syn-Acetophenone-(2,4-dinitro­phen­yl)hydrazone

The crystal structure of the title compound, C₁₄H₁₂N₄O₄, has been determined on a sample prepared in 1968. The nonplanar conformation differs from the previously published anti-isomer which is almost planar. However, the intra­molecular hydrogen bond N—H...O to the meta-nitro group is preserved with N...O 2.617 (4) Å.

Key indicators

• Single-crystal X-ray study
• T = 180 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.051
• wR factor = 0.128
• Data-to-parameter ratio = 6.7

checkCIF/PLATON results

No syntax errors found



Alert level A
THETM01_ALERT_3_A  The value of sine(theta_max)/wavelength is less than 0.550
            Calculated sin(theta_max)/wavelength =    0.4898

Author Response: The sample crystals are extremely thin plates and there is no practical possibility of growing better crystals. Dissolving in solvents at room temperature causes transformation to the anti-isomer. This resulted in less than the normal number of diffraction data, but sufficent to characterise the molecular and crystal strucutre correctly.

PLAT023_ALERT_3_A Resolution (too) Low [sin(th)/Lambda < 0.6].....      20.37 Deg.

Author Response: As above

PLAT027_ALERT_3_A _diffrn_reflns_theta_full (too) Low ............      20.37 Deg.

Author Response: As above

Alert level B
ABSTM02_ALERT_3_B  The ratio of expected to reported Tmax/Tmin(RR') is < 0.75
            Tmin and Tmax reported:      0.700     1.000
            Tmin(prime) and Tmax expected:      0.962     0.999
            RR(prime) =      0.727
            Please check that your absorption correction is appropriate.
REFNR01_ALERT_3_B  Ratio of reflections to parameters is < 8 for a
            centrosymmetric structure
            sine(theta)/lambda                0.4898
            Proportion of unique data used    1.0000
            Ratio reflections to parameters   6.7300
PLAT061_ALERT_3_B Tmax/Tmin Range Test RR' too Large .............       0.73
PLAT088_ALERT_3_B Poor Data / Parameter Ratio ....................       6.73

Alert level C
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N4     -   C12     ..       5.10 su
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.999
            Tmax scaled      0.999 Tmin scaled      0.699

   3 ALERT level A = In general: serious problem
   4 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   9 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The structure of the anti-isomer of acetophenone-(2,4-dinitrophenyl)hydrazone has been previously reported by Shan et al. (2002). We have been aware of the existence of the syn-isomer since 1963 (Ramsay, 1963), with the molecular structure (I) as shown in Fig. 1. This syn-isomer is more difficult to prepare experimentally, and was first characterized by Khromov-Borisov (1955). Attempts to recrystallize the syn isomer at room temperature lead to conversion to the anti-isomer. We prepared our sample following the method of Khromov-Borisov. The crystals used for the analysis were extemely thin plates, obtained by slow growth in a refrigerator. These gave less diffraction data than optimal, but sufficient to establish the correctness of the molecular and crystal structure.

The molecule has a non-planar structure as expected, in contrast to the planar structure of the anti-isomer. There are no unusual bond lengths or angles, and comparison of the C—N—N=C region to the anti-isomer shows no significant differences, indicating the same level of delocalization with C9—N2 1.348 (4) Å (anti, 1.351 (3) Å), N2—N1 1.383 (4) Å (anti, 1.367 (3) Å) and N1=C7 1.282 (4) Å, (anti 1.286 (3) Å). The intra-molecular hydrogen bond length N2···O31 of 2.617 (4) Å is similar to that of the anti-isomer, 2.607 (3) Å.

The packing of the molecules (Fig. 2) shows stacking of the planar dinitrophenyl fragments along the short b axis.

Related literature

For related literature, see: Khromov-Borisov (1955); Lomer et al. (1963); Rabinovich & Kraut (1964); Ramsay (1963); Shan et al. (2002).

S2. Experimental

4 g of 2,4-dinitrophenyl-hydrazine and 10.6 ml of acetophenone were gently heated for 10 min resulting in a red precipitate of the anti-isomer. After removal of the anti-isomer by vacuum filtration, and standing the residual solution in a refigerator for several days we obtained very thin plates of yellow crystals of the syn-isomer (m.p. 147°C.) These crystals are stable in air at room temperature, and a sample actually 42 years old, prepared in 1964, was used for the single-crystal XRD.

S3. Refinement

All hydrogen atoms were located in the final difference map without any difficulty. The positions of the methyl hydrogen atoms were refined independently and the aromatic C—H were constrained with a bond length of 0.95 Å and N—H constrained with 0.88 Å.

Computing details

Data collection: COLLECT (Nonius, 1998); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. Structre of (I), with non-hydrogen displacement ellipsoids drawn at the 50% probability level.
	Fig. 2. Packing diagram viewed in b axis projection, c-horizontal, a-vertical. The intra-molecular hydrogen bond is shown as dotted lines.

syn-Acetophenone(2,4-dinitrophenyl)hydrazone

Crystal data

C14H12N4O4	F(000) = 624
Mr = 300.28	Dx = 1.439 Mg m^−3
Monoclinic, P21/c	Melting point: 420 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 8.3339 (5) Å	Cell parameters from 35234 reflections
b = 6.4906 (3) Å	θ = 1.0–20.4°
c = 25.6571 (15) Å	µ = 0.11 mm^−1
β = 92.804 (2)°	T = 180 K
V = 1386.18 (13) Å^3	Thin plate, yellow
Z = 4	0.35 × 0.23 × 0.01 mm

Data collection

Nonius KappaCCD diffractometer	1055 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.066
Thin slice ω and φ scans	θmax = 20.4°, θmin = 3.5°
Absorption correction: multi-scan (SORTAV; Blessing, 1995)	h = −8→8
Tmin = 0.70, Tmax = 1.00	k = −6→6
4331 measured reflections	l = −24→25
1346 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)] = 0.051	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.128	H-atom parameters constrained
S = 1.15	w = 1/[σ^2(Fo^2) + (0.0434P)^2 + 0.862P] where P = (Fo^2 + 2Fc^2)/3
1346 reflections	(Δ/σ)max < 0.001
200 parameters	Δρmax = 0.15 e Å^−3
0 restraints	Δρmin = −0.20 e Å^−3

Special details

Experimental. Small thin crystal, poor data (theta max 20 degrees).

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
N1	0.1144 (3)	0.2778 (4)	0.37811 (12)	0.0364 (8)
C1	0.3611 (4)	0.2247 (6)	0.33049 (13)	0.0368 (10)
N2	0.2113 (3)	0.2447 (4)	0.42264 (11)	0.0357 (8)
H2N	0.3147	0.2229	0.4199	0.043*
C2	0.4779 (4)	0.3655 (7)	0.34654 (14)	0.0466 (11)
H2	0.4475	0.4952	0.3601	0.056*
C3	0.6392 (5)	0.3179 (7)	0.34289 (16)	0.0558 (12)
H3	0.7191	0.4150	0.3539	0.067*
N3	0.4217 (3)	0.2396 (5)	0.51692 (14)	0.0451 (9)
O31	0.4881 (3)	0.2325 (5)	0.47533 (11)	0.0591 (9)
O32	0.4969 (3)	0.2462 (5)	0.55887 (12)	0.0731 (10)
N4	−0.0500 (4)	0.2448 (5)	0.61941 (12)	0.0409 (8)
O41	−0.1970 (3)	0.2486 (4)	0.62148 (9)	0.0503 (8)
O42	0.0416 (3)	0.2419 (4)	0.65840 (10)	0.0580 (8)
C4	0.6831 (5)	0.1320 (8)	0.32354 (18)	0.0621 (13)
H4	0.7937	0.0991	0.3217	0.075*
C5	0.5681 (6)	−0.0085 (7)	0.30668 (17)	0.0664 (14)
H5	0.5995	−0.1376	0.2930	0.080*
C6	0.4060 (5)	0.0388 (6)	0.30970 (15)	0.0512 (12)
H6	0.3265	−0.0568	0.2975	0.061*
C7	0.1861 (4)	0.2723 (6)	0.33503 (14)	0.0390 (10)
C8	0.0899 (5)	0.3143 (7)	0.28589 (15)	0.0590 (13)
H8A	−0.0211	0.3457	0.2940	0.089*
H8B	0.0914	0.1928	0.2632	0.089*
H8C	0.1360	0.4322	0.2680	0.089*
C9	0.1495 (4)	0.2455 (5)	0.47021 (13)	0.0290 (9)
C10	−0.0200 (4)	0.2529 (5)	0.47562 (14)	0.0297 (9)
H10	−0.0896	0.2593	0.4452	0.036*
C11	−0.0838 (4)	0.2511 (5)	0.52317 (13)	0.0291 (9)
H11	−0.1970	0.2540	0.5259	0.035*
C12	0.0166 (4)	0.2451 (5)	0.56803 (13)	0.0310 (9)
C13	0.1813 (4)	0.2380 (5)	0.56530 (14)	0.0342 (10)
H13	0.2488	0.2322	0.5962	0.041*
C14	0.2463 (4)	0.2395 (5)	0.51691 (14)	0.0298 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0337 (17)	0.045 (2)	0.030 (2)	−0.0033 (15)	0.0000 (17)	0.0008 (15)
C1	0.034 (2)	0.047 (3)	0.029 (2)	−0.002 (2)	0.0081 (18)	−0.002 (2)
N2	0.0244 (15)	0.048 (2)	0.034 (2)	0.0039 (15)	−0.0025 (15)	−0.0005 (16)
C2	0.037 (2)	0.051 (3)	0.053 (3)	0.000 (2)	0.0086 (19)	−0.014 (2)
C3	0.038 (3)	0.066 (3)	0.064 (3)	−0.006 (2)	0.007 (2)	−0.011 (2)
N3	0.032 (2)	0.059 (2)	0.044 (2)	0.0022 (17)	−0.004 (2)	−0.0035 (18)
O31	0.0313 (15)	0.097 (2)	0.0492 (19)	0.0026 (15)	0.0081 (14)	0.0034 (17)
O32	0.0339 (16)	0.133 (3)	0.051 (2)	0.0041 (17)	−0.0101 (15)	−0.0187 (19)
N4	0.043 (2)	0.040 (2)	0.040 (2)	0.0040 (16)	0.0015 (19)	0.0015 (17)
O41	0.0384 (18)	0.065 (2)	0.0486 (18)	−0.0044 (14)	0.0117 (13)	0.0014 (14)
O42	0.0544 (17)	0.087 (2)	0.0320 (17)	0.0142 (17)	−0.0024 (14)	−0.0018 (16)
C4	0.045 (3)	0.068 (3)	0.075 (3)	0.007 (3)	0.023 (2)	0.010 (3)
C5	0.073 (3)	0.049 (3)	0.080 (4)	0.007 (3)	0.039 (3)	−0.001 (2)
C6	0.052 (3)	0.049 (3)	0.054 (3)	−0.008 (2)	0.021 (2)	−0.007 (2)
C7	0.040 (2)	0.044 (2)	0.032 (2)	−0.0089 (19)	0.001 (2)	−0.0011 (18)
C8	0.045 (2)	0.094 (4)	0.038 (3)	−0.007 (2)	0.002 (2)	0.001 (2)
C9	0.032 (2)	0.024 (2)	0.031 (2)	−0.0013 (16)	0.0066 (18)	−0.0038 (17)
C10	0.022 (2)	0.033 (2)	0.034 (2)	0.0023 (16)	−0.0029 (16)	0.0006 (17)
C11	0.0245 (19)	0.025 (2)	0.038 (2)	0.0008 (16)	−0.0005 (19)	−0.0045 (17)
C12	0.031 (2)	0.034 (2)	0.029 (2)	0.0009 (17)	0.0049 (18)	−0.0007 (17)
C13	0.035 (3)	0.033 (2)	0.034 (2)	0.0020 (17)	−0.0081 (18)	−0.0036 (17)
C14	0.022 (2)	0.031 (2)	0.036 (2)	0.0020 (16)	0.0002 (18)	−0.0046 (17)

Geometric parameters (Å, º)

N1—N2	1.383 (4)	C4—H4	0.9500
N1—C7	1.282 (4)	C5—C6	1.391 (6)
C1—C2	1.383 (5)	C5—H5	0.9500
C1—C6	1.378 (5)	C6—H6	0.9500
C1—C7	1.501 (5)	C7—C8	1.486 (5)
N2—C9	1.348 (4)	C8—H8A	0.9800
N2—H2N	0.8800	C8—H8B	0.9800
C2—C3	1.387 (5)	C8—H8C	0.9800
C2—H2	0.9500	C9—C14	1.412 (5)
C3—C4	1.361 (6)	C9—C10	1.427 (5)
C3—H3	0.9500	C10—C11	1.354 (4)
N3—O31	1.227 (4)	C10—H10	0.9500
N3—O32	1.219 (4)	C11—C12	1.390 (5)
N3—C14	1.462 (4)	C11—H11	0.9500
N4—O41	1.230 (4)	C12—C13	1.379 (4)
N4—O42	1.228 (4)	C13—C14	1.378 (5)
N4—C12	1.455 (4)	C13—H13	0.9500
C4—C5	1.377 (6)
C7—N1—N2	115.4 (3)	N1—C7—C8	118.1 (3)
C6—C1—C2	119.5 (3)	N1—C7—C1	124.6 (3)
C6—C1—C7	119.6 (3)	C8—C7—C1	117.3 (3)
C2—C1—C7	120.9 (3)	C7—C8—H8A	109.5
C9—N2—N1	120.9 (3)	C7—C8—H8B	109.5
C9—N2—H2N	119.5	H8A—C8—H8B	109.5
N1—N2—H2N	119.5	C7—C8—H8C	109.5
C1—C2—C3	120.2 (4)	H8A—C8—H8C	109.5
C1—C2—H2	119.9	H8B—C8—H8C	109.5
C3—C2—H2	119.9	N2—C9—C14	122.7 (3)
C4—C3—C2	120.1 (4)	N2—C9—C10	120.8 (3)
C4—C3—H3	120.0	C14—C9—C10	116.5 (3)
C2—C3—H3	120.0	C11—C10—C9	121.4 (3)
O32—N3—O31	122.3 (3)	C11—C10—H10	119.3
O32—N3—C14	118.1 (3)	C9—C10—H10	119.3
O31—N3—C14	119.6 (3)	C10—C11—C12	120.0 (3)
O42—N4—O41	123.1 (3)	C10—C11—H11	120.0
O42—N4—C12	119.3 (3)	C12—C11—H11	120.0
O41—N4—C12	117.7 (3)	C13—C12—C11	121.3 (3)
C3—C4—C5	120.4 (4)	C13—C12—N4	118.1 (3)
C3—C4—H4	119.8	C11—C12—N4	120.7 (3)
C5—C4—H4	119.8	C14—C13—C12	118.8 (3)
C4—C5—C6	119.9 (4)	C14—C13—H13	120.6
C4—C5—H5	120.0	C12—C13—H13	120.6
C6—C5—H5	120.0	C13—C14—C9	122.1 (3)
C1—C6—C5	119.8 (4)	C13—C14—N3	115.9 (3)
C1—C6—H6	120.1	C9—C14—N3	122.0 (3)
C5—C6—H6	120.1
C7—N1—N2—C9	−179.6 (3)	C9—C10—C11—C12	1.0 (5)
C6—C1—C2—C3	−1.5 (6)	C10—C11—C12—C13	−0.9 (5)
C7—C1—C2—C3	178.9 (4)	C10—C11—C12—N4	179.5 (3)
C1—C2—C3—C4	−0.1 (6)	O42—N4—C12—C13	1.2 (5)
C2—C3—C4—C5	1.1 (7)	O41—N4—C12—C13	−179.1 (3)
C3—C4—C5—C6	−0.4 (7)	O42—N4—C12—C11	−179.1 (3)
C2—C1—C6—C5	2.2 (6)	O41—N4—C12—C11	0.5 (5)
C7—C1—C6—C5	−178.3 (3)	C11—C12—C13—C14	0.8 (5)
C4—C5—C6—C1	−1.2 (6)	N4—C12—C13—C14	−179.6 (3)
N2—N1—C7—C8	−177.8 (3)	C12—C13—C14—C9	−0.8 (5)
N2—N1—C7—C1	2.7 (5)	C12—C13—C14—N3	177.8 (3)
C6—C1—C7—N1	108.2 (4)	N2—C9—C14—C13	−179.2 (3)
C2—C1—C7—N1	−72.2 (5)	C10—C9—C14—C13	0.8 (5)
C6—C1—C7—C8	−71.3 (5)	N2—C9—C14—N3	2.3 (5)
C2—C1—C7—C8	108.2 (4)	C10—C9—C14—N3	−177.6 (3)
N1—N2—C9—C14	−171.5 (3)	O32—N3—C14—C13	−2.7 (5)
N1—N2—C9—C10	8.4 (5)	O31—N3—C14—C13	177.1 (3)
N2—C9—C10—C11	179.1 (3)	O32—N3—C14—C9	175.9 (4)
C14—C9—C10—C11	−1.0 (5)	O31—N3—C14—C9	−4.4 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2N···O31	0.88	1.98	2.617 (4)	128