1-(4-Chloro­phenac­yl)-2-methyl-4,5-dinitro-1H-imidazole

In the title compound, C₁₂H₉ClN₄O₅, both nitro groups are rotated significantly from the imidazole plane. The C-4—NO₂ bond length is only slightly shorter than the value for a normal single Csp²—NO₂ bond and the C-5—NO₂ bond length is significantly shorter than C-4—NO₂. In consequence, the C-4-nitro group is easily replaced by morpholine, while the C-5-nitro group shows an extraordinary stability on treatment with the amine. In the crystal structure, the mol­ecules are linked through C—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.038
• wR factor = 0.117
• Data-to-parameter ratio = 13.1

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature .        293 K
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        N16

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

   2 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
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: KM-4 Software (Kuma, 1996); cell refinement: KM-4 Software; data reduction: KM-4 Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); 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).

1-(4-Chlorophenacyl)-2-methyl-4,5-dinitro-1H-imidazole

Crystal data

C12H9ClN4O5	F(000) = 1328
Mr = 324.68	Dx = 1.572 Mg m^−3
Monoclinic, C2/c	Melting point = 397 K–399 K K
Hall symbol: -C 2yc	Cu Kα radiation, λ = 1.54178 Å
a = 20.094 (3) Å	Cell parameters from 44 reflections
b = 9.4907 (14) Å	θ = 14.8–30.3°
c = 15.0418 (17) Å	µ = 2.78 mm^−1
β = 106.953 (12)°	T = 293 K
V = 2743.9 (7) Å^3	Prism, yellow
Z = 8	0.60 × 0.30 × 0.28 mm

Data collection

Kuma KM-4 diffractometer	2316 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.024
Graphite monochromator	θmax = 70.1°, θmin = 4.6°
ω–2θ scans	h = −23→23
Absorption correction: ψ scan (North et al., 1968)	k = −11→11
Tmin = 0.203, Tmax = 0.459	l = 0→18
5181 measured reflections	2 standard reflections every 100 reflections
2615 independent reflections	intensity decay: <2%

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)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.117	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0681P)^2 + 0.8575P] where P = (Fo^2 + 2Fc^2)/3
2615 reflections	(Δ/σ)max = 0.001
200 parameters	Δρmax = 0.31 e Å^−3
0 restraints	Δρmin = −0.21 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
Cl	0.94374 (3)	0.53587 (7)	0.64330 (3)	0.0931 (2)
N1	0.64276 (7)	0.44071 (14)	0.14589 (9)	0.0559 (3)
C2	0.59627 (9)	0.33533 (18)	0.14111 (12)	0.0603 (4)
N3	0.55914 (7)	0.30914 (16)	0.05479 (10)	0.0630 (3)
C4	0.58307 (8)	0.39949 (18)	0.00294 (11)	0.0577 (4)
C5	0.63506 (8)	0.48195 (17)	0.05603 (11)	0.0565 (4)
C6	0.68749 (8)	0.49844 (18)	0.23221 (11)	0.0599 (4)
H6A	0.6655	0.4853	0.2811	0.072*
H6B	0.6930	0.5989	0.2247	0.072*
C7	0.75868 (8)	0.42901 (16)	0.26088 (11)	0.0561 (4)
O8	0.77411 (7)	0.34448 (14)	0.20995 (9)	0.0741 (4)
C9	0.80532 (8)	0.46508 (16)	0.35368 (11)	0.0554 (4)
C10	0.78442 (9)	0.55381 (18)	0.41450 (12)	0.0605 (4)
H10	0.7415	0.5986	0.3948	0.073*
C11	0.82703 (9)	0.5755 (2)	0.50357 (12)	0.0660 (4)
H11	0.8131	0.6343	0.5443	0.079*
C12	0.89069 (10)	0.50852 (19)	0.53119 (12)	0.0661 (4)
C13	0.91334 (9)	0.4222 (2)	0.47239 (14)	0.0698 (5)
H13	0.9567	0.3788	0.4923	0.084*
C14	0.87061 (9)	0.40142 (19)	0.38360 (13)	0.0648 (4)
H14	0.8855	0.3441	0.3430	0.078*
C15	0.58922 (13)	0.2586 (3)	0.22370 (15)	0.0851 (6)
H15A	0.5572	0.1819	0.2040	0.128*
H15B	0.5721	0.3217	0.2619	0.128*
H15C	0.6338	0.2226	0.2587	0.128*
N16	0.55417 (8)	0.39464 (18)	−0.09698 (10)	0.0701 (4)
O17	0.49124 (8)	0.3855 (2)	−0.12742 (11)	0.1021 (6)
O18	0.59485 (9)	0.3921 (2)	−0.14309 (10)	0.0983 (5)
N19	0.67354 (8)	0.59358 (16)	0.03119 (11)	0.0680 (4)
O20	0.65071 (10)	0.64037 (17)	−0.04737 (12)	0.0972 (5)
O21	0.72564 (8)	0.63469 (16)	0.08906 (12)	0.0891 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl	0.0902 (4)	0.1076 (4)	0.0618 (3)	−0.0054 (3)	−0.0086 (2)	0.0119 (2)
N1	0.0518 (7)	0.0598 (7)	0.0541 (7)	−0.0011 (5)	0.0124 (5)	−0.0053 (5)
C2	0.0596 (8)	0.0638 (9)	0.0584 (9)	−0.0055 (7)	0.0184 (7)	−0.0040 (7)
N3	0.0583 (7)	0.0700 (8)	0.0604 (8)	−0.0094 (6)	0.0169 (6)	−0.0072 (6)
C4	0.0535 (8)	0.0641 (9)	0.0541 (8)	0.0005 (6)	0.0137 (6)	−0.0039 (7)
C5	0.0558 (8)	0.0569 (8)	0.0573 (8)	0.0007 (6)	0.0176 (7)	−0.0013 (6)
C6	0.0540 (8)	0.0650 (9)	0.0572 (8)	0.0004 (7)	0.0106 (7)	−0.0112 (7)
C7	0.0547 (8)	0.0539 (8)	0.0594 (8)	−0.0013 (6)	0.0162 (7)	−0.0008 (7)
O8	0.0697 (7)	0.0766 (8)	0.0720 (7)	0.0123 (6)	0.0144 (6)	−0.0173 (6)
C9	0.0518 (8)	0.0540 (8)	0.0581 (8)	−0.0022 (6)	0.0126 (6)	0.0030 (6)
C10	0.0554 (8)	0.0656 (9)	0.0572 (8)	0.0006 (7)	0.0111 (7)	0.0001 (7)
C11	0.0659 (10)	0.0717 (10)	0.0572 (9)	−0.0045 (8)	0.0130 (7)	−0.0012 (8)
C12	0.0637 (9)	0.0683 (9)	0.0580 (9)	−0.0097 (8)	0.0045 (7)	0.0128 (8)
C13	0.0548 (9)	0.0668 (10)	0.0787 (12)	0.0020 (7)	0.0051 (8)	0.0119 (9)
C14	0.0555 (9)	0.0629 (9)	0.0729 (10)	0.0012 (7)	0.0141 (8)	0.0002 (8)
C15	0.0988 (14)	0.0926 (14)	0.0670 (11)	−0.0203 (12)	0.0288 (10)	0.0027 (10)
N16	0.0700 (9)	0.0788 (9)	0.0569 (8)	0.0009 (7)	0.0112 (7)	−0.0039 (7)
O17	0.0706 (9)	0.1477 (16)	0.0735 (9)	0.0151 (9)	−0.0017 (7)	−0.0161 (9)
O18	0.0978 (11)	0.1401 (14)	0.0626 (8)	−0.0269 (10)	0.0324 (8)	−0.0060 (8)
N19	0.0742 (9)	0.0601 (8)	0.0742 (9)	−0.0054 (7)	0.0286 (8)	−0.0047 (7)
O20	0.1273 (13)	0.0823 (10)	0.0847 (10)	−0.0141 (9)	0.0351 (9)	0.0163 (8)
O21	0.0808 (9)	0.0830 (9)	0.1053 (11)	−0.0259 (7)	0.0298 (8)	−0.0116 (8)

Geometric parameters (Å, º)

Cl—C12	1.7319 (18)	C9—C10	1.395 (2)
N1—C2	1.356 (2)	C10—C11	1.379 (2)
N1—C5	1.372 (2)	C10—H10	0.9300
N1—C6	1.454 (2)	C11—C12	1.380 (3)
C2—N3	1.319 (2)	C11—H11	0.9300
C2—C15	1.482 (3)	C12—C13	1.377 (3)
N3—C4	1.339 (2)	C13—C14	1.375 (3)
C4—C5	1.362 (2)	C13—H13	0.9300
C4—N16	1.445 (2)	C14—H14	0.9300
C5—N19	1.424 (2)	C15—H15A	0.9600
C6—C7	1.519 (2)	C15—H15B	0.9600
C6—H6A	0.9700	C15—H15C	0.9600
C6—H6B	0.9700	N16—O17	1.216 (2)
C7—O8	1.210 (2)	N16—O18	1.217 (2)
C7—C9	1.477 (2)	N19—O21	1.214 (2)
C9—C14	1.394 (2)	N19—O20	1.220 (2)
C2—N1—C5	106.26 (13)	C11—C10—H10	119.8
C2—N1—C6	124.22 (14)	C9—C10—H10	119.8
C5—N1—C6	129.44 (14)	C10—C11—C12	118.82 (17)
N3—C2—N1	112.00 (15)	C10—C11—H11	120.6
N3—C2—C15	124.59 (16)	C12—C11—H11	120.6
N1—C2—C15	123.40 (16)	C13—C12—C11	122.15 (16)
C2—N3—C4	104.86 (14)	C13—C12—Cl	119.32 (14)
N3—C4—C5	111.76 (15)	C11—C12—Cl	118.53 (15)
N3—C4—N16	118.78 (14)	C14—C13—C12	118.65 (16)
C5—C4—N16	129.42 (16)	C14—C13—H13	120.7
C4—C5—N1	105.12 (14)	C12—C13—H13	120.7
C4—C5—N19	130.98 (16)	C13—C14—C9	120.90 (18)
N1—C5—N19	123.83 (15)	C13—C14—H14	119.5
N1—C6—C7	112.08 (13)	C9—C14—H14	119.5
N1—C6—H6A	109.2	C2—C15—H15A	109.5
C7—C6—H6A	109.2	C2—C15—H15B	109.5
N1—C6—H6B	109.2	H15A—C15—H15B	109.5
C7—C6—H6B	109.2	C2—C15—H15C	109.5
H6A—C6—H6B	107.9	H15A—C15—H15C	109.5
O8—C7—C9	122.87 (15)	H15B—C15—H15C	109.5
O8—C7—C6	120.12 (15)	O17—N16—O18	125.57 (17)
C9—C7—C6	116.96 (14)	O17—N16—C4	116.89 (16)
C14—C9—C10	118.99 (16)	O18—N16—C4	117.40 (15)
C14—C9—C7	118.86 (15)	O21—N19—O20	125.42 (17)
C10—C9—C7	122.03 (14)	O21—N19—C5	118.13 (16)
C11—C10—C9	120.46 (16)	O20—N19—C5	116.45 (16)
C5—N1—C2—N3	−1.07 (19)	C6—C7—C9—C14	178.65 (15)
C6—N1—C2—N3	175.82 (14)	O8—C7—C9—C10	−174.56 (16)
C5—N1—C2—C15	178.30 (18)	C6—C7—C9—C10	2.8 (2)
C6—N1—C2—C15	−4.8 (3)	C14—C9—C10—C11	−1.5 (2)
N1—C2—N3—C4	0.58 (19)	C7—C9—C10—C11	174.34 (15)
C15—C2—N3—C4	−178.78 (19)	C9—C10—C11—C12	0.3 (3)
C2—N3—C4—C5	0.15 (19)	C10—C11—C12—C13	0.8 (3)
C2—N3—C4—N16	178.02 (15)	C10—C11—C12—Cl	−179.76 (13)
N3—C4—C5—N1	−0.78 (19)	C11—C12—C13—C14	−0.6 (3)
N16—C4—C5—N1	−178.37 (16)	Cl—C12—C13—C14	179.95 (14)
N3—C4—C5—N19	−177.76 (16)	C12—C13—C14—C9	−0.7 (3)
N16—C4—C5—N19	4.7 (3)	C10—C9—C14—C13	1.7 (3)
C2—N1—C5—C4	1.08 (18)	C7—C9—C14—C13	−174.28 (16)
C6—N1—C5—C4	−175.60 (15)	N3—C4—N16—O17	44.8 (2)
C2—N1—C5—N19	178.33 (15)	C5—C4—N16—O17	−137.8 (2)
C6—N1—C5—N19	1.7 (3)	N3—C4—N16—O18	−131.22 (19)
C2—N1—C6—C7	94.56 (18)	C5—C4—N16—O18	46.2 (3)
C5—N1—C6—C7	−89.3 (2)	C4—C5—N19—O21	−167.24 (18)
N1—C6—C7—O8	5.5 (2)	N1—C5—N19—O21	16.3 (2)
N1—C6—C7—C9	−171.95 (13)	C4—C5—N19—O20	13.0 (3)
O8—C7—C9—C14	1.3 (2)	N1—C5—N19—O20	−163.44 (17)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6B···O21	0.97	2.34	2.803 (2)	108
C6—H6B···O8^i	0.97	2.54	3.427 (2)	152
C6—H6A···O18^ii	0.97	2.37	3.178 (2)	140

Symmetry codes: (i) −x+3/2, y+1/2, −z+1/2; (ii) x, −y+1, z+1/2.