Bis(2,2-dinitro­prop­yl)formal

Abstract

The complete mol­ecule of the title compound [systematic name: bis(2,2-dinitro­prop­oxy)methane], C₇H₁₂N₄O₁₀, which was synthesized by the condensation reaction between 2,2-dinitro­propanol and paraformaldehyde in methyl­ene chloride, is generated by crystallographic twofold symmetry with one C atom lying on the rotation axis. In the crystal structure, mol­ecules are linked into chains running parallel to the b axis by inter­molecular C—H⋯O hydrogen-bond inter­actions, generating rings of graph-set motif R ₂ ²(14).

Related literature

For the applications and chemistry of the title compound, see: Garver et al. (1985 ▶); Hamilton & Wardle (1995 ▶); Adolph (1991 ▶); Hamilton & Wardle (1997 ▶). For graph-set motifs, see: Bernstein (1995 ▶).

Experimental

Crystal data

• C₇H₁₂N₄O₁₀

• M _r = 312.21

• Monoclinic,

• a = 23.330 (3) Å

• b = 6.207 (3) Å

• c = 10.009 (6) Å

• β = 109.60 (3)°

• V = 1365.6 (11) ų

• Z = 4

• Mo Kα radiation

• μ = 0.14 mm⁻¹

• T = 291 K

• 0.48 × 0.44 × 0.28 mm

Data collection

• Enraf–Nonius CAD-4 diffractometer

• Absorption correction: none

• 1404 measured reflections

• 1255 independent reflections

• 863 reflections with I > 2σ(I)

• R _int = 0.008

• 3 standard reflections every 100 reflections intensity decay: 1.5%

Refinement

• R[F ² > 2σ(F ²)] = 0.046

• wR(F ²) = 0.138

• S = 1.09

• 1255 reflections

• 98 parameters

• H-atom parameters constrained

• Δρ_max = 0.18 e Å⁻³

• Δρ_min = −0.17 e Å⁻³

Data collection: DIFRAC (Gabe & White, 1993 ▶); cell refinement: DIFRAC; data reduction: NRCVAX (Gabe et al., 1989 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1A⋯O4i	0.97	2.59	3.509 (3)	158
C1—H1B⋯O4ii	0.97	2.59	3.509 (3)	158

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

The title compound is an important energetic material used in propellant and explosive formulations (Garver et al. 1985; Hamilton & Wardle, 1995). It was also combined with liquid bis(2,2-dinitropropyl)acetal (BDNPA) to prepare the BDNPF/A energetic plasticizer (Adolph, 1991; Hamilton & Wardle, 1997). Here we report the crystal structure of the title compound.

The molecule of the title compound (Fig. 1), has crystallographically imposed two-fold symmetry. The average of N—O bond length is 1.204 (3) Å. The dihedral angle formed by the planes through the nitro group is 74.3 (2)°. The O(1)—C(2)—C(3)—N(1), O(5)—N(2)—C(3)—C(4) and O(4)—N(2)—C(3)—C(4) torsion angles are 172.59 (17), -176.2 (2) and 5.6 (3) ° respectively. In the crystal structure, the molecules are linked into chains running parallel to the b axis by intermolecular C—H···O hydrogen interactions (Table 1) generating rings of graph set motif R²₂(14).

Experimental

The title compound was synthesized by reacting 2,2-dinitropropanol (6.0 g) with paraformaldehyde (0.6 g) in the presence of concentrated sulfuric acid as catalyst in methylene chloride below 5°C. Single crystals suitable for X-ray analysis were obtained by slow evaporation of a diethyl ether/mineral ether (1:6 v/v) solution.

Refinement

All non-H atoms were refined with anisotropic atomic displacement parameters. All H atoms were positioned geometrically and refined using a riding model, with C—H =0.96–0.97 Å and with U_iso(H) = 1.2 U_eq(C) or 1.5 U_eq(C) for methyl H atoms.

Figures

Fig. 1.

The molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level. Atoms labelled with the suffix 2 are generated by the symmetry operator (1-x, y, 1/2-z).

Crystal data

C7H12N4O10	F(000) = 648
Mr = 312.21	Dx = 1.519 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 23 reflections
a = 23.330 (3) Å	θ = 5.2–8.7°
b = 6.207 (3) Å	µ = 0.14 mm−1
c = 10.009 (6) Å	T = 291 K
β = 109.60 (3)°	Block, colourless
V = 1365.6 (11) Å3	0.48 × 0.44 × 0.28 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer	Rint = 0.008
Radiation source: fine-focus sealed tube	θmax = 25.5°, θmin = 1.9°
graphite	h = −28→20
ω/2θ scans	k = 0→7
1404 measured reflections	l = −12→12
1255 independent reflections	3 standard reflections every 100 reflections
863 reflections with I > 2σ(I)	intensity decay: 1.5%

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.046	H-atom parameters constrained
wR(F2) = 0.138	w = 1/[σ2(Fo2) + (0.0654P)2 + 0.7176P] where P = (Fo2 + 2Fc2)/3
S = 1.09	(Δ/σ)max < 0.001
1255 reflections	Δρmax = 0.18 e Å−3
98 parameters	Δρmin = −0.17 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.032 (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	Occ. (<1)
O1	0.54239 (7)	0.5416 (3)	0.21472 (18)	0.0661 (6)
O2	0.68680 (8)	0.8202 (3)	0.51558 (17)	0.0706 (6)
O3	0.70016 (9)	1.0217 (3)	0.3547 (2)	0.0854 (7)
O4	0.60961 (13)	0.8225 (4)	0.0432 (2)	0.1153 (10)
O5	0.57606 (12)	1.0244 (4)	0.1735 (3)	0.1154 (9)
N1	0.67637 (8)	0.8730 (3)	0.3932 (2)	0.0538 (5)
N2	0.60412 (11)	0.8729 (4)	0.1542 (2)	0.0702 (7)
C1	0.5000	0.4161 (6)	0.2500	0.0721 (11)
H1A	0.5211	0.3241	0.3297	0.087*	0.50
H1B	0.4789	0.3241	0.1703	0.087*	0.50
C2	0.58346 (10)	0.6513 (4)	0.3320 (2)	0.0619 (7)
H2A	0.5991	0.5550	0.4124	0.074*
H2B	0.5636	0.7721	0.3596	0.074*
C3	0.63384 (9)	0.7279 (3)	0.2821 (2)	0.0470 (6)
C4	0.67114 (13)	0.5524 (5)	0.2509 (4)	0.0887 (10)
H4A	0.7000	0.6135	0.2122	0.133*
H4B	0.6450	0.4542	0.1835	0.133*
H4C	0.6924	0.4765	0.3368	0.133*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0497 (9)	0.0705 (11)	0.0702 (11)	−0.0102 (8)	0.0098 (8)	−0.0145 (8)
O2	0.0670 (11)	0.0859 (12)	0.0506 (10)	−0.0086 (9)	0.0086 (7)	−0.0062 (9)
O3	0.0912 (13)	0.0750 (13)	0.0901 (14)	−0.0353 (11)	0.0306 (11)	−0.0070 (10)
O4	0.179 (3)	0.1115 (18)	0.0553 (12)	−0.0540 (17)	0.0396 (14)	−0.0049 (12)
O5	0.1221 (19)	0.0748 (14)	0.127 (2)	0.0347 (14)	0.0122 (15)	0.0233 (13)
N1	0.0481 (10)	0.0533 (11)	0.0610 (12)	−0.0045 (9)	0.0193 (9)	−0.0076 (9)
N2	0.0834 (15)	0.0650 (14)	0.0552 (13)	−0.0133 (12)	0.0137 (11)	0.0046 (11)
C1	0.0401 (16)	0.0499 (18)	0.114 (3)	0.000	0.0094 (17)	0.000
C2	0.0580 (13)	0.0718 (15)	0.0523 (13)	−0.0174 (12)	0.0138 (10)	−0.0065 (11)
C3	0.0464 (11)	0.0457 (11)	0.0454 (11)	0.0006 (9)	0.0107 (9)	−0.0038 (9)
C4	0.0676 (16)	0.0807 (19)	0.108 (2)	0.0146 (14)	0.0159 (15)	−0.0383 (18)

Geometric parameters (Å, °)

O1—C1	1.394 (3)	C1—H1A	0.9700
O1—C2	1.416 (3)	C1—H1B	0.9700
O2—N1	1.211 (2)	C2—C3	1.500 (3)
O3—N1	1.205 (2)	C2—H2A	0.9700
O4—N2	1.202 (3)	C2—H2B	0.9700
O5—N2	1.198 (3)	C3—C4	1.491 (3)
N1—C3	1.514 (3)	C4—H4A	0.9600
N2—C3	1.528 (3)	C4—H4B	0.9600
C1—O1i	1.394 (3)	C4—H4C	0.9600
C1—O1—C2	113.52 (16)	O1—C2—H2B	110.7
O3—N1—O2	124.98 (19)	C3—C2—H2B	110.7
O3—N1—C3	118.63 (19)	H2A—C2—H2B	108.8
O2—N1—C3	116.20 (18)	C4—C3—C2	114.6 (2)
O5—N2—O4	126.0 (3)	C4—C3—N1	107.70 (18)
O5—N2—C3	116.5 (2)	C2—C3—N1	109.75 (17)
O4—N2—C3	117.5 (2)	C4—C3—N2	112.8 (2)
O1—C1—O1i	112.1 (3)	C2—C3—N2	106.23 (18)
O1—C1—H1A	109.2	N1—C3—N2	105.44 (18)
O1i—C1—H1A	109.2	C3—C4—H4A	109.5
O1—C1—H1B	109.2	C3—C4—H4B	109.5
O1i—C1—H1B	109.2	H4A—C4—H4B	109.5
H1A—C1—H1B	107.9	C3—C4—H4C	109.5
O1—C2—C3	105.36 (18)	H4A—C4—H4C	109.5
O1—C2—H2A	110.7	H4B—C4—H4C	109.5
C3—C2—H2A	110.7
C2—O1—C1—O1i	70.17 (16)	O3—N1—C3—N2	−31.8 (3)
C1—O1—C2—C3	165.8 (2)	O2—N1—C3—N2	152.91 (19)
O1—C2—C3—C4	−66.1 (3)	O5—N2—C3—C4	−176.2 (2)
O1—C2—C3—N1	172.59 (17)	O4—N2—C3—C4	5.6 (3)
O1—C2—C3—N2	59.1 (2)	O5—N2—C3—C2	57.6 (3)
O3—N1—C3—C4	88.8 (3)	O4—N2—C3—C2	−120.7 (2)
O2—N1—C3—C4	−86.4 (3)	O5—N2—C3—N1	−58.9 (3)
O3—N1—C3—C2	−145.9 (2)	O4—N2—C3—N1	122.9 (2)
O2—N1—C3—C2	38.9 (3)

Symmetry codes: (i) −x+1, y, −z+1/2.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···O4ii	0.97	2.59	3.509 (3)	158
C1—H1B···O4iii	0.97	2.59	3.509 (3)	158

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