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ISSN: 2056-9890

Crystal structure of 7-bromo-4-oxo-4H-chromene-3-carbaldehyde

aSchool of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
*Correspondence e-mail: ishi206@u-shizuoka-ken.ac.jp

Edited by E. R. T. Tiekink, University of Malaya, Malaysia (Received 6 August 2014; accepted 7 August 2014; online 13 August 2014)

In the title compound, C10H5BrO3, a brominated 3-formyl­chromone derivative, all atoms are essentially coplanar (r.m.s. = 0.0631 Å for the non-H atoms), with the largest deviation from the least-squares plane [0.215 (3) Å] being for the formyl O atom. In the crystal, mol­ecules are linked into tapes through C—H⋯O hydrogen bonds and these tapes are assembled by stacking inter­actions [centroid–centroid distance between the pyran rings = 3.858 (3) Å] to form supra­molecular layers that stack along the c axis.

1. Related literature

For related structures, see: Ishikawa (2014a[Ishikawa, Y. (2014a). Acta Cryst. E70, o439.],b[Ishikawa, Y. (2014b). Acta Cryst. E70, o555.]). For halogen bonding, see: Auffinger et al. (2004[Auffinger, P., Hays, F. A., Westhof, E. & Ho, P. S. (2004). Proc. Natl Acad. Sci. USA, 101, 16789-16794.]); Metrangolo et al. (2005[Metrangolo, P., Neukirch, H., Pilati, T. & Resnati, G. (2005). Acc. Chem. Res. 38, 386-395.]); Wilcken et al. (2013[Wilcken, R., Zimmermann, M. O., Lange, A., Joerger, A. C. & Boeckler, F. M. (2013). J. Med. Chem. 56, 1363-1388.]); Sirimulla et al. (2013[Sirimulla, S., Bailey, J. B., Vegesna, R. & Narayan, M. (2013). J. Chem. Inf. Model. 53, 2781-2791.]). For halogen–halogen inter­actions, see: Metrangolo & Resnati (2014[Metrangolo, P. & Resnati, G. (2014). IUCrJ, 1, 5-7.]); Mukherjee & Desiraju (2014[Mukherjee, A. & Desiraju, G. R. (2014). IUCrJ, 1, 49-60.]).

[Scheme 1]

2. Experimental

2.1. Crystal data

  • C10H5BrO3

  • Mr = 253.05

  • Monoclinic, P 21 /c

  • a = 3.8580 (18) Å

  • b = 6.054 (4) Å

  • c = 37.268 (13) Å

  • β = 90.39 (4)°

  • V = 870.4 (8) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 4.71 mm−1

  • T = 100 K

  • 0.45 × 0.20 × 0.10 mm

2.1.2. Data collection

  • Rigaku AFC-7R diffractometer

  • Absorption correction: ψ scan (North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.339, Tmax = 0.624

  • 4817 measured reflections

  • 1980 independent reflections

  • 1710 reflections with F2 > 2σ(F2)

  • Rint = 0.024

  • 3 standard reflections every 150 reflections intensity decay: 4.8%

2.1.3. Refinement

  • R[F2 > 2σ(F2)] = 0.038

  • wR(F2) = 0.109

  • S = 1.07

  • 1980 reflections

  • 127 parameters

  • H-atom parameters constrained

  • Δρmax = 1.26 e Å−3

  • Δρmin = −1.73 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C7i—H4i⋯O2 0.95 2.30 3.149 (4) 149 (1)
C1ii—H1ii⋯O3 0.95 2.37 3.228 (5) 149 (1)
Symmetry codes: (i) x+1, y+1, z; (ii) -x, -y+1, -z+1.

Data collection: WinAFC Diffractometer Control Software (Rigaku, 1999[Rigaku (1999). WinAFC Diffractometer Control Software. Rigaku Corporation, Tokyo, Japan.]); cell refinement: WinAFC Diffractometer Control Software; data reduction: WinAFC Diffractometer Control Software; program(s) used to solve structure: SIR2008 (Burla et al., 2007[Burla, M. C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G. L., De Caro, L., Giacovazzo, C., Polidori, G., Siliqi, D. & Spagna, R. (2007). J. Appl. Cryst. 40, 609-613.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: CrystalStructure (Rigaku, 2010[Rigaku (2010). CrystalStructure. Rigaku Corporation, Tokyo, Japan.]); software used to prepare material for publication: CrystalStructure.

Supporting information


Structural commentary top

Halogen bonding and halogen···halogen inter­action have recently attracted much attention in medicinal chemistry, chemical biology, supra­molecular chemistry and crystal engineering (Auffinger et al., 2004, Metrangolo et al., 2005, Wilcken et al., 2013, Sirimulla et al., 2013, Mukherjee & Desiraju, 2014, Metrangolo & Resnati, 2014). We have recently reported the crystal structures of a dibrominated 3-formyl­chromone derivative 6,8-di­bromo-4-oxo-4H-chromene-3-carbaldehyde (Ishikawa, 2014a) and a monobrominated 3-formyl­chromone derivative 6-bromo-4-oxo-4H-chromene-3-carbaldehyde (Ishikawa, 2014b). Halogen bonding between the formyl oxygen atom and the bromine atom at 8-position and type II halogen···halogen inter­action between the bromine atoms at 6-position are observed in 6,8-di­bromo-4-oxo-4H-chromene-3-carbaldehyde (Fig.3, top). On the other hand, halogen bonding between the formyl oxygen atom and the bromine atom at 6-position is found in 6-bromo-4-oxo-4H-chromene-3-carbaldehyde (Fig.3, middle). As part of our inter­est in these types of chemical bonding, we herein report the crystal structure of a monobrominated 3-formyl­chromone derivative 7-bromo-4-oxo-4H-chromene-3-carbaldehyde.

The objective of this study is to reveal whether a short contact is found for the bromine atom at 7-position. The mean deviation of the least-square planes for the non-hydrogen atoms is 0.0631 Å, and the largest deviation is 0.215 (3) Å for the formyl O3 atom (Fig. 1). In the crystal, the molecules are linked through C–H···O hydrogen bonds between the translation-symmetryi and inversion-symmetry equivalentsii,iii to form tapes [i: x + 1, y + 1, z, ii: –x, –y + 1, –z + 1, iii: –x + 1, –y + 2, –z + 1], which are further assembled by stacking inter­actions [centroid–centroid distance between the pyran rings of the 4H-chromene units = 3.858 (3) Å], as shown in Fig. 2. A short contact for the bromine atom at 7-position is not observed (Fig. 3, bottom).

Synthesis and crystallization top

To a solution of 4-bromo-2-hy­droxy­aceto­phenone (4.7 mmol) in N,N-di­methyl­formamide (15 ml) was added drop-wise POCl3 (11.6 mmol) at 0 °C. After the mixture was stirred for 14 h at room temperature, water (50 ml) was added. The precipitates were collected, washed with water, and dried in vacuo (yield: 84%). 1H NMR (400 MHz, CDCl3): δ = 7.48 (d, 1H, J = 8.8 Hz), 7.57 (s, 1H), 8.24 (d, 1H, J = 8.8 Hz), 8.52 (s, 1H), 10.37 (s, 1H). DART-MS calcd for [C10H5BrO3 + H+]: 252.950, found 252.981. Single crystals suitable for X-ray diffraction were obtained from a 1,2-di­chloro­ethane/cyclo­hexane solution of the title compound at room temperature.

Refinement top

Crystal data, data collection and structure refinement details are summarized in Table 1. The C(sp2)-bound hydrogen atoms were placed in geometrical positions [C–H 0.95 Å, Uiso(H) = 1.2Ueq(C)], and refined using a riding model.

Related literature top

For related structures, see: Ishikawa (2014a,b). For halogen bonding, see: Auffinger et al. (2004); Metrangolo et al. (2005); Wilcken et al. (2013); Sirimulla et al. (2013). For halogen–halogen interactions, see: Metrangolo & Resnati (2014); Mukherjee & Desiraju (2014).

Computing details top

Data collection: WinAFC Diffractometer Control Software (Rigaku, 1999); cell refinement: WinAFC Diffractometer Control Software (Rigaku, 1999); data reduction: WinAFC Diffractometer Control Software (Rigaku, 1999); program(s) used to solve structure: SIR2008 (Burla et al., 2007); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalStructure (Rigaku, 2010); software used to prepare material for publication: CrystalStructure (Rigaku, 2010).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. Hydrogen atoms are shown as small spheres of arbitrary radius.
[Figure 2] Fig. 2. A packing view of the title compound. C—H···O hydrogen bonds are represented by dashed lines.
[Figure 3] Fig. 3. Sphere models of the crystal structures of 6,8-dibromo-4-oxo-4H-chromene-3-carbaldehyde (top, Ishikawa, 2014a), 6-bromo-4-oxo-4H-chromene-3-carbaldehyde (middle, Ishikawa, 2014b), and the title compound (bottom, this work).
7-Bromo-4-oxo-4H-chromene-3-carbaldehyde top
Crystal data top
C10H5BrO3F(000) = 496.00
Mr = 253.05Dx = 1.931 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ybcCell parameters from 25 reflections
a = 3.8580 (18) Åθ = 15.3–17.5°
b = 6.054 (4) ŵ = 4.71 mm1
c = 37.268 (13) ÅT = 100 K
β = 90.39 (4)°Plate, colourless
V = 870.4 (8) Å30.45 × 0.20 × 0.10 mm
Z = 4
Data collection top
Rigaku AFC-7R
diffractometer
Rint = 0.024
ω scansθmax = 27.5°
Absorption correction: ψ scan
(North et al., 1968)
h = 52
Tmin = 0.339, Tmax = 0.624k = 77
4817 measured reflectionsl = 4848
1980 independent reflections3 standard reflections every 150 reflections
1710 reflections with F2 > 2σ(F2) intensity decay: 4.8%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.109H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.0756P)2 + 0.989P]
where P = (Fo2 + 2Fc2)/3
1980 reflections(Δ/σ)max = 0.002
127 parametersΔρmax = 1.26 e Å3
0 restraintsΔρmin = 1.73 e Å3
Primary atom site location: structure-invariant direct methods
Crystal data top
C10H5BrO3V = 870.4 (8) Å3
Mr = 253.05Z = 4
Monoclinic, P21/cMo Kα radiation
a = 3.8580 (18) ŵ = 4.71 mm1
b = 6.054 (4) ÅT = 100 K
c = 37.268 (13) Å0.45 × 0.20 × 0.10 mm
β = 90.39 (4)°
Data collection top
Rigaku AFC-7R
diffractometer
1710 reflections with F2 > 2σ(F2)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.024
Tmin = 0.339, Tmax = 0.6243 standard reflections every 150 reflections
4817 measured reflections intensity decay: 4.8%
1980 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.109H-atom parameters constrained
S = 1.07Δρmax = 1.26 e Å3
1980 reflectionsΔρmin = 1.73 e Å3
127 parameters
Special details top

Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F2. R-factor (gt) are based on F. The threshold expression of F2 > 2.0 σ(F2) is used only for calculating R-factor (gt).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Br10.08234 (8)0.06978 (6)0.719199 (7)0.01987 (15)
O10.1286 (6)0.3047 (4)0.58604 (6)0.0198 (5)
O20.6540 (7)0.8813 (4)0.60418 (6)0.0253 (6)
O30.2989 (8)0.7487 (5)0.50270 (6)0.0321 (6)
C10.1969 (9)0.4490 (6)0.55957 (8)0.0199 (7)
C20.3614 (9)0.6437 (6)0.56382 (8)0.0190 (7)
C30.4862 (8)0.7122 (6)0.59908 (8)0.0181 (6)
C40.4730 (9)0.6080 (6)0.66421 (8)0.0173 (6)
C50.3830 (9)0.4628 (6)0.69123 (8)0.0187 (7)
C60.2140 (8)0.2670 (6)0.68222 (8)0.0167 (6)
C70.1322 (8)0.2111 (6)0.64716 (8)0.0170 (6)
C80.3930 (9)0.5598 (5)0.62828 (8)0.0169 (7)
C90.2221 (8)0.3622 (6)0.62059 (8)0.0164 (6)
C100.4165 (9)0.7874 (7)0.53244 (9)0.0256 (8)
H10.12330.41060.53600.0238*
H20.59000.74150.67000.0207*
H30.43570.49610.71560.0224*
H40.01970.07590.64150.0203*
H50.55120.91740.53560.0307*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0190 (3)0.0305 (3)0.01010 (19)0.00138 (11)0.00019 (12)0.00367 (11)
O10.0260 (12)0.0252 (12)0.0083 (10)0.0074 (10)0.0036 (9)0.0010 (9)
O20.0336 (14)0.0259 (12)0.0162 (11)0.0107 (11)0.0033 (10)0.0010 (10)
O30.0437 (16)0.0392 (15)0.0133 (12)0.0131 (12)0.0067 (11)0.0046 (11)
C10.0209 (16)0.0291 (18)0.0095 (14)0.0034 (13)0.0018 (12)0.0010 (12)
C20.0214 (16)0.0261 (16)0.0096 (13)0.0028 (13)0.0008 (12)0.0006 (12)
C30.0197 (15)0.0240 (15)0.0107 (14)0.0011 (12)0.0011 (11)0.0015 (12)
C40.0175 (15)0.0245 (16)0.0098 (14)0.0003 (12)0.0021 (11)0.0049 (12)
C50.0192 (16)0.0268 (17)0.0099 (14)0.0008 (12)0.0015 (12)0.0030 (12)
C60.0149 (14)0.0260 (16)0.0091 (13)0.0001 (12)0.0003 (10)0.0001 (12)
C70.0154 (14)0.0226 (15)0.0128 (14)0.0035 (12)0.0017 (11)0.0022 (12)
C80.0179 (15)0.0231 (16)0.0095 (14)0.0023 (12)0.0013 (12)0.0014 (11)
C90.0175 (15)0.0247 (15)0.0070 (13)0.0010 (12)0.0022 (11)0.0043 (12)
C100.0299 (19)0.0299 (17)0.0171 (16)0.0078 (15)0.0006 (14)0.0021 (14)
Geometric parameters (Å, º) top
Br1—C61.895 (4)C4—C81.403 (5)
O1—C11.345 (4)C5—C61.393 (5)
O1—C91.379 (4)C6—C71.384 (5)
O2—C31.226 (4)C7—C91.394 (5)
O3—C101.217 (5)C8—C91.395 (5)
C1—C21.348 (5)C1—H10.950
C2—C31.457 (5)C4—H20.950
C2—C101.474 (5)C5—H30.950
C3—C81.473 (5)C7—H40.950
C4—C51.382 (5)C10—H50.950
O1···C32.866 (5)C10···H12.5501
O2···C13.561 (5)H1···H53.4843
O2···C42.873 (4)H2···H32.3357
O2···C102.877 (5)Br1···H2i3.2968
O3···C12.820 (4)Br1···H2ii3.3454
C1···C73.578 (5)Br1···H3iii3.5917
C1···C82.748 (5)Br1···H3x3.1886
C2···C92.772 (5)Br1···H3xi3.0827
C4···C72.810 (5)O1···H5ii3.4250
C5···C92.769 (5)O2···H4iv3.0581
C6···C82.771 (5)O2···H4v2.2984
O1···O2i3.224 (4)O3···H1ix2.3733
O1···O2ii3.334 (4)O3···H1vii2.8324
O1···C3iii3.533 (5)O3···H5iii3.3041
O2···O1iv3.334 (4)O3···H5viii2.5428
O2···O1v3.224 (4)C2···H1vi3.4277
O2···C2vi3.440 (5)C3···H4iv3.2588
O2···C3vi3.376 (5)C3···H4v3.3965
O2···C7iv3.263 (4)C4···H2iii3.5093
O2···C7v3.149 (4)C4···H4iv3.4320
O2···C8vi3.562 (5)C5···H2iii3.5776
O2···C9iv3.412 (5)C6···H2ii3.5270
O3···O3vii3.394 (5)C6···H3iii3.5409
O3···O3viii3.422 (5)C7···H2ii3.4509
O3···C1ix3.228 (5)C7···H4vi3.5285
O3···C1vii3.265 (5)C8···H4iv3.4764
O3···C10iii3.595 (5)C10···H1vi3.5572
O3···C10viii3.290 (5)C10···H1ix3.4940
C1···O3ix3.228 (5)C10···H1vii3.3402
C1···O3vii3.265 (5)C10···H5iii3.4327
C1···C2iii3.437 (5)C10···H5viii3.1048
C1···C3iii3.504 (5)H1···O3ix2.3733
C2···O2iii3.440 (5)H1···O3vii2.8324
C2···C1vi3.437 (5)H1···C2iii3.4277
C3···O1vi3.533 (5)H1···C10iii3.5572
C3···O2iii3.376 (5)H1···C10ix3.4940
C3···C1vi3.504 (5)H1···C10vii3.3402
C4···C6vi3.586 (5)H1···H1ix3.0401
C4···C7vi3.559 (5)H1···H5ii3.4115
C5···C6vi3.437 (5)H1···H5vii3.5617
C6···C4iii3.586 (5)H2···Br1iv3.3454
C6···C5iii3.437 (5)H2···Br1v3.2968
C7···O2i3.149 (4)H2···C4vi3.5093
C7···O2ii3.263 (4)H2···C5vi3.5776
C7···C4iii3.559 (5)H2···C6iv3.5270
C8···O2iii3.562 (5)H2···C7iv3.4509
C8···C9vi3.429 (5)H2···H4iv3.1684
C9···O2ii3.412 (5)H2···H4v2.8291
C9···C8iii3.429 (5)H3···Br1vi3.5917
C10···O3vi3.595 (5)H3···Br1xii3.1886
C10···O3viii3.290 (5)H3···Br1xiii3.0827
C10···C10viii3.593 (6)H3···C6vi3.5409
Br1···H32.9226H4···O2i2.2984
Br1···H42.9055H4···O2ii3.0581
O1···H42.5249H4···C3i3.3965
O2···H22.6093H4···C3ii3.2588
O2···H52.5934H4···C4ii3.4320
O3···H12.4901H4···C7iii3.5285
C1···H53.2749H4···C8ii3.4764
C3···H13.2825H4···H2i2.8291
C3···H22.6775H4···H2ii3.1684
C3···H52.6858H5···O1iv3.4250
C5···H43.2949H5···O3vi3.3041
C6···H23.2513H5···O3viii2.5428
C7···H33.2879H5···C10vi3.4327
C8···H33.2793H5···C10viii3.1048
C8···H43.3027H5···H1iv3.4115
C9···H13.1864H5···H1vii3.5617
C9···H23.2628H5···H5viii2.8597
C1—O1—C9118.0 (3)C4—C8—C9118.4 (3)
O1—C1—C2125.2 (3)O1—C9—C7115.7 (3)
C1—C2—C3120.5 (3)O1—C9—C8121.9 (3)
C1—C2—C10119.6 (3)C7—C9—C8122.4 (3)
C3—C2—C10120.0 (3)O3—C10—C2123.6 (4)
O2—C3—C2123.3 (3)O1—C1—H1117.410
O2—C3—C8122.7 (3)C2—C1—H1117.401
C2—C3—C8114.0 (3)C5—C4—H2119.709
C5—C4—C8120.6 (3)C8—C4—H2119.732
C4—C5—C6119.0 (3)C4—C5—H3120.507
Br1—C6—C5119.2 (3)C6—C5—H3120.495
Br1—C6—C7118.2 (3)C6—C7—H4121.481
C5—C6—C7122.6 (3)C9—C7—H4121.508
C6—C7—C9117.0 (3)O3—C10—H5118.165
C3—C8—C4121.4 (3)C2—C10—H5118.205
C3—C8—C9120.2 (3)
C1—O1—C9—C7177.4 (3)C8—C4—C5—C60.5 (5)
C1—O1—C9—C82.2 (4)C8—C4—C5—H3179.5
C9—O1—C1—C22.5 (5)H2—C4—C5—C6179.5
C9—O1—C1—H1177.5H2—C4—C5—H30.5
O1—C1—C2—C30.9 (5)H2—C4—C8—C30.0
O1—C1—C2—C10179.4 (3)H2—C4—C8—C9179.8
H1—C1—C2—C3179.1C4—C5—C6—Br1178.8 (3)
H1—C1—C2—C100.6C4—C5—C6—C70.1 (5)
C1—C2—C3—O2175.8 (3)H3—C5—C6—Br11.1
C1—C2—C3—C84.2 (5)H3—C5—C6—C7179.9
C1—C2—C10—O35.6 (5)Br1—C6—C7—C9178.02 (18)
C1—C2—C10—H5174.4Br1—C6—C7—H42.0
C3—C2—C10—O3174.7 (3)C5—C6—C7—C90.9 (5)
C3—C2—C10—H55.3C5—C6—C7—H4179.1
C10—C2—C3—O23.9 (5)C6—C7—C9—O1178.3 (3)
C10—C2—C3—C8176.1 (3)C6—C7—C9—C81.2 (5)
O2—C3—C8—C44.2 (5)H4—C7—C9—O11.7
O2—C3—C8—C9175.6 (3)H4—C7—C9—C8178.8
C2—C3—C8—C4175.8 (3)C3—C8—C9—O11.4 (5)
C2—C3—C8—C94.4 (4)C3—C8—C9—C7179.2 (3)
C5—C4—C8—C3180.0 (3)C4—C8—C9—O1178.8 (3)
C5—C4—C8—C90.2 (5)C4—C8—C9—C70.7 (5)
Symmetry codes: (i) x1, y1, z; (ii) x, y1, z; (iii) x1, y, z; (iv) x, y+1, z; (v) x+1, y+1, z; (vi) x+1, y, z; (vii) x+1, y+1, z+1; (viii) x+1, y+2, z+1; (ix) x, y+1, z+1; (x) x, y1/2, z+3/2; (xi) x+1, y1/2, z+3/2; (xii) x, y+1/2, z+3/2; (xiii) x+1, y+1/2, z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7v—H4v···O20.952.303.149 (4)149 (1)
C1ix—H1ix···O30.952.373.228 (5)149 (1)
Symmetry codes: (v) x+1, y+1, z; (ix) x, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7i—H4i···O20.952.303.149 (4)148.7 (2)
C1ii—H1ii···O30.952.373.228 (5)149.4 (2)
Symmetry codes: (i) x+1, y+1, z; (ii) x, y+1, z+1.
 

Acknowledgements

The University of Shizuoka is acknowledged for instrument support.

References

First citationAuffinger, P., Hays, F. A., Westhof, E. & Ho, P. S. (2004). Proc. Natl Acad. Sci. USA, 101, 16789–16794.  Web of Science CrossRef PubMed CAS Google Scholar
First citationBurla, M. C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G. L., De Caro, L., Giacovazzo, C., Polidori, G., Siliqi, D. & Spagna, R. (2007). J. Appl. Cryst. 40, 609–613.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationIshikawa, Y. (2014a). Acta Cryst. E70, o439.  CSD CrossRef IUCr Journals Google Scholar
First citationIshikawa, Y. (2014b). Acta Cryst. E70, o555.  CSD CrossRef IUCr Journals Google Scholar
First citationMetrangolo, P., Neukirch, H., Pilati, T. & Resnati, G. (2005). Acc. Chem. Res. 38, 386–395.  Web of Science CrossRef PubMed CAS Google Scholar
First citationMetrangolo, P. & Resnati, G. (2014). IUCrJ, 1, 5–7.  CrossRef CAS PubMed IUCr Journals Google Scholar
First citationMukherjee, A. & Desiraju, G. R. (2014). IUCrJ, 1, 49–60.  CSD CrossRef CAS PubMed IUCr Journals Google Scholar
First citationNorth, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.  CrossRef IUCr Journals Web of Science Google Scholar
First citationRigaku (1999). WinAFC Diffractometer Control Software. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationRigaku (2010). CrystalStructure. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSirimulla, S., Bailey, J. B., Vegesna, R. & Narayan, M. (2013). J. Chem. Inf. Model. 53, 2781–2791.  Web of Science CrossRef CAS PubMed Google Scholar
First citationWilcken, R., Zimmermann, M. O., Lange, A., Joerger, A. C. & Boeckler, F. M. (2013). J. Med. Chem. 56, 1363–1388.  Web of Science CrossRef CAS PubMed Google Scholar

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