organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
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ISSN: 2056-9890
Volume 70| Part 11| November 2014| Pages o1165-o1166

Crystal structure of 4-(2-bromo­prop­ion­yl)-3-phenyl­sydnone

aWright State University, Chemistry, 3649 Colonel Glenn Hwy, Dayton, Ohio 45435, USA
*Correspondence e-mail: david.grossie@wright.edu

Edited by S. Parkin, University of Kentucky, USA (Received 12 September 2014; accepted 8 October 2014; online 18 October 2014)

Sydnones are a class of mesoionic compounds containing a five-membered heterocyclic ring. In general, sydnone com­pounds are synthesized with an aromatic substutuent at the N3 position. This feature, adds to the stability of the heterocyclic ring. In the title compound {systematic name: 4-(2-bromo­propano­yl)-3-phenyl-1,2,3λ5-oxa­diazol-3-ylium-5-olate}, C11H9BrN2O3, the aromatic substitutent is an unsubstituted phenyl ring. The sydnone ring is almost planar, with a maximum deviation from the mean plane of 0.023 (1) Å, but is not coplanar with the phenyl ring, having a dihedral angle of 40.93 (8)°. The carbonyl side chain is twisted relative to the syndone ring by 15.8 (2)°. The mol­ecules are packed in the unit cell as pairs related by an inversion center at (1, 0, 1/2). The pairs inter­act via π-stacking, with the distance separating the centroids being 3.824 (1) Å. The Br atom has two contacts, one to an N atom in a neighboring asymmetric unit with a distance of 3.346 (2) Å (the sum of the van der Waals radii is 3.40 Å) and a second to an H atom with a distance of 3.03 Å. The contact with the H atom is perpendicular (C—Br⋯H = 98.60°) to the C—Br bond, and that to the N atom is linear [C—Br⋯N = 169.10 (5)°] to the C—Br bond. The O atom of the sydnone ring is involved in two hydrogen bonds, one intra­molecular with a donor–acceptor distance of 3.1486 (19) Å and a second that is inter­molecular, with a phenyl H atom as the donor and has a donor–acceptor distance of 3.346 (2) Å.

1. Related literature

For more information on the sydnone family of compounds, see: Ohta & Kato (1969[Ohta, M. & Kato, H. (1969). Nonbenzenoid Aromatics, edited by J. P. Snyder, pp. 117-248. New York: Academic Press.]). For synthesis and structural information, see: Hope & Thiessen (1969[Hope, H. & Thiessen, W. E. (1969). Acta Cryst. B25, 1237-1247.]); Ollis & Ramsden (1976[Ollis, W. D. & Ramsden, C. A. (1976). Adv. Heterocycl. Chem. 19, 1-122.]); Hodson & Turnbull (1985[Hodson, S. J. & Turnbull, K. (1985). J. Heterocycl. Chem. 22, 1223-1227.]); Grossie & Turnbull (1992[Grossie, D. A. & Turnbull, K. (1992). Acta Cryst. C48, 377-379.]); Grossie et al. (2001[Grossie, D. A., Turnbull, K. & Krein, D. M. (2001). Acta Cryst. E57, o985-o987.], 2007[Grossie, D. A., Sun, L. & Turnbull, K. (2007). Acta Cryst. E63, o2042-o2043.]); Riddle et al. (2004a[Riddle, G. B., Grossie, D. A. & Turnbull, K. (2004a). Acta Cryst. E60, o258-o259.],b[Riddle, G. B., Grossie, D. A. & Turnbull, K. (2004b). Acta Cryst. E60, o977-o978.],c[Riddle, G. B., Grossie, D. A. & Turnbull, K. (2004c). Acta Cryst. E60, o1568-o1570.]). For further synthesis information, see: Balaguer et al. (2013[Balaguer, A., Selhorst, R. & Turnbull, K. (2013). Synth. Commun. 43, 1626-1632.]). For halogen-bond information, see: Politzer et al. (2010[Politzer, P., Murray, J. & Clark, T. (2010). Phys. Chem. Chem. Phys. 12, 7748-7757.]).

[Scheme 1]

2. Experimental

2.1. Crystal data

  • C11H9BrN2O3

  • Mr = 297.11

  • Triclinic, [P \overline 1]

  • a = 7.5388 (8) Å

  • b = 7.8094 (8) Å

  • c = 10.2470 (11) Å

  • α = 89.1333 (14)°

  • β = 77.2754 (14)°

  • γ = 72.6502 (13)°

  • V = 560.86 (10) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 3.66 mm−1

  • T = 173 K

  • 0.48 × 0.43 × 0.21 mm

2.2. Data collection

  • Bruker APEXII diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2006[Bruker (2006). APEX2 and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.586, Tmax = 0.746

  • 8816 measured reflections

  • 3313 independent reflections

  • 3091 reflections with I > 2σ(I)

  • Rint = 0.019

2.3. Refinement

  • R[F2 > 2σ(F2)] = 0.025

  • wR(F2) = 0.068

  • S = 1.06

  • 3313 reflections

  • 155 parameters

  • H-atom parameters constrained

  • Δρmax = 0.83 e Å−3

  • Δρmin = −0.24 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C35—H35⋯O41i 0.95 2.52 3.346 (2) 146
C42—H42⋯O5 1.00 2.43 3.1486 (19) 128
Symmetry code: (i) -x+2, -y, -z+1.

Data collection: APEX2 (Bruker, 2006[Bruker (2006). APEX2 and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: APEX2; data reduction: APEX2; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]); software used to prepare material for publication: OLEX2.

Supporting information


Comment top

The molecule contains one chiral center, C42, which in the asymmetric unit used in refinement has an S configuration. The sydnone (O1 - C5) and phenyl ring (C31 - C36) are planar with maximum deviation from the mean plane of 0.023 (1) and 0.006 (1) Å, respectively. The angle between the planes of the sydnone (O1 – C5) and phenyl ring (C31 – C36) is 40.93 (8)°. The molecule is packed in the unit cell with the phenyl ring of neighboring molecules lying parallel to one another, with a separation of 3.346 (2) Å. The molecules are related by an inversion center at (1, 0, 0.5), lying head-to-tail with the centroids of the parallel phenyl rings shifted by 1.851 (1) Å. Each pair of molecules is repeated with a separation between nearest rings of 3.317 (2) Å and an offset of 4.600 (2) Å. In addition, weak hydrogen- and halogen-bonding is observed around the bromine atom, a halogen-bond to N2 in a neighboring asymmetric unit with a distance of 3.346 (2) Å and a hydrogen-bond to H42 with a distance of 3.028Å. The hydrogen-bond with H42 has an angle at Br1 of 98.60° and the halogen bond has an angle of 169.10 (5)°. This behavior is characteristic of the "flattening" of halogen atoms in the direction of the C—Br bond as discussed by Politzer et al. (2010). The oxygen atom O5 of the sydnone ring is involved in two hydrogen bonds, one intra­molecular to H42 with a D···A distance of 3.1486 (19) Å and a second that is inter­molecular, using a phenyl hydrogen atom, H35, as the donor and has a D···A distance of 3.346 (2) Å. The packing of the molecules is shown in Fig. 2.

Synthesis top

3-Phenyl-4-(2-bromo­propionyl)sydnone was prepared in 84% yield from 3-phenyl-4-propionyl)sydnone (itself synthesized in 63% yield from 3-phenyl­sydnone by Friedel-Crafts acyl­ation with propionic anhydride, bis­muth triflate and lithium perchlorate) by treatment with bromine (10 eq) in glacial acetic acid with a few drops of concentrated sulfuric acid at 40°C for 2 hours (Balaguer et al., 2013).

Refinement top

Crystal data, data collection and structure refinement details are summarized in the following tables. Refinement of the compound resulted in residual positive electron density (0.83 e Å-3) in the vicinity the the Br atom. Hydrogen atom positions were calculated using geometric parameters and allowed to refined as a "riding" atom with a isotropic thermal factor equal to 1.5 Ueq of the attached atoms with sp3 hybridization and 1.2 Ueq of the attached atoms with sp2 hybridization positions.

Related literature top

For more information on the sydnone family of compounds, see: Ohta & Kato (1969). For synthesis and structural information, see: Hope & Thiessen (1969); Ollis & Ramsden (1976); Hodson & Turnbull (1985); Grossie & Turnbull (1992); Grossie et al. (2001, 2007); Riddle et al. (2004a,b,c). For further synthesis information, see: Balaguer et al. (2013). For halogen-bond information, see: Politzer et al. (2010).

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: APEX2 (Bruker, 2006); data reduction: APEX2 (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Figures top
Fig. 1. The title compound with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitary radius.

Fig. 2. The packing diagram of the title compound, viewed down the a-axis.
4-(2-Bromopropanoyl)-3-phenyl-1,2,3λ5-oxadiazol-3-ylium-5-olate top
Crystal data top
C11H9BrN2O3Z = 2
Mr = 297.11F(000) = 296
Triclinic, P1Dx = 1.759 Mg m3
a = 7.5388 (8) ÅMo Kα radiation, λ = 0.71073 Å
b = 7.8094 (8) ÅCell parameters from 4182 reflections
c = 10.2470 (11) Åθ = 2.7–30.7°
α = 89.1333 (14)°µ = 3.66 mm1
β = 77.2754 (14)°T = 173 K
γ = 72.6502 (13)°Block, clear colourless
V = 560.86 (10) Å30.48 × 0.43 × 0.21 mm
Data collection top
Bruker APEXII
diffractometer
3091 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.019
ω scansθmax = 31.3°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Bruker, 2006)
h = 1010
Tmin = 0.586, Tmax = 0.746k = 1111
8816 measured reflectionsl = 1414
3313 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.025H-atom parameters constrained
wR(F2) = 0.068 w = 1/[σ2(Fo2) + (0.047P)2 + 0.071P]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max = 0.001
3313 reflectionsΔρmax = 0.83 e Å3
155 parametersΔρmin = 0.24 e Å3
0 restraints
Crystal data top
C11H9BrN2O3γ = 72.6502 (13)°
Mr = 297.11V = 560.86 (10) Å3
Triclinic, P1Z = 2
a = 7.5388 (8) ÅMo Kα radiation
b = 7.8094 (8) ŵ = 3.66 mm1
c = 10.2470 (11) ÅT = 173 K
α = 89.1333 (14)°0.48 × 0.43 × 0.21 mm
β = 77.2754 (14)°
Data collection top
Bruker APEXII
diffractometer
3313 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2006)
3091 reflections with I > 2σ(I)
Tmin = 0.586, Tmax = 0.746Rint = 0.019
8816 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0250 restraints
wR(F2) = 0.068H-atom parameters constrained
S = 1.06Δρmax = 0.83 e Å3
3313 reflectionsΔρmin = 0.24 e Å3
155 parameters
Special details top

Experimental. Absorption correction: SADABS-2008/1 (Bruker,2008) was used for absorption correction. wR2(int) was 0.1048 before and 0.0276 after correction. The Ratio of minimum to maximum transmission is 0.7846. The λ/2 correction factor is 0.0015.

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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

Sydnone:O1—C5

0.7220 (5) x - 0.4771 (6) y + 0.5010 (7) z = 7.363 (6)

0.023 (1) O1* -0.016 (1) N2* 0.002 (1) N3* 0.012 (1) C4* -0.022 (2) C5*

Attached phenyl ring: C31–36

-0.1134 (6) x + 0.8146 (4) y - 0.5688 (5) z = -2.369 (5)

-0.004 (1) C31* -0.006 (1) C32* 0.004 (1) C33* -0.002 (1) C34* 0.005 (1) C35* -0.005 (1) C36

Angle to previous plane (with approximate e.s.d.) = 40.93 (8)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Br10.08657 (2)0.41054 (2)0.79958 (2)0.02060 (6)
O50.37447 (17)0.66470 (15)0.94737 (11)0.0212 (2)
O410.55129 (15)0.11464 (14)0.77220 (11)0.0188 (2)
N30.66206 (17)0.42537 (16)0.66182 (12)0.0141 (2)
O10.61412 (16)0.67163 (14)0.76973 (11)0.0186 (2)
N20.71705 (18)0.56946 (17)0.65504 (13)0.0174 (2)
C310.7431 (2)0.30011 (19)0.54603 (14)0.0147 (2)
C40.52361 (19)0.42322 (18)0.77203 (14)0.0143 (2)
C360.9357 (2)0.26502 (19)0.48800 (15)0.0163 (3)
H361.01290.31730.52590.020*
C320.6253 (2)0.2270 (2)0.49368 (14)0.0170 (3)
H320.49330.25480.53460.020*
C330.7057 (2)0.1117 (2)0.37938 (15)0.0193 (3)
H330.62870.05830.34220.023*
C420.2688 (2)0.30934 (19)0.91455 (14)0.0153 (3)
H420.25970.40370.98270.018*
C410.4596 (2)0.26752 (19)0.81517 (14)0.0143 (2)
C50.4824 (2)0.58994 (19)0.84533 (15)0.0164 (3)
C340.8990 (2)0.0748 (2)0.31958 (15)0.0202 (3)
H340.95310.00350.24150.024*
C351.0130 (2)0.1516 (2)0.37324 (15)0.0186 (3)
H351.14440.12640.33130.022*
C430.2287 (2)0.1487 (2)0.98465 (15)0.0206 (3)
H43A0.09560.18251.03490.031*
H43B0.31330.10801.04650.031*
H43C0.25110.05140.91800.031*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.01601 (8)0.02299 (9)0.02065 (9)0.00160 (6)0.00565 (5)0.00083 (6)
O50.0253 (6)0.0159 (5)0.0184 (5)0.0025 (4)0.0019 (4)0.0031 (4)
O410.0191 (5)0.0133 (5)0.0201 (5)0.0018 (4)0.0003 (4)0.0004 (4)
N30.0130 (5)0.0146 (5)0.0152 (5)0.0042 (4)0.0042 (4)0.0009 (4)
O10.0204 (5)0.0160 (5)0.0201 (5)0.0069 (4)0.0040 (4)0.0013 (4)
N20.0176 (6)0.0168 (5)0.0188 (6)0.0068 (4)0.0039 (4)0.0004 (4)
C310.0161 (6)0.0142 (6)0.0131 (6)0.0038 (5)0.0032 (5)0.0015 (5)
C40.0142 (6)0.0142 (6)0.0134 (6)0.0038 (5)0.0015 (5)0.0003 (5)
C360.0162 (6)0.0163 (6)0.0167 (6)0.0060 (5)0.0033 (5)0.0030 (5)
C320.0163 (6)0.0189 (6)0.0165 (6)0.0053 (5)0.0051 (5)0.0021 (5)
C330.0241 (7)0.0191 (7)0.0172 (6)0.0076 (5)0.0083 (5)0.0012 (5)
C420.0159 (6)0.0158 (6)0.0131 (6)0.0035 (5)0.0025 (5)0.0001 (5)
C410.0159 (6)0.0144 (6)0.0124 (6)0.0038 (5)0.0039 (5)0.0013 (5)
C50.0186 (6)0.0144 (6)0.0168 (6)0.0043 (5)0.0059 (5)0.0018 (5)
C340.0263 (7)0.0170 (6)0.0153 (6)0.0054 (5)0.0021 (5)0.0001 (5)
C350.0186 (6)0.0170 (6)0.0175 (6)0.0043 (5)0.0002 (5)0.0025 (5)
C430.0231 (7)0.0206 (7)0.0168 (7)0.0078 (6)0.0003 (5)0.0024 (5)
Geometric parameters (Å, º) top
Br1—C421.9842 (14)C32—H320.9500
O5—C51.2070 (18)C32—C331.394 (2)
O41—C411.2192 (17)C33—H330.9500
N3—N21.3062 (17)C33—C341.394 (2)
N3—C311.4483 (18)C42—H421.0000
N3—C41.3622 (18)C42—C411.5158 (19)
O1—N21.3701 (16)C42—C431.512 (2)
O1—C51.4200 (18)C34—H340.9500
C31—C361.3873 (19)C34—C351.388 (2)
C31—C321.3872 (19)C35—H350.9500
C4—C411.4649 (19)C43—H43A0.9800
C4—C51.4289 (19)C43—H43B0.9800
C36—H360.9500C43—H43C0.9800
C36—C351.389 (2)
N2—N3—C31115.61 (12)C41—C42—H42109.5
N2—N3—C4114.72 (12)C43—C42—Br1111.26 (10)
C4—N3—C31129.37 (12)C43—C42—H42109.5
N2—O1—C5110.83 (10)C43—C42—C41114.62 (12)
N3—N2—O1105.26 (11)O41—C41—C4122.48 (13)
C36—C31—N3117.95 (13)O41—C41—C42121.98 (13)
C32—C31—N3119.37 (12)C4—C41—C42115.52 (12)
C32—C31—C36122.61 (13)O5—C5—O1120.00 (13)
N3—C4—C41125.59 (12)O5—C5—C4136.41 (14)
N3—C4—C5105.46 (12)O1—C5—C4103.57 (12)
C5—C4—C41128.09 (13)C33—C34—H34119.7
C31—C36—H36120.8C35—C34—C33120.51 (14)
C31—C36—C35118.43 (14)C35—C34—H34119.7
C35—C36—H36120.8C36—C35—H35119.9
C31—C32—H32120.9C34—C35—C36120.20 (13)
C31—C32—C33118.20 (13)C34—C35—H35119.9
C33—C32—H32120.9C42—C43—H43A109.5
C32—C33—H33120.0C42—C43—H43B109.5
C32—C33—C34120.04 (14)C42—C43—H43C109.5
C34—C33—H33120.0H43A—C43—H43B109.5
Br1—C42—H42109.5H43A—C43—H43C109.5
C41—C42—Br1102.16 (9)H43B—C43—H43C109.5
Br1—C42—C41—O41103.92 (14)C31—C36—C35—C340.5 (2)
Br1—C42—C41—C474.62 (12)C31—C32—C33—C341.0 (2)
N3—C31—C36—C35177.06 (13)C4—N3—N2—O11.77 (16)
N3—C31—C32—C33177.78 (13)C4—N3—C31—C36144.40 (15)
N3—C4—C41—O4115.8 (2)C4—N3—C31—C3238.7 (2)
N3—C4—C41—C42162.76 (13)C36—C31—C32—C331.0 (2)
N3—C4—C5—O5178.85 (18)C32—C31—C36—C350.2 (2)
N3—C4—C5—O12.85 (15)C32—C33—C34—C350.3 (2)
N2—N3—C31—C3642.21 (18)C33—C34—C35—C360.5 (2)
N2—N3—C31—C32134.71 (14)C41—C4—C5—O511.4 (3)
N2—N3—C4—C41169.29 (13)C41—C4—C5—O1166.87 (13)
N2—N3—C4—C50.77 (17)C5—O1—N2—N33.68 (15)
N2—O1—C5—O5177.26 (13)C5—C4—C41—O41152.03 (15)
N2—O1—C5—C44.09 (15)C5—C4—C41—C4229.4 (2)
C31—N3—N2—O1176.15 (11)C43—C42—C41—O4116.5 (2)
C31—N3—C4—C4117.3 (2)C43—C42—C41—C4164.94 (13)
C31—N3—C4—C5172.67 (13)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C35—H35···O41i0.952.523.346 (2)146
C42—H42···O51.002.433.1486 (19)128
Symmetry code: (i) x+2, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C35—H35···O41i0.952.523.346 (2)146
C42—H42···O51.002.433.1486 (19)128
Symmetry code: (i) x+2, y, z+1.
Halogen-bond Geometry (Å, °) top
D-Br···AD-BrBr···AD···AD-Br···A
C42-Br1···N2i1.9842 (15)3.3458 (14)5.307 (2)169.10 (5)
C42-Br1···H42ii1.9842 (15)3.033.86098.60
(i) 1-x,y,z (ii) -x,1-y,2-z

Acknowledgements

The authors would like to acknowledge the diffractometer time granted by A. Hunter, Youngstown State University.

References

First citationBalaguer, A., Selhorst, R. & Turnbull, K. (2013). Synth. Commun. 43, 1626–1632.  Web of Science CrossRef CAS Google Scholar
First citationBruker (2006). APEX2 and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationDolomanov, 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
First citationGrossie, D. A., Sun, L. & Turnbull, K. (2007). Acta Cryst. E63, o2042–o2043.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationGrossie, D. A. & Turnbull, K. (1992). Acta Cryst. C48, 377–379.  CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationGrossie, D. A., Turnbull, K. & Krein, D. M. (2001). Acta Cryst. E57, o985–o987.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationHodson, S. J. & Turnbull, K. (1985). J. Heterocycl. Chem. 22, 1223–1227.  CrossRef CAS Google Scholar
First citationHope, H. & Thiessen, W. E. (1969). Acta Cryst. B25, 1237–1247.  CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
First citationOhta, M. & Kato, H. (1969). Nonbenzenoid Aromatics, edited by J. P. Snyder, pp. 117–248. New York: Academic Press.  Google Scholar
First citationOllis, W. D. & Ramsden, C. A. (1976). Adv. Heterocycl. Chem. 19, 1–122.  CrossRef CAS Google Scholar
First citationPolitzer, P., Murray, J. & Clark, T. (2010). Phys. Chem. Chem. Phys. 12, 7748–7757.  Web of Science CrossRef CAS PubMed Google Scholar
First citationRiddle, G. B., Grossie, D. A. & Turnbull, K. (2004a). Acta Cryst. E60, o258–o259.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationRiddle, G. B., Grossie, D. A. & Turnbull, K. (2004b). Acta Cryst. E60, o977–o978.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationRiddle, G. B., Grossie, D. A. & Turnbull, K. (2004c). Acta Cryst. E60, o1568–o1570.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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Volume 70| Part 11| November 2014| Pages o1165-o1166
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