4-[4-(4-Amino-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazol-3-yl]-1,2,5-oxadiazol-3-amine

Abstract

The complete molecule of the compound, C₆H₄N₈O₃, is generated by a crystallographic twofold rotation axis that runs through the central ring. The flanking ring is twisted by 20.2 (1)° with respect to the central ring. One of the amino H atoms forms an intra­molecular N—H⋯N hydrogen bond; adjacent mol­ecules are linked by N—H⋯N hydrogen bonds forming a chain running along [10-2].

Related literature  

For the synthesis, see: Kulikov & Kakhova (1994 ▶); Zhou et al. (2007 ▶).

Experimental  

Crystal data  

• C₆H₄N₈O₃

• M _r = 236.17

• Monoclinic,

• a = 7.1681 (9) Å

• b = 10.8147 (13) Å

• c = 12.3448 (18) Å

• β = 103.155 (1)°

• V = 931.9 (2) ų

• Z = 4

• Mo Kα radiation

• μ = 0.14 mm⁻¹

• T = 293 K

• 0.33 × 0.26 × 0.17 mm

Data collection  

• Bruker SMART APEX diffractometer

• 2675 measured reflections

• 1047 independent reflections

• 933 reflections with I > 2σ(I)

• R _int = 0.014

Refinement  

• R[F ² > 2σ(F ²)] = 0.031

• wR(F ²) = 0.096

• S = 1.08

• 1047 reflections

• 87 parameters

• All H-atom parameters refined

• Δρ_max = 0.28 e Å⁻³

• Δρ_min = −0.17 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: X-SEED (Barbour, 2001 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Supplementary material file. DOI: 10.1107/S1600536812017825/bt5881Isup3.cml

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
N4—H1⋯N1	0.90 (2)	2.37 (2)	2.932 (2)	121 (1)
N4—H2⋯N3i	0.87 (2)	2.23 (2)	3.070 (2)	162 (2)

Symmetry code: (i) .

supplementary crystallographic information

Comment

We are interested in N-heterocyclic compounds having few hydrogen atoms as these compounds are a source of explosives. In the title compound (Scheme I), the hydrogen atoms constitute an amino group. In NH₂–C₂N₂O–C₂N₂O–C₂N₂O–NH₂, two amino-subsituted 1,2,5-oxadiazole rings flanking a central 1,2,5-oxadiazole ring; the molecule lies on a twofold rotation axis that relates one flanking ring to the other (Fig. 1). The flanking ring is twisted by 20.2 (1) ° with respect to the central ring. One of the amino H atoms forms an intramolecular hydrogen bond; adjacent molecules are linked by an N–H···N hydrogen bond (Table 1, Fig. 2). to form a chain running along [1 0 -2].

Experimental

3,4-Bis(4'-aminofurazano-3')furoxan was synthesized by using a literature procedure (Zhou et al., 2007). The compound (7.5 g) was dissolved in acetic acid (30 ml). The solution was added to a reducing agent prepared from stannous chloride dihydrate (22.6 g. 100 mm mol) dissolved in acetic anhydride (20 ml), acetic acid (100 ml) and concentrated hydrochloric acid (20 ml). The reduction was performed according to an literature procedure (Kulikov & Kakhova, 1994). The mixture was heated atto 348 K for 8 h. The cool mixture was then poured into water (150 ml). The white precipitate that separated was collected and recrystallized from an ethyl acetate/ether mixture; yield 70%, m.pt. 456–457 K. The purity was established by HPLC to be 99.6%. CH&N elemental analysis. Calculated for C₆H₄N₈O₃ (%): C 30.51, N 47.46, H1.69. Found: C 30.41, N 47.58,H 1.61.

Refinement

The H-atoms were located in a difference Fourier map, and were refined freely.

Figures

Fig. 1.

Anisotropic displacement ellipsoid plot (Barbour, 2001) of C6H4N8O3 at the 50% probability level; hydrogen atoms are drawn as spheres of arbitrary radius. The molecule is located on a twofold rotation axis; symmetry-related atoms are not labeled.

Fig. 2.

Hydrogen-bonded chain structure. The intermolecular H bond is drawn as a dashed line, the intramolecular H bond is not shown.

Crystal data

C6H4N8O3	F(000) = 480
Mr = 236.17	Dx = 1.683 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 1575 reflections
a = 7.1681 (9) Å	θ = 3.4–27.7°
b = 10.8147 (13) Å	µ = 0.14 mm−1
c = 12.3448 (18) Å	T = 293 K
β = 103.155 (1)°	Prism, colorless
V = 931.9 (2) Å3	0.33 × 0.26 × 0.17 mm
Z = 4

Data collection

Bruker SMART APEX diffractometer	933 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.014
Graphite monochromator	θmax = 27.5°, θmin = 3.4°
ω scans	h = −9→9
2675 measured reflections	k = −14→13
1047 independent reflections	l = −15→8

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)] = 0.031	All H-atom parameters refined
wR(F2) = 0.096	w = 1/[σ2(Fo2) + (0.0566P)2 + 0.219P] where P = (Fo2 + 2Fc2)/3
S = 1.08	(Δ/σ)max < 0.001
1047 reflections	Δρmax = 0.28 e Å−3
87 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: 0.020 (3)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.0000	0.80892 (10)	0.7500	0.0471 (3)
O2	0.16242 (12)	0.35531 (8)	0.56878 (8)	0.0482 (3)
N1	0.09563 (14)	0.73719 (9)	0.68904 (8)	0.0431 (3)
N2	0.06415 (14)	0.41475 (9)	0.63634 (9)	0.0446 (3)
N3	0.29963 (15)	0.43342 (9)	0.54042 (9)	0.0453 (3)
N4	0.3974 (2)	0.63687 (11)	0.58898 (12)	0.0626 (4)
H1	0.372 (2)	0.7101 (14)	0.6165 (12)	0.059 (4)*
H2	0.480 (3)	0.6342 (15)	0.5474 (15)	0.064 (5)*
C1	0.06039 (15)	0.62259 (9)	0.71097 (9)	0.0349 (3)
C2	0.13553 (15)	0.52528 (10)	0.65104 (9)	0.0358 (3)
C3	0.28563 (16)	0.53785 (10)	0.59138 (10)	0.0393 (3)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0644 (8)	0.0324 (6)	0.0520 (7)	0.000	0.0291 (6)	0.000
O2	0.0540 (5)	0.0385 (5)	0.0600 (6)	−0.0051 (4)	0.0291 (4)	−0.0103 (4)
N1	0.0529 (6)	0.0356 (5)	0.0471 (6)	−0.0024 (4)	0.0248 (5)	−0.0011 (4)
N2	0.0460 (5)	0.0397 (5)	0.0549 (6)	−0.0046 (4)	0.0255 (5)	−0.0068 (4)
N3	0.0513 (6)	0.0401 (5)	0.0526 (6)	0.0004 (4)	0.0287 (5)	−0.0004 (4)
N4	0.0745 (8)	0.0423 (6)	0.0915 (10)	−0.0118 (5)	0.0614 (8)	−0.0088 (6)
C1	0.0364 (5)	0.0344 (5)	0.0373 (5)	−0.0010 (4)	0.0151 (4)	0.0007 (4)
C2	0.0374 (5)	0.0349 (6)	0.0390 (6)	−0.0004 (4)	0.0166 (4)	0.0010 (4)
C3	0.0435 (6)	0.0366 (6)	0.0436 (6)	0.0017 (4)	0.0223 (5)	0.0022 (4)

Geometric parameters (Å, º)

O1—N1i	1.3685 (11)	N4—C3	1.3419 (16)
O1—N1	1.3686 (11)	N4—H1	0.896 (16)
O2—N2	1.3684 (12)	N4—H2	0.871 (19)
O2—N3	1.4001 (13)	C1—C1i	1.434 (2)
N1—C1	1.3055 (14)	C1—C2	1.4582 (15)
N2—C2	1.2967 (15)	C2—C3	1.4419 (15)
N3—C3	1.3077 (15)
N1i—O1—N1	110.94 (11)	N1—C1—C2	117.95 (9)
N2—O2—N3	110.93 (8)	C1i—C1—C2	133.62 (6)
C1—N1—O1	106.22 (9)	N2—C2—C3	109.39 (10)
C2—N2—O2	106.07 (9)	N2—C2—C1	123.83 (9)
C3—N3—O2	105.40 (9)	C3—C2—C1	126.57 (10)
C3—N4—H1	121.5 (10)	N3—C3—N4	124.54 (11)
C3—N4—H2	118.5 (11)	N3—C3—C2	108.19 (10)
H1—N4—H2	118.6 (15)	N4—C3—C2	127.25 (11)
N1—C1—C1i	108.31 (6)
N1i—O1—N1—C1	0.18 (6)	N1—C1—C2—C3	17.47 (17)
N3—O2—N2—C2	−0.32 (13)	C1i—C1—C2—C3	−167.05 (15)
N2—O2—N3—C3	0.77 (13)	O2—N3—C3—N4	177.65 (12)
O1—N1—C1—C1i	−0.43 (14)	O2—N3—C3—C2	−0.87 (13)
O1—N1—C1—C2	176.12 (8)	N2—C2—C3—N3	0.73 (14)
O2—N2—C2—C3	−0.23 (13)	C1—C2—C3—N3	−174.16 (11)
O2—N2—C2—C1	174.83 (10)	N2—C2—C3—N4	−177.73 (13)
N1—C1—C2—N2	−156.72 (11)	C1—C2—C3—N4	7.4 (2)
C1i—C1—C2—N2	18.8 (2)

Symmetry code: (i) −x, y, −z+3/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N4—H1···N1	0.90 (2)	2.37 (2)	2.932 (2)	121 (1)
N4—H2···N3ii	0.87 (2)	2.23 (2)	3.070 (2)	162 (2)

Symmetry code: (ii) −x+1, −y+1, −z+1.