Azido­acet­amide, a neutral small organic azide

The structure of the title compound, C₂H₄N₄O, was determined and found to be almost planar, excluding H atoms. The N-N bond lengths of 1.130 (2) and 1.231 (2) Å in the azide group exhibited a resonance effect and the characteristic organic azide structure.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.001 Å
• R factor = 0.050
• wR factor = 0.095
• Data-to-parameter ratio = 10.6

checkCIF results

No syntax errors found



ADDSYM reports no extra symmetry


 Alert Level A:



DIFF_020  Alert A _diffrn_standards_interval_count and
          _diffrn_standards_interval_time are missing. Number of measurements
          between standards or time (min) between standards.


 Alert Level B:



ABSMU_01  Alert B The ratio of given/expected absorption coefficient lies
          outside the range 0.95 <> 1.05
          Calculated value of mu =     0.124
          Value of mu given      =     0.130


 Alert Level C:



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           26.40
         From the CIF: _reflns_number_total                848
         TEST2: Reflns within _diffrn_reflns_theta_max
         Count of symmetry unique reflns          910
         Completeness (_total/calc)             93.19%
          Alert C: < 95% complete


 1 Alert Level A = Potentially serious problem

 1 Alert Level B = Potential problem

 1 Alert Level C = Please check

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S1. Comment

Azide compounds constitute a category of energetic materials. Since their properties are of great interest, much effort has been devoted to clarify their decomposition processes, conformation and molecular structures with molecular orbital calculations. However, there have been few experimental studies of the molecular structures in crystals, since azide compounds are potentially explosive and it is difficult to safely treat crystals. In this study, the structure determination of the title compound, azidoacetamide, (I), was carried out to obtain more knowledge about azide compounds.

Azidoacetamide is the smallest compound of the neutral organic azides whose crystal structures have been determined. In this study, it was revealed that non-H atoms were close to planar as the maximum deviation from the least-squares plane was <0.184 Å.

Azideacetamide easily releases the N6—N7 part as a nitrogen molecule. However, the N6—N7 bond length of 1.130 (2) Å is longer than the N≡N bond length of 1.0977 Å (Sasada, 1984). The N5—N6 bond length of 1.231 (2) Å is slightly shorter than the N═N bond length of 1.247 Å in azomethane (CH₃N═NCH₃) (Sasada, 1984). Therefore, the bond lengths are influenced by the resonance effect.

Table 4 summarizes the bond lengths and angles of the azide groups in organic azide compounds whose structures have already been determined. In C₃N₃(N₃)₃ (Knaggs, 1935) and [(H₂N)₂CN₃]Cl (Henke & Bärnighausen, 1972), the conjugated systems were extended over the molecules. CH₃N₃ (Livingston & Rao, 1960) is the archetypical alkyl azide. Since the table indicates that the bond lengths in azide groups are almost the same, it could be said that these parameters would be characteristic of organic azide compounds.

The molecular arrangement indicates that two acetamide groups are favourably located so that the H atoms form hydrogen bonds in the bc plane. The O···HN distances are typical hydrogen-bond distances. The same interactions can be found in the intramolecular N5···H3B—N3 arrangement. However, H3B is not in an effective position to form a hydrogen bond. Therefore, H3B—N3 is shorter than H3A—N3.

S2. Experimental

Chloroacetamide and sodium azide were mixed in water and stirred until the water evaporated. The residue was dissolved in acetone and the solution filtered and allowed to evaporate. Azidoacetamide was obtained as colourless crystals. Single crystals were prepared by recrystallization from benzene.

S3. Refinement

The H atoms were refined and the C—H and N—H distances are in the range 0.89 (2)–1.01 (1) Å. The H–atom U_iso values are <0.038 Ų.

Computing details

Data collection: DIP Image Plate Control Software (MacScience, 1992); cell refinement: MAC-DENZO (Otwinowski & Minor, 1996); data reduction: maXus (Mackay et al., 1997); program(s) used to solve structure: maXus; program(s) used to refine structure: maXus; molecular graphics: maXus; software used to prepare material for publication: maXus.

Figures

Azidoacetamide

Crystal data

C2H4N4O	Dx = 1.509 Mg m^−3
Mr = 100.08	Mo Kα radiation, λ = 0.71073 Å
Monoclinic, P21/n	Cell parameters from 192 reflections
a = 6.648 (4) Å	θ = 1.0–26.4°
b = 5.1190 (9) Å	µ = 0.13 mm^−1
c = 13.124 (5) Å	T = 100 K
β = 99.36 (2)°	Prism, colourless
V = 440.7 (5) Å^3	0.2 × 0.2 × 0.2 mm
Z = 4

Data collection

DIP Image Plate diffractometer	Rint = 0.029
φ scans	θmax = 26.4°
1544 measured reflections	h = 0→8
848 independent reflections	k = −6→6
848 reflections with I > 0	l = −16→16

Refinement

Refinement on F^2	All H-atom parameters refined
R[F^2 > 2σ(F^2)] = 0.050	Weighting scheme based on measured s.u.'s w = 1/[σ^2(Fo) + 0.03Fo^2]
wR(F^2) = 0.095	(Δ/σ)max < 0.001
S = 1.14	Δρmax = 0.22 e Å^−3
848 reflections	Δρmin = −0.29 e Å^−3
80 parameters

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

	x	y	z	Uiso*/Ueq
O1	0.7318 (1)	0.0469 (1)	0.13075 (4)	0.0258 (3)
N3	0.7744 (1)	0.4839 (1)	0.14557 (6)	0.0169 (3)
N5	0.7519 (1)	0.5552 (1)	−0.05640 (5)	0.0231 (4)
N6	0.6982 (1)	0.5954 (1)	−0.14931 (6)	0.0206 (3)
N7	0.6518 (1)	0.6566 (2)	−0.23253 (6)	0.0368 (4)
C2	0.7489 (1)	0.2646 (1)	0.09127 (6)	0.0135 (3)
C4	0.7399 (2)	0.2802 (1)	−0.02374 (6)	0.0165 (4)
H3A	0.772 (2)	0.482 (2)	0.2186 (8)	0.028 (3)*
H3B	0.777 (2)	0.635 (2)	0.1125 (8)	0.038 (3)*
H4A	0.610 (2)	0.196 (2)	−0.0601 (7)	0.028 (2)*
H4B	0.857 (2)	0.181 (2)	−0.0425 (8)	0.036 (3)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0551 (5)	0.0086 (2)	0.0121 (3)	0.0008 (3)	0.0015 (3)	0.0025 (2)
N3	0.0321 (5)	0.0089 (3)	0.0088 (4)	−0.0024 (3)	0.0023 (3)	−0.0016 (2)
N5	0.0421 (5)	0.0162 (3)	0.0099 (4)	−0.0035 (3)	0.0024 (3)	0.0036 (3)
N6	0.0266 (5)	0.0173 (3)	0.0179 (4)	0.0022 (3)	0.0075 (3)	0.0048 (3)
N7	0.0508 (7)	0.0381 (4)	0.0203 (5)	0.0041 (4)	0.0039 (4)	0.0149 (3)
C2	0.0194 (5)	0.0112 (3)	0.0091 (4)	0.0012 (3)	−0.0007 (3)	−0.0005 (3)
C4	0.0281 (5)	0.0102 (3)	0.0104 (4)	0.0008 (3)	0.0020 (3)	0.0007 (3)

Geometric parameters (Å, º)

O1—C2	1.242 (1)	C2—C4	1.503 (2)
N3—C2	1.326 (1)	N3—H3A	0.96 (2)
N5—N6	1.231 (2)	N3—H3B	0.89 (2)
N5—C4	1.478 (1)	C4—H4A	1.01 (1)
N6—N7	1.130 (2)	C4—H4B	0.99 (2)
O1···N3^i	2.899 (1)	N7···H4B^v	2.946 (9)
O1···N3^ii	2.960 (1)	C2···H3A^ii	2.906 (9)
O1···H3A^ii	2.01 (1)	H3A···H3A^ii	2.72 (1)
O1···H3B^i	2.15 (1)	H3A···H3A^vii	2.72 (1)
O1···H4A^iii	2.626 (9)	H3A···H3B^ii	2.90 (1)
N6···N7^iv	2.991 (1)	H3B···H4A^vi	2.70 (1)
N7···N7^iv	2.943 (1)	H3B···H4B^viii	2.90 (1)
N7···N7^v	2.943 (1)	H4B···H4B^ix	2.76 (1)
N7···H3A^vi	2.94 (1)
N6—N5—C4	115.2 (1)	C2—N3—H3B	119.1 (7)
N5—N6—N7	173.5 (1)	H3A—N3—H3B	119.9 (9)
O1—C2—N3	123.2 (1)	N5—C4—H4A	110.6 (5)
O1—C2—C4	118.4 (1)	N5—C4—H4B	109.6 (6)
N3—C2—C4	118.4 (1)	C2—C4—H4A	110.1 (6)
N5—C4—C2	110.3 (1)	C2—C4—H4B	108.5 (6)
C2—N3—H3A	120.5 (5)	H4A—C4—H4B	107.8 (8)
N6—N5—C4—C2	−163.6 (1)	N6—N5—C4—H4A	−41.6 (6)
O1—C2—C4—N5	176.9 (1)	N6—N5—C4—H4B	77.1 (7)
N3—C2—C4—N5	−2.9 (1)	O1—C2—C4—H4A	54.7 (6)
H3A—N3—C2—O1	−4.1 (7)	O1—C2—C4—H4B	−63.0 (7)
H3A—N3—C2—C4	175.8 (7)	N3—C2—C4—H4A	−125.2 (6)
H3B—N3—C2—O1	−175.6 (8)	N3—C2—C4—H4B	117.1 (7)
H3B—N3—C2—C4	4.3 (8)

Symmetry codes: (i) x, y−1, z; (ii) −x+3/2, y−1/2, −z+1/2; (iii) −x+1, −y, −z; (iv) −x+3/2, y−1/2, −z−1/2; (v) −x+3/2, y+1/2, −z−1/2; (vi) −x+1, −y+1, −z; (vii) −x+3/2, y+1/2, −z+1/2; (viii) −x+2, −y+1, −z; (ix) −x+2, −y, −z.

Hydrogen-bond geometry (Å)

D—H···A	D—H	H···A	D···A
N3^ii—H3A^ii···O1	0.96 (2)	2.01 (1)	2.960 (1)
N3^i—H3B^i···O1	0.89 (2)	2.15 (1)	2.899 (1)
N3—H3B···N5	0.89 (2)	2.23 (1)	2.656 (1)

Symmetry codes: (i) x, y−1, z; (ii) −x+3/2, y−1/2, −z+1/2.