3,3-Bis­(di­fluoro­amino­methyl)­oxetane, a promising new energetic material

The title compound, a promising new energetic material, 3,3-bis­(di­fluoro­amino­methyl)­oxetane, (F₂NCH₂)₂C(CH₂)₂O or C₅H₈F₄N₂O, contains two difluoro­amine (NF₂) substituents, rather uncommon energetic groups, which tend to be disordered in crystal structures. The mol­ecule occupies a special position on a twofold axis, and its two equivalent difluoro­amine groups show no signs of disorder.

Key indicators

• Single-crystal X-ray study
• T = 93 K
• Mean [sigma](C-C) = 0.001 Å
• R factor = 0.036
• wR factor = 0.102
• Data-to-parameter ratio = 12.2

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT029_ALERT_3_B _diffrn_measured_fraction_theta_full Low .......       0.98

Alert level C
PLAT063_ALERT_3_C Crystal Probably too Large for Beam Size .......       0.70 mm
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N5     -   C4       =       5.30 su

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

   0 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
   2 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: SMART (Bruker,2001); cell refinement: SAINT (Bruker,2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXTL (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

3,3-bis(difluoroaminomethyl)oxetane

Crystal data

C5H8F4N2O	F(000) = 384
Mr = 188.13	Dx = 1.728 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 2766 reflections
a = 10.3304 (13) Å	θ = 2.9–28.5°
b = 10.6065 (13) Å	µ = 0.19 mm^−1
c = 6.8638 (8) Å	T = 93 K
β = 105.931 (2)°	Rounded chunk, colorless
V = 723.18 (15) Å^3	0.70 × 0.65 × 0.60 mm
Z = 4

Data collection

Bruker CCD area-detector diffractometer	877 independent reflections
Radiation source: fine-focus sealed tube	840 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.060
φ and ω scans	θmax = 28.2°, θmin = 2.8°
Absorption correction: integration (Wuensch & Prewitt, 1965)	h = −12→13
Tmin = 0.858, Tmax = 0.919	k = −14→14
2995 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: structure-invariant direct methods
R[F^2 > 2σ(F^2)] = 0.036	Hydrogen site location: difference Fourier map
wR(F^2) = 0.102	Only H-atom coordinates refined
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0627P)^2 + 0.609P] where P = (Fo^2 + 2Fc^2)/3
877 reflections	(Δ/σ)max = 0.002
72 parameters	Δρmax = 0.47 e Å^−3
0 restraints	Δρmin = −0.26 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 > 2σ(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
F5A	0.12220 (7)	0.42556 (7)	−0.04368 (11)	0.0225 (3)
F5B	0.23894 (7)	0.30290 (7)	0.19704 (11)	0.0214 (3)
O1	0.0000	−0.01437 (11)	0.2500	0.0202 (3)
C2	−0.10373 (11)	0.08116 (10)	0.18578 (17)	0.0160 (3)
H2A	−0.1480 (16)	0.0769 (14)	0.042 (3)	0.019*
H2B	−0.1717 (17)	0.0754 (13)	0.262 (3)	0.019*
C3	0.0000	0.18930 (13)	0.2500	0.0125 (3)
N5	0.11361 (9)	0.36818 (9)	0.13797 (14)	0.0161 (3)
C4	0.01238 (11)	0.26786 (10)	0.06953 (16)	0.0138 (3)
H4A	−0.0654 (16)	0.3128 (14)	0.009 (2)	0.017*
H4B	0.0346 (15)	0.2159 (14)	−0.026 (2)	0.017*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
F5A	0.0229 (4)	0.0209 (4)	0.0261 (4)	−0.0036 (3)	0.0110 (3)	0.0075 (3)
F5B	0.0110 (4)	0.0238 (4)	0.0284 (4)	−0.0008 (2)	0.0035 (3)	0.0017 (3)
O1	0.0200 (6)	0.0106 (5)	0.0306 (6)	0.000	0.0076 (5)	0.000
C2	0.0148 (5)	0.0116 (5)	0.0222 (6)	−0.0023 (4)	0.0060 (4)	−0.0001 (4)
C3	0.0105 (6)	0.0106 (7)	0.0172 (7)	0.000	0.0052 (5)	0.000
N5	0.0141 (5)	0.0155 (5)	0.0206 (5)	−0.0007 (3)	0.0076 (4)	0.0025 (3)
C4	0.0122 (5)	0.0131 (5)	0.0165 (5)	−0.0014 (4)	0.0048 (4)	−0.0001 (4)

Geometric parameters (Å, º)

F5A—N5	1.4120 (11)	C2—H2B	0.987 (17)
F5B—N5	1.4255 (11)	C3—C4	1.5271 (13)
O1—C2	1.4526 (13)	N5—C4	1.4754 (14)
C2—C3	1.5488 (14)	C4—H4A	0.929 (16)
C2—H2A	0.968 (16)	C4—H4B	0.931 (16)
C2^i—O1—C2	91.54 (11)	C2—C3—C2^i	84.45 (11)
O1—C2—C3	92.01 (8)	F5A—N5—F5B	100.85 (7)
O1—C2—H2A	112.3 (9)	F5A—N5—C4	103.92 (8)
C3—C2—H2A	114.9 (9)	F5B—N5—C4	104.44 (8)
O1—C2—H2B	111.6 (9)	N5—C4—C3	110.19 (8)
C3—C2—H2B	115.6 (9)	N5—C4—H4A	102.9 (9)
H2A—C2—H2B	109.5 (14)	C3—C4—H4A	113.0 (9)
C4^i—C3—C4	113.86 (12)	N5—C4—H4B	111.2 (9)
C4^i—C3—C2	115.43 (6)	C3—C4—H4B	109.8 (9)
C4—C3—C2	112.25 (6)	H4A—C4—H4B	109.7 (14)
C2^i—O1—C2—C3	0.0	F5B—N5—C4—C3	70.06 (10)
O1—C2—C3—C4^i	−112.03 (8)	C4^i—C3—C4—N5	47.35 (6)
O1—C2—C3—C4	115.24 (8)	C2—C3—C4—N5	−179.15 (8)
O1—C2—C3—C2^i	0.0	C2^i—C3—C4—N5	−84.63 (11)
F5A—N5—C4—C3	175.36 (7)

Symmetry code: (i) −x, y, −z+1/2.