HAR, TAAM and BODD refinements of model crystal structures using Cu Kα and Mo Kα X-ray diffraction data

The Independent Atom Model (IAM) of electron density is used in routine X-ray data analysis. However, this model does not give a quantitative description of the electron-density distribution. A better model that allows for modelling of aspherical charge density deformations is introduced by the Hansen–Coppens variant of the multipole model of electron density. However, the application of this model requires crystals of excellent quality and high-resolution XRD data which are quite often difficult criteria to fulfil. Therefore, Mo Kα and Cu Kα data of three model com­pounds (tricyclic imide, xylitol and methyl­uracil) were refined using IAM and new methods which enabled the refinement and reconstruction of charge density based on the Cu Kα data. These methods were the Bond-Oriented Deformation Density (BODD) model, Hirshfeld Atom Refinement (HAR) and the Transferable Aspherical Atom Model (TAAM). The final results were compared to the model obtained from neutron diffraction experiments. Our results demonstrated not only that Cu Kα data may be refined using BODD, HAR and TAAM methods, but also revealed systematic errors arising from the use of Cu Kα data. These errors were a result of the limited information in the low-resolution data set that manifested as higher values for the anisotropic displacement parameters (ADPs) and smaller maxima and minima of the residual electron density for the Cu Kα data com­pared to the Mo Kα data. Notably, these systematic errors were much less significant than those found for the IAM. Therefore, the application of BODD, HAR and TAAM on Cu Kα data has a more significant influence on the final results of refinement than for the Mo Kα data.

Computing details

Data collection: CrysAlis PRO (Agilent, 2014) for 1Cu, 2Cu, 3Cu, 3Mo; SXD2001 (Gutmann, 2005) for 1Neu. Cell refinement: CrysAlis PRO (Agilent, 2014) for 1Cu, 2Cu, 3Cu, 3Mo. Data reduction: CrysAlis PRO (Agilent, 2014) for 1Cu, 2Cu, 3Cu, 3Mo; SXD2001 (Gutmann, 2005) for 1Neu. Program(s) used to solve structure: SHELXS97 (Sheldrick, 2008) for 1Cu, 2Cu, 3Cu, 3Mo. Program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015) for 1Cu, 2Cu, 3Cu, 3Mo; SHELXL97 (Sheldrick, 2008) for 1Neu. Molecular graphics: OLEX2 (Dolomanov et al., 2009) for 1Cu, 2Cu, 3Cu, 3Mo. Software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009) for 1Cu, 2Cu, 3Cu, 3Mo.

10-Oxa-4-azatricyclo[5.2.1.0^2,6]dec-8-ene-3,5-dione (1Cu)

Crystal data

C10H11NO3	F(000) = 408
Mr = 193.20	Dx = 1.413 Mg m^−3
Monoclinic, P21/c	Cu Kα radiation, λ = 1.54184 Å
a = 8.6896 (1) Å	Cell parameters from 25673 reflections
b = 10.8910 (1) Å	θ = 4.6–71.4°
c = 9.5960 (1) Å	µ = 0.88 mm^−1
β = 90.075 (1)°	T = 100 K
V = 908.15 (2) Å^3	Block
Z = 4	0.34 × 0.26 × 0.17 mm

Data collection

Agilent SuperNova Dual four-circle diffractometer with an Atlas detector	1767 independent reflections
Radiation source: sealed X-ray tube, SuperNova (Cu) X-ray Source	1728 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.029
Detector resolution: 5.2195 pixels mm^-1	θmax = 71.5°, θmin = 5.1°
ω scans	h = −10→10
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014)	k = −13→13
Tmin = 0.700, Tmax = 1.000	l = −11→11
31209 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.034	H-atom parameters constrained
wR(F^2) = 0.085	w = 1/[σ^2(Fo^2) + (0.0388P)^2 + 0.509P] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max < 0.001
1767 reflections	Δρmax = 0.27 e Å^−3
128 parameters	Δρmin = −0.28 e Å^−3
0 restraints

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

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

	x	y	z	Uiso*/Ueq
O1	0.36276 (10)	0.47007 (8)	0.14418 (9)	0.0164 (2)
O3	0.16094 (9)	0.19482 (7)	−0.03330 (8)	0.0137 (2)
O2	0.57726 (10)	0.16063 (8)	−0.10936 (9)	0.0182 (2)
N1	0.48504 (11)	0.33324 (9)	−0.00031 (10)	0.0142 (2)
H1N	0.535717	0.386282	−0.048234	0.017*
C9	0.03590 (13)	0.34783 (11)	0.11652 (12)	0.0159 (3)
H9A	0.077065	0.410264	0.054872	0.019*
H9B	0.038878	0.380120	0.210689	0.019*
C6	0.38508 (13)	0.36508 (11)	0.10480 (12)	0.0131 (2)
C1	0.49639 (13)	0.20788 (11)	−0.02167 (12)	0.0138 (2)
C3	0.14991 (13)	0.02619 (11)	0.11128 (12)	0.0165 (3)
H3	0.139093	−0.057373	0.128658	0.020*
C5	0.13690 (13)	0.23569 (10)	0.10900 (12)	0.0127 (2)
C4	0.08248 (13)	0.11771 (11)	0.17867 (12)	0.0154 (3)
H4	0.015253	0.111223	0.253643	0.018*
C2	0.24825 (13)	0.08589 (10)	0.00010 (12)	0.0143 (3)
H2	0.274586	0.033390	−0.079308	0.017*
C10	−0.13125 (14)	0.32263 (12)	0.07646 (14)	0.0219 (3)
H10A	−0.135305	0.290738	−0.016732	0.033*
H10B	−0.189111	0.397597	0.081215	0.033*
H10C	−0.174416	0.263710	0.139726	0.033*
C8	0.30909 (13)	0.24969 (10)	0.15899 (12)	0.0127 (2)
H8	0.319697	0.241068	0.260207	0.015*
C7	0.38819 (13)	0.14403 (10)	0.07896 (12)	0.0136 (3)
H7	0.440862	0.085721	0.140461	0.016*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0192 (4)	0.0116 (4)	0.0183 (4)	−0.0013 (3)	0.0033 (3)	−0.0014 (3)
O3	0.0160 (4)	0.0131 (4)	0.0120 (4)	0.0007 (3)	0.0017 (3)	−0.0014 (3)
O2	0.0160 (4)	0.0166 (4)	0.0220 (4)	0.0012 (3)	0.0057 (3)	−0.0021 (3)
N1	0.0143 (5)	0.0117 (5)	0.0166 (5)	−0.0017 (4)	0.0042 (4)	0.0009 (4)
C9	0.0154 (6)	0.0136 (6)	0.0187 (6)	0.0009 (4)	0.0023 (4)	−0.0008 (5)
C6	0.0126 (5)	0.0137 (6)	0.0131 (5)	−0.0007 (4)	−0.0011 (4)	0.0005 (4)
C1	0.0122 (5)	0.0135 (6)	0.0156 (6)	0.0003 (4)	−0.0010 (4)	0.0006 (4)
C3	0.0173 (6)	0.0121 (6)	0.0200 (6)	−0.0035 (5)	0.0025 (5)	0.0010 (5)
C5	0.0139 (6)	0.0129 (6)	0.0114 (5)	−0.0011 (4)	0.0025 (4)	−0.0010 (4)
C4	0.0150 (5)	0.0153 (6)	0.0159 (6)	−0.0026 (4)	0.0035 (4)	0.0014 (4)
C2	0.0160 (6)	0.0107 (5)	0.0163 (6)	−0.0003 (4)	0.0029 (4)	−0.0017 (4)
C10	0.0166 (6)	0.0207 (6)	0.0284 (7)	0.0015 (5)	0.0000 (5)	0.0003 (5)
C8	0.0147 (6)	0.0113 (5)	0.0121 (5)	−0.0002 (4)	0.0013 (4)	0.0007 (4)
C7	0.0145 (5)	0.0110 (6)	0.0152 (5)	0.0005 (4)	0.0018 (4)	0.0012 (4)

Geometric parameters (Å, º)

O1—C6	1.2198 (15)	C6—C8	1.5122 (15)
O3—C5	1.4516 (13)	C1—C7	1.5174 (15)
O3—C2	1.4440 (14)	C3—C4	1.3252 (17)
O2—C1	1.2118 (14)	C3—C2	1.5144 (15)
N1—C6	1.3764 (15)	C5—C4	1.5240 (15)
N1—C1	1.3841 (15)	C5—C8	1.5781 (15)
C9—C5	1.5057 (16)	C2—C7	1.5652 (16)
C9—C10	1.5268 (16)	C8—C7	1.5452 (15)
C2—O3—C5	96.85 (8)	C9—C5—C4	118.79 (10)
C6—N1—C1	113.72 (9)	C9—C5—C8	117.36 (9)
C5—C9—C10	113.36 (10)	C4—C5—C8	104.05 (9)
O1—C6—N1	124.33 (10)	C3—C4—C5	106.41 (10)
O1—C6—C8	127.07 (10)	O3—C2—C3	102.26 (9)
N1—C6—C8	108.60 (9)	O3—C2—C7	100.52 (8)
O2—C1—N1	124.28 (11)	C3—C2—C7	105.77 (9)
O2—C1—C7	127.42 (11)	C6—C8—C5	112.95 (9)
N1—C1—C7	108.27 (9)	C6—C8—C7	104.67 (9)
C4—C3—C2	105.73 (10)	C7—C8—C5	101.49 (9)
O3—C5—C9	112.24 (9)	C1—C7—C2	111.06 (9)
O3—C5—C4	101.49 (9)	C1—C7—C8	104.56 (9)
O3—C5—C8	100.26 (8)	C8—C7—C2	101.29 (9)

(2R,3R,4S)-Pentane-1,2,3,4,5-pentol (2Cu)

Crystal data

C5H12O5	F(000) = 328
Mr = 152.15	Dx = 1.538 Mg m^−3
Orthorhombic, P212121	Cu Kα radiation, λ = 1.54184 Å
a = 8.2707 (2) Å	Cell parameters from 8709 reflections
b = 8.9022 (2) Å	θ = 4.9–76.8°
c = 8.9217 (2) Å	µ = 1.20 mm^−1
V = 656.88 (3) Å^3	T = 123 K
Z = 4	0.35 × 0.22 × 0.18 mm

Data collection

Agilent SuperNova Dual four-circle diffractometer with an Atlas detector	1383 independent reflections
Radiation source: sealed X-ray tube, SuperNova (Cu) X-ray Source	1370 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.046
Detector resolution: 10.4391 pixels mm^-1	θmax = 76.8°, θmin = 7.0°
ω scans	h = −10→10
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014)	k = −10→11
Tmin = 0.383, Tmax = 1.000	l = −11→11
14853 measured reflections

Refinement

Refinement on F^2	Hydrogen site location: mixed
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.028	w = 1/[σ^2(Fo^2) + (0.0541P)^2 + 0.0779P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.077	(Δ/σ)max = 0.001
S = 1.09	Δρmax = 0.32 e Å^−3
1383 reflections	Δρmin = −0.21 e Å^−3
99 parameters	Absolute structure: Flack x determined using 550 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
0 restraints	Absolute structure parameter: 0.03 (7)
Primary atom site location: dual

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

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

	x	y	z	Uiso*/Ueq
O2	0.77119 (14)	0.12974 (13)	0.39217 (12)	0.0196 (3)
H12	0.731315	0.058671	0.346871	0.029*
O3	0.68182 (14)	0.43057 (12)	0.46015 (12)	0.0195 (3)
H13	0.673179	0.522334	0.459687	0.029*
O4	0.38520 (13)	0.43642 (13)	0.31715 (13)	0.0200 (3)
O5	0.32133 (14)	0.22866 (13)	0.07769 (13)	0.0198 (3)
H15	0.262808	0.236754	0.151439	0.030*
O1	1.08879 (14)	0.20493 (13)	0.28331 (13)	0.0212 (3)
H11	1.118613	0.166007	0.361889	0.032*
C3	0.67256 (18)	0.37517 (18)	0.30950 (16)	0.0175 (3)
H3	0.698937	0.457733	0.241076	0.021*
C4	0.49923 (19)	0.32248 (18)	0.27568 (17)	0.0170 (3)
H4	0.476441	0.230237	0.331797	0.020*
C2	0.79918 (18)	0.25174 (18)	0.28953 (17)	0.0174 (3)
H2	0.792172	0.213142	0.186864	0.021*
C1	0.96814 (19)	0.31470 (17)	0.31456 (19)	0.0195 (3)
H1A	0.984316	0.401182	0.250144	0.023*
H1B	0.978498	0.347751	0.417710	0.023*
C5	0.47587 (19)	0.29389 (18)	0.10928 (17)	0.0194 (3)
H5A	0.485905	0.388049	0.055358	0.023*
H5B	0.560241	0.227015	0.073929	0.023*
H14	0.353 (3)	0.414 (3)	0.412 (3)	0.040 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0239 (6)	0.0160 (5)	0.0189 (5)	−0.0029 (4)	−0.0020 (4)	0.0017 (4)
O3	0.0249 (6)	0.0179 (5)	0.0157 (5)	−0.0003 (5)	−0.0001 (4)	−0.0010 (4)
O4	0.0209 (5)	0.0207 (6)	0.0185 (5)	0.0039 (4)	0.0010 (4)	0.0007 (4)
O5	0.0187 (5)	0.0242 (5)	0.0165 (5)	−0.0020 (5)	0.0001 (4)	−0.0011 (4)
O1	0.0192 (5)	0.0249 (6)	0.0197 (5)	0.0031 (5)	0.0008 (4)	0.0022 (5)
C3	0.0193 (7)	0.0186 (7)	0.0145 (7)	−0.0007 (6)	−0.0002 (5)	0.0014 (6)
C4	0.0177 (6)	0.0171 (7)	0.0163 (7)	0.0017 (5)	−0.0004 (6)	0.0016 (5)
C2	0.0196 (7)	0.0185 (7)	0.0139 (7)	−0.0002 (6)	−0.0003 (5)	0.0020 (6)
C1	0.0189 (7)	0.0177 (7)	0.0218 (7)	−0.0010 (6)	−0.0003 (6)	0.0019 (6)
C5	0.0182 (7)	0.0226 (8)	0.0174 (7)	−0.0011 (6)	−0.0002 (6)	0.0003 (6)

Geometric parameters (Å, º)

O2—H12	0.8200	C3—C4	1.538 (2)
O2—C2	1.4394 (19)	C3—C2	1.528 (2)
O3—H13	0.8200	C4—H4	0.9800
O3—C3	1.4337 (17)	C4—C5	1.519 (2)
O4—C4	1.4336 (19)	C2—H2	0.9800
O4—H14	0.91 (3)	C2—C1	1.522 (2)
O5—H15	0.8200	C1—H1A	0.9700
O5—C5	1.4319 (19)	C1—H1B	0.9700
O1—H11	0.8200	C5—H5A	0.9700
O1—C1	1.4242 (19)	C5—H5B	0.9700
C3—H3	0.9800
C2—O2—H12	109.5	O2—C2—H2	108.7
C3—O3—H13	109.5	O2—C2—C1	109.40 (12)
C4—O4—H14	106.2 (16)	C3—C2—H2	108.7
C5—O5—H15	109.5	C1—C2—C3	110.32 (13)
C1—O1—H11	109.5	C1—C2—H2	108.7
O3—C3—H3	108.3	O1—C1—C2	111.22 (13)
O3—C3—C4	109.79 (12)	O1—C1—H1A	109.4
O3—C3—C2	108.66 (12)	O1—C1—H1B	109.4
C4—C3—H3	108.3	C2—C1—H1A	109.4
C2—C3—H3	108.3	C2—C1—H1B	109.4
C2—C3—C4	113.36 (13)	H1A—C1—H1B	108.0
O4—C4—C3	110.28 (12)	O5—C5—C4	111.96 (13)
O4—C4—H4	109.5	O5—C5—H5A	109.2
O4—C4—C5	106.69 (13)	O5—C5—H5B	109.2
C3—C4—H4	109.5	C4—C5—H5A	109.2
C5—C4—C3	111.18 (12)	C4—C5—H5B	109.2
C5—C4—H4	109.5	H5A—C5—H5B	107.9
O2—C2—C3	110.98 (12)

1-Methylpyrimidine-2,4(1H,3H)-dione (3Cu)

Crystal data

C5H6N2O2	Dx = 1.549 Mg m^−3
Mr = 126.12	Cu Kα radiation, λ = 1.54184 Å
Orthorhombic, Ibam	Cell parameters from 13558 reflections
a = 13.17921 (17) Å	θ = 4.7–75.3°
b = 13.20059 (19) Å	µ = 1.04 mm^−1
c = 6.21502 (11) Å	T = 123 K
V = 1081.25 (3) Å^3	Needle, clear light colourless
Z = 8	0.31 × 0.07 × 0.04 mm
F(000) = 528

Data collection

Agilent SuperNova Dual four-circle diffractometer with an Atlas detector	627 independent reflections
Radiation source: sealed X-ray tube, SuperNova (Cu) X-ray Source	599 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.047
Detector resolution: 5.2195 pixels mm^-1	θmax = 75.5°, θmin = 4.7°
ω scans	h = −16→16
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014)	k = −16→16
Tmin = 0.505, Tmax = 1.000	l = −7→7
627 measured reflections

Refinement

Refinement on F^2	Primary atom site location: dual
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.034	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.104	w = 1/[σ^2(Fo^2) + (0.0647P)^2 + 0.5188P] where P = (Fo^2 + 2Fc^2)/3
S = 1.10	(Δ/σ)max < 0.001
627 reflections	Δρmax = 0.31 e Å^−3
62 parameters	Δρmin = −0.28 e Å^−3
0 restraints

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

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

	x	y	z	Uiso*/Ueq
O2	0.63511 (7)	0.48095 (7)	0.500000	0.0192 (3)
O1	0.45425 (7)	0.77438 (7)	0.500000	0.0210 (3)
N2	0.54736 (8)	0.62905 (9)	0.500000	0.0161 (3)
H1	0.492152	0.594313	0.500000	0.019*
N1	0.62700 (8)	0.78643 (9)	0.500000	0.0163 (3)
C2	0.63704 (10)	0.57489 (11)	0.500000	0.0156 (3)
C1	0.53713 (10)	0.73314 (10)	0.500000	0.0163 (4)
C3	0.72749 (10)	0.63638 (10)	0.500000	0.0171 (3)
H2	0.791236	0.606155	0.500000	0.020*
C4	0.71868 (10)	0.73803 (10)	0.500000	0.0160 (3)
H3	0.777498	0.776949	0.500000	0.019*
C5	0.62025 (11)	0.89691 (11)	0.500000	0.0236 (4)
H5	0.5834 (10)	0.9191 (10)	0.629 (2)	0.030 (3)*
H4	0.6866 (14)	0.9189 (14)	0.500000	0.022 (4)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0169 (5)	0.0142 (6)	0.0265 (6)	−0.0004 (3)	0.000	0.000
O1	0.0142 (5)	0.0188 (5)	0.0300 (6)	0.0018 (3)	0.000	0.000
N2	0.0122 (6)	0.0146 (6)	0.0214 (6)	−0.0017 (4)	0.000	0.000
N1	0.0149 (6)	0.0131 (6)	0.0208 (6)	−0.0007 (4)	0.000	0.000
C2	0.0161 (7)	0.0163 (6)	0.0145 (6)	−0.0011 (5)	0.000	0.000
C1	0.0143 (7)	0.0179 (7)	0.0166 (7)	−0.0010 (5)	0.000	0.000
C3	0.0122 (6)	0.0178 (7)	0.0213 (7)	0.0006 (5)	0.000	0.000
C4	0.0124 (7)	0.0189 (7)	0.0166 (7)	−0.0025 (5)	0.000	0.000
C5	0.0182 (7)	0.0137 (7)	0.0389 (9)	−0.0005 (5)	0.000	0.000

Geometric parameters (Å, º)

O2—C2	1.2403 (18)	N1—C5	1.4611 (16)
O1—C1	1.2204 (16)	C2—C3	1.4422 (18)
N2—H1	0.8600	C3—H2	0.9300
N2—C2	1.3813 (17)	C3—C4	1.3469 (19)
N2—C1	1.3807 (18)	C4—H3	0.9300
N1—C1	1.3776 (17)	C5—H5	0.980 (14)
N1—C4	1.3669 (17)	C5—H4	0.921 (19)
C2—N2—H1	116.6	N1—C1—N2	115.10 (11)
C1—N2—H1	116.6	C2—C3—H2	120.3
C1—N2—C2	126.78 (11)	C4—C3—C2	119.30 (12)
C1—N1—C5	117.22 (11)	C4—C3—H2	120.3
C4—N1—C1	121.42 (12)	N1—C4—H3	118.6
C4—N1—C5	121.36 (11)	C3—C4—N1	122.82 (11)
O2—C2—N2	120.00 (11)	C3—C4—H3	118.6
O2—C2—C3	125.42 (12)	N1—C5—H5	109.1 (8)
N2—C2—C3	114.58 (13)	N1—C5—H4	104.9 (12)
O1—C1—N2	122.10 (11)	H5—C5—H4	112.1 (10)
O1—C1—N1	122.79 (12)

1-Methylpyrimidine-2,4(1H,3H)-dione (3Mo)

Crystal data

C5H6N2O2	Dx = 1.555 Mg m^−3
Mr = 126.12	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Ibam	Cell parameters from 14193 reflections
a = 13.1643 (1) Å	θ = 2.2–52.0°
b = 13.1840 (2) Å	µ = 0.12 mm^−1
c = 6.2067 (2) Å	T = 123 K
V = 1077.22 (4) Å^3	Block
Z = 8	0.41 × 0.23 × 0.14 mm
F(000) = 528

Data collection

Agilent SuperNova Dual four-circle diffractometer with an Atlas detector	3266 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	2580 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.056
Detector resolution: 16.0026 pixels mm^-1	θmax = 52.2°, θmin = 2.2°
ω scans	h = −33→33
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014)	k = −33→33
Tmin = 0.517, Tmax = 1.000	l = −15→13
3266 measured reflections

Refinement

Refinement on F^2	Primary atom site location: dual
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.044	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.129	w = 1/[σ^2(Fo^2) + (0.0739P)^2 + 0.0821P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
3266 reflections	Δρmax = 0.78 e Å^−3
62 parameters	Δρmin = −0.29 e Å^−3
0 restraints

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

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

	x	y	z	Uiso*/Ueq
O2	0.63523 (3)	0.51908 (3)	0.500000	0.01549 (8)
O1	0.45422 (3)	0.22546 (3)	0.500000	0.01730 (8)
N2	0.54722 (3)	0.37095 (3)	0.500000	0.01268 (7)
H1	0.491917	0.405672	0.500000	0.015*
N1	0.62703 (3)	0.21344 (3)	0.500000	0.01261 (7)
C1	0.53733 (3)	0.26711 (4)	0.500000	0.01209 (7)
C3	0.72746 (3)	0.36378 (4)	0.500000	0.01317 (8)
H2	0.791239	0.394113	0.500000	0.016*
C4	0.71868 (3)	0.26175 (3)	0.500000	0.01227 (7)
H3	0.777566	0.222777	0.500000	0.015*
C2	0.63704 (3)	0.42505 (3)	0.500000	0.01164 (7)
C5	0.62029 (4)	0.10342 (4)	0.500000	0.02022 (11)
H4	0.6883 (10)	0.0828 (10)	0.500000	0.020 (3)*
H5	0.5862 (7)	0.0807 (7)	0.6241 (16)	0.028 (2)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.01175 (12)	0.01082 (11)	0.0239 (2)	0.00063 (8)	0.000	0.000
O1	0.00829 (10)	0.01549 (13)	0.0281 (2)	−0.00171 (9)	0.000	0.000
N2	0.00769 (10)	0.01167 (12)	0.01868 (19)	0.00116 (8)	0.000	0.000
N1	0.00852 (11)	0.01082 (11)	0.01848 (18)	0.00088 (8)	0.000	0.000
C1	0.00760 (12)	0.01240 (13)	0.01628 (19)	0.00041 (9)	0.000	0.000
C3	0.00776 (12)	0.01254 (13)	0.0192 (2)	0.00031 (9)	0.000	0.000
C4	0.00795 (11)	0.01275 (14)	0.01611 (19)	0.00152 (9)	0.000	0.000
C2	0.00884 (12)	0.01148 (13)	0.01460 (18)	0.00082 (9)	0.000	0.000
C5	0.01406 (17)	0.01151 (15)	0.0351 (4)	0.00049 (12)	0.000	0.000

Geometric parameters (Å, º)

O2—C2	1.2399 (6)	N1—C5	1.4533 (6)
O1—C1	1.2242 (6)	C3—H2	0.9300
N2—H1	0.8600	C3—C4	1.3501 (7)
N2—C1	1.3752 (6)	C3—C2	1.4385 (6)
N2—C2	1.3809 (6)	C4—H3	0.9300
N1—C1	1.3765 (6)	C5—H4	0.935 (13)
N1—C4	1.3643 (6)	C5—H5	0.940 (10)
C1—N2—H1	116.7	C2—C3—H2	120.4
C1—N2—C2	126.53 (4)	N1—C4—H3	118.6
C2—N2—H1	116.7	C3—C4—N1	122.74 (4)
C1—N1—C5	117.43 (4)	C3—C4—H3	118.6
C4—N1—C1	121.24 (4)	O2—C2—N2	120.01 (4)
C4—N1—C5	121.33 (4)	O2—C2—C3	125.26 (4)
O1—C1—N2	122.08 (4)	N2—C2—C3	114.74 (4)
O1—C1—N1	122.42 (4)	N1—C5—H4	103.4 (8)
N2—C1—N1	115.50 (4)	N1—C5—H5	110.3 (6)
C4—C3—H2	120.4	H4—C5—H5	111.4 (7)
C4—C3—C2	119.25 (4)

10-Oxa-4-azatricyclo[5.2.1.0^2,6]dec-8-ene-3,5-dione (1Neu)

Crystal data

C10H11NO3	Z = 4
Mr = 193.20	F(000) = 208
Monoclinic, P21/c	Dx = 1.412 Mg m^−3
a = 8.6809 (6) Å	Neutron radiation, λ = 0.38- 8.8 Å
b = 10.8826 (7) Å	µ = 4.23+ 0.0137 * lambda mm^−1
c = 9.6214 (8) Å	T = 100 K
β = 90.150 (9)°	Block
V = 908.94 (11) Å^3	5.00 × 2.00 × 1.00 mm

Data collection

SXD diffractometer	7034 independent reflections
Radiation source: ISIS spallation neutron source	7034 reflections with I > 2σ(I)
time–of–flight LAUE diffraction scans	θmax = 84.7°, θmin = 8.3°
Absorption correction: numerical SXD2001 Gaussian numerical integration	h = −26→22
Tmin = 0.530, Tmax = 0.566	k = −27→31
7034 measured reflections	l = −19→27

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.095	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.220	w = 1/[σ^2(Fo^2) + (0.1P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.56	(Δ/σ)max < 0.001
7034 reflections	Δρmax = 2.46 e Å^−3
227 parameters	Δρmin = −2.46 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0179 (6)

Special details

Experimental. The range of wavelengths used was 0.48-7.0 Angstroms, BUT the bulk of the diffraction information is obtained from wavelengths in the range 0.7-2.5 Angstroms. The data collection procedures on the SXD instrument used for the single crystal neutron data collection are most recently summarised in the Appendix to the following paper Wilson, C.C. (1997). J. Mol. Struct. 405, 207-217

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. The variable wavelength nature of the data collection procedure means that sensible values of _diffrn_reflns_theta_min & _diffrn_reflns_theta_max cannot be given instead the following limits are given _diffrn_reflns_sin(theta)/lambda_min 0.07 _diffrn_reflns_sin(theta)/lambda_max 2.09 _refine_diff_density_max/min is given in Fermi per per angstrom cubed not electrons per angstrom cubed. Another way to consider the _refine_diff_density_ is as a percentage of the diffracted intensity of a given atom: _refine_diff_density_max = 5% of Carbon _refine_diff_density_min = -4% of Carbon 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 > 2sigma(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
C1	0.4962 (2)	0.20805 (16)	−0.0216 (2)	0.0083 (3)
C2	0.2480 (2)	0.08601 (16)	0.0004 (2)	0.0090 (3)
H2	0.2756 (5)	0.0332 (4)	−0.0938 (5)	0.0237 (9)
C3	0.1503 (2)	0.02552 (16)	0.1110 (2)	0.0107 (4)
C4	0.0818 (2)	0.11778 (17)	0.1793 (2)	0.0100 (3)
C5	0.13709 (19)	0.23578 (15)	0.10855 (19)	0.0067 (3)
C6	0.3853 (2)	0.36527 (15)	0.10469 (19)	0.0079 (3)
C7	0.3881 (2)	0.14395 (15)	0.07906 (19)	0.0076 (3)
H7	0.4500 (5)	0.0769 (4)	0.1423 (5)	0.0217 (9)
C8	0.30904 (19)	0.24944 (15)	0.15894 (19)	0.0066 (3)
H8	0.3154 (5)	0.2463 (4)	0.2723 (4)	0.0212 (9)
C9	0.0361 (2)	0.34814 (16)	0.1160 (2)	0.0102 (4)
H9A	0.0834 (5)	0.4199 (4)	0.0496 (6)	0.0300 (11)
H9B	0.0433 (5)	0.3833 (4)	0.2229 (5)	0.0275 (10)
C10	−0.1313 (2)	0.3226 (2)	0.0765 (2)	0.0165 (4)
H10A	−0.1406 (6)	0.2884 (6)	−0.0295 (6)	0.0442 (15)
H10B	−0.1991 (6)	0.4063 (5)	0.0827 (7)	0.0405 (15)
H10C	−0.1847 (6)	0.2554 (6)	0.1442 (7)	0.0442 (16)
N1	0.48544 (15)	0.33352 (12)	−0.00041 (15)	0.0092 (2)
O1	0.3631 (3)	0.47004 (18)	0.1440 (2)	0.0106 (4)
O2	0.5774 (3)	0.1604 (2)	−0.1094 (3)	0.0129 (4)
O3	0.1609 (2)	0.19477 (18)	−0.0329 (2)	0.0084 (4)
H3	0.1500 (6)	−0.0715 (4)	0.1332 (6)	0.0317 (11)
H4	0.0117 (6)	0.1149 (5)	0.2723 (5)	0.0287 (10)
H1N	0.5480 (5)	0.3978 (4)	−0.0566 (5)	0.0218 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0058 (7)	0.0086 (7)	0.0104 (8)	0.0017 (5)	0.0011 (6)	−0.0017 (5)
C2	0.0085 (7)	0.0075 (7)	0.0109 (8)	−0.0021 (6)	0.0024 (6)	−0.0015 (5)
H2	0.026 (2)	0.023 (2)	0.022 (2)	0.0013 (16)	0.0057 (18)	−0.0097 (15)
C3	0.0111 (8)	0.0068 (7)	0.0143 (9)	−0.0012 (6)	0.0049 (7)	0.0006 (6)
C4	0.0093 (7)	0.0095 (7)	0.0111 (8)	−0.0024 (6)	0.0035 (7)	0.0013 (6)
C5	0.0061 (6)	0.0062 (6)	0.0077 (7)	−0.0010 (5)	0.0014 (6)	0.0011 (5)
C6	0.0077 (7)	0.0064 (6)	0.0096 (8)	0.0001 (5)	0.0008 (6)	−0.0013 (5)
C7	0.0070 (7)	0.0061 (6)	0.0096 (8)	0.0008 (5)	0.0002 (6)	0.0013 (5)
H7	0.0202 (18)	0.0197 (18)	0.025 (2)	0.0050 (14)	−0.0011 (17)	0.0075 (14)
C8	0.0052 (6)	0.0077 (7)	0.0068 (7)	−0.0014 (5)	0.0007 (6)	0.0005 (5)
H8	0.027 (2)	0.0228 (19)	0.0138 (18)	−0.0019 (15)	−0.0025 (17)	0.0027 (14)
C9	0.0072 (7)	0.0090 (7)	0.0144 (9)	0.0019 (5)	0.0007 (7)	−0.0014 (6)
H9A	0.023 (2)	0.024 (2)	0.042 (3)	−0.0005 (16)	0.002 (2)	0.0119 (19)
H9B	0.025 (2)	0.031 (2)	0.026 (2)	0.0049 (17)	−0.0022 (19)	−0.0140 (18)
C10	0.0066 (7)	0.0200 (10)	0.0228 (11)	0.0018 (6)	−0.0020 (8)	−0.0009 (8)
H10A	0.028 (3)	0.066 (4)	0.038 (3)	−0.002 (3)	−0.009 (2)	−0.017 (3)
H10B	0.023 (2)	0.039 (3)	0.059 (4)	0.014 (2)	−0.006 (3)	−0.006 (3)
H10C	0.024 (2)	0.053 (4)	0.056 (4)	−0.009 (2)	0.003 (3)	0.023 (3)
N1	0.0074 (5)	0.0085 (5)	0.0117 (6)	−0.0014 (4)	0.0035 (5)	0.0003 (4)
O1	0.0119 (9)	0.0070 (8)	0.0129 (10)	−0.0018 (6)	0.0048 (8)	−0.0011 (7)
O2	0.0115 (9)	0.0113 (9)	0.0160 (11)	0.0007 (7)	0.0049 (8)	−0.0012 (7)
O3	0.0079 (8)	0.0115 (8)	0.0056 (8)	−0.0004 (6)	0.0000 (7)	−0.0003 (6)
H3	0.041 (3)	0.0117 (18)	0.042 (3)	−0.0014 (17)	0.012 (2)	0.0052 (16)
H4	0.033 (2)	0.030 (2)	0.023 (2)	−0.0030 (19)	0.013 (2)	0.0030 (17)
H1N	0.0213 (18)	0.0157 (17)	0.028 (2)	−0.0038 (14)	0.0083 (18)	0.0040 (15)

Geometric parameters (Å, º)

C1—O2	1.217 (3)	C5—O3	1.448 (3)
C1—N1	1.384 (2)	C5—C9	1.506 (2)
C1—C7	1.520 (3)	C5—C8	1.575 (2)
C2—O3	1.440 (3)	C6—O1	1.217 (3)
C2—C3	1.513 (3)	C6—N1	1.379 (3)
C2—C7	1.564 (2)	C6—C8	1.517 (3)
C3—C4	1.340 (3)	C7—C8	1.544 (3)
C4—C5	1.531 (3)	C9—C10	1.526 (2)
O2—C1—N1	124.2 (2)	C4—C5—C8	103.92 (12)
O2—C1—C7	127.33 (19)	O1—C6—N1	124.3 (2)
N1—C1—C7	108.48 (16)	O1—C6—C8	127.0 (2)
O3—C2—C3	102.64 (17)	N1—C6—C8	108.70 (14)
O3—C2—C7	100.58 (13)	C1—C7—C8	104.59 (14)
C3—C2—C7	105.75 (15)	C1—C7—C2	110.91 (15)
C4—C3—C2	105.61 (16)	C8—C7—C2	101.22 (13)
C3—C4—C5	105.69 (18)	C6—C8—C7	104.57 (16)
O3—C5—C9	112.29 (14)	C6—C8—C5	112.75 (12)
O3—C5—C4	101.82 (15)	C7—C8—C5	101.46 (12)
C9—C5—C4	118.44 (17)	C5—C9—C10	113.21 (15)
O3—C5—C8	100.44 (15)	C6—N1—C1	113.46 (15)
C9—C5—C8	117.38 (13)	C2—O3—C5	96.92 (15)