Pitfalls of data mining: triclinic polymorph of 2,2-aziridinedicarboxamide revisited

Podsiadło, M.; Dziubek, K.; Katrusiak, A.

doi:10.1107/S0108768106045344

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Pitfalls of data mining: triclinic polymorph of 2,2-aziridinedicarboxamide revisited

M. Podsiadło, K. Dziubek and A. Katrusiak

Several procedures have been employed for validating structural models refined on poor quality single-crystal diffraction data. Analysis of intra- and intermolecular distances in the structures of 2,2-aziridinedicarboxamide polymorphs proved to be a robust means, and a means independent of the chosen unit cell and symmetry, of detecting several incorrect atom-type assignments in the reported structure of the triclinic polymorph of 2,2-aziridinedicarboxamide [Brückner (1982). Acta Cryst. B38, 2405–2408]. The corrected model, refined in the space group $P\overline 1$ , rules out the existence of any conformational polymorphism in this compound. Small differences in the powder-diffraction patterns calculated for the original and corrected structures of the triclinic polymorph illustrate the sensitivity of the above method for polymorph validation.

Keywords: data validation; polymorphism; intermolecular contacts.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768106045344/av5079sup1.cif Contains datablock bipcos
	Structure factor file (CIF format) https://doi.org/10.1107/S0108768106045344/av5079sup2.hkl Contains datablock bipcos

CCDC reference: 637750

Computing details top

Program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1990); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures top

2,2-aziridinedicarboxamide top

Crystal data top

C₄H₇N₃O₂	Z = 16
M_r = 129.13	F(000) = 1088
Triclinic, P1	D_x = 1.479 Mg m⁻³
a = 15.829 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 12.381 (2) Å	Cell parameters from 5683 reflections
c = 12.391 (2) Å	θ = 4–22.2°
α = 90.0 (1)°	µ = 0.12 mm⁻¹
β = 74.3 (1)°	T = 293 K
γ = 83.1 (1)°	× × mm
V = 2319.5 (6) Å³

Data collection top

Philips PW1100 diffractometer	R_int = 0.000
Radiation source: fine-focus sealed tube	θ_max = 22.2°, θ_min = 3.1°
Graphite monochromator	h = −15→16
5683 measured reflections	k = −12→12
5683 independent reflections	l = 0→12
2534 reflections with > 2.5σ(I)

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.095	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.218	H atoms treated by a mixture of independent and constrained refinement
S = 1.21	w = 1/[σ²(F_o²) + (0.0337P)² + 35.3943P] where P = (F_o² + 2F_c²)/3
2534 reflections	(Δ/σ)_max < 0.001
585 parameters	Δρ_max = 0.49 e Å⁻³
24 restraints	Δρ_min = −0.38 e Å⁻³

Crystal data top

C₄H₇N₃O₂	γ = 83.1 (1)°
M_r = 129.13	V = 2319.5 (6) Å³
Triclinic, P1	Z = 16
a = 15.829 (2) Å	Mo Kα radiation
b = 12.381 (2) Å	µ = 0.12 mm⁻¹
c = 12.391 (2) Å	T = 293 K
α = 90.0 (1)°	× × mm
β = 74.3 (1)°

Data collection top

Philips PW1100 diffractometer	2534 reflections with > 2.5σ(I)
5683 measured reflections	R_int = 0.000
5683 independent reflections	θ_max = 22.2°

Refinement top

R[F² > 2σ(F²)] = 0.095	24 restraints
wR(F²) = 0.218	H atoms treated by a mixture of independent and constrained refinement
S = 1.21	w = 1/[σ²(F_o²) + (0.0337P)² + 35.3943P] where P = (F_o² + 2F_c²)/3
2534 reflections	Δρ_max = 0.49 e Å⁻³
585 parameters	Δρ_min = −0.38 e Å⁻³

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	U_iso*/U_eq
O1H	0.0979 (8)	1.0024 (8)	−0.3911 (10)	0.043 (3)
O2H	0.1325 (8)	0.7014 (8)	−0.5616 (10)	0.045 (3)
N1H	0.0966 (11)	0.8065 (12)	−0.2757 (13)	0.045 (4)
H1H	0.0646 (17)	0.8695 (17)	−0.2452 (15)	0.054*
N2H	0.1001 (8)	0.9223 (11)	−0.5517 (12)	0.032 (4)*
H21H	0.0886	0.9831	−0.5814	0.038*
H22H	0.1072	0.8621	−0.5896	0.038*
N3H	0.1033 (9)	0.6203 (10)	−0.4003 (12)	0.038 (4)
H31H	0.1062	0.5589	−0.4344	0.046*
H32H	0.0919	0.6238	−0.3284	0.046*
C1H	0.1901 (12)	0.8074 (14)	−0.3333 (14)	0.046 (5)
H11H	0.2296	0.7406	−0.3359	0.055*
H12H	0.2160	0.8736	−0.3274	0.055*
C2H	0.1230 (11)	0.8099 (12)	−0.4013 (16)	0.033 (5)
C3H	0.1072 (11)	0.9212 (13)	−0.4466 (15)	0.031 (4)*
C4H	0.1160 (10)	0.7076 (12)	−0.4573 (14)	0.024 (4)*
O1G	0.0957 (8)	0.5003 (8)	−0.1760 (10)	0.043 (3)
O2G	0.1335 (7)	0.1991 (8)	−0.0278 (9)	0.033 (3)*
N1G	0.0937 (10)	0.3074 (11)	−0.2901 (10)	0.035 (4)
H1G	0.0641 (16)	0.3721 (15)	−0.299 (2)	0.043*
N2G	0.0992 (11)	0.4204 (11)	−0.0166 (11)	0.048 (5)
H21G	0.0879	0.4818	0.0201	0.058*
H22G	0.1065	0.3608	0.0173	0.058*
N3G	0.1024 (10)	0.1190 (10)	−0.1747 (12)	0.051 (5)
H31G	0.1019	0.0569	−0.1435	0.061*
H32G	0.0925	0.1254	−0.2394	0.061*
C1G	0.1869 (12)	0.3031 (15)	−0.2987 (15)	0.052 (6)
H11G	0.2151	0.3675	−0.3236	0.063*
H12G	0.2240	0.2346	−0.3235	0.063*
C2G	0.1228 (10)	0.3087 (12)	−0.1855 (14)	0.025 (4)*
C3G	0.1055 (13)	0.4177 (12)	−0.1245 (16)	0.042 (5)
C4G	0.1187 (11)	0.2055 (13)	−0.1225 (15)	0.033 (5)*
O1F	0.1248 (7)	0.4165 (9)	−0.5259 (10)	0.042 (3)*
O2F	0.0909 (8)	0.1257 (8)	−0.6732 (10)	0.042 (3)
N1F	0.0942 (10)	0.3189 (12)	−0.7867 (13)	0.047 (5)*
H1F	0.0691 (14)	0.2659 (18)	−0.8113 (17)	0.056*
N2F	0.1036 (10)	0.5037 (11)	−0.6783 (12)	0.051 (5)
H21F	0.1057	0.5662	−0.6496	0.062*
H22F	0.0955	0.4991	−0.7440	0.062*
N3F	0.0960 (8)	0.2047 (11)	−0.5159 (11)	0.037 (4)*
H31F	0.0847	0.1475	−0.4779	0.044*
H32F	0.1039	0.2625	−0.4834	0.044*
C1F	0.1867 (10)	0.2897 (15)	−0.7943 (15)	0.046 (5)*
H11F	0.2262	0.3442	−0.8196	0.056*
H12F	0.2124	0.2154	−0.8176	0.056*
C2F	0.1211 (11)	0.3082 (12)	−0.6815 (14)	0.029 (4)
C3F	0.1129 (11)	0.4135 (13)	−0.6209 (15)	0.031 (4)
C4F	0.1010 (11)	0.2037 (13)	−0.6202 (14)	0.031 (4)
O1E	0.1297 (8)	−0.0845 (8)	−0.0638 (10)	0.041 (3)
O2E	0.0929 (9)	−0.3772 (8)	0.1108 (9)	0.047 (4)
N1E	0.0974 (10)	−0.1834 (11)	0.2202 (11)	0.036 (4)
H1E	0.0674 (18)	−0.2347 (19)	0.2590 (15)	0.043*
N2E	0.1009 (11)	0.0016 (10)	0.1078 (12)	0.054 (5)
H21E	0.0980	0.0659	0.0817	0.065*
H22E	0.0931	−0.0064	0.1786	0.065*
N3E	0.1010 (11)	−0.2984 (10)	−0.0555 (12)	0.051 (5)
H31E	0.0888	−0.3555	−0.0847	0.062*
H32E	0.1104	−0.2415	−0.0946	0.062*
C1E	0.1900 (13)	−0.2125 (15)	0.1651 (15)	0.055 (6)
H11E	0.2157	−0.2867	0.1707	0.067*
H12E	0.2293	−0.1578	0.1631	0.067*
C2E	0.1250 (12)	−0.1944 (12)	0.0998 (14)	0.030 (4)
C3E	0.1179 (11)	−0.0879 (12)	0.0367 (15)	0.030 (4)
C4E	0.1055 (15)	−0.2981 (14)	0.0478 (16)	0.054 (6)
O1D	0.5925 (10)	0.3756 (10)	0.8318 (10)	0.066 (4)
O2D	0.6116 (12)	0.2171 (12)	0.5250 (11)	0.087 (6)
N1D	0.5895 (9)	0.4931 (10)	0.6503 (11)	0.029 (4)
H1D	0.5592 (18)	0.5184 (14)	0.7198 (14)	0.034*
N2D	0.6175 (9)	0.2127 (12)	0.7432 (13)	0.049 (4)*
H21D	0.6136	0.1808	0.8057	0.059*
H22D	0.6278	0.1746	0.6819	0.059*
N3D	0.5970 (9)	0.3768 (10)	0.4513 (10)	0.034 (4)
H31D	0.5913	0.3461	0.3919	0.041*
H32D	0.5950	0.4464	0.4559	0.041*
C1D	0.6805 (12)	0.4571 (13)	0.6118 (14)	0.048 (6)
H11D	0.7164	0.4662	0.6627	0.058*
H12D	0.7097	0.4670	0.5335	0.058*
C2D	0.6189 (10)	0.3728 (13)	0.6380 (13)	0.027 (4)
C3D	0.6080 (10)	0.3168 (12)	0.7413 (13)	0.023 (4)*
C4D	0.6084 (13)	0.3204 (16)	0.5310 (15)	0.047 (5)
O1C	0.6012 (9)	0.5928 (11)	0.3248 (9)	0.054 (4)
O2C	0.6197 (11)	0.7499 (10)	0.0179 (10)	0.075 (5)
N1C	0.5990 (10)	0.4781 (10)	0.1310 (12)	0.038 (4)
H1C	0.5772 (16)	0.4599 (16)	0.2026 (13)	0.046*
N2C	0.6210 (8)	0.7507 (11)	0.2373 (12)	0.034 (4)*
H21C	0.6130	0.7853	0.3001	0.041*
H22C	0.6317	0.7850	0.1756	0.041*
N3C	0.6028 (9)	0.5947 (10)	−0.0556 (10)	0.036 (4)
H31C	0.5980	0.6266	−0.1158	0.043*
H32C	0.5994	0.5261	−0.0499	0.043*
C1C	0.6978 (11)	0.4867 (14)	0.1023 (16)	0.053 (6)
H11C	0.7326	0.4708	0.0253	0.064*
H12C	0.7285	0.4668	0.1587	0.064*
C2C	0.6266 (10)	0.5900 (13)	0.1268 (13)	0.025 (4)
C3C	0.6169 (10)	0.6472 (12)	0.2354 (13)	0.023 (4)*
C4C	0.6145 (10)	0.6486 (14)	0.0239 (13)	0.030 (4)*
O1B	0.6152 (13)	0.2527 (11)	0.2408 (11)	0.095 (6)
O2B	0.5956 (10)	0.0896 (10)	−0.0473 (10)	0.062 (4)
N1B	0.5904 (10)	−0.0176 (12)	0.1509 (11)	0.037 (4)
H1B	0.5594 (17)	−0.0320 (17)	0.103 (2)	0.044*
N2B	0.5922 (9)	0.0979 (10)	0.3323 (10)	0.038 (4)
H21B	0.5931	0.1268	0.3950	0.046*
H22B	0.5840	0.0307	0.3286	0.046*
N3B	0.6130 (8)	0.2498 (12)	0.0292 (12)	0.038 (4)*
H31B	0.6087	0.2851	−0.0292	0.045*
H32B	0.6211	0.2832	0.0858	0.045*
C1B	0.6797 (11)	−0.0073 (13)	0.1132 (16)	0.055 (6)
H11B	0.7095	−0.0278	0.0354	0.066*
H12B	0.7154	−0.0241	0.1649	0.066*
C2B	0.6195 (11)	0.0891 (13)	0.1350 (14)	0.032 (4)
C3B	0.6030 (13)	0.1551 (16)	0.2443 (14)	0.044 (5)
C4B	0.6075 (11)	0.1469 (12)	0.0321 (14)	0.036 (5)
O1A	0.6186 (12)	0.7136 (10)	−0.2637 (11)	0.091 (6)
O2A	0.6017 (9)	0.8785 (11)	−0.5547 (10)	0.060 (4)
N1A	0.6020 (11)	0.9898 (12)	−0.3696 (12)	0.048 (5)
H1A	0.5844 (15)	1.0219 (11)	−0.426 (2)	0.058*
N2A	0.6019 (8)	0.8751 (11)	−0.1747 (10)	0.026 (3)*
H21A	0.5949	0.8447	−0.1110	0.032*
H22A	0.6000	0.9447	−0.1781	0.032*
N3A	0.6167 (8)	0.7140 (11)	−0.4759 (11)	0.031 (4)*
H31A	0.6111	0.6801	−0.5336	0.038*
H32A	0.6246	0.6782	−0.4193	0.038*
C1A	0.6971 (11)	0.9471 (13)	−0.3970 (17)	0.046 (5)
H11A	0.7278	0.9542	−0.3398	0.055*
H12A	0.7327	0.9525	−0.4735	0.055*
C2A	0.6278 (11)	0.8732 (12)	−0.3763 (13)	0.031 (4)
C3A	0.6153 (14)	0.8164 (14)	−0.2650 (15)	0.055 (6)
C4A	0.6134 (10)	0.8163 (11)	−0.4743 (13)	0.025 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1H	0.057 (9)	0.025 (6)	0.047 (8)	−0.010 (6)	−0.014 (7)	−0.005 (6)
O2H	0.084 (10)	0.014 (6)	0.040 (8)	−0.005 (6)	−0.024 (7)	0.000 (5)
N1H	0.059 (12)	0.038 (10)	0.044 (11)	0.002 (8)	−0.026 (9)	−0.001 (8)
N3H	0.056 (10)	0.031 (8)	0.035 (10)	−0.017 (7)	−0.018 (8)	0.012 (7)
C1H	0.062 (15)	0.038 (11)	0.052 (13)	−0.012 (10)	−0.038 (12)	0.013 (9)
C2H	0.042 (12)	0.019 (9)	0.042 (12)	−0.004 (8)	−0.021 (10)	0.013 (8)
O1G	0.077 (10)	0.016 (6)	0.045 (8)	−0.011 (6)	−0.030 (7)	0.001 (6)
N1G	0.072 (12)	0.030 (9)	0.011 (7)	−0.002 (7)	−0.024 (7)	0.001 (6)
N2G	0.114 (14)	0.023 (8)	0.017 (9)	−0.025 (8)	−0.026 (8)	0.011 (6)
N3G	0.123 (15)	0.015 (7)	0.032 (9)	−0.011 (8)	−0.052 (10)	0.004 (7)
C1G	0.077 (17)	0.037 (11)	0.042 (12)	0.005 (10)	−0.020 (11)	−0.010 (9)
C3G	0.086 (16)	0.007 (9)	0.039 (13)	−0.008 (9)	−0.028 (11)	0.000 (8)
O2F	0.064 (9)	0.025 (6)	0.044 (8)	−0.007 (6)	−0.024 (7)	−0.008 (6)
N2F	0.099 (14)	0.026 (8)	0.032 (10)	−0.011 (8)	−0.022 (9)	0.005 (7)
C2F	0.044 (12)	0.028 (9)	0.019 (9)	−0.001 (8)	−0.016 (8)	0.004 (7)
C3F	0.034 (11)	0.033 (10)	0.029 (11)	0.002 (8)	−0.015 (9)	0.001 (8)
C4F	0.038 (12)	0.039 (11)	0.022 (10)	−0.001 (8)	−0.023 (8)	−0.001 (8)
O1E	0.078 (10)	0.023 (6)	0.022 (7)	0.002 (6)	−0.015 (7)	0.004 (5)
O2E	0.093 (10)	0.017 (6)	0.028 (7)	−0.010 (6)	−0.011 (7)	0.006 (6)
N1E	0.055 (11)	0.035 (9)	0.016 (8)	−0.003 (7)	−0.006 (8)	0.002 (7)
N2E	0.120 (15)	0.024 (8)	0.025 (9)	0.005 (8)	−0.040 (9)	−0.009 (7)
N3E	0.131 (15)	0.010 (7)	0.035 (10)	−0.009 (8)	−0.060 (10)	0.007 (6)
C1E	0.096 (19)	0.038 (11)	0.050 (13)	−0.008 (11)	−0.050 (13)	0.003 (10)
C2E	0.057 (13)	0.027 (9)	0.014 (10)	−0.012 (8)	−0.018 (9)	−0.008 (7)
C3E	0.042 (12)	0.016 (9)	0.027 (11)	0.014 (7)	−0.010 (9)	−0.010 (8)
C4E	0.106 (18)	0.027 (10)	0.032 (12)	−0.020 (10)	−0.019 (11)	0.006 (9)
O1D	0.138 (14)	0.021 (7)	0.047 (8)	−0.004 (7)	−0.042 (8)	−0.003 (6)
O2D	0.211 (19)	0.038 (9)	0.027 (8)	−0.016 (9)	−0.061 (10)	−0.003 (6)
N1D	0.045 (10)	0.016 (8)	0.019 (8)	−0.001 (7)	0.000 (7)	−0.008 (6)
N3D	0.077 (11)	0.012 (7)	0.031 (8)	−0.013 (7)	−0.043 (8)	0.012 (7)
C1D	0.075 (16)	0.033 (11)	0.027 (11)	−0.017 (11)	0.006 (10)	0.005 (8)
C2D	0.028 (10)	0.024 (10)	0.035 (10)	−0.006 (8)	−0.017 (8)	−0.015 (8)
C4D	0.063 (14)	0.035 (13)	0.043 (13)	0.005 (10)	−0.019 (10)	−0.006 (11)
O1C	0.086 (11)	0.054 (9)	0.033 (7)	−0.031 (8)	−0.026 (7)	0.010 (7)
O2C	0.182 (16)	0.023 (7)	0.041 (8)	−0.022 (8)	−0.061 (9)	0.010 (6)
N1C	0.055 (11)	0.012 (8)	0.036 (9)	0.001 (7)	0.005 (8)	0.003 (7)
N3C	0.071 (11)	0.014 (8)	0.025 (8)	−0.004 (7)	−0.018 (7)	−0.008 (6)
C1C	0.054 (14)	0.037 (11)	0.071 (15)	0.019 (10)	−0.032 (12)	−0.014 (10)
C2C	0.027 (10)	0.030 (10)	0.025 (9)	−0.013 (8)	−0.017 (8)	0.025 (8)
O1B	0.25 (2)	0.024 (8)	0.042 (9)	−0.033 (10)	−0.080 (11)	0.011 (6)
O2B	0.125 (13)	0.039 (8)	0.038 (8)	−0.024 (8)	−0.047 (8)	0.005 (7)
N1B	0.053 (11)	0.042 (10)	0.025 (9)	−0.021 (8)	−0.022 (8)	0.005 (7)
N2B	0.080 (12)	0.011 (7)	0.025 (8)	0.000 (7)	−0.018 (8)	−0.002 (6)
C1B	0.091 (18)	0.017 (10)	0.041 (12)	0.020 (10)	−0.002 (11)	0.003 (8)
C2B	0.049 (12)	0.011 (9)	0.039 (11)	−0.003 (8)	−0.019 (9)	−0.013 (8)
C3B	0.075 (15)	0.042 (12)	0.022 (11)	0.010 (10)	−0.031 (10)	−0.003 (9)
C4B	0.051 (12)	0.011 (9)	0.035 (11)	−0.010 (8)	0.011 (9)	−0.002 (8)
O1A	0.24 (2)	0.011 (7)	0.051 (9)	−0.017 (9)	−0.092 (11)	0.009 (6)
O2A	0.095 (11)	0.047 (9)	0.034 (8)	0.009 (8)	−0.019 (7)	0.002 (7)
N1A	0.080 (13)	0.029 (10)	0.034 (10)	−0.012 (8)	−0.009 (9)	0.002 (8)
C1A	0.033 (12)	0.039 (11)	0.077 (14)	0.003 (10)	−0.037 (11)	−0.006 (10)
C2A	0.054 (12)	0.009 (9)	0.026 (10)	−0.003 (8)	−0.005 (8)	0.010 (7)
C3A	0.115 (19)	0.024 (11)	0.040 (12)	−0.018 (11)	−0.043 (12)	0.013 (9)
C4A	0.035 (11)	0.006 (8)	0.032 (10)	−0.005 (7)	−0.006 (8)	0.002 (8)

Geometric parameters (Å, º) top

O1H—C3H	1.189 (18)	O1D—C3D	1.288 (18)
O2H—C4H	1.248 (18)	O2D—C4D	1.27 (2)
N1H—C1H	1.46 (2)	N1D—C1D	1.41 (2)
N1H—C2H	1.50 (2)	N1D—C2D	1.501 (19)
N2H—C3H	1.34 (2)	N2D—C3D	1.281 (19)
N3H—C4H	1.298 (18)	N3D—C4D	1.25 (2)
C1H—C2H	1.52 (2)	C1D—C2D	1.49 (2)
C2H—C4H	1.47 (2)	C2D—C3D	1.43 (2)
C2H—C3H	1.51 (2)	C2D—C4D	1.53 (2)
O1G—C3G	1.222 (18)	O1C—C3C	1.278 (18)
O2G—C4G	1.258 (19)	O2C—C4C	1.268 (19)
N1G—C1G	1.44 (2)	N1C—C2C	1.50 (2)
N1G—C2G	1.49 (2)	N1C—C1C	1.52 (2)
N2G—C3G	1.31 (2)	N2C—C3C	1.291 (18)
N3G—C4G	1.338 (19)	N3C—C4C	1.257 (19)
C1G—C2G	1.49 (2)	C1C—C2C	1.57 (2)
C2G—C3G	1.51 (2)	C2C—C3C	1.48 (2)
C2G—C4G	1.50 (2)	C2C—C4C	1.51 (2)
O1F—C3F	1.243 (19)	O1B—C3B	1.25 (2)
O2F—C4F	1.218 (17)	O2B—C4B	1.279 (19)
N1F—C1F	1.443 (19)	N1B—C1B	1.385 (19)
N1F—C2F	1.48 (2)	N1B—C2B	1.45 (2)
N2F—C3F	1.34 (2)	N2B—C3B	1.28 (2)
N3F—C4F	1.273 (19)	N3B—C4B	1.288 (19)
C1F—C2F	1.50 (2)	C1B—C2B	1.41 (2)
C2F—C3F	1.48 (2)	C2B—C4B	1.51 (2)
C2F—C4F	1.52 (2)	C2B—C3B	1.53 (2)
O1E—C3E	1.210 (18)	O1A—C3A	1.27 (2)
O2E—C4E	1.254 (19)	O2A—C4A	1.298 (18)
N1E—C2E	1.44 (2)	N1A—C1A	1.48 (2)
N1E—C1E	1.44 (2)	N1A—C2A	1.45 (2)
N2E—C3E	1.371 (19)	N2A—C3A	1.29 (2)
N3E—C4E	1.30 (2)	N3A—C4A	1.261 (18)
C1E—C2E	1.47 (2)	C1A—C2A	1.48 (2)
C2E—C4E	1.54 (2)	C2A—C3A	1.52 (2)
C2E—C3E	1.54 (2)	C2A—C4A	1.49 (2)

C1H—N1H—C2H	61.9 (11)	C1D—N1D—C2D	61.6 (10)
N1H—C1H—C2H	60.4 (11)	N1D—C1D—C2D	62.3 (11)
C4H—C2H—N1H	113.6 (13)	C3D—C2D—C4D	122.6 (16)
C4H—C2H—C3H	124.1 (16)	C3D—C2D—C1D	119.6 (14)
N1H—C2H—C3H	114.5 (14)	C4D—C2D—C1D	111.6 (16)
C4H—C2H—C1H	117.8 (14)	C3D—C2D—N1D	115.2 (13)
N1H—C2H—C1H	57.8 (11)	C4D—C2D—N1D	113.7 (14)
C3H—C2H—C1H	111.1 (14)	C1D—C2D—N1D	56.1 (10)
O1H—C3H—N2H	122.3 (16)	N2D—C3D—O1D	121.2 (15)
O1H—C3H—C2H	122.3 (17)	N2D—C3D—C2D	121.6 (15)
N2H—C3H—C2H	115.4 (15)	O1D—C3D—C2D	117.1 (15)
O2H—C4H—N3H	119.3 (15)	O2D—C4D—N3D	120.5 (17)
O2H—C4H—C2H	119.9 (14)	O2D—C4D—C2D	118.3 (17)
N3H—C4H—C2H	120.3 (16)	N3D—C4D—C2D	121.2 (18)
C1G—N1G—C2G	61.0 (11)	C2C—N1C—C1C	62.6 (10)
N1G—C1G—C2G	61.0 (11)	N1C—C1C—C2C	57.9 (9)
C3G—C2G—N1G	115.0 (14)	C3C—C2C—N1C	117.2 (13)
C3G—C2G—C4G	120.9 (16)	C3C—C2C—C4C	122.9 (15)
N1G—C2G—C4G	115.7 (14)	N1C—C2C—C4C	111.9 (13)
C3G—C2G—C1G	115.1 (15)	C3C—C2C—C1C	114.0 (13)
N1G—C2G—C1G	58.0 (10)	N1C—C2C—C1C	59.5 (10)
C4G—C2G—C1G	116.4 (14)	C4C—C2C—C1C	115.0 (15)
O1G—C3G—N2G	122.2 (15)	N2C—C3C—O1C	122.2 (15)
O1G—C3G—C2G	119.2 (17)	N2C—C3C—C2C	119.1 (14)
N2G—C3G—C2G	118.6 (15)	O1C—C3C—C2C	118.6 (14)
O2G—C4G—N3G	121.7 (15)	O2C—C4C—N3C	121.5 (15)
O2G—C4G—C2G	122.0 (15)	O2C—C4C—C2C	119.4 (15)
N3G—C4G—C2G	116.3 (16)	N3C—C4C—C2C	119.0 (16)
C1F—N1F—C2F	61.6 (11)	C1B—N1B—C2B	59.7 (11)
N1F—C1F—C2F	60.3 (11)	N1B—C1B—C2B	62.3 (11)
N1F—C2F—C1F	58.0 (10)	C1B—C2B—N1B	58.0 (10)
N1F—C2F—C3F	113.1 (14)	C1B—C2B—C4B	114.9 (15)
C1F—C2F—C3F	118.5 (15)	N1B—C2B—C4B	116.3 (13)
N1F—C2F—C4F	114.8 (14)	C1B—C2B—C3B	120.5 (15)
C1F—C2F—C4F	113.6 (14)	N1B—C2B—C3B	113.4 (15)
C3F—C2F—C4F	122.1 (15)	C4B—C2B—C3B	118.9 (15)
O1F—C3F—N2F	122.1 (16)	N2B—C3B—O1B	125.0 (16)
O1F—C3F—C2F	120.5 (15)	N2B—C3B—C2B	114.4 (17)
N2F—C3F—C2F	116.9 (16)	O1B—C3B—C2B	119.4 (16)
O2F—C4F—N3F	124.6 (16)	O2B—C4B—N3B	124.9 (17)
O2F—C4F—C2F	118.5 (15)	O2B—C4B—C2B	117.7 (14)
N3F—C4F—C2F	116.9 (15)	N3B—C4B—C2B	117.3 (16)
C2E—N1E—C1E	61.4 (11)	C1A—N1A—C2A	60.8 (11)
N1E—C1E—C2E	59.2 (11)	N1A—C1A—C2A	58.5 (10)
N1E—C2E—C1E	59.4 (11)	N1A—C2A—C1A	60.7 (10)
N1E—C2E—C4E	116.5 (14)	N1A—C2A—C3A	116.3 (14)
C1E—C2E—C4E	114.8 (15)	C1A—C2A—C3A	113.6 (16)
N1E—C2E—C3E	115.8 (13)	N1A—C2A—C4A	114.8 (14)
C1E—C2E—C3E	119.7 (14)	C1A—C2A—C4A	118.3 (14)
C4E—C2E—C3E	117.7 (15)	C3A—C2A—C4A	119.6 (14)
O1E—C3E—N2E	124.7 (15)	O1A—C3A—N2A	122.1 (16)
O1E—C3E—C2E	123.7 (14)	O1A—C3A—C2A	119.5 (16)
N2E—C3E—C2E	111.5 (15)	N2A—C3A—C2A	118.5 (16)
O2E—C4E—N3E	124.2 (16)	N3A—C4A—O2A	125.3 (15)
O2E—C4E—C2E	116.3 (16)	N3A—C4A—C2A	119.3 (15)
N3E—C4E—C2E	119.4 (15)	O2A—C4A—C2A	115.3 (13)

Experimental details

Crystal data
Chemical formula	C₄H₇N₃O₂
M_r	129.13
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	15.829 (2), 12.381 (2), 12.391 (2)
α, β, γ (°)	90.0 (1), 74.3 (1), 83.1 (1)
V (Å³)	2319.5 (6)
Z	16
Radiation type	Mo Kα
µ (mm⁻¹)	0.12
Crystal size (mm)	× ×

Data collection
Diffractometer	Philips PW1100 diffractometer
Absorption correction	–
No. of measured, independent and observed [ > 2.5σ(I)] reflections	5683, 5683, 2534
R_int	0.000
θ_max (°)	22.2
(sin θ/λ)_max (Å⁻¹)	0.532

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.095, 0.218, 1.21
No. of reflections	2534
No. of parameters	585
No. of restraints	24
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
	w = 1/[σ²(F_o²) + (0.0337P)² + 35.3943P] where P = (F_o² + 2F_c²)/3
Δρ_max, Δρ_min (e Å⁻³)	0.49, −0.38

Computer programs: SHELXL97 (Sheldrick, 1997), XP (Siemens, 1990).

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