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The title compound, C4H4N4O7, is a bicyclic carbonate ester of 1,3-di­nitro­imidazolidine-4,5-diol. It contains only C, H, N, and O, and has a remarkably high density of 1.953 Mg m-3, one of the top 12 densities in the CHNO realm. Such high densities are usually only observed in strained polycyclic ring compounds such as the nitro­cubanes and hexanitro­hexa­aza­isowurtzitane.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801013915/om6043sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801013915/om6043Isup2.hkl
Contains datablock I

CCDC reference: 172224

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.033
  • wR factor = 0.092
  • Data-to-parameter ratio = 10.2

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes

REFLT_03 From the CIF: _diffrn_reflns_theta_max 32.48 From the CIF: _reflns_number_total 1568 Count of symmetry unique reflns 1568 Completeness (_total/calc) 100.00% TEST3: Check Friedels for noncentro structure Estimate of Friedel pairs measured 0 Fraction of Friedel pairs measured 0.000 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.

Comment top

The title compound, 6,8-diaza-6,8-dinitro-2,4-dioxabicyclo[3.3.0]octan-3-one, C4H4N4O7 (I), contains only C, H, N, and O, and has a remarkably high density of 1.953 g cm-3. This value is one of the top 12 in the CHNO realm [based on the results of a search of version 5.2 (April 2001) of the Cambridge Structural Database (Allen et al., 1991) using CONQUEST (CCDC, 2001)]. The synthesis of new energetic CHNO compounds that have high densities is a prime goal in the field of energetic compounds. Such high densities are usually only observed in strained polycyclic ring compounds such as the nitrocubanes (Zhang et al., 2000; Lukin et al., 1997; Lukin et al., 1996) and hexanitrohexaazaisowurtzitane (Nielsen et al., 1998) or in a few planar molecules linked by inter- and intramolecular hydrogen bonding (Gilardi & Butcher, 2001) that can stack in parallel layers. In the present instance, the central core of the molecule contains no double bonds and consists of a cyclic carbonate ring fused to an imidazolidine ring. The molecule is not planar but is folded about the C1A—C1B ring juction (the angle between the carbonate and imidazolidine rings is 61.3°). It is thus related to another dense energetic cyclic carbonate, 4,5-bis(fluorodinitromethyl)-1,3-dioxolan-2-one (Ammon & Bhattacharjee, 1984). Metrical parameters for the cyclic carbonate ring are within the normal range observed for such compounds (Allen et al., 1991). However, the metrical parameters of the imidazolidine ring are affected by the nitration of nitrogen atoms. This nitration results in a lengthening of the two C—N distances [C1A—N6 1.443 (2) and C1B—N8 1.440 (2) versus 1.466 Å], an increase in the C—N—C angles (115.4 versus 108.7°) and a corresponding decrease in the N—C—N angle (99.4 versus 103.6°).

Experimental top

Crystals of the title compound were supplied by Dr Michael Chaykovsky, Naval Surface Warfare Center - White Oak, Silver Spring, MD.

Refinement top

Crystal and reflection data were obtained using standard procedures (Butcher et al., 1995).

Computing details top

Data collection: XSCANS (Siemens, 1994); cell refinement: XSCANS; data reduction: SHELXTL (Sheldrick, 1997a); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997b); 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 6,8-diaza-6,8-dinitro-2,4-dioxabicyclo[3.3.0]octan-3-one. Displacement ellipsoids are drawn at the 20% level; hydrogen atoms are shown as small circles of arbitrary radii.
[Figure 2] Fig. 2. Packing diagram of 6,8-diaza-6,8-dinitro-2,4-dioxabicyclo[3.3.0]-octan-3-one. A recurrent short (2.88 Å) distance between a nitro-O atom and a ring-O atom is indicated by dashed lines.
(I) top
Crystal data top
C4H4N4O7Dx = 1.953 Mg m3
Mr = 220.11Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P212121Cell parameters from 69 reflections
a = 6.7249 (5) Åθ = 7.9–43.5°
b = 9.979 (2) ŵ = 0.19 mm1
c = 11.1574 (10) ÅT = 293 K
V = 748.74 (19) Å3Octahedron, colorless
Z = 40.36 × 0.28 × 0.24 mm
F(000) = 448
Data collection top
Bruker P4
diffractometer
1371 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.000
Graphite monochromatorθmax = 32.5°, θmin = 2.7°
2θ/ω scansh = 010
Absorption correction: integration
(Wuensch & Prewitt, 1965)
k = 015
Tmin = 0.627, Tmax = 0.689l = 016
1568 measured reflections3 standard reflections every 97 reflections
1568 independent reflections intensity decay: none
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.033All H-atom parameters refined
wR(F2) = 0.092 w = 1/[σ2(Fo2) + (0.0565P)2 + 0.024P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max = 0.002
1568 reflectionsΔρmax = 0.30 e Å3
153 parametersΔρmin = 0.21 e Å3
0 restraintsExtinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.024 (6)
Crystal data top
C4H4N4O7V = 748.74 (19) Å3
Mr = 220.11Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 6.7249 (5) ŵ = 0.19 mm1
b = 9.979 (2) ÅT = 293 K
c = 11.1574 (10) Å0.36 × 0.28 × 0.24 mm
Data collection top
Bruker P4
diffractometer
1371 reflections with I > 2σ(I)
Absorption correction: integration
(Wuensch & Prewitt, 1965)
Rint = 0.000
Tmin = 0.627, Tmax = 0.6893 standard reflections every 97 reflections
1568 measured reflections intensity decay: none
1568 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0330 restraints
wR(F2) = 0.092All H-atom parameters refined
S = 1.07Δρmax = 0.30 e Å3
1568 reflectionsΔρmin = 0.21 e Å3
153 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
O20.2215 (2)0.12580 (14)0.51995 (12)0.0343 (3)
O30.0907 (2)0.06886 (16)0.47342 (15)0.0437 (4)
O40.16679 (18)0.01969 (13)0.37260 (11)0.0299 (3)
O610.5899 (3)0.18155 (14)0.68059 (14)0.0442 (4)
O620.7293 (2)0.01084 (19)0.71922 (13)0.0443 (4)
O810.4497 (3)0.22123 (14)0.24039 (12)0.0399 (3)
O820.6257 (3)0.32115 (13)0.37769 (14)0.0394 (3)
N60.5056 (2)0.00221 (14)0.57590 (12)0.0270 (3)
N610.6181 (2)0.06247 (16)0.66343 (13)0.0317 (3)
N80.4611 (2)0.13675 (13)0.42254 (12)0.0268 (3)
N810.5176 (2)0.23172 (13)0.34053 (13)0.0280 (3)
C1A0.4159 (3)0.08496 (15)0.48455 (14)0.0245 (3)
H1A0.485 (3)0.163 (2)0.4662 (18)0.019 (5)*
C1B0.3792 (2)0.01207 (15)0.38072 (13)0.0227 (3)
H1B0.422 (4)0.011 (2)0.3045 (16)0.023 (5)*
C30.0826 (3)0.05866 (17)0.45753 (14)0.0282 (3)
C70.5678 (3)0.13027 (17)0.53632 (15)0.0281 (3)
H720.522 (4)0.198 (3)0.585 (2)0.041 (7)*
H710.708 (4)0.134 (2)0.520 (2)0.034 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O20.0323 (6)0.0374 (6)0.0331 (6)0.0111 (5)0.0041 (5)0.0100 (5)
O30.0268 (6)0.0571 (9)0.0472 (8)0.0081 (6)0.0066 (6)0.0045 (7)
O40.0233 (5)0.0340 (6)0.0323 (6)0.0025 (5)0.0036 (5)0.0071 (5)
O610.0534 (9)0.0407 (7)0.0386 (7)0.0087 (7)0.0045 (7)0.0108 (6)
O620.0370 (7)0.0620 (9)0.0339 (6)0.0021 (7)0.0129 (6)0.0056 (6)
O810.0546 (9)0.0371 (6)0.0281 (6)0.0054 (7)0.0035 (6)0.0057 (5)
O820.0452 (8)0.0290 (6)0.0440 (7)0.0112 (6)0.0008 (7)0.0016 (5)
N60.0268 (6)0.0286 (6)0.0257 (6)0.0013 (5)0.0057 (5)0.0005 (5)
N610.0278 (7)0.0420 (8)0.0252 (6)0.0069 (6)0.0027 (6)0.0018 (6)
N80.0318 (7)0.0255 (5)0.0231 (5)0.0060 (5)0.0022 (5)0.0007 (5)
N810.0307 (7)0.0239 (6)0.0295 (6)0.0010 (5)0.0040 (6)0.0005 (5)
C1A0.0255 (7)0.0225 (6)0.0255 (6)0.0007 (5)0.0015 (6)0.0003 (5)
C1B0.0216 (6)0.0251 (6)0.0213 (5)0.0015 (5)0.0012 (5)0.0016 (5)
C30.0258 (7)0.0311 (7)0.0277 (7)0.0038 (6)0.0024 (6)0.0026 (6)
C70.0300 (7)0.0275 (6)0.0268 (7)0.0029 (6)0.0047 (6)0.0017 (6)
Geometric parameters (Å, º) top
O2—C31.344 (2)N6—C1A1.444 (2)
O2—C1A1.425 (2)N6—C71.455 (2)
O3—C31.183 (2)N8—N811.3709 (19)
O4—C31.3526 (19)N8—C1B1.4385 (19)
O4—C1B1.4333 (19)N8—C71.460 (2)
O61—N611.219 (2)C1A—C1B1.530 (2)
O62—N611.217 (2)C1A—H1A0.93 (2)
O81—N811.211 (2)C1B—H1B0.926 (19)
O82—N811.2237 (19)C7—H720.91 (3)
N6—N611.3741 (19)C7—H710.96 (2)
C3—O2—C1A110.56 (12)O4—C1B—C1A104.02 (12)
C3—O4—C1B110.00 (13)N8—C1B—C1A103.88 (12)
N61—N6—C1A118.79 (13)O3—C3—O2124.32 (18)
N61—N6—C7117.05 (14)O3—C3—O4124.53 (18)
C1A—N6—C7115.18 (12)O2—C3—O4111.13 (14)
O62—N61—O61126.97 (17)N6—C7—N899.37 (12)
O62—N61—N6116.03 (15)O2—C1A—H1A106.4 (12)
O61—N61—N6116.91 (16)N6—C1A—H1A115.1 (13)
N81—N8—C1B119.17 (12)C1B—C1A—H1A116.3 (13)
N81—N8—C7118.35 (14)O4—C1B—H1B105.3 (15)
C1B—N8—C7115.60 (13)N8—C1B—H1B113.0 (13)
O81—N81—O82126.82 (15)C1A—C1B—H1B119.3 (13)
O81—N81—N8116.85 (14)N6—C7—H72113.0 (17)
O82—N81—N8116.27 (14)N8—C7—H72108.3 (17)
O2—C1A—N6110.56 (13)N6—C7—H71111.8 (14)
O2—C1A—C1B104.06 (12)N8—C7—H71108.5 (15)
N6—C1A—C1B103.89 (12)H72—C7—H71115 (2)
O4—C1B—N8110.87 (13)
C1A—N6—N61—O62162.26 (15)N81—N8—C1B—O491.65 (17)
C7—N6—N61—O6216.6 (2)C7—N8—C1B—O4117.82 (15)
C1A—N6—N61—O6120.9 (2)N81—N8—C1B—C1A157.18 (14)
C7—N6—N61—O61166.60 (17)C7—N8—C1B—C1A6.65 (18)
C1B—N8—N81—O8118.6 (2)O2—C1A—C1B—O42.48 (15)
C7—N8—N81—O81168.35 (16)N6—C1A—C1B—O4113.30 (14)
C1B—N8—N81—O82163.99 (15)O2—C1A—C1B—N8118.58 (13)
C7—N8—N81—O8214.3 (2)N6—C1A—C1B—N82.80 (16)
C3—O2—C1A—N6106.42 (15)C1A—O2—C3—O3176.24 (18)
C3—O2—C1A—C1B4.58 (17)C1A—O2—C3—O45.10 (18)
N61—N6—C1A—O290.98 (17)C1B—O4—C3—O3178.03 (18)
C7—N6—C1A—O2122.74 (15)C1B—O4—C3—O23.32 (18)
N61—N6—C1A—C1B157.92 (14)N61—N6—C7—N8161.69 (14)
C7—N6—C1A—C1B11.64 (18)C1A—N6—C7—N814.80 (18)
C3—O4—C1B—N8110.75 (14)N81—N8—C7—N6163.57 (14)
C3—O4—C1B—C1A0.34 (17)C1B—N8—C7—N612.79 (18)

Experimental details

Crystal data
Chemical formulaC4H4N4O7
Mr220.11
Crystal system, space groupOrthorhombic, P212121
Temperature (K)293
a, b, c (Å)6.7249 (5), 9.979 (2), 11.1574 (10)
V3)748.74 (19)
Z4
Radiation typeMo Kα
µ (mm1)0.19
Crystal size (mm)0.36 × 0.28 × 0.24
Data collection
DiffractometerBruker P4
diffractometer
Absorption correctionIntegration
(Wuensch & Prewitt, 1965)
Tmin, Tmax0.627, 0.689
No. of measured, independent and
observed [I > 2σ(I)] reflections
1568, 1568, 1371
Rint0.000
(sin θ/λ)max1)0.756
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.033, 0.092, 1.07
No. of reflections1568
No. of parameters153
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.30, 0.21

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

 

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