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The molecule of title compound, C2H7N3O2, has a zwitterionic structure. All non-H atoms, apart from the terminal N atom of the NH3 group, lie in the same plane, with a maximum deviation of 0.056 (1) Å for the amine N atom of the nitramine group, whereas the deviation of the terminal N atom of the NH3 group from the same plane is 1.222 (2) Å. Intermolecular hydrogen bonds within the crystal form a three-dimensional network.
Supporting information
CCDC reference: 174835
Compound (I) was synthesized as described by Astachov et al.
(2000b).
H atoms were located on a difference Fourier map and refined as riding, with a
common isotropic displacement parameter of 0.032 Å2 for CH2 groups and
0.039 Å2 for the NH3 group. C—H distances were constrained to 0.97 Å
and N—H distances to 0.935 Å.
Data collection: KM-4 Software (Kuma, 1991); cell refinement: KM-4 Software; data reduction: DATARED in KM-4 Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1995); software used to prepare material for publication: SHELXL97.
1-Amino-2-nitraminoethane
top
Crystal data top
C2H7N3O2 | Z = 2 |
Mr = 105.11 | F(000) = 112 |
Triclinic, P1 | Dx = 1.563 Mg m−3 |
a = 4.3449 (2) Å | Cu Kα radiation, λ = 1.5418 Å |
b = 6.2955 (3) Å | Cell parameters from 25 reflections |
c = 8.5432 (5) Å | θ = 27–35° |
α = 105.240 (5)° | µ = 1.17 mm−1 |
β = 92.743 (4)° | T = 293 K |
γ = 96.356 (4)° | Lump, colourless |
V = 223.36 (2) Å3 | 0.36 × 0.32 × 0.27 mm |
Data collection top
Kuma KM-4 diffractometer | Rint = 0.029 |
Radiation source: fine-focus sealed tube | θmax = 64.8°, θmin = 5.4° |
Graphite monochromator | h = −5→5 |
θ/2θ scans | k = −7→7 |
814 measured reflections | l = 0→9 |
756 independent reflections | 2 standard reflections every 40 reflections |
685 reflections with I > 2σ(I) | intensity decay: no decay, variation 0.4% |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.029 | H-atom parameters constrained |
wR(F2) = 0.082 | w = 1/[σ2(Fo2) + (0.0534P)2 + 0.0467P] where P = (Fo2 + 2Fc2)/3 |
S = 1.02 | (Δ/σ)max = 0.002 |
756 reflections | Δρmax = 0.21 e Å−3 |
67 parameters | Δρmin = −0.14 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.135 (10) |
Crystal data top
C2H7N3O2 | γ = 96.356 (4)° |
Mr = 105.11 | V = 223.36 (2) Å3 |
Triclinic, P1 | Z = 2 |
a = 4.3449 (2) Å | Cu Kα radiation |
b = 6.2955 (3) Å | µ = 1.17 mm−1 |
c = 8.5432 (5) Å | T = 293 K |
α = 105.240 (5)° | 0.36 × 0.32 × 0.27 mm |
β = 92.743 (4)° | |
Data collection top
Kuma KM-4 diffractometer | Rint = 0.029 |
814 measured reflections | 2 standard reflections every 40 reflections |
756 independent reflections | intensity decay: no decay, variation 0.4% |
685 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.029 | 0 restraints |
wR(F2) = 0.082 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.21 e Å−3 |
756 reflections | Δρmin = −0.14 e Å−3 |
67 parameters | |
Special details top
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 (Å2) top | x | y | z | Uiso*/Ueq | |
N1 | 0.0237 (2) | 0.32208 (17) | 0.21151 (12) | 0.0220 (3) | |
O1 | −0.1902 (2) | 0.21586 (15) | 0.09892 (11) | 0.0333 (3) | |
O2 | 0.0966 (2) | 0.23165 (16) | 0.32042 (12) | 0.0359 (3) | |
N2 | 0.1460 (2) | 0.51362 (17) | 0.20486 (12) | 0.0240 (3) | |
C1 | 0.3897 (3) | 0.6137 (2) | 0.33447 (15) | 0.0250 (3) | |
H1 | 0.5417 | 0.5121 | 0.3352 | 0.032* | |
H2 | 0.3015 | 0.6457 | 0.4391 | 0.032* | |
C2 | 0.5438 (3) | 0.8261 (2) | 0.30539 (16) | 0.0264 (4) | |
H3 | 0.3949 | 0.9320 | 0.3161 | 0.032* | |
H4 | 0.7145 | 0.8897 | 0.3877 | 0.032* | |
N3 | 0.6629 (2) | 0.78806 (17) | 0.14224 (13) | 0.0241 (3) | |
H5 | 0.8118 | 0.6899 | 0.1328 | 0.039* | |
H6 | 0.7533 | 0.9230 | 0.1282 | 0.039* | |
H7 | 0.4989 | 0.7272 | 0.0625 | 0.039* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.0224 (6) | 0.0211 (5) | 0.0250 (6) | 0.0040 (4) | 0.0037 (4) | 0.0100 (4) |
O1 | 0.0337 (6) | 0.0291 (5) | 0.0350 (6) | −0.0072 (4) | −0.0085 (4) | 0.0116 (4) |
O2 | 0.0423 (6) | 0.0316 (6) | 0.0395 (6) | −0.0009 (4) | −0.0047 (4) | 0.0235 (5) |
N2 | 0.0259 (6) | 0.0210 (6) | 0.0272 (6) | 0.0011 (4) | 0.0012 (4) | 0.0109 (4) |
C1 | 0.0272 (7) | 0.0264 (7) | 0.0226 (7) | 0.0030 (5) | 0.0018 (5) | 0.0089 (5) |
C2 | 0.0292 (7) | 0.0220 (6) | 0.0254 (7) | 0.0005 (5) | 0.0029 (5) | 0.0031 (5) |
N3 | 0.0248 (6) | 0.0210 (6) | 0.0270 (6) | −0.0003 (4) | 0.0012 (4) | 0.0088 (4) |
Geometric parameters (Å, º) top
N1—O2 | 1.2571 (14) | C2—N3 | 1.4794 (16) |
N1—N2 | 1.2794 (15) | C2—H3 | 0.9700 |
N1—O1 | 1.2942 (14) | C2—H4 | 0.9700 |
N2—C1 | 1.4551 (16) | N3—H5 | 0.9350 |
C1—C2 | 1.5136 (17) | N3—H6 | 0.9350 |
C1—H1 | 0.9700 | N3—H7 | 0.9350 |
C1—H2 | 0.9700 | | |
| | | |
O2—N1—N2 | 124.29 (10) | N3—C2—H3 | 109.2 |
O2—N1—O1 | 118.17 (10) | C1—C2—H3 | 109.2 |
N2—N1—O1 | 117.53 (10) | N3—C2—H4 | 109.2 |
N1—N2—C1 | 112.56 (10) | C1—C2—H4 | 109.2 |
N2—C1—C2 | 108.58 (10) | H3—C2—H4 | 107.9 |
N2—C1—H1 | 110.0 | C2—N3—H5 | 109.5 |
C2—C1—H1 | 110.0 | C2—N3—H6 | 109.5 |
N2—C1—H2 | 110.0 | H5—N3—H6 | 109.5 |
C2—C1—H2 | 110.0 | C2—N3—H7 | 109.5 |
H1—C1—H2 | 108.4 | H5—N3—H7 | 109.5 |
N3—C2—C1 | 112.00 (10) | H6—N3—H7 | 109.5 |
| | | |
O2—N1—N2—C1 | 2.25 (16) | N1—N2—C1—C2 | 173.66 (10) |
O1—N1—N2—C1 | −178.19 (9) | N2—C1—C2—N3 | −55.64 (13) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H5···N2i | 0.94 | 2.09 | 2.976 (2) | 159 |
N3—H6···O1ii | 0.94 | 1.92 | 2.822 (2) | 163 |
N3—H7···O1iii | 0.94 | 2.00 | 2.832 (2) | 147 |
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1, z; (iii) −x, −y+1, −z. |
Experimental details
Crystal data |
Chemical formula | C2H7N3O2 |
Mr | 105.11 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 4.3449 (2), 6.2955 (3), 8.5432 (5) |
α, β, γ (°) | 105.240 (5), 92.743 (4), 96.356 (4) |
V (Å3) | 223.36 (2) |
Z | 2 |
Radiation type | Cu Kα |
µ (mm−1) | 1.17 |
Crystal size (mm) | 0.36 × 0.32 × 0.27 |
|
Data collection |
Diffractometer | Kuma KM-4 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 814, 756, 685 |
Rint | 0.029 |
(sin θ/λ)max (Å−1) | 0.587 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.029, 0.082, 1.02 |
No. of reflections | 756 |
No. of parameters | 67 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.21, −0.14 |
Selected geometric parameters (Å, º) topN1—O2 | 1.2571 (14) | N2—C1 | 1.4551 (16) |
N1—N2 | 1.2794 (15) | C1—C2 | 1.5136 (17) |
N1—O1 | 1.2942 (14) | C2—N3 | 1.4794 (16) |
| | | |
O2—N1—N2 | 124.29 (10) | N1—N2—C1 | 112.56 (10) |
O2—N1—O1 | 118.17 (10) | N2—C1—C2 | 108.58 (10) |
N2—N1—O1 | 117.53 (10) | N3—C2—C1 | 112.00 (10) |
| | | |
O2—N1—N2—C1 | 2.25 (16) | N1—N2—C1—C2 | 173.66 (10) |
O1—N1—N2—C1 | −178.19 (9) | N2—C1—C2—N3 | −55.64 (13) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H5···N2i | 0.935 | 2.09 | 2.976 (2) | 159 |
N3—H6···O1ii | 0.935 | 1.92 | 2.822 (2) | 163 |
N3—H7···O1iii | 0.935 | 2.00 | 2.832 (2) | 147 |
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1, z; (iii) −x, −y+1, −z. |
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Aminonitramines are of interest as biologically active non-protein amino acids (Alston et al., 1981; Nilsson et al., 1983) and as a new class of energetic compounds (Astachov et al., 2000a). The zwitterionic nature of aminonitramines was established on the basis of indirect physical and chemical investigations (McKay et al., 1954). Here, we present an X-ray structure determination of 1-amino-2-nitraminoethane, (I), which belongs to the same class of compounds. \sch
The present study unambiguously confirms the zwitterionic structure of (I). Fig. 1 provides a view of the crystal packing with the numbering scheme; selected molecular bond lengths and angles are given in Table 1. The C2—N3 bond length is in accord with that of various salts of organic amines (1.474–1.480 Å; Allen & Kennard, 1993; Georg et al., 1991; Burgess et al., 1991). The N—N bond length of the molecular nitramine part is shorter, and N—O bond lengths are longer, than the corresponding values in primary nitramines (N—N 1.301, and N—O 1.236 and 1.240 Å in 1,2-dinitraminoethane; Turley, 1968). As a whole, the nitramine fragment and bond lengths in (I) are close to the values characteristic of onium salts of primary nitramines (N—N 1.273 and N—O 1.283 Å in the dihydrazinium salt of 1,2-dinitraminoethane; Allen & Kennard, 1993; Bircher et al., 1996).
In the structure of (I), atom O1 forms two short hydrogen bonds with atoms H6 and H7 of two neighbouring molecules. The second oxygen, O2, is not involved in any hydrogen-bonding contacts. As a consequence, there is a significant difference in N—O bond lengths in (I) compared with both 1,2-dinitraminoethane (Turley, 1968) and its dihydrazine salt (Bircher et al., 1996). An intermolecular N3—H5···N2 hydrogen bond (Table 2) completes the picture of molecular packing.
From the established bond length values, it is difficult to fix the negative charge unambiguously on any atom of the nitramine part of the molecule. By analogy with salts of primary nitramines (Avakyan, 1971), the anion charge is rather delocalized over the whole nitramine fragment, but the electron density is distributed unevenly: the negative charge on atom O1 exceeds that on atoms N2 and O2.
In conclusion, the zwitterionic structure of aminonitramines, and of (I) in particular, leads to an increase in intermolecular interaction (crystal lattice energy) and, as a consequence, to an increase in thermal stability and the density of the compounds in comparison with the primary nitramines (Astachov et al., 2000a; Astachov, 1999).