8-Thia-1,6-diaza­bicyclo­[4.3.0]nonane-7,9-dione

Xi, B.; Shi, L.; Huang, H.; Wang, Q.; Zhu, H.-J.

doi:10.1107/S1600536811038785

organic compounds

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ISSN: 2056-9890

Volume 67| Part 10| October 2011| Page o2771

https://doi.org/10.1107/S1600536811038785

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8-Thia-1,6-diazabicyclo[4.3.0]nonane-7,9-dione

Bin-bin Xi,^a Lu Shi,^a Hai Huang,^a Qin Wang ^a and Hong-Jun Zhu ^b ^*

^aDepartment of Organic Chemistry, College of Science, Nanjing University of Technology, Nanjing 210009, People's Republic of China, and ^bDepartment of Applied Chemistry, College of Science, Nanjing University of Technology, Nanjing 210009, People's Republic of China
^*Correspondence e-mail: zhuhj@njut.edu.cn

(Received 24 July 2011; accepted 21 September 2011; online 30 September 2011)

There are two independent molecules, A and B, in the asymmetric unit of the title compound, C₆H₈N₂O₂S. In the crystal, pairs of intermolecular S⋯O contacts [3.286 (1) Å] link the B molecules into inversion dimers.

Related literature

For applications of the title compound, see: Yamaguchi et al. (1989 ). For the synthesis, see: Zhu et al. (2011 ). For bond-length data, see: Allen et al. (1987 ). For a review of carbonyl–carbonyl interactions, see: Allen et al. (1998 ).

Experimental

Crystal data

C₆H₈N₂O₂S
M_r = 172.20
Triclinic, $[P \overline 1]$
a = 7.8400 (16) Å
b = 10.464 (2) Å
c = 10.514 (2) Å
α = 63.84 (3)°
β = 79.62 (3)°
γ = 89.42 (3)°
V = 759.2 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.37 mm⁻¹
T = 293 K
0.30 × 0.20 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ) T_min = 0.896, T_max = 0.964
3018 measured reflections
2795 independent reflections
2092 reflections with I > 2σ(I)
R_int = 0.041
3 standard reflections every 200 reflections intensity decay: 1%

Refinement

R[F² > 2σ(F²)] = 0.044
wR(F²) = 0.125
S = 1.00
2795 reflections
200 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 ); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo,1995 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536811038785/lx2196sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811038785/lx2196Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S1600536811038785/lx2196Isup3.cml

checkCIF report

Comment top

The title compound, 8-thia-1,6-diazabicyclo[4.3.0]nonane-7,9-dione, is an important intermediate for a kind of manufacturing agrochemical, especially for Fluthiacet-methyl as a super-effective, wide-spectral and safe herbicide (Yamaguchi et al., 1989). We report herein the crystal structure of the title compound.

The asymmetric unit of the title compound is shown in Fig. 1 and there are two independent unique molecules [labeled A & B]. The bond lengths and angles are within normal ranges (Allen et al., 1987). The crystal packing (Fig. 2) is stabilized by an intermolecular S···O interaction between the sulfur and the O atom of the carbonyl group interpreted as similar to type-II carbonyl–carbonyl interaction (Allen et al., 1998), with S1···O2ⁱ distance of 3.286 (1) Å.

Related literature top

For applications of the title compound, see: Yamaguchi et al. (1989). For the synthesis, see: Zhu et al. (2011). For bond-length data, see: Allen et al. (1987). For a review of carbonyl–carbonyl interactions, see: Allen et al. (1998).

Experimental top

The title compound was prepared according to reported in literature (Zhu et al., 2011). Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in ethanol at room temperature for ca. 6 d.

Structure description top

For applications of the title compound, see: Yamaguchi et al. (1989). For the synthesis, see: Zhu et al. (2011). For bond-length data, see: Allen et al. (1987). For a review of carbonyl–carbonyl interactions, see: Allen et al. (1998).

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo,1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as small spheres of arbitrary radius.
	Fig. 2. A view of the S···O interactions (dotted lines) in the crystal structure of the title compound. [Symmetry codes: (i) - x, - y + 2, - z.]

8-Thia-1,6-diazabicyclo[4.3.0]nonane-7,9-dione top

Crystal data top

C₆H₈N₂O₂S	Z = 4
M_r = 172.20	F(000) = 360
Triclinic, P1	D_x = 1.507 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.8400 (16) Å	Cell parameters from 25 reflections
b = 10.464 (2) Å	θ = 10–13°
c = 10.514 (2) Å	µ = 0.37 mm⁻¹
α = 63.84 (3)°	T = 293 K
β = 79.62 (3)°	Block, colourless
γ = 89.42 (3)°	0.30 × 0.20 × 0.10 mm
V = 759.2 (3) Å³

Data collection top

Enraf–Nonius CAD-4 diffractometer	2092 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.041
Graphite monochromator	θ_max = 25.4°, θ_min = 2.2°
ω/2θ scans	h = 0→9
Absorption correction: ψ scan (North et al., 1968)	k = −12→12
T_min = 0.896, T_max = 0.964	l = −12→12
3018 measured reflections	3 standard reflections every 200 reflections
2795 independent reflections	intensity decay: 1%

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)] = 0.044	H-atom parameters constrained
wR(F²) = 0.125	w = 1/[σ²(F_o²) + (0.077P)²] where P = (F_o² + 2F_c²)/3
S = 1.00	(Δ/σ)_max < 0.001
2795 reflections	Δρ_max = 0.22 e Å⁻³
200 parameters	Δρ_min = −0.32 e Å⁻³
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.327 (16)

Crystal data top

C₆H₈N₂O₂S	γ = 89.42 (3)°
M_r = 172.20	V = 759.2 (3) Å³
Triclinic, P1	Z = 4
a = 7.8400 (16) Å	Mo Kα radiation
b = 10.464 (2) Å	µ = 0.37 mm⁻¹
c = 10.514 (2) Å	T = 293 K
α = 63.84 (3)°	0.30 × 0.20 × 0.10 mm
β = 79.62 (3)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	2092 reflections with I > 2σ(I)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.041
T_min = 0.896, T_max = 0.964	3 standard reflections every 200 reflections
3018 measured reflections	intensity decay: 1%
2795 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.044	0 restraints
wR(F²) = 0.125	H-atom parameters constrained
S = 1.00	Δρ_max = 0.22 e Å⁻³
2795 reflections	Δρ_min = −0.32 e Å⁻³
200 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	U_iso*/U_eq
S1	−0.09731 (11)	0.82576 (8)	0.04086 (8)	0.0598 (3)
O1	−0.3185 (3)	0.5944 (3)	0.1791 (3)	0.0737 (7)
O2	0.2479 (3)	0.8734 (2)	−0.0219 (2)	0.0632 (6)
N1	−0.0292 (2)	0.5625 (2)	0.1507 (2)	0.0416 (5)
N2	0.1318 (3)	0.6432 (2)	0.1083 (2)	0.0411 (5)
C1	0.2837 (3)	0.5721 (3)	0.0768 (3)	0.0464 (6)
H1A	0.3892	0.6300	0.0591	0.056*
H1B	0.2803	0.5604	−0.0092	0.056*
C2	0.2842 (4)	0.4278 (3)	0.2034 (3)	0.0547 (7)
H2A	0.3027	0.4404	0.2860	0.066*
H2B	0.3789	0.3771	0.1791	0.066*
C3	0.1134 (4)	0.3408 (3)	0.2418 (3)	0.0529 (7)
H3A	0.1002	0.3205	0.1623	0.063*
H3B	0.1137	0.2505	0.3261	0.063*
C4	−0.0370 (4)	0.4199 (3)	0.2726 (3)	0.0491 (7)
H4A	−0.1456	0.3669	0.2878	0.059*
H4B	−0.0326	0.4290	0.3599	0.059*
C5	−0.1691 (3)	0.6421 (3)	0.1356 (3)	0.0497 (7)
C6	0.1243 (4)	0.7859 (3)	0.0365 (3)	0.0462 (6)
S2	0.16047 (9)	0.00770 (8)	0.62686 (8)	0.0517 (3)
O3	0.3930 (3)	−0.1856 (2)	0.6988 (2)	0.0625 (6)
O4	0.1494 (2)	0.2796 (2)	0.5788 (2)	0.0585 (5)
N3	0.4698 (2)	0.0396 (2)	0.6615 (2)	0.0396 (5)
N4	0.3934 (3)	0.1675 (2)	0.6431 (2)	0.0379 (5)
C7	0.5149 (3)	0.2948 (3)	0.5815 (3)	0.0462 (6)
H7A	0.4534	0.3749	0.5837	0.055*
H7B	0.5648	0.3187	0.4817	0.055*
C8	0.6568 (4)	0.2672 (3)	0.6669 (3)	0.0567 (8)
H8A	0.6083	0.2567	0.7629	0.068*
H8B	0.7430	0.3483	0.6203	0.068*
C9	0.7431 (3)	0.1341 (3)	0.6786 (3)	0.0541 (7)
H9A	0.8298	0.1158	0.7384	0.065*
H9B	0.8015	0.1481	0.5833	0.065*
C10	0.6102 (3)	0.0070 (3)	0.7438 (3)	0.0502 (7)
H10A	0.6655	−0.0756	0.7418	0.060*
H10B	0.5628	−0.0153	0.8437	0.060*
C11	0.3614 (3)	−0.0634 (3)	0.6686 (3)	0.0433 (6)
C12	0.2314 (3)	0.1752 (3)	0.6121 (3)	0.0412 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0698 (5)	0.0513 (5)	0.0626 (5)	0.0262 (4)	−0.0203 (4)	−0.0268 (4)
O1	0.0382 (12)	0.0922 (17)	0.0976 (17)	0.0078 (11)	−0.0077 (11)	−0.0508 (14)
O2	0.0749 (14)	0.0403 (11)	0.0593 (13)	−0.0102 (10)	0.0012 (11)	−0.0138 (10)
N1	0.0357 (11)	0.0393 (11)	0.0448 (12)	0.0011 (9)	−0.0052 (9)	−0.0153 (10)
N2	0.0369 (11)	0.0349 (11)	0.0453 (12)	0.0006 (9)	−0.0038 (9)	−0.0139 (9)
C1	0.0375 (14)	0.0472 (15)	0.0502 (15)	0.0045 (11)	0.0008 (11)	−0.0213 (13)
C2	0.0508 (17)	0.0486 (16)	0.0617 (18)	0.0155 (13)	−0.0147 (14)	−0.0209 (14)
C3	0.073 (2)	0.0344 (14)	0.0467 (15)	0.0053 (13)	−0.0151 (14)	−0.0130 (12)
C4	0.0545 (16)	0.0431 (15)	0.0406 (14)	−0.0101 (12)	−0.0044 (12)	−0.0120 (12)
C5	0.0418 (16)	0.0638 (18)	0.0531 (16)	0.0122 (13)	−0.0109 (13)	−0.0343 (15)
C6	0.0585 (17)	0.0418 (15)	0.0362 (13)	0.0039 (13)	−0.0048 (12)	−0.0172 (12)
S2	0.0443 (4)	0.0511 (4)	0.0589 (5)	−0.0031 (3)	−0.0175 (3)	−0.0208 (3)
O3	0.0769 (15)	0.0407 (11)	0.0712 (14)	0.0081 (10)	−0.0188 (11)	−0.0247 (10)
O4	0.0494 (11)	0.0536 (12)	0.0682 (13)	0.0176 (10)	−0.0212 (10)	−0.0200 (10)
N3	0.0358 (11)	0.0354 (11)	0.0451 (12)	0.0058 (9)	−0.0080 (9)	−0.0159 (9)
N4	0.0328 (10)	0.0335 (11)	0.0445 (12)	0.0028 (8)	−0.0076 (9)	−0.0150 (9)
C7	0.0446 (15)	0.0356 (13)	0.0543 (16)	−0.0040 (11)	−0.0011 (12)	−0.0195 (12)
C8	0.0418 (15)	0.0667 (19)	0.0708 (19)	−0.0067 (14)	−0.0050 (14)	−0.0409 (16)
C9	0.0312 (13)	0.076 (2)	0.0632 (18)	0.0066 (13)	−0.0108 (13)	−0.0377 (16)
C10	0.0381 (14)	0.0576 (16)	0.0520 (16)	0.0119 (12)	−0.0132 (12)	−0.0204 (14)
C11	0.0467 (15)	0.0393 (15)	0.0413 (14)	0.0016 (12)	−0.0056 (11)	−0.0167 (11)
C12	0.0386 (13)	0.0453 (14)	0.0359 (13)	0.0049 (12)	−0.0095 (11)	−0.0138 (11)

Geometric parameters (Å, º) top

S1—C5	1.771 (3)	S2—C12	1.776 (3)
S1—C6	1.780 (3)	S2—C11	1.779 (3)
O1—C5	1.203 (3)	O3—C11	1.208 (3)
O2—C6	1.209 (3)	O4—C12	1.208 (3)
N1—C5	1.360 (3)	N3—C11	1.347 (3)
N1—N2	1.411 (3)	N3—N4	1.409 (3)
N1—C4	1.470 (3)	N3—C10	1.467 (3)
N2—C6	1.351 (3)	N4—C12	1.360 (3)
N2—C1	1.463 (3)	N4—C7	1.464 (3)
C1—C2	1.510 (4)	C7—C8	1.501 (4)
C1—H1A	0.9700	C7—H7A	0.9700
C1—H1B	0.9700	C7—H7B	0.9700
C2—C3	1.514 (4)	C8—C9	1.508 (4)
C2—H2A	0.9700	C8—H8A	0.9700
C2—H2B	0.9700	C8—H8B	0.9700
C3—C4	1.503 (4)	C9—C10	1.514 (4)
C3—H3A	0.9700	C9—H9A	0.9700
C3—H3B	0.9700	C9—H9B	0.9700
C4—H4A	0.9700	C10—H10A	0.9700
C4—H4B	0.9700	C10—H10B	0.9700

C5—S1—C6	91.50 (13)	C12—S2—C11	91.50 (12)
C5—N1—N2	114.0 (2)	C11—N3—N4	114.76 (19)
C5—N1—C4	121.3 (2)	C11—N3—C10	122.2 (2)
N2—N1—C4	114.5 (2)	N4—N3—C10	114.6 (2)
C6—N2—N1	114.8 (2)	C12—N4—N3	114.5 (2)
C6—N2—C1	121.8 (2)	C12—N4—C7	121.1 (2)
N1—N2—C1	115.11 (19)	N3—N4—C7	115.35 (19)
N2—C1—C2	109.5 (2)	N4—C7—C8	109.7 (2)
N2—C1—H1A	109.8	N4—C7—H7A	109.7
C2—C1—H1A	109.8	C8—C7—H7A	109.7
N2—C1—H1B	109.8	N4—C7—H7B	109.7
C2—C1—H1B	109.8	C8—C7—H7B	109.7
H1A—C1—H1B	108.2	H7A—C7—H7B	108.2
C1—C2—C3	110.6 (2)	C7—C8—C9	111.1 (2)
C1—C2—H2A	109.5	C7—C8—H8A	109.4
C3—C2—H2A	109.5	C9—C8—H8A	109.4
C1—C2—H2B	109.5	C7—C8—H8B	109.4
C3—C2—H2B	109.5	C9—C8—H8B	109.4
H2A—C2—H2B	108.1	H8A—C8—H8B	108.0
C4—C3—C2	110.8 (2)	C8—C9—C10	110.7 (2)
C4—C3—H3A	109.5	C8—C9—H9A	109.5
C2—C3—H3A	109.5	C10—C9—H9A	109.5
C4—C3—H3B	109.5	C8—C9—H9B	109.5
C2—C3—H3B	109.5	C10—C9—H9B	109.5
H3A—C3—H3B	108.1	H9A—C9—H9B	108.1
N1—C4—C3	109.9 (2)	N3—C10—C9	109.7 (2)
N1—C4—H4A	109.7	N3—C10—H10A	109.7
C3—C4—H4A	109.7	C9—C10—H10A	109.7
N1—C4—H4B	109.7	N3—C10—H10B	109.7
C3—C4—H4B	109.7	C9—C10—H10B	109.7
H4A—C4—H4B	108.2	H10A—C10—H10B	108.2
O1—C5—N1	125.0 (3)	O3—C11—N3	126.2 (3)
O1—C5—S1	125.5 (2)	O3—C11—S2	124.5 (2)
N1—C5—S1	109.5 (2)	N3—C11—S2	109.34 (18)
O2—C6—N2	125.7 (3)	O4—C12—N4	125.5 (2)
O2—C6—S1	125.1 (2)	O4—C12—S2	125.4 (2)
N2—C6—S1	109.2 (2)	N4—C12—S2	109.10 (18)

C5—N1—N2—C6	−11.3 (3)	C11—N3—N4—C12	−10.1 (3)
C4—N1—N2—C6	−157.2 (2)	C10—N3—N4—C12	−159.0 (2)
C5—N1—N2—C1	−160.4 (2)	C11—N3—N4—C7	−157.8 (2)
C4—N1—N2—C1	53.6 (3)	C10—N3—N4—C7	53.3 (3)
C6—N2—C1—C2	160.1 (2)	C12—N4—C7—C8	162.2 (2)
N1—N2—C1—C2	−53.2 (3)	N3—N4—C7—C8	−52.4 (3)
N2—C1—C2—C3	54.1 (3)	N4—C7—C8—C9	53.6 (3)
C1—C2—C3—C4	−56.3 (3)	C7—C8—C9—C10	−56.1 (3)
C5—N1—C4—C3	164.3 (2)	C11—N3—C10—C9	161.2 (2)
N2—N1—C4—C3	−52.4 (3)	N4—N3—C10—C9	−52.4 (3)
C2—C3—C4—N1	53.8 (3)	C8—C9—C10—N3	53.8 (3)
N2—N1—C5—O1	−171.7 (3)	N4—N3—C11—O3	−171.8 (2)
C4—N1—C5—O1	−28.3 (4)	C10—N3—C11—O3	−25.6 (4)
N2—N1—C5—S1	8.8 (3)	N4—N3—C11—S2	7.9 (3)
C4—N1—C5—S1	152.26 (19)	C10—N3—C11—S2	154.20 (19)
C6—S1—C5—O1	176.8 (3)	C12—S2—C11—O3	176.4 (2)
C6—S1—C5—N1	−3.76 (19)	C12—S2—C11—N3	−3.33 (19)
N1—N2—C6—O2	−172.2 (2)	N3—N4—C12—O4	−172.5 (2)
C1—N2—C6—O2	−25.3 (4)	C7—N4—C12—O4	−26.9 (4)
N1—N2—C6—S1	7.8 (3)	N3—N4—C12—S2	6.9 (3)
C1—N2—C6—S1	154.63 (19)	C7—N4—C12—S2	152.55 (18)
C5—S1—C6—O2	177.7 (3)	C11—S2—C12—O4	177.4 (2)
C5—S1—C6—N2	−2.26 (19)	C11—S2—C12—N4	−2.03 (19)

Experimental details

Crystal data
Chemical formula	C₆H₈N₂O₂S
M_r	172.20
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	7.8400 (16), 10.464 (2), 10.514 (2)
α, β, γ (°)	63.84 (3), 79.62 (3), 89.42 (3)
V (Å³)	759.2 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.37
Crystal size (mm)	0.30 × 0.20 × 0.10

Data collection
Diffractometer	Enraf–Nonius CAD-4
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.896, 0.964
No. of measured, independent and observed [I > 2σ(I)] reflections	3018, 2795, 2092
R_int	0.041
(sin θ/λ)_max (Å⁻¹)	0.603

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.125, 1.00
No. of reflections	2795
No. of parameters	200
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.22, −0.32

Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994), XCAD4 (Harms & Wocadlo,1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Acknowledgements

The authors thank the Center of Testing and Analysis, Nanjing University, for support.

References

Allen, F. H., Baalham, C. A., Lommerse, J. P. M. & Raithby, P. R. (1998). Acta Cryst. B54, 320–329. Web of Science CrossRef CAS IUCr Journals Google Scholar
Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CSD CrossRef Web of Science Google Scholar
Enraf–Nonius (1994). CAD-4 EXPRESS. Enraf–Nonius, Delft, The Netherlands. Google Scholar
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany. Google Scholar
North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359. CrossRef IUCr Journals Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Yamaguchi, M., Suzuki, C., Matsunari, K., Miyazawa, T. & Nakamura, Y. (1989). EP Patent 0312064A2. Google Scholar
Zhu, H. J., Xi, B. B., Feng, M. L., Wang, K., Li, Y. F., Shi, L. & Chen, C. (2011). CN Patent Appl. CN 201110091918.8. Google Scholar