Crystal structure of 2-diazo­imidazole-4,5-dicarbo­nitrile

In the title compound, C₅N₆, all the atoms are approximately coplanar. In the crystal, mol­ecules are packed with short contact distances of 2.885 (2) (between the diazo N atom connected to the ring and a cyano N atom on a neighboring mol­ecule) and 3.012 (2) Å (between the terminal diazo N atom and an N atom of a neighboring imidazole ring).

1. Related literature

For synthesis of the title compound, see: Lu & Just (2001); Sheppard & Webster (1973). Few diazo-containing mol­ecules have been isolated, and of these, only a small number have been examined by X-ray diffraction, see: Daidone et al. (2005); Dippold et al. (2012). The majority of these compounds are found as diazo­nium ions, rather than the neutral diazo species, see: Bugg et al. (1964).

2. Experimental

2.1. Crystal data

• C₅N₆

• M_r = 144.11

• Trigonal, P 3₂ 21

• a = 8.0746 (3) Å

• c = 16.7315 (6) Å

• V = 944.73 (8) ų

• Z = 6

• Mo Kα radiation

• μ = 0.11 mm⁻¹

• T = 150 K

• 0.37 × 0.30 × 0.08 mm

2.2. Data collection

• Bruker SMART APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2008) T_min = 0.930, T_max = 0.991

• 9178 measured reflections

• 1289 independent reflections

• 1269 reflections with I > 2σ(I)

• R_int = 0.019

2.3. Refinement

• R[F² > 2σ(F²)] = 0.021

• wR(F²) = 0.058

• S = 1.09

• 1289 reflections

• 100 parameters

• Δρ_max = 0.14 e Å⁻³

• Δρ_min = −0.11 e Å⁻³

Data collection: APEX2 (Bruker, 2009); cell refinement: APEX2 and SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009) and XPREP (Bruker, 2008); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; 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

Diazo moieties are ubiquitious in organic chemistry due to their ability to act as as outstanding leaving groups in substitution reactions. This same reactivity also leads to their instability, and most are prone to decomposition, often violently. For this reason, few diazo-containing molecules have been isolated, and of these, only a small number have been examined by X-ray diffraction [Daidone et al. (2005), Dippold et al. (2012)]. The majority of these compounds are found as diazonium ions, rather than the neutral diazo species [Bugg et al. (1964)]. In contrast, the title compound has a neutral diazo moiety on C2 and is unusual in that it contains only carbon and nitrogen.

Related literature

For synthesis of the title compound, see: Lu & Just (2001); Sheppard & Webster (1973). For this reason, few diazo-containing molecules have been isolated, and of these, only a small number have been examined by X-ray diffraction, see: Daidone et al. (2005); Dippold et al. (2012). The majority of these compounds are found as diazonium ions, rather than the neutral diazo species, see: Bugg et al. (1964)

S2. Experimental

Caution! This compound can explode from slight friction, impact, or thermal shock. Although the explosion is not powerful, it is recommended that this material is only prepared in less than 5 gram quantities, handled wet, and not confined in any way.

The title compound was prepared by the literature method (Lu and Just, 2001). Crystals were obtained by slow evaporation of a dilute aqueous solution of the title compound.

S3. Refinement

The Flack parameter initially refined to 0.3 (5). Before the final refinement cycle, this parameter was reset to zero and the Friedel pairs merged.

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: APEX2 and SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009) and XPREP (Bruker, 2008); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (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 (displacement ellipsoids are drawn at the 50% probability level).
	Fig. 2. A packing diagram of the title compound viewed along the b axis. Close contacts are represented by dashed lines.

2-Diazoimidazole-4,5-dicarbonitrile

Crystal data

C5N6	Dx = 1.520 Mg m^−3
Mr = 144.11	Melting point: 413 K (expl.) K
Trigonal, P3221	Mo Kα radiation, λ = 0.71073 Å
a = 8.0746 (3) Å	µ = 0.11 mm^−1
c = 16.7315 (6) Å	T = 150 K
V = 944.73 (8) Å^3	Plate, purple
Z = 6	0.37 × 0.30 × 0.08 mm
F(000) = 432

Data collection

Bruker SMART APEXII CCD diffractometer	1269 reflections with I > 2σ(I)
Radiation source: fine focus sealed tube	Rint = 0.019
ω scans	θmax = 26.4°, θmin = 3.2°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −10→10
Tmin = 0.930, Tmax = 0.991	k = −10→10
9178 measured reflections	l = −20→20
1289 independent reflections

Refinement

Refinement on F^2	100 parameters
Least-squares matrix: full	0 restraints
R[F^2 > 2σ(F^2)] = 0.021	w = 1/[σ^2(Fo^2) + (0.0333P)^2 + 0.1041P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.058	(Δ/σ)max = 0.001
S = 1.09	Δρmax = 0.14 e Å^−3
1289 reflections	Δρmin = −0.11 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	0.61645 (16)	0.00825 (16)	0.93835 (6)	0.0254 (3)
C2	0.7396 (2)	0.16549 (19)	0.89882 (7)	0.0226 (3)
N3	0.91448 (16)	0.28157 (17)	0.92732 (6)	0.0239 (3)
C4	0.90565 (19)	0.18858 (19)	0.99570 (7)	0.0225 (3)
C5	0.72502 (19)	0.02197 (19)	1.00215 (7)	0.0240 (3)
N6	0.68567 (16)	0.20682 (16)	0.82574 (6)	0.0238 (3)
N7	0.6461 (2)	0.23873 (19)	0.76756 (7)	0.0329 (3)
C8	1.0629 (2)	0.2582 (2)	1.05016 (7)	0.0258 (3)
N9	1.18839 (19)	0.3094 (2)	1.09341 (7)	0.0351 (3)
C10	0.6572 (2)	−0.1202 (2)	1.06366 (8)	0.0299 (3)
N11	0.6055 (2)	−0.2345 (2)	1.11254 (8)	0.0441 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0235 (6)	0.0266 (6)	0.0250 (5)	0.0117 (5)	−0.0016 (4)	−0.0005 (5)
C2	0.0241 (6)	0.0255 (6)	0.0200 (5)	0.0138 (5)	−0.0021 (5)	−0.0011 (5)
N3	0.0234 (6)	0.0258 (6)	0.0226 (5)	0.0125 (5)	−0.0006 (4)	−0.0012 (4)
C4	0.0223 (6)	0.0251 (6)	0.0223 (6)	0.0135 (5)	−0.0002 (5)	−0.0022 (5)
C5	0.0237 (6)	0.0266 (6)	0.0237 (6)	0.0140 (6)	0.0002 (4)	−0.0005 (5)
N6	0.0231 (6)	0.0256 (6)	0.0244 (5)	0.0136 (5)	−0.0005 (4)	−0.0020 (4)
N7	0.0370 (7)	0.0425 (8)	0.0282 (6)	0.0265 (6)	−0.0027 (5)	−0.0003 (5)
C8	0.0266 (7)	0.0298 (7)	0.0239 (6)	0.0161 (6)	0.0024 (5)	−0.0005 (5)
N9	0.0310 (7)	0.0467 (8)	0.0306 (6)	0.0216 (6)	−0.0070 (5)	−0.0064 (5)
C10	0.0240 (7)	0.0324 (7)	0.0314 (7)	0.0127 (6)	−0.0020 (5)	0.0025 (6)
N11	0.0362 (7)	0.0456 (8)	0.0451 (8)	0.0164 (7)	−0.0007 (6)	0.0179 (6)

Geometric parameters (Å, º)

N1—C2	1.3327 (18)	C4—C8	1.4297 (18)
N1—C5	1.3502 (16)	C5—C10	1.4314 (18)
C2—N3	1.3325 (18)	N6—N7	1.0946 (15)
C2—N6	1.3936 (15)	C8—N9	1.1415 (19)
N3—C4	1.3507 (17)	C10—N11	1.144 (2)
C4—C5	1.4094 (18)
C2—N1—C5	99.75 (11)	C5—C4—C8	128.18 (12)
N3—C2—N1	121.08 (11)	N1—C5—C4	109.72 (11)
N3—C2—N6	119.59 (12)	N1—C5—C10	122.03 (12)
N1—C2—N6	119.33 (12)	C4—C5—C10	128.23 (12)
C2—N3—C4	99.74 (11)	N7—N6—C2	178.50 (12)
N3—C4—C5	109.70 (11)	N9—C8—C4	178.23 (16)
N3—C4—C8	122.12 (13)	N11—C10—C5	178.82 (17)
C5—N1—C2—N3	−0.01 (16)	C2—N1—C5—C4	0.36 (14)
C5—N1—C2—N6	178.72 (11)	C2—N1—C5—C10	−178.37 (13)
N1—C2—N3—C4	−0.34 (16)	N3—C4—C5—N1	−0.61 (16)
N6—C2—N3—C4	−179.07 (11)	C8—C4—C5—N1	179.57 (12)
C2—N3—C4—C5	0.53 (14)	N3—C4—C5—C10	178.02 (13)
C2—N3—C4—C8	−179.64 (12)	C8—C4—C5—C10	−1.8 (2)