organic compounds
4-Chloro-1H-indole-2,3-dione
aDepartment of Chemistry and Biochemistry, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02747, USA
*Correspondence e-mail: dmanke@umassd.edu
The title compound, C8H4ClNO2, has two planar molecules in the with the non-H atoms showing a mean deviation from planarity of 0.015 and 0.022 Å, respectively. In the crystal, the molecules are linked through N—H⋯O hydrogen bonds to form infinite chains along [010]. They are further connected through C—H⋯Cl close contacts with a donor–acceptor distance of 3.682 (5) Å. No π–π interactions are observed in the structure.
Keywords: crystal structure; hydrogen bonding; isatins.
CCDC reference: 1476174
Structure description
As part of a continuing study of halogenated isatins, we report the H-indole-2,3-dione), Fig. 1. The of the structure contains two molecules that are nearly planar, with the non-H atoms possessing a mean deviation from planarity of 0.015 and 0.022 Å, respectively. The bond lengths and angles observed in the molecule are similar to those observed in the parent isatin (Goldschmidt & Llewellyn, 1950).
of 4-chloroisatin (4-chloro-1In the crystal, molecules form infinite chains along [010] through N1—H1⋯O3 and N2—H2⋯O1 hydrogen bonds (Table 1). These chains are further linked through C5—H5⋯Cl2 close contacts (Fig. 2). Similar C—H⋯Cl close contacts were not observed in the other 4-chloroisatin structures that have been reported (Hughes & Fenical, 2010; Wang et al., 2012; Yu et al., 2012). Halogen–oxygen rather than C—H⋯halogen interactions are observed in the structures of 4-bromoisatin (Huang et al., 2016) and 4-iodoisatin (Golen & Manke, 2016).
Synthesis and crystallization
A commercial sample (Matrix Scientific) of 4-chloro-1H-indole-2,3-dione was used for crystallization. A sample suitable for single-crystal X-ray analysis was grown by slow evaporation from an acetone solution.
Refinement
Crystal data, data collection and structure .
details are summarized in Table 2Structural data
CCDC reference: 1476174
10.1107/S2414314616006891/sj4026sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S2414314616006891/sj4026Isup2.hkl
Supporting information file. DOI: 10.1107/S2414314616006891/sj4026Isup3.cml
A commercial sample (Matrix Scientific) of 4-chloro-1H-indole-2,3-dione was used for crystallization. A sample suitable for single-crystal X-ray analysis was grown by slow evaporation from an acetone solution.
As part of a continuing study of halogenated isatins, we report the
of 4-chloroisatin (4-chloro-1H-indole-2,3-dione), Fig.1. The of the structure contains two molecules that are nearly planar, with the non-H atoms possessing a mean deviation from planarity of 0.015 and 0.022 Å, respectively. The bond lengths and angles observed in the molecule are similar to those observed in the parent isatin (Goldschmidt & Llewellyn, 1950).In the crystal, molecules form infinite chains along [010] through N1—H1···O3 and N2—H2···O1 hydrogen bonds (Table 1). These chains are further linked through C5—H5···Cl2 close contacts (Fig. 2). Similar C—H···Cl close contacts were not observed in the other 4-chloroisatin structures that have been reported (Hughes & Fenical, 2010; Wang et al., 2012; Yu et al., 2012). Halogen–oxygen rather than C—H···halogen interactions are observed in the structures of 4-bromoisatin (Huang et al., 2016) and 4-iodoisatin (Golen & Manke, 2016).
Data collection: APEX2 (Bruker, 2014); cell
SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009) and publCIF (Westrip, 2010).Fig. 1. The molecular structure of the title compound, showing the atom-labeling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are drawn as spheres of arbitrary radius. | |
Fig. 2. The molecular packing of the title compound viewed along the b axis, with hydrogen bonding shown as dashed lines. |
C8H4ClNO2 | F(000) = 368 |
Mr = 181.57 | Dx = 1.680 Mg m−3 |
Monoclinic, P21 | Cu Kα radiation, λ = 1.54178 Å |
Hall symbol: P 2yb | Cell parameters from 6743 reflections |
a = 8.2745 (8) Å | θ = 3.1–68.5° |
b = 6.0367 (6) Å | µ = 4.31 mm−1 |
c = 14.8609 (14) Å | T = 120 K |
β = 104.746 (5)° | Block, orange |
V = 717.86 (12) Å3 | 0.25 × 0.04 × 0.04 mm |
Z = 4 |
Bruker CMOS diffractometer | 2579 independent reflections |
Radiation source: Cu | 2388 reflections with I > 2σ(I) |
HELIOS MX monochromator | Rint = 0.058 |
φ and ω scans | θmax = 68.5°, θmin = 3.1° |
Absorption correction: multi-scan (SADABS; Bruker, 2014) | h = −9→9 |
Tmin = 0.205, Tmax = 0.311 | k = −7→7 |
9961 measured reflections | l = −17→17 |
Refinement on F2 | Hydrogen site location: mixed |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.038 | w = 1/[σ2(Fo2) + (0.0531P)2 + 0.171P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.096 | (Δ/σ)max < 0.001 |
S = 1.04 | Δρmax = 0.58 e Å−3 |
2579 reflections | Δρmin = −0.27 e Å−3 |
224 parameters | Absolute structure: Refined as an inversion twin. |
3 restraints | Absolute structure parameter: 0.11 (3) |
C8H4ClNO2 | V = 717.86 (12) Å3 |
Mr = 181.57 | Z = 4 |
Monoclinic, P21 | Cu Kα radiation |
a = 8.2745 (8) Å | µ = 4.31 mm−1 |
b = 6.0367 (6) Å | T = 120 K |
c = 14.8609 (14) Å | 0.25 × 0.04 × 0.04 mm |
β = 104.746 (5)° |
Bruker CMOS diffractometer | 2579 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2014) | 2388 reflections with I > 2σ(I) |
Tmin = 0.205, Tmax = 0.311 | Rint = 0.058 |
9961 measured reflections |
R[F2 > 2σ(F2)] = 0.038 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.096 | Δρmax = 0.58 e Å−3 |
S = 1.04 | Δρmin = −0.27 e Å−3 |
2579 reflections | Absolute structure: Refined as an inversion twin. |
224 parameters | Absolute structure parameter: 0.11 (3) |
3 restraints |
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. Refined as a 2-component inversion twin. |
x | y | z | Uiso*/Ueq | ||
Cl1 | 0.82671 (11) | −0.28031 (19) | 0.40490 (7) | 0.0329 (3) | |
Cl2 | 1.05021 (12) | 1.19333 (19) | 0.35368 (6) | 0.0317 (3) | |
O1 | 0.2975 (4) | −0.0106 (5) | 0.09037 (18) | 0.0293 (7) | |
O2 | 0.5638 (3) | −0.2926 (6) | 0.19884 (19) | 0.0332 (7) | |
O3 | 1.1154 (3) | 0.4626 (5) | 0.11689 (18) | 0.0279 (7) | |
O4 | 1.1901 (3) | 0.7341 (6) | 0.28454 (17) | 0.0289 (7) | |
N1 | 0.3652 (4) | 0.2002 (7) | 0.2246 (2) | 0.0246 (7) | |
H1 | 0.295 (5) | 0.309 (6) | 0.208 (3) | 0.029* | |
N2 | 0.9124 (4) | 0.7291 (7) | 0.0657 (2) | 0.0248 (8) | |
H2 | 0.868 (5) | 0.688 (9) | 0.0088 (14) | 0.030* | |
C1 | 0.3785 (5) | 0.0273 (7) | 0.1694 (3) | 0.0240 (9) | |
C2 | 0.5204 (5) | −0.1236 (7) | 0.2281 (3) | 0.0251 (9) | |
C3 | 0.5750 (5) | −0.0089 (7) | 0.3177 (3) | 0.0235 (9) | |
C4 | 0.6994 (5) | −0.0499 (8) | 0.3987 (3) | 0.0267 (9) | |
C5 | 0.7209 (5) | 0.0939 (8) | 0.4734 (3) | 0.0285 (10) | |
H5 | 0.8050 | 0.0660 | 0.5290 | 0.034* | |
C6 | 0.6195 (5) | 0.2785 (8) | 0.4667 (3) | 0.0285 (10) | |
H6 | 0.6340 | 0.3741 | 0.5189 | 0.034* | |
C7 | 0.4963 (5) | 0.3293 (8) | 0.3859 (3) | 0.0281 (9) | |
H7 | 0.4289 | 0.4582 | 0.3815 | 0.034* | |
C8 | 0.4775 (4) | 0.1828 (8) | 0.3127 (2) | 0.0226 (8) | |
C9 | 1.0412 (5) | 0.6310 (7) | 0.1266 (3) | 0.0229 (9) | |
C10 | 1.0799 (5) | 0.7769 (7) | 0.2159 (3) | 0.0221 (9) | |
C11 | 0.9586 (5) | 0.9583 (7) | 0.1941 (3) | 0.0229 (9) | |
C12 | 0.9285 (5) | 1.1431 (7) | 0.2424 (3) | 0.0252 (9) | |
C13 | 0.8008 (5) | 1.2893 (8) | 0.2018 (3) | 0.0290 (10) | |
H13 | 0.7766 | 1.4130 | 0.2357 | 0.035* | |
C14 | 0.7089 (5) | 1.2512 (8) | 0.1105 (3) | 0.0297 (10) | |
H14 | 0.6232 | 1.3527 | 0.0823 | 0.036* | |
C15 | 0.7387 (5) | 1.0694 (8) | 0.0594 (3) | 0.0273 (10) | |
H15 | 0.6758 | 1.0467 | −0.0029 | 0.033* | |
C16 | 0.8623 (5) | 0.9235 (7) | 0.1022 (3) | 0.0237 (9) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0260 (5) | 0.0331 (6) | 0.0362 (5) | 0.0057 (5) | 0.0014 (4) | 0.0081 (5) |
Cl2 | 0.0317 (5) | 0.0347 (6) | 0.0287 (5) | −0.0035 (5) | 0.0076 (4) | −0.0071 (5) |
O1 | 0.0320 (15) | 0.0288 (18) | 0.0237 (14) | 0.0041 (13) | 0.0010 (12) | −0.0016 (12) |
O2 | 0.0370 (15) | 0.0285 (18) | 0.0328 (14) | 0.0111 (17) | 0.0064 (12) | −0.0021 (16) |
O3 | 0.0281 (14) | 0.0259 (17) | 0.0290 (14) | 0.0051 (14) | 0.0061 (12) | 0.0007 (13) |
O4 | 0.0260 (13) | 0.035 (2) | 0.0231 (13) | 0.0010 (15) | 0.0006 (11) | 0.0019 (14) |
N1 | 0.0230 (16) | 0.0250 (19) | 0.0253 (15) | 0.0065 (17) | 0.0054 (12) | 0.0030 (17) |
N2 | 0.0238 (16) | 0.026 (2) | 0.0228 (15) | 0.0023 (16) | 0.0026 (12) | −0.0016 (15) |
C1 | 0.023 (2) | 0.023 (2) | 0.027 (2) | 0.0023 (17) | 0.0082 (17) | 0.0029 (17) |
C2 | 0.022 (2) | 0.025 (2) | 0.029 (2) | 0.0027 (17) | 0.0095 (17) | 0.0053 (18) |
C3 | 0.0212 (19) | 0.024 (2) | 0.0264 (19) | −0.0024 (17) | 0.0081 (15) | 0.0050 (17) |
C4 | 0.0191 (19) | 0.031 (3) | 0.030 (2) | −0.0020 (18) | 0.0067 (16) | 0.0081 (18) |
C5 | 0.021 (2) | 0.039 (3) | 0.024 (2) | −0.0023 (19) | 0.0034 (16) | 0.0054 (18) |
C6 | 0.030 (2) | 0.035 (3) | 0.0202 (19) | −0.0077 (19) | 0.0056 (17) | −0.0027 (17) |
C7 | 0.025 (2) | 0.028 (3) | 0.033 (2) | −0.0001 (18) | 0.0099 (18) | 0.0007 (18) |
C8 | 0.0179 (17) | 0.028 (2) | 0.0219 (17) | −0.0005 (18) | 0.0051 (14) | 0.0031 (17) |
C9 | 0.0207 (19) | 0.025 (2) | 0.0237 (19) | −0.0012 (17) | 0.0078 (15) | 0.0035 (16) |
C10 | 0.0199 (19) | 0.025 (2) | 0.0226 (19) | −0.0002 (16) | 0.0069 (16) | 0.0037 (15) |
C11 | 0.0214 (19) | 0.025 (2) | 0.0245 (18) | −0.0005 (17) | 0.0098 (15) | 0.0043 (17) |
C12 | 0.0214 (19) | 0.028 (3) | 0.028 (2) | −0.0020 (17) | 0.0099 (16) | 0.0025 (17) |
C13 | 0.029 (2) | 0.024 (2) | 0.039 (2) | 0.0022 (17) | 0.0165 (19) | 0.0006 (18) |
C14 | 0.0245 (19) | 0.028 (3) | 0.039 (2) | 0.0070 (18) | 0.0126 (17) | 0.0083 (19) |
C15 | 0.021 (2) | 0.032 (3) | 0.029 (2) | 0.0031 (17) | 0.0052 (17) | 0.0057 (18) |
C16 | 0.0213 (19) | 0.027 (2) | 0.0241 (19) | −0.0003 (17) | 0.0076 (15) | 0.0037 (17) |
Cl1—C4 | 1.733 (5) | C5—H5 | 0.9500 |
Cl2—C12 | 1.730 (4) | C5—C6 | 1.383 (7) |
O1—C1 | 1.217 (5) | C6—H6 | 0.9500 |
O2—C2 | 1.200 (6) | C6—C7 | 1.398 (6) |
O3—C9 | 1.215 (5) | C7—H7 | 0.9500 |
O4—C10 | 1.210 (5) | C7—C8 | 1.379 (6) |
N1—H1 | 0.869 (7) | C9—C10 | 1.557 (6) |
N1—C1 | 1.349 (6) | C10—C11 | 1.465 (6) |
N1—C8 | 1.404 (4) | C11—C12 | 1.383 (6) |
N2—H2 | 0.869 (7) | C11—C16 | 1.410 (6) |
N2—C9 | 1.347 (5) | C12—C13 | 1.391 (6) |
N2—C16 | 1.399 (6) | C13—H13 | 0.9500 |
C1—C2 | 1.564 (6) | C13—C14 | 1.395 (6) |
C2—C3 | 1.467 (6) | C14—H14 | 0.9500 |
C3—C4 | 1.393 (6) | C14—C15 | 1.392 (6) |
C3—C8 | 1.402 (6) | C15—H15 | 0.9500 |
C4—C5 | 1.385 (6) | C15—C16 | 1.376 (6) |
C1—N1—H1 | 124 (3) | C3—C8—N1 | 110.3 (4) |
C1—N1—C8 | 111.9 (4) | C7—C8—N1 | 127.1 (4) |
C8—N1—H1 | 124 (3) | C7—C8—C3 | 122.7 (4) |
C9—N2—H2 | 127 (4) | O3—C9—N2 | 128.7 (4) |
C9—N2—C16 | 111.7 (3) | O3—C9—C10 | 125.0 (4) |
C16—N2—H2 | 122 (4) | N2—C9—C10 | 106.3 (3) |
O1—C1—N1 | 128.5 (4) | O4—C10—C9 | 123.0 (4) |
O1—C1—C2 | 125.4 (4) | O4—C10—C11 | 132.3 (4) |
N1—C1—C2 | 106.1 (3) | C11—C10—C9 | 104.7 (3) |
O2—C2—C1 | 123.0 (4) | C12—C11—C10 | 133.8 (4) |
O2—C2—C3 | 132.8 (4) | C12—C11—C16 | 119.4 (4) |
C3—C2—C1 | 104.2 (3) | C16—C11—C10 | 106.9 (3) |
C4—C3—C2 | 133.7 (4) | C11—C12—Cl2 | 120.0 (3) |
C4—C3—C8 | 118.8 (4) | C11—C12—C13 | 120.3 (4) |
C8—C3—C2 | 107.5 (3) | C13—C12—Cl2 | 119.7 (3) |
C3—C4—Cl1 | 119.6 (3) | C12—C13—H13 | 120.6 |
C5—C4—Cl1 | 120.6 (3) | C12—C13—C14 | 118.9 (4) |
C5—C4—C3 | 119.8 (4) | C14—C13—H13 | 120.6 |
C4—C5—H5 | 120.2 | C13—C14—H14 | 118.9 |
C6—C5—C4 | 119.7 (4) | C15—C14—C13 | 122.1 (4) |
C6—C5—H5 | 120.2 | C15—C14—H14 | 118.9 |
C5—C6—H6 | 118.8 | C14—C15—H15 | 121.1 |
C5—C6—C7 | 122.4 (4) | C16—C15—C14 | 117.8 (4) |
C7—C6—H6 | 118.8 | C16—C15—H15 | 121.1 |
C6—C7—H7 | 121.7 | N2—C16—C11 | 110.5 (3) |
C8—C7—C6 | 116.6 (4) | C15—C16—N2 | 128.0 (4) |
C8—C7—H7 | 121.7 | C15—C16—C11 | 121.5 (4) |
Cl1—C4—C5—C6 | 179.2 (3) | C5—C6—C7—C8 | 1.4 (6) |
Cl2—C12—C13—C14 | 177.2 (3) | C6—C7—C8—N1 | −178.8 (4) |
O1—C1—C2—O2 | 1.0 (7) | C6—C7—C8—C3 | 0.3 (6) |
O1—C1—C2—C3 | −178.8 (4) | C8—N1—C1—O1 | 178.1 (4) |
O2—C2—C3—C4 | 2.8 (8) | C8—N1—C1—C2 | −1.0 (4) |
O2—C2—C3—C8 | −179.3 (4) | C8—C3—C4—Cl1 | −177.6 (3) |
O3—C9—C10—O4 | 0.3 (6) | C8—C3—C4—C5 | 2.1 (6) |
O3—C9—C10—C11 | −179.9 (4) | C9—N2—C16—C11 | −1.7 (4) |
O4—C10—C11—C12 | 1.0 (8) | C9—N2—C16—C15 | 178.1 (4) |
O4—C10—C11—C16 | 179.0 (4) | C9—C10—C11—C12 | −178.7 (4) |
N1—C1—C2—O2 | −179.9 (4) | C9—C10—C11—C16 | −0.8 (4) |
N1—C1—C2—C3 | 0.3 (4) | C10—C11—C12—Cl2 | 0.0 (6) |
N2—C9—C10—O4 | −180.0 (4) | C10—C11—C12—C13 | 179.9 (4) |
N2—C9—C10—C11 | −0.2 (4) | C10—C11—C16—N2 | 1.5 (4) |
C1—N1—C8—C3 | 1.3 (5) | C10—C11—C16—C15 | −178.4 (4) |
C1—N1—C8—C7 | −179.6 (4) | C11—C12—C13—C14 | −2.7 (6) |
C1—C2—C3—C4 | −177.4 (4) | C12—C11—C16—N2 | 179.8 (3) |
C1—C2—C3—C8 | 0.4 (4) | C12—C11—C16—C15 | 0.0 (6) |
C2—C3—C4—Cl1 | 0.0 (6) | C12—C13—C14—C15 | 1.3 (6) |
C2—C3—C4—C5 | 179.7 (4) | C13—C14—C15—C16 | 0.7 (6) |
C2—C3—C8—N1 | −1.0 (4) | C14—C15—C16—N2 | 178.9 (4) |
C2—C3—C8—C7 | 179.8 (4) | C14—C15—C16—C11 | −1.3 (6) |
C3—C4—C5—C6 | −0.5 (6) | C16—N2—C9—O3 | −179.2 (4) |
C4—C3—C8—N1 | 177.2 (3) | C16—N2—C9—C10 | 1.1 (4) |
C4—C3—C8—C7 | −2.0 (6) | C16—C11—C12—Cl2 | −177.8 (3) |
C4—C5—C6—C7 | −1.3 (6) | C16—C11—C12—C13 | 2.1 (6) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O3i | 0.87 (1) | 1.97 (2) | 2.768 (5) | 152 (4) |
N2—H2···O1ii | 0.87 (1) | 2.11 (2) | 2.905 (4) | 152 (5) |
C5—H5···Cl2iii | 0.95 | 2.91 | 3.682 (5) | 139 |
Symmetry codes: (i) x−1, y, z; (ii) −x+1, y+1/2, −z; (iii) −x+2, y−3/2, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O3i | 0.869 (7) | 1.97 (2) | 2.768 (5) | 152 (4) |
N2—H2···O1ii | 0.869 (7) | 2.11 (2) | 2.905 (4) | 152 (5) |
C5—H5···Cl2iii | 0.95 | 2.91 | 3.682 (5) | 139.2 |
Symmetry codes: (i) x−1, y, z; (ii) −x+1, y+1/2, −z; (iii) −x+2, y−3/2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C8H4ClNO2 |
Mr | 181.57 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 120 |
a, b, c (Å) | 8.2745 (8), 6.0367 (6), 14.8609 (14) |
β (°) | 104.746 (5) |
V (Å3) | 717.86 (12) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 4.31 |
Crystal size (mm) | 0.25 × 0.04 × 0.04 |
Data collection | |
Diffractometer | Bruker CMOS |
Absorption correction | Multi-scan (SADABS; Bruker, 2014) |
Tmin, Tmax | 0.205, 0.311 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9961, 2579, 2388 |
Rint | 0.058 |
(sin θ/λ)max (Å−1) | 0.603 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.096, 1.04 |
No. of reflections | 2579 |
No. of parameters | 224 |
No. of restraints | 3 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.58, −0.27 |
Absolute structure | Refined as an inversion twin. |
Absolute structure parameter | 0.11 (3) |
Computer programs: APEX2 (Bruker, 2014), SAINT (Bruker, 2014), SHELXS97 (Sheldrick, 2008), SHELXL2014 (Sheldrick, 2015), OLEX2 (Dolomanov et al., 2009) and publCIF (Westrip, 2010).
Acknowledgements
We greatly acknowledge support from the National Science Foundation (CHE-1429086).
References
Bruker (2014). APEX2, SAINT, and SADABS. Bruker AXS Inc. Madison, Wisconsin, USA. Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Goldschmidt, G. H. & Llewellyn, F. J. (1950). Acta Cryst. 3, 294–305. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Golen, J. A. & Manke, D. R. (2016). IUCrData, 1, x160215. Google Scholar
Huang, H., Golen, J. A. & Manke, D. R. (2016). IUCrData, 1, x160007. Google Scholar
Hughes, C. C. & Fenical, W. (2010). J. Am. Chem. Soc. 132, 2528–2529. Web of Science CSD CrossRef CAS PubMed Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Wang, D. C., Leng, B. R., Wang, G. B., Wei, P. & Ou-yang, P. K. (2012). Acta Cryst. E68, o37. Web of Science CSD CrossRef IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Yu, J. G., Tang, W., Wang, D. C. & Xu, H. (2012). Acta Cryst. E68, o219. Web of Science CSD CrossRef IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.