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The title compound, C5H6N4O7, is a cyclic carbonate ester of 1,4-piperazine-2,3-diol. It contains only C, H, N, and O atoms, and has a high density of 1.828 Mg m-3.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801014131/om6044sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801014131/om6044Isup2.hkl
Contains datablock I

CCDC reference: 175350

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.007 Å
  • Disorder in main residue
  • R factor = 0.045
  • wR factor = 0.111
  • Data-to-parameter ratio = 6.4

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
PLAT_213 Alert C Atom PLAT_301 Alert C Main Residue Disorder ........................ 11.00 Perc. General Notes
REFLT_03 From the CIF: _diffrn_reflns_theta_max 27.48 From the CIF: _reflns_number_total 1049 Count of symmetry unique reflns 1048 Completeness (_total/calc) 100.10% TEST3: Check Friedels for noncentro structure Estimate of Friedel pairs measured 1 Fraction of Friedel pairs measured 0.001 Are heavy atom types Z>Si present no Please check that the estimate of the number of Friedel pairs is correct. If it is not, please give the correct count in the _publ_section_exptl_refinement section of the submitted CIF.
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
2 Alert Level C = Please check

Comment top

The title compound, 2,5-diaza-2,5-dinitro-7,9-dioxabicyclo[4.3.0]nonan-8-one, (I), crystallizes in the orthorhombic space group Pna21, contains only C, H, N, and O, and has a density of 1.828 Mg m-3. The central core of the molecule contains no double bonds and consists of a cyclic carbonate ring fused to a piperazine ring. The molecule is not planar but is folded about the C1—C6 ring junction (the angle between the carbonate and piperazine rings is 61.8°). It is thus related to the other dense energetic cyclic carbonates, 6,8-diaza-6,8-dinitro-2,4-dioxabicyclo[3.3.0]octan-3-one (Gilardi & Butcher, 2001), and 4,5-bis(fluorodinitromethyl)-1,3-dioxolan-2-one (Ammon & Bhattacharjee, 1984). The synthesis of new energetic CHNO compounds that have high densities is a prime goal in the field of energetic compounds. However, 2,5-diaza-2,5-dinitro-7,9-dioxabicyclo[4.3.0]nonan-8-one has a much lower density than 6,8-diaza-6,8-dinitro-2,4-dioxabicyclo[3.3.0]octan-3-one (1.828 versus 1.953 Mg m-3). One factor which contributes to this is the conformational flexibility of the –NCH2CH2N– backbone of the piperazine ring, which is disordered over two conformations with occupancies of 0.60:0.40 (2). Metrical parameters for the cyclic carbonate ring are within the normal range observed for such compounds (as summarized in the Cambridge Structural Database; Allen et al., 1991). However, the metrical parameters of the piperazine ring are affected by the nitration of the N atoms, and the disorder of the ethylene backbone, and the connection with the cyclic carbonate ring. The major differences are found in the C1—N2 and C6—N5 bond lengths which, at 1.416 (5) Å, are considerably shortened from the expected value of 1.464 Å (Allen et al., 1991).

Experimental top

Crystals of the title compound were supplied by Dr Michael Chaykovsky, Naval Surface Warfare Center – White Oak, Silver Spring, MD. Crystal and reflection data were obtained using standard procedures (Butcher et al., 1995).

Refinement top

The ethylene (–NCH2CH2N–) backbone of the piperazine ring was found to be disordered over two conformations. Using the SHELXTL refinement package, the disordered ethylene segments of the two conformers shown in Fig. 3 were constrained to be equivalent in their bond distances and angles, while their occupancies refined to convergance at 0.596 (16) and 0.404 (16). H atoms were found in difference maps, except for those in the disordered segment, where they were generated to be in ideal tetrahedral positions. All H atoms were constrained in the refinement to ideal positions, with C—H distances of 0.97 or 0.98 Å, and angles as close to 109.5° as possible. Each was assigned a Uiso value equal to 1.2Ueq of the neighboring C atom.

Computing details top

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

Figures top
[Figure 1] Fig. 1. View of 2,5-dinitro-7,9-dioxabicyclo[4.3.0]nonan-8-one. 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 2,5-dinitro-7,9-dioxabicyclo[4.3.0]nonan-8-one.
[Figure 3] Fig. 3. A side view of the disordered diazacyclohexane ring of the title molecule, with displacement ellipsoids at the 20% level. There is a 60:40 (2) ratio between the occupancies of the C3–C4 and the C3'–C4' segments.
(I) top
Crystal data top
C5H6N4O7Dx = 1.828 Mg m3
Mr = 234.14Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pna21Cell parameters from 44 reflections
a = 14.609 (2) Åθ = 2.8–17.0°
b = 8.4266 (12) ŵ = 0.17 mm1
c = 6.9097 (8) ÅT = 293 K
V = 850.61 (19) Å3Plate, colorless
Z = 40.45 × 0.39 × 0.03 mm
F(000) = 480
Data collection top
Bruker P4
diffractometer
805 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.000
Graphite monochromatorθmax = 27.5°, θmin = 2.8°
2θ/ω scansh = 018
Absorption correction: integration
(Wuensch & Prewitt; 1965)
k = 010
Tmin = 0.947, Tmax = 0.992l = 08
1049 measured reflections3 standard reflections every 97 reflections
1049 independent reflections intensity decay: none
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)] = 0.046H-atom parameters constrained
wR(F2) = 0.111 w = 1/[σ2(Fo2) + (0.047P)2 + 0.4504P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max < 0.001
1049 reflectionsΔρmax = 0.24 e Å3
165 parametersΔρmin = 0.19 e Å3
8 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.025 (6)
Crystal data top
C5H6N4O7V = 850.61 (19) Å3
Mr = 234.14Z = 4
Orthorhombic, Pna21Mo Kα radiation
a = 14.609 (2) ŵ = 0.17 mm1
b = 8.4266 (12) ÅT = 293 K
c = 6.9097 (8) Å0.45 × 0.39 × 0.03 mm
Data collection top
Bruker P4
diffractometer
805 reflections with I > 2σ(I)
Absorption correction: integration
(Wuensch & Prewitt; 1965)
Rint = 0.000
Tmin = 0.947, Tmax = 0.9923 standard reflections every 97 reflections
1049 measured reflections intensity decay: none
1049 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0468 restraints
wR(F2) = 0.111H-atom parameters constrained
S = 1.04Δρmax = 0.24 e Å3
1049 reflectionsΔρmin = 0.19 e Å3
165 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*/UeqOcc. (<1)
C10.3886 (3)0.1680 (5)0.2406 (8)0.0290 (11)
H1A0.40020.19270.37700.035*
N20.3125 (3)0.2561 (6)0.1730 (7)0.0411 (11)
C30.3059 (5)0.2900 (10)0.0363 (10)0.036 (3)0.596 (16)
H3A0.30650.19190.10970.044*0.596 (16)
H3B0.24940.34600.06450.044*0.596 (16)
C40.3848 (5)0.3879 (9)0.0876 (13)0.041 (3)0.596 (16)
H4A0.38100.48950.02210.049*0.596 (16)
H4B0.38530.40710.22600.049*0.596 (16)
N50.4697 (3)0.3044 (5)0.0293 (8)0.0405 (11)
C60.4766 (3)0.1917 (5)0.1218 (8)0.0314 (11)
H6A0.52760.21920.20770.038*
O70.4915 (3)0.0358 (4)0.0382 (8)0.0531 (12)
C80.4323 (3)0.0699 (6)0.1083 (8)0.0352 (11)
O80.4364 (3)0.2070 (4)0.0759 (7)0.0507 (11)
O90.3697 (2)0.0002 (4)0.2185 (6)0.0368 (8)
C3'0.3122 (7)0.3628 (17)0.0065 (15)0.058 (6)0.404 (16)
H3'A0.25210.36170.05320.070*0.404 (16)
H3'B0.32460.47020.04970.070*0.404 (16)
C4'0.3807 (5)0.3159 (17)0.1359 (12)0.053 (5)0.404 (16)
H4'A0.38480.39440.23830.063*0.404 (16)
H4'B0.36490.21440.19290.063*0.404 (16)
N2A0.2585 (3)0.3273 (6)0.3134 (9)0.0484 (12)
O2A0.2037 (3)0.4269 (5)0.2554 (9)0.0699 (15)
O2B0.2681 (3)0.2838 (7)0.4779 (8)0.0776 (17)
N5A0.5444 (3)0.3976 (5)0.0631 (8)0.0380 (10)
O5A0.5339 (3)0.5113 (5)0.1697 (8)0.0592 (13)
O5B0.6160 (3)0.3612 (5)0.0127 (7)0.0586 (13)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.032 (2)0.028 (2)0.027 (2)0.0006 (19)0.002 (2)0.002 (2)
N20.036 (2)0.048 (2)0.040 (2)0.015 (2)0.0058 (19)0.001 (2)
C30.036 (5)0.042 (6)0.032 (5)0.013 (4)0.002 (4)0.006 (4)
C40.042 (6)0.040 (5)0.041 (6)0.009 (4)0.018 (5)0.002 (5)
N50.035 (2)0.044 (2)0.042 (3)0.009 (2)0.000 (2)0.014 (2)
C60.034 (2)0.026 (2)0.035 (3)0.001 (2)0.005 (2)0.000 (2)
O70.055 (2)0.0304 (18)0.074 (3)0.0002 (18)0.034 (2)0.006 (2)
C80.040 (2)0.031 (3)0.035 (3)0.007 (2)0.002 (2)0.001 (2)
O80.064 (2)0.0283 (19)0.060 (3)0.0048 (17)0.000 (2)0.0033 (19)
O90.0356 (17)0.0313 (17)0.0433 (19)0.0046 (14)0.0072 (17)0.0018 (17)
C3'0.058 (11)0.077 (14)0.040 (10)0.032 (10)0.008 (8)0.005 (10)
C4'0.048 (9)0.086 (13)0.023 (7)0.032 (9)0.021 (6)0.005 (8)
N2A0.037 (2)0.046 (3)0.062 (3)0.003 (2)0.009 (2)0.013 (3)
O2A0.052 (2)0.054 (2)0.104 (4)0.024 (2)0.006 (3)0.011 (3)
O2B0.060 (3)0.126 (5)0.046 (3)0.020 (3)0.017 (2)0.011 (3)
N5A0.039 (2)0.032 (2)0.043 (3)0.0047 (18)0.009 (2)0.001 (2)
O5A0.077 (3)0.037 (2)0.064 (3)0.004 (2)0.017 (2)0.015 (2)
O5B0.034 (2)0.075 (3)0.067 (3)0.010 (2)0.003 (2)0.011 (3)
Geometric parameters (Å, º) top
C1—N21.416 (6)C3'—C4'1.459 (10)
C1—O91.449 (5)N2A—O2B1.202 (8)
C1—C61.539 (6)N2A—O2A1.227 (7)
N2—N2A1.387 (7)N5A—O5B1.209 (6)
N2—C3'1.460 (9)N5A—O5A1.218 (6)
N2—C31.477 (9)C1—H1A0.9800
C3—C41.461 (10)C3—H3A0.9700
C4—N51.483 (8)C3—H3B0.9700
N5—N5A1.365 (5)C4—H4A0.9700
N5—C61.415 (7)C4—H4B0.9700
N5—C4'1.497 (8)C6—H6A0.9800
C6—O71.451 (6)C3'—H3'A0.9700
O7—C81.332 (6)C3'—H3'B0.9700
C8—O81.178 (6)C4'—H4'A0.9700
C8—O91.328 (6)C4'—H4'B0.9700
N2—C1—O9109.1 (4)O5B—N5A—N5118.1 (4)
N2—C1—C6114.3 (4)O5A—N5A—N5117.1 (5)
O9—C1—C6103.3 (4)N2—C1—H1A110.0
N2A—N2—C1116.3 (5)O9—C1—H1A110.0
N2A—N2—C3'106.4 (6)C6—C1—H1A110.0
C1—N2—C3'125.8 (5)C4—C3—H3A110.3
N2A—N2—C3124.3 (5)N2—C3—H3A110.3
C1—N2—C3118.4 (5)C4—C3—H3B110.3
C4—C3—N2107.2 (6)N2—C3—H3B110.3
C3—C4—N5109.0 (6)H3A—C3—H3B108.5
N5A—N5—C6117.1 (4)C3—C4—H4A109.9
N5A—N5—C4110.4 (4)N5—C4—H4A109.9
C6—N5—C4125.4 (5)C3—C4—H4B109.9
N5A—N5—C4'124.9 (6)N5—C4—H4B109.9
C6—N5—C4'117.9 (5)H4A—C4—H4B108.3
N5—C6—O7109.0 (4)N5—C6—H6A110.0
N5—C6—C1114.9 (4)O7—C6—H6A110.0
O7—C6—C1102.7 (3)C1—C6—H6A110.0
C8—O7—C6111.3 (4)C4'—C3'—H3'A109.4
O8—C8—O9125.5 (5)N2—C3'—H3'A109.4
O8—C8—O7123.6 (5)C4'—C3'—H3'B109.4
O9—C8—O7111.0 (4)N2—C3'—H3'B109.4
C8—O9—C1111.3 (4)H3'A—C3'—H3'B108.0
C4'—C3'—N2111.2 (7)C3'—C4'—H4'A110.5
C3'—C4'—N5106.4 (7)N5—C4'—H4'A110.5
O2B—N2A—O2A126.4 (6)C3'—C4'—H4'B110.5
O2B—N2A—N2117.6 (5)N5—C4'—H4'B110.5
O2A—N2A—N2116.0 (6)H4'A—C4'—H4'B108.6
O5B—N5A—O5A124.9 (5)

Experimental details

Crystal data
Chemical formulaC5H6N4O7
Mr234.14
Crystal system, space groupOrthorhombic, Pna21
Temperature (K)293
a, b, c (Å)14.609 (2), 8.4266 (12), 6.9097 (8)
V3)850.61 (19)
Z4
Radiation typeMo Kα
µ (mm1)0.17
Crystal size (mm)0.45 × 0.39 × 0.03
Data collection
DiffractometerBruker P4
diffractometer
Absorption correctionIntegration
(Wuensch & Prewitt; 1965)
Tmin, Tmax0.947, 0.992
No. of measured, independent and
observed [I > 2σ(I)] reflections
1049, 1049, 805
Rint0.000
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.111, 1.04
No. of reflections1049
No. of parameters165
No. of restraints8
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.24, 0.19

Computer programs: XSCANS (Siemens, 1994), XSCANS, SHELXTL (Sheldrick, 1997a), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997b), SHELXTL.

 

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