C—C bonds in the same ring. The overlapped arrangement and separations of 3.387 (15) and 3.369 (15) Å between parallel rings suggest the existence of π–π-stacking interactions between neighboring mol­ecules.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.067
• wR factor = 0.159
• Data-to-parameter ratio = 17.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

Some phenylhydrazones have been shown to be potentially DNA-damaging and mutagenic agents (Okabe et al., 1993). In order to investigate the relationship of the molecular structure and biological activity, a series of phenylhydrazones has been synthesized and their structures determined in this laboratory (Shan et al., 2003).

The molecular structure of the title compound, (I), is shown in Fig. 1. The compound crystallizes in an E configuration, with the isobutyl and dinitrophenyl groups on opposite sides of the N4═C7 double bond. Distances of 1.420 (3) and 1.418 (3) Å for the bonds C1—C2 and C1—C6, both adjacent to the imino group, are appreciably longer than the average distance of 1.375 (3) Å for the other aromatic C—C bonds, ranging from 1.356 (3) to 1.397 (3) Å, in the same phenyl ring. This agrees with the situation found in 2,4-dinitrophenylhydrazones reported previously (Bolte & Dill, 1998; Ohba, 1996; Borwick et al., 1997; Naidu et al., 1996; Shan et al., 2002, 2003). The molecule is essentially planar, except for the C9-methyl group, H8 attached to C8, and the H atom attached to C10. The C10—C8—C7—H7 torsion angle of 179° and the deviation of 0.049 (3) Å for the C10 atom from the phenylhydrazone mean plane confirms the coplanarity of atom C10 with the phenylhydrazone moiety. This configuration minimizes repulsion between atom H7 and the adjacent isobutyl group.

Hydrogen bonding occurs in the crystal structure, as shown in Fig. 1. Both intramolecular and intermolecular hydrogen bonding exists between the imino and nitro groups; the latter very weak interaction results in a short O1···O1(-x, 2 − y, 1 − z) distance of 2.758 (3) Å. A weak intermolecular C—H···O hydrogen bond occurs between the nitro and phenyl groups, as shown in Fig. 1 and Table 2.

The overlapped arrangement of phenyl rings from neighboring molecules (Fig. 2) and the separations of 3.387 (15) Å (symmetry code: 1 − x, 1 − y, 1 − z) and 3.369 (15) Å (symmetry code: 1 − x, 2 − y,1 − z) between parallel phenyl rings suggest the existence of π–π-stacking interactions between neighboring molecules.

S2. Experimental

2,4-Dinitrophenylhydrazine (0.4 g, 0.2 mmol) was dissolved in ethanol (10 ml), and H₂SO₄ solution (98%, 0.5 ml) was slowly added to the ethanol solution with stirring. The solution was heated at about 333 K for several minutes until the solution cleared. Isobutyraldehyde (0.14 g, 2 mmol) was added dropwise to the solution with continuous stirring, and the mixture was refluxed for 30 min. When the solution had cooled to room temperature yellow powdery crystals appeared. The powdery crystals were separated and washed with water three times. Recrystallization with absolute ethanol yielded well shaped single crystals.

S3. Refinement

The H atoms were placed in calculated positions with C—H = 0.93–0.98 Å and N—H = 0.86 Å; they were included in the final cycles of refinement in the riding-model approximation, with U_iso(H) = 1.2U_eq or 1.5U_eq of the carrier atoms.

Computing details

Data collection: PROCESS–AUTO (Rigaku, 1998); cell refinement: PROCESS–AUTO; data reduction: CrystalStructure (Rigaku/MSC and Rigaku, 2002); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecular structure of (I), with 30% probability displacement ellipsoids. Dashed lines indicate the intermolecular hydrogen bonding. [Symmetry codes: (i)-x, 2 − y, 1 − z; (ii) 2 − x, 1 − y, 1 − z.]
	Fig. 2. A molecular packing diagram, showing π–π stacking between neighboring phenyl rings. [Symmetry code: (iii) 1 − x, 1 − y, 1 − z.]

(I)

Crystal data

C10H12N4O4	F(000) = 528
Mr = 252.24	Dx = 1.362 Mg m^−3
Monoclinic, P21/c	Melting point: 186-187 °C K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71069 Å
a = 7.0514 (10) Å	Cell parameters from 6730 reflections
b = 7.3862 (12) Å	θ = 1.8–27.4°
c = 23.6459 (16) Å	µ = 0.11 mm^−1
β = 92.372 (13)°	T = 298 K
V = 1230.5 (3) Å^3	Plate, yellow
Z = 4	0.22 × 0.20 × 0.11 mm

Data collection

Rigaku R-AXIS RAPID diffractometer	1899 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.037
Graphite monochromator	θmax = 27.5°, θmin = 1.7°
Detector resolution: 10.00 pixels mm^-1	h = −8→9
ω scans	k = −9→9
11248 measured reflections	l = −30→30
2820 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.067	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.159	H-atom parameters constrained
S = 1.07	w = 1/[σ^2(Fo^2) + (0.059P)^2 + 0.539P] where P = (Fo^2 + 2Fc^2)/3
2820 reflections	(Δ/σ)max = 0.001
163 parameters	Δρmax = 0.36 e Å^−3
0 restraints	Δρmin = −0.24 e Å^−3

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 F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.0950 (2)	0.9175 (3)	0.45718 (7)	0.0621 (5)
O2	0.2090 (3)	0.8964 (3)	0.37445 (7)	0.0790 (7)
O3	0.8037 (3)	0.6397 (3)	0.34322 (8)	0.0821 (7)
O4	0.9771 (3)	0.5301 (3)	0.41206 (8)	0.0728 (6)
N1	0.2230 (3)	0.8747 (3)	0.42553 (8)	0.0495 (5)
N2	0.8348 (3)	0.6090 (3)	0.39334 (9)	0.0568 (5)
N3	0.3009 (3)	0.8305 (3)	0.54811 (7)	0.0463 (5)
H3	0.1907	0.8703	0.5373	0.056*
N4	0.3519 (3)	0.8173 (3)	0.60526 (8)	0.0546 (5)
C1	0.4268 (3)	0.7801 (3)	0.50982 (8)	0.0404 (5)
C2	0.3952 (3)	0.7962 (3)	0.45034 (8)	0.0409 (5)
C3	0.5280 (3)	0.7400 (3)	0.41259 (9)	0.0440 (5)
H3A	0.5036	0.7509	0.3738	0.053*
C4	0.6952 (3)	0.6685 (3)	0.43314 (9)	0.0463 (5)
C5	0.7346 (3)	0.6518 (3)	0.49129 (9)	0.0486 (6)
H5	0.8496	0.6030	0.5046	0.058*
C6	0.6047 (3)	0.7071 (3)	0.52833 (9)	0.0474 (5)
H6	0.6331	0.6969	0.5670	0.057*
C7	0.2288 (4)	0.8699 (4)	0.63867 (10)	0.0636 (7)
H7	0.1126	0.9110	0.6237	0.076*
C8	0.2621 (5)	0.8688 (5)	0.70176 (11)	0.0871 (10)
H8	0.2619	0.9960	0.7135	0.104*
C9	0.0978 (7)	0.7834 (7)	0.72861 (14)	0.1354 (18)
H9A	0.1186	0.7841	0.7690	0.203*
H9B	0.0841	0.6608	0.7156	0.203*
H9C	−0.0155	0.8501	0.7186	0.203*
C10	0.4528 (6)	0.7967 (7)	0.71953 (13)	0.1278 (17)
H10A	0.5490	0.8631	0.7008	0.192*
H10B	0.4602	0.6710	0.7095	0.192*
H10C	0.4721	0.8095	0.7598	0.192*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0475 (9)	0.0875 (14)	0.0515 (9)	0.0158 (9)	0.0029 (8)	−0.0060 (9)
O2	0.0671 (12)	0.1269 (19)	0.0427 (9)	0.0267 (12)	−0.0032 (8)	0.0078 (10)
O3	0.0791 (14)	0.1139 (18)	0.0545 (11)	0.0270 (12)	0.0190 (10)	0.0046 (11)
O4	0.0550 (10)	0.0827 (14)	0.0813 (13)	0.0209 (10)	0.0109 (9)	−0.0031 (11)
N1	0.0456 (10)	0.0580 (13)	0.0445 (10)	0.0024 (9)	−0.0022 (9)	−0.0009 (9)
N2	0.0532 (12)	0.0589 (14)	0.0589 (12)	0.0048 (10)	0.0113 (10)	−0.0029 (10)
N3	0.0443 (10)	0.0566 (12)	0.0381 (9)	0.0032 (9)	0.0025 (8)	0.0012 (8)
N4	0.0592 (12)	0.0647 (14)	0.0400 (10)	0.0041 (10)	0.0031 (9)	0.0007 (9)
C1	0.0441 (11)	0.0359 (12)	0.0413 (10)	−0.0072 (9)	0.0031 (9)	0.0000 (9)
C2	0.0399 (11)	0.0398 (12)	0.0429 (11)	−0.0020 (9)	0.0006 (9)	0.0009 (9)
C3	0.0477 (12)	0.0431 (13)	0.0414 (11)	−0.0044 (10)	0.0032 (9)	−0.0007 (9)
C4	0.0452 (12)	0.0446 (13)	0.0495 (12)	−0.0006 (10)	0.0089 (10)	0.0000 (10)
C5	0.0431 (12)	0.0473 (14)	0.0553 (13)	0.0037 (10)	−0.0012 (10)	0.0036 (10)
C6	0.0490 (12)	0.0508 (14)	0.0419 (11)	−0.0018 (11)	−0.0029 (10)	0.0032 (10)
C7	0.0700 (17)	0.076 (2)	0.0448 (13)	0.0132 (14)	0.0061 (12)	0.0041 (13)
C8	0.105 (2)	0.112 (3)	0.0452 (14)	0.024 (2)	0.0097 (16)	0.0015 (16)
C9	0.178 (4)	0.162 (4)	0.070 (2)	0.025 (4)	0.058 (3)	0.019 (2)
C10	0.147 (4)	0.181 (5)	0.0531 (18)	0.041 (3)	−0.023 (2)	0.007 (2)

Geometric parameters (Å, º)

O1—N1	1.238 (2)	C4—C5	1.397 (3)
O2—N1	1.218 (2)	C5—C6	1.356 (3)
O3—N2	1.218 (3)	C5—H5	0.930
O4—N2	1.227 (3)	C6—H6	0.930
N1—C2	1.447 (3)	C7—C8	1.501 (3)
N2—C4	1.458 (3)	C7—H7	0.930
N3—C1	1.346 (3)	C8—C9	1.485 (5)
N3—N4	1.387 (2)	C8—C10	1.490 (5)
N3—H3	0.860	C8—H8	0.980
N4—C7	1.259 (3)	C9—H9A	0.960
C1—C6	1.418 (3)	C9—H9B	0.960
C1—C2	1.420 (3)	C9—H9C	0.960
C2—C3	1.384 (3)	C10—H10A	0.960
C3—C4	1.363 (3)	C10—H10B	0.960
C3—H3A	0.930	C10—H10C	0.960
O2—N1—O1	122.3 (2)	C5—C6—C1	121.9 (2)
O2—N1—C2	119.15 (19)	C5—C6—H6	119.1
O1—N1—C2	118.56 (17)	C1—C6—H6	119.1
O3—N2—O4	123.5 (2)	N4—C7—C8	122.6 (3)
O3—N2—C4	118.2 (2)	N4—C7—H7	118.7
O4—N2—C4	118.3 (2)	C8—C7—H7	118.7
C1—N3—N4	118.97 (18)	C9—C8—C10	116.0 (3)
C1—N3—H3	120.5	C9—C8—C7	109.5 (3)
N4—N3—H3	120.5	C10—C8—C7	112.6 (3)
C7—N4—N3	115.6 (2)	C9—C8—H8	106.0
N3—C1—C6	119.80 (19)	C10—C8—H8	106.0
N3—C1—C2	124.22 (19)	C7—C8—H8	106.0
C6—C1—C2	115.97 (19)	C8—C9—H9A	109.5
C3—C2—C1	122.1 (2)	C8—C9—H9B	109.5
C3—C2—N1	115.93 (19)	H9A—C9—H9B	109.5
C1—C2—N1	121.96 (18)	C8—C9—H9C	109.5
C4—C3—C2	119.0 (2)	H9A—C9—H9C	109.5
C4—C3—H3A	120.5	H9B—C9—H9C	109.5
C2—C3—H3A	120.5	C8—C10—H10A	109.5
C3—C4—C5	121.3 (2)	C8—C10—H10B	109.5
C3—C4—N2	118.9 (2)	H10A—C10—H10B	109.5
C5—C4—N2	119.8 (2)	C8—C10—H10C	109.5
C6—C5—C4	119.8 (2)	H10A—C10—H10C	109.5
C6—C5—H5	120.1	H10B—C10—H10C	109.5
C4—C5—H5	120.1
C1—N3—N4—C7	178.7 (2)	C2—C3—C4—N2	179.9 (2)
N4—N3—C1—C6	2.9 (3)	O3—N2—C4—C3	6.2 (3)
N4—N3—C1—C2	−176.6 (2)	O4—N2—C4—C3	−173.5 (2)
N3—C1—C2—C3	−179.1 (2)	O3—N2—C4—C5	−173.7 (2)
C6—C1—C2—C3	1.5 (3)	O4—N2—C4—C5	6.6 (3)
N3—C1—C2—N1	1.8 (3)	C3—C4—C5—C6	0.1 (4)
C6—C1—C2—N1	−177.6 (2)	N2—C4—C5—C6	−180.0 (2)
O2—N1—C2—C3	−4.1 (3)	C4—C5—C6—C1	0.9 (4)
O1—N1—C2—C3	175.9 (2)	N3—C1—C6—C5	178.9 (2)
O2—N1—C2—C1	175.0 (2)	C2—C1—C6—C5	−1.6 (3)
O1—N1—C2—C1	−5.0 (3)	N3—N4—C7—C8	−178.6 (3)
C1—C2—C3—C4	−0.6 (3)	N4—C7—C8—C9	−131.7 (3)
N1—C2—C3—C4	178.6 (2)	N4—C7—C8—C10	−1.0 (5)
C2—C3—C4—C5	−0.3 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3···O1	0.86	2.02	2.624 (2)	127
N3—H3···O1^i	0.86	2.56	3.353 (3)	154
C5—H5···O4^ii	0.93	2.48	3.283 (3)	145

Symmetry codes: (i) −x, −y+2, −z+1; (ii) −x+2, −y+1, −z+1.