Crystal structure of 2-azido-1H-imidazole-4,5-di­carbo­nitrile

In the title compound, C₅HN₇, the nitrile and azido substituents are close to being coplanar with the central ring. Mol­ecules in the crystal are linked via an N—H⋯N hydrogen bond to a nitrile acceptor, forming a chain extending along the c-axis direction.

1. Related literature

For background to imidazole applications, see: Windaus & Vogt (1907); Katritzky et al. (2006); Epishina et al. (1967); Srinivas et al. (2014). For preparations, see: Sheppard & Webster (1973); Lu & Just (2001); Parrish et al. (2015).

2. Experimental

2.1. Crystal data

• C₅HN₇

• M_r = 159.13

• Monoclinic, P 2₁ /n

• a = 7.3217 (6) Å

• b = 12.8128 (11) Å

• c = 7.5202 (6) Å

• β = 102.215 (2)°

• V = 689.51 (10) ų

• Z = 4

• Mo Kα radiation

• μ = 0.11 mm⁻¹

• T = 100 K

• 0.36 × 0.24 × 0.10 mm

2.2. Data collection

• Bruker D8 Quest with CMOS diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2009) T_min = 0.960, T_max = 0.989

• 13020 measured reflections

• 2943 independent reflections

• 2535 reflections with I > 2σ(I)

• R_int = 0.024

2.3. Refinement

• R[F² > 2σ(F²)] = 0.036

• wR(F²) = 0.117

• S = 1.56

• 2943 reflections

• 112 parameters

• All H-atom parameters refined

• Δρ_max = 0.51 e Å⁻³

• Δρ_min = −0.25 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯N4^i	0.89 (2)	2.00 (2)	2.8572 (9)	160.9 (14)
Symmetry code: (i) x, y, z-1.

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: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: CHEMDRAW Ultra (Cambridge Soft, 2014).

Supporting information

S1. Comment

Imidazoles have a storied history in the pharmaceutical (Windaus et al., 1907), ionic liquid (Katritzky et al., 2006), and energetic materials communities (Epishina et al. 1967). Recently, the title compound, C₅HN₇, appeared in a study of imidazoles as potential gas generators (Srinivas et al., 2014). Given this background, we synthesized the title compound to examine the crystal structure, reported herein.

The entire molecule is essentially planar, with the maximum deviation indicated by the torsion angle in the ring atoms of 0.65 (7)° (C2—C1—N1—C3) and among the substituent groups, 176.76 (6)° (C3—N5—N6—N7) (Fig. 1). An intermolecular N1—H···N4 hydrogen bond involving a cyano N-atom acceptor (Table 1) generates a one-dimensional chain structure, extending along c (Fig. 2).

Related literature

For background to imidazole applications, see: Windaus & Vogt (1907); Katritzky et al. (2006); Epishina et al. (1967); Srinivas et al. (2014). For preparations, see: Sheppard & Webster (1973); Lu & Just (2001); Parrish et al. (2015).

S2. Experimental

To a stirred room temperature solution of sodium azide (4.40 g, 67.7 mmol) in water (100 ml) was added 2-diazo-4,5-dicyanoimidazole (4.05 g, 28.1 mmol) in portions (Sheppard & Webster, 1973; Lu & Just, 2001; Parrish et al., 2015). Vigorous effervescence of liberated nitrogen gas occurred with each addition. The reaction was allowed to stir for a further 90 min after gas evolution ceased and was then extracted with ethyl acetate (4 x 20 ml). The organic layer was dried over magnesium sulfate and the solvent was removed by rotary evaporation to afford a light yellow solid. Crystals of the title compound suitable for X-ray diffraction were obtained by crystallization from ethyl acetate.

S3. Refinement

The hydrogen atom was located in a difference-Fourier and the positional parameters were fully refined, with U_iso(H) set invariant at 0.08.

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: CHEMDRAW Ultra (Cambridge Soft, 2014).

Figures

	Fig. 1. The molecular structure of the title compound with atom labeling. Ellipsoids are drawn at the 50% probability level, and the hydrogen atom is drawn as a sphere of arbitrary size.
	Fig. 2. A crystal packing diagram of the title compound viewed along the b axis. The N—H···N hydrogen bond is shown as a dashed line.

2-Azido-1H-imidazole-4,5-dicarbonitrile

Crystal data

C5HN7	F(000) = 320
Mr = 159.13	Dx = 1.533 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 2943 reflections
a = 7.3217 (6) Å	θ = 3.2–35.1°
b = 12.8128 (11) Å	µ = 0.11 mm^−1
c = 7.5202 (6) Å	T = 100 K
β = 102.215 (2)°	Block, pale yellow
V = 689.51 (10) Å^3	0.36 × 0.24 × 0.10 mm
Z = 4

Data collection

Bruker D8 Quest with CMOS diffractometer	2943 independent reflections
Radiation source: fine-focus sealed tube	2535 reflections with I > 2σ(I)
Bruker Triumph curved graphite monochromator	Rint = 0.024
ω scans	θmax = 35.1°, θmin = 3.2°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −11→11
Tmin = 0.960, Tmax = 0.989	k = −20→19
13020 measured reflections	l = −12→12

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.117	All H-atom parameters refined
S = 1.56	w = 1/[σ^2(Fo^2) + (0.0562P)^2] where P = (Fo^2 + 2Fc^2)/3
2943 reflections	(Δ/σ)max = 0.001
112 parameters	Δρmax = 0.51 e Å^−3
0 restraints	Δρmin = −0.25 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 > 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
N1	0.95971 (8)	0.23656 (4)	0.20204 (8)	0.01244 (12)
H1	0.946 (2)	0.2147 (12)	0.087 (3)	0.080*
N3	0.79681 (9)	−0.00660 (5)	0.33122 (9)	0.01989 (14)
N4	0.97866 (9)	0.20303 (5)	0.83076 (8)	0.01915 (14)
N5	1.08587 (9)	0.39994 (5)	0.14988 (8)	0.01601 (13)
N6	1.15492 (9)	0.48197 (5)	0.22731 (9)	0.01800 (14)
N7	1.21954 (11)	0.55869 (5)	0.27860 (11)	0.02869 (17)
N2	1.05744 (8)	0.33629 (4)	0.44841 (8)	0.01346 (13)
C1	0.92901 (9)	0.17977 (5)	0.34810 (8)	0.01148 (13)
C2	0.98919 (9)	0.24295 (5)	0.49778 (8)	0.01203 (13)
C3	1.03672 (9)	0.32810 (5)	0.27026 (9)	0.01232 (13)
C4	0.85397 (9)	0.07743 (5)	0.33564 (9)	0.01397 (13)
C5	0.98406 (9)	0.22016 (5)	0.68201 (9)	0.01401 (14)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0156 (3)	0.0141 (3)	0.0079 (2)	0.00008 (18)	0.00303 (19)	0.00052 (17)
N3	0.0220 (3)	0.0172 (3)	0.0203 (3)	−0.0027 (2)	0.0043 (2)	−0.0015 (2)
N4	0.0240 (3)	0.0226 (3)	0.0118 (3)	−0.0040 (2)	0.0057 (2)	−0.0011 (2)
N5	0.0204 (3)	0.0149 (3)	0.0138 (3)	−0.00141 (19)	0.0059 (2)	0.00269 (19)
N6	0.0200 (3)	0.0162 (3)	0.0196 (3)	−0.0002 (2)	0.0082 (2)	0.0035 (2)
N7	0.0357 (4)	0.0186 (3)	0.0346 (4)	−0.0069 (3)	0.0137 (3)	−0.0007 (3)
N2	0.0162 (3)	0.0143 (3)	0.0104 (2)	−0.00187 (18)	0.00392 (19)	−0.00013 (18)
C1	0.0136 (3)	0.0123 (3)	0.0088 (3)	−0.0004 (2)	0.0029 (2)	0.00006 (19)
C2	0.0140 (3)	0.0136 (3)	0.0088 (3)	−0.0007 (2)	0.0033 (2)	−0.00039 (19)
C3	0.0132 (3)	0.0136 (3)	0.0107 (3)	0.0005 (2)	0.0036 (2)	0.0010 (2)
C4	0.0154 (3)	0.0159 (3)	0.0105 (3)	0.0004 (2)	0.0027 (2)	−0.0001 (2)
C5	0.0160 (3)	0.0154 (3)	0.0110 (3)	−0.0025 (2)	0.0038 (2)	−0.0021 (2)

Geometric parameters (Å, º)

N1—C3	1.3545 (8)	N6—N7	1.1232 (9)
N1—C1	1.3752 (8)	N2—C3	1.3202 (8)
N1—H1	0.893 (19)	N2—C2	1.3770 (9)
N3—C4	1.1530 (8)	C1—C2	1.3808 (9)
N4—C5	1.1489 (9)	C1—C4	1.4171 (9)
N5—N6	1.2549 (8)	C2—C5	1.4241 (9)
N5—C3	1.3907 (8)
C3—N1—C1	106.32 (5)	N2—C2—C1	111.15 (6)
C3—N1—H1	126.2 (11)	N2—C2—C5	121.75 (6)
C1—N1—H1	127.1 (10)	C1—C2—C5	127.10 (6)
N6—N5—C3	112.74 (6)	N2—C3—N1	113.73 (6)
N7—N6—N5	172.47 (8)	N2—C3—N5	128.17 (6)
C3—N2—C2	103.55 (5)	N1—C3—N5	118.09 (6)
N1—C1—C2	105.25 (6)	N3—C4—C1	177.65 (7)
N1—C1—C4	124.29 (6)	N4—C5—C2	179.07 (8)
C2—C1—C4	130.45 (6)
C3—N1—C1—C2	0.65 (7)	C2—N2—C3—N5	−178.86 (7)
C3—N1—C1—C4	−178.28 (6)	N6—N5—C3—N1	179.67 (6)
C1—N1—C3—N2	−0.56 (8)	N6—N5—C3—N2	−1.31 (11)
C1—N1—C3—N5	178.61 (6)	N1—C1—C2—N2	−0.56 (8)
C3—N2—C2—C1	0.24 (8)	N1—C1—C2—C5	178.90 (7)
C3—N2—C2—C5	−179.26 (6)	C4—C1—C2—N2	178.28 (7)
C2—N2—C3—N1	0.20 (8)	C4—C1—C2—C5	−2.26 (12)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N4^i	0.89 (2)	2.00 (2)	2.8572 (9)	160.9 (14)

Symmetry code: (i) x, y, z−1.