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The title compound, C4H4N6O4·C2H6OS, crystallizes in the triclinic space group P\overline 1. It is a di­methyl sulfoxide (DMSO) solvate of the insensitive energetic compound 2,6-di­amino-3,5-di­nitro-1,4-pyrazine (ANPZ). The structure has been determined to obtain more accurate metrical parameters for the 2,6-di­amino-3,5-di­nitro-1,4-pyrazine moiety than those obtained from unsolvated crystals which are invariably twinned. The packing motif consists of two formula units linked by strong complementary hydrogen bonds between the ANPZ units with the two DMSO solvate mol­ecules each linked by two bifurcated hydogen bonds to the two ANPZ units. This central motif is further linked into planar sheets by weaker interactions between the DMSO methyl H atoms and the O atoms from the nitro groups. This looser packing arrangement compared to ANPZ is reflected in a lower density (1.662 Mg m-3 versus 1.812 Mg m-3 for ANPZ).

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801011722/wn6030sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801011722/wn6030Isup2.hkl
Contains datablock I

CCDC reference: 170918

Key indicators

  • Single-crystal X-ray study
  • T = 93 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.035
  • wR factor = 0.091
  • Data-to-parameter ratio = 12.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
PLAT_030 Alert C Refined Extinction parameter within range .... 2.50 Sigma
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
1 Alert Level C = Please check

Comment top

The title compound, 2,6-diamino-3,5-dinitro-1,4-pyrazine dimethyl sulfoxide solvate, (I), is a dimethyl sulfoxide (DMSO) solvate of the insensitive energetic molecule 2,6-diamino-3,5-dinitro-1,4-pyrazine (ANPZ). ANPZ is a member of an important family of insensitive energetic compounds (TATB: Cady & Larson, 1965; Kolb & Rizzo, 1979; ANPZ: Gilardi & Butcher, 2001; ANPZO: Gilardi & Butcher, 2001), in which the molecules exhibit both multiple intramolecular and intermolecular hydrogen bonding interactions (TATB is 1,3,5-triamino-2,4,6-trinitrobenzene and ANPZO is 2,6-diamino-3,5-dinitropyrazine-1-oxide).

The intermolecular hydrogen-bonding interactions result in a planar sheet-like packing arrangement where the spacing between the layers resembles that of graphite. The significant feature of this family of energetic molecules is their insensitivity. Sensitivity is often tested via the drop height method, i.e. the height of the drop of a steel ball required to detonate the compound, with large values reflecting insensitivity. In such testing, in common with TATB, the benchmark compound as regards insensitivity, ANPZ has values which are so large they cannot be accurately measured, while ANPZO has a value of 117 cm (Pagoria et al., 1998). Thus ANPZ is much safer than other commonly used energetic compounds such as trinitrotoluene (80 cm) and HMX (32 cm). The primary motivating factor in determining the structure of the ANPZ solvate was to obtain more accurate metrical parameters for ANPZ as its crystals are invariably twinned (Gilardi & Butcher, 2001). The packing motif for the DMSO solvate consists of two ANPZ molecules linked by strong complementary hydrogen bonds and DMSO solvate molecules, each linked by two bifurcated hydrogen bonds to the ANPZ dimer. This central motif is further linked into planar sheets by weaker interactions between the DMSO methyl H atoms and the O atoms from the nitro groups. This packing arrangement is looser than that of ANPZ, and results in a lower density (1.662 Mg m-3 versus 1.812 Mg m-3 for ANPZ). Fig. 1 shows the structure and labeling scheme for the title compound, while Fig. 2 shows the packing arrangement. Hydrogen-bonding metrical parameters are given in Table 1.

Experimental top

Crystals of the title compound were supplied by Dr Philip Pagoria, Energetic Materials Laboratory, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. Crystal and reflection data were obtained using standard procedures (Butcher et al., 1995).

Computing details top

Data collection: SMART (Bruker, 1994); cell refinement: SMART; data reduction: SHELXTL (Bruker, 1994); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. View of 2,6-diamino-3,5-dinitro-1,4-pyrazine dimethyl sulfoxide solvate showing the labeling of all non-H atoms. Displacement ellipsoids are at the 20% probability level and H atoms are drawn as small circles of arbitrary radii.
[Figure 2] Fig. 2. Packing diagram of 2,6-diamino-3,5-dinitro-1,4-pyrazine dimethyl sulfoxide solvate.
2,6-diamino-3,5-dinitro-1,4-pyrazine dimethyl sulfoxide solvate top
Crystal data top
C4H4N6O4·C2H6OSZ = 2
Mr = 278.26F(000) = 288
Triclinic, P1Dx = 1.662 Mg m3
a = 5.7817 (5) ÅMo Kα radiation, λ = 0.71073 Å
b = 8.1353 (8) ÅCell parameters from 3759 reflections
c = 12.0270 (11) Åθ = 2.5–28.3°
α = 99.253 (2)°µ = 0.32 mm1
β = 94.113 (2)°T = 93 K
γ = 92.482 (2)°Prism, yellow
V = 556.04 (9) Å30.65 × 0.22 × 0.07 mm
Data collection top
CCD area detector
diffractometer
2638 independent reflections
Radiation source: fine-focus sealed tube2505 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.031
ϕ and ω scansθmax = 28.3°, θmin = 1.7°
Absorption correction: integration
(Wuensch & Prewitt, 1965)
h = 67
Tmin = 0.919, Tmax = 0.969k = 1010
4175 measured reflectionsl = 1516
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.035H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.091 w = 1/[σ2(Fo2) + (0.0434P)2 + 0.3143P]
where P = (Fo2 + 2Fc2)/3
S = 1.14(Δ/σ)max = 0.006
2638 reflectionsΔρmax = 0.44 e Å3
204 parametersΔρmin = 0.25 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.005 (2)
Crystal data top
C4H4N6O4·C2H6OSγ = 92.482 (2)°
Mr = 278.26V = 556.04 (9) Å3
Triclinic, P1Z = 2
a = 5.7817 (5) ÅMo Kα radiation
b = 8.1353 (8) ŵ = 0.32 mm1
c = 12.0270 (11) ÅT = 93 K
α = 99.253 (2)°0.65 × 0.22 × 0.07 mm
β = 94.113 (2)°
Data collection top
CCD area detector
diffractometer
2638 independent reflections
Absorption correction: integration
(Wuensch & Prewitt, 1965)
2505 reflections with I > 2σ(I)
Tmin = 0.919, Tmax = 0.969Rint = 0.031
4175 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0350 restraints
wR(F2) = 0.091H atoms treated by a mixture of independent and constrained refinement
S = 1.14Δρmax = 0.44 e Å3
2638 reflectionsΔρmin = 0.25 e Å3
204 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
S1S1.17993 (6)0.66666 (4)1.34974 (3)0.01204 (11)
O1S1.03544 (19)0.62121 (14)1.23767 (9)0.0172 (2)
N10.7338 (2)0.64907 (15)0.94637 (10)0.0127 (2)
C20.5825 (2)0.61920 (17)0.85410 (12)0.0123 (3)
N20.3974 (2)0.51846 (17)0.85675 (11)0.0159 (3)
H2A0.299 (4)0.494 (2)0.8020 (18)0.016 (5)*
H2B0.379 (4)0.480 (3)0.9132 (19)0.017 (5)*
C30.6322 (2)0.69773 (17)0.75867 (12)0.0121 (3)
N30.4786 (2)0.67906 (15)0.65560 (10)0.0134 (2)
O3A0.29497 (19)0.59424 (15)0.65159 (10)0.0215 (3)
O3B0.53576 (19)0.74861 (15)0.57813 (9)0.0193 (2)
N40.8207 (2)0.79105 (15)0.75808 (10)0.0123 (2)
C50.9692 (2)0.81529 (17)0.84709 (12)0.0123 (3)
N51.1745 (2)0.91916 (15)0.83599 (11)0.0140 (2)
O5A1.32413 (18)0.94817 (14)0.91680 (10)0.0190 (2)
O5B1.1932 (2)0.97274 (15)0.74713 (10)0.0208 (2)
C60.9299 (2)0.74434 (17)0.94705 (12)0.0121 (3)
N61.0750 (2)0.76880 (17)1.03955 (11)0.0155 (3)
H6A1.207 (4)0.820 (3)1.0382 (17)0.020 (5)*
H6B1.048 (4)0.724 (3)1.094 (2)0.023 (5)*
C1S0.9899 (3)0.7636 (2)1.44803 (14)0.0205 (3)
H1SA0.877 (4)0.682 (3)1.458 (2)0.038 (6)*
H1SB0.920 (4)0.848 (3)1.4155 (19)0.026 (5)*
H1SC1.080 (4)0.803 (3)1.518 (2)0.031 (6)*
C2S1.3558 (3)0.8471 (2)1.33623 (15)0.0215 (3)
H2SA1.463 (5)0.817 (3)1.282 (2)0.041 (7)*
H2SB1.441 (4)0.884 (3)1.407 (2)0.029 (6)*
H2SC1.259 (4)0.932 (3)1.315 (2)0.037 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S1S0.01286 (18)0.01223 (18)0.01090 (18)0.00085 (12)0.00046 (12)0.00252 (12)
O1S0.0177 (5)0.0214 (5)0.0114 (5)0.0058 (4)0.0017 (4)0.0028 (4)
N10.0145 (6)0.0133 (6)0.0104 (5)0.0007 (4)0.0000 (4)0.0029 (4)
C20.0141 (6)0.0120 (6)0.0110 (6)0.0010 (5)0.0018 (5)0.0022 (5)
N20.0159 (6)0.0205 (6)0.0116 (6)0.0052 (5)0.0023 (5)0.0064 (5)
C30.0121 (6)0.0137 (6)0.0107 (6)0.0005 (5)0.0001 (5)0.0033 (5)
N30.0139 (6)0.0153 (6)0.0113 (6)0.0009 (4)0.0003 (4)0.0036 (4)
O3A0.0174 (5)0.0272 (6)0.0200 (5)0.0096 (4)0.0054 (4)0.0103 (5)
O3B0.0188 (5)0.0276 (6)0.0127 (5)0.0031 (4)0.0007 (4)0.0091 (4)
N40.0129 (5)0.0118 (5)0.0125 (6)0.0018 (4)0.0018 (4)0.0026 (4)
C50.0117 (6)0.0120 (6)0.0135 (6)0.0009 (5)0.0016 (5)0.0030 (5)
N50.0129 (5)0.0140 (6)0.0152 (6)0.0004 (4)0.0012 (4)0.0030 (5)
O5A0.0148 (5)0.0222 (5)0.0190 (5)0.0040 (4)0.0048 (4)0.0047 (4)
O5B0.0199 (5)0.0259 (6)0.0178 (5)0.0070 (4)0.0002 (4)0.0107 (4)
C60.0131 (6)0.0120 (6)0.0112 (6)0.0016 (5)0.0017 (5)0.0018 (5)
N60.0150 (6)0.0193 (6)0.0126 (6)0.0031 (5)0.0006 (5)0.0056 (5)
C1S0.0188 (7)0.0257 (8)0.0158 (7)0.0037 (6)0.0021 (6)0.0011 (6)
C2S0.0218 (8)0.0209 (8)0.0216 (8)0.0091 (6)0.0051 (6)0.0090 (6)
Geometric parameters (Å, º) top
S1S—O1S1.5174 (11)N3—O3B1.2226 (16)
S1S—C2S1.7852 (16)N3—O3A1.2347 (16)
S1S—C1S1.7855 (16)N4—C51.3069 (19)
N1—C61.3438 (18)C5—C61.4426 (19)
N1—C21.3458 (18)C5—N51.4535 (17)
C2—N21.3251 (18)N5—O5B1.2273 (17)
C2—C31.4405 (19)N5—O5A1.2396 (16)
C3—N41.3018 (18)C6—N61.3274 (19)
C3—N31.4555 (17)
O1S—S1S—C2S105.12 (7)O3A—N3—C3117.79 (11)
O1S—S1S—C1S106.08 (7)C3—N4—C5119.07 (12)
C2S—S1S—C1S98.55 (9)N4—C5—C6122.24 (13)
C6—N1—C2120.51 (12)N4—C5—N5114.15 (12)
N2—C2—N1117.72 (13)C6—C5—N5123.61 (13)
N2—C2—C3124.14 (13)O5B—N5—O5A122.99 (12)
N1—C2—C3118.14 (12)O5B—N5—C5118.81 (12)
N4—C3—C2122.12 (13)O5A—N5—C5118.19 (12)
N4—C3—N3114.65 (12)N6—C6—N1118.34 (13)
C2—C3—N3123.22 (12)N6—C6—C5123.80 (13)
O3B—N3—O3A123.32 (12)N1—C6—C5117.87 (12)
O3B—N3—C3118.88 (12)
C6—N1—C2—N2177.11 (13)C3—N4—C5—C61.1 (2)
C6—N1—C2—C32.6 (2)C3—N4—C5—N5179.04 (12)
N2—C2—C3—N4177.40 (13)N4—C5—N5—O5B0.68 (19)
N1—C2—C3—N42.3 (2)C6—C5—N5—O5B179.41 (13)
N2—C2—C3—N32.2 (2)N4—C5—N5—O5A179.98 (12)
N1—C2—C3—N3178.10 (12)C6—C5—N5—O5A0.1 (2)
N4—C3—N3—O3B0.54 (19)C2—N1—C6—N6179.27 (12)
C2—C3—N3—O3B179.13 (13)C2—N1—C6—C51.2 (2)
N4—C3—N3—O3A178.82 (13)N4—C5—C6—N6178.79 (13)
C2—C3—N3—O3A1.5 (2)N5—C5—C6—N61.1 (2)
C2—C3—N4—C50.4 (2)N4—C5—C6—N10.7 (2)
N3—C3—N4—C5179.91 (12)N5—C5—C6—N1179.40 (12)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O3A0.83 (2)2.10 (2)2.6703 (18)125.6 (17)
N2—H2A···O1Si0.83 (2)2.10 (2)2.7884 (17)139.9 (18)
N2—H2B···N1i0.80 (2)2.25 (2)3.0407 (18)170 (2)
N6—H6A···O5A0.86 (2)2.06 (2)2.6831 (18)128.8 (18)
N6—H6B···O1S0.82 (2)2.05 (2)2.8541 (17)171 (2)
Symmetry code: (i) x+1, y+1, z+2.

Experimental details

Crystal data
Chemical formulaC4H4N6O4·C2H6OS
Mr278.26
Crystal system, space groupTriclinic, P1
Temperature (K)93
a, b, c (Å)5.7817 (5), 8.1353 (8), 12.0270 (11)
α, β, γ (°)99.253 (2), 94.113 (2), 92.482 (2)
V3)556.04 (9)
Z2
Radiation typeMo Kα
µ (mm1)0.32
Crystal size (mm)0.65 × 0.22 × 0.07
Data collection
DiffractometerCCD area detector
diffractometer
Absorption correctionIntegration
(Wuensch & Prewitt, 1965)
Tmin, Tmax0.919, 0.969
No. of measured, independent and
observed [I > 2σ(I)] reflections
4175, 2638, 2505
Rint0.031
(sin θ/λ)max1)0.667
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.035, 0.091, 1.14
No. of reflections2638
No. of parameters204
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.44, 0.25

Computer programs: SMART (Bruker, 1994), SMART, SHELXTL (Bruker, 1994), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), SHELXTL.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O3A0.83 (2)2.10 (2)2.6703 (18)125.6 (17)
N2—H2A···O1Si0.83 (2)2.10 (2)2.7884 (17)139.9 (18)
N2—H2B···N1i0.80 (2)2.25 (2)3.0407 (18)170 (2)
N6—H6A···O5A0.86 (2)2.06 (2)2.6831 (18)128.8 (18)
N6—H6B···O1S0.82 (2)2.05 (2)2.8541 (17)171 (2)
Symmetry code: (i) x+1, y+1, z+2.
 

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