supplementary materials


HTML versionpdf versioncif file3d viewstructure factorssupplementary materialsCIF check reportsimilar papers Open access

tk2275 scheme

Acta Cryst. (2008). E64, o1345-o1346    [ doi:10.1107/S1600536808018709 ]

Cytenamide-1,4-dioxane (2/1)

A. Johnston, A. J. Florence, F. J. A. Fabbiani, K. Shankland and C. T. Bedford

Abstract top

In the crystal structure of the title compound [systematic name: 5H-dibenzo[a,d]cycloheptatriene-5-carboxamide-1,4-dioxane (2/1)], 2C16H13NO·C4H8O2, the cytenamide molecules form a hydrogen-bonded R22(8) dimer. The solvent molecule is located between two adjacent cytenamide dimers and forms N-H...O hydrogen bonds with one cytenamide molecule from each dimer.

Comment top

Cytenamide (CYT) is an analogue of carbamazepine (CBZ), a dibenzazepine drug used to control seizures (Cyr et al., 1987). CYT-dioxane hemisolvate was produced during an automated parallel crystallization study of CYT (Florence, Johnston, Fernandes et al., 2006) as part of a wider investigation that couples automated parallel crystallization with crystal structure prediction methodology to investigate the basic science underlying the solid-state diversity of CBZ (Florence, Johnston, Price et al., 2006; Florence, Leech et al., 2006; Fleischman et al., 2003) and its closely related analogues: CYT (Florence et al., 2008a),10,11-dihydrocarbamazepine (Bandoli et al., 1992; Harrison et al., 2006; Leech et al., 2007) and cyheptamide (Florence, Shankland et al., 2008). The sample was identified as a new form using multi-sample foil transmission X-ray powder diffraction analysis (Florence et al., 2003). Subsequent manual recrystallization from a saturated 1,4-dioxane solution by slow evaporation at 298 K yielded a sample suitable for single-crystal X-ray diffraction (Fig. 1).

The reported crystal structure is essentially isostructural with that of CBZ-dioxane solvate (2/1) (Florence, Johnston, Price et al., 2006) and accordingly displays very similar packing arrangements. Specifically, the molecules crystallize with two CYT and one 1,4-dioxane molecules in the asymmetric unit. Pairs of CYT molecules form an R22(8) dimer motif (Etter, 1990) via two N—H···O hydrogen bonds and a further two N—H···O contacts link CYT dimers with solvent molecules to form an infinite chain that extends in the c-direction (Table 1 & Fig. 2).

Related literature top

For details on experimental methods used to obtain this form, see: Davis et al. (1964); Florence et al. (2003); Florence, Johnston, Fernandes et al. (2006). For related literature on cytenamide, see: (Florence, Bedford et al. (2008). For literature on related molecules, see: Cyr et al. (1987); Fleischman et al. (2003); Florence, Johnston, Price et al. (2006); Florence, Leech et al. (2006); Bandoli et al. (1992); Harrison et al. (2006); Leech et al. (2007); Florence, Shankland et al. (2008). For other related literature, see: Etter (1990).

Experimental top

A sample of cytenamide was synthesized according to a modification of the published method (Davis et al., 1964). A single crystal of (I) was grown from a saturated solution of cytenamide in 1,4-dioxane by isothermal solvent evaporation at 298 K.

Refinement top

Data were merged with SORTAV (Blessing, 1997) and a theta cut off of 25.0 ° was applied due to weak scattering. H-atoms were found on a difference Fourier map and were initially refined with soft restraints on the bond lengths and angles to regularize their geometry. The C-H distances are in the range 0.92 - 0.98 Å and Uiso(H) = 1.2-1.5Ueq(C). Atoms C12 C13 C14 and to some extent C15 suffer from large and prolate thermal ellipsoids. During refinement, the crystal was found to be twinned, according to the twin law expressed by the following matrix: 1 0 0.012, 0 - 1 0, 0 0 - 1 i.e. approximately about the a axis, giving rise to a twin component of ca 10%. Inclusion of the twin resulted in a reduction of the R-factor by ca 1%.

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2007); cell refinement: CrysAlis RED (Oxford Diffraction, 2007); data reduction: CrysAlis RED (Oxford Diffraction, 2007); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), showing 50% probablility displacement ellipsoids.
[Figure 2] Fig. 2. Packing diagram for (I) viewed down the b axis, showing the CYT R22(8) dimer motif further linked by N—H···O hydrogen bonds between CYT and dioxane molecules to form an infinite chain in the [001] direction. Molecules are coloured according to symmetry equivalence (CYT blue and green, dioxane molecules red) and hydrogen bonds are represented by dashed lines.
5H-dibenzo[a,d]cycloheptatriene-5-carboxamide 1,4-dioxane hemisolvate top
Crystal data top
2C16H13NO·C4H8O2F000 = 1184
Mr = 558.68Dx = 1.302 Mg m−3
Monoclinic, P21/cMo Kα radiation
λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 4484 reflections
a = 24.0888 (7) Åθ = 3–27º
b = 5.6066 (2) ŵ = 0.09 mm−1
c = 21.1050 (6) ÅT = 160 K
β = 90.313 (3)ºPlate, colourless
V = 2850.32 (15) Å30.48 × 0.09 × 0.03 mm
Z = 4
Data collection top
Area
diffractometer		5125 independent reflections
Monochromator: graphite3677 reflections with I > 2σ(I)
Detector resolution: 15.9745 pixels mm-1Rint = 0.057
T = 160 Kθmax = 25.2º
ω scansθmin = 2.6º
Absorption correction: multi-scan
(ABSPACK; Oxford Diffraction, 2007)		h = −28→28
Tmin = 0.84, Tmax = 1.00k = 0→6
23004 measured reflectionsl = 0→25
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.068  Method = Modified Sheldrick w = 1/[σ2(F2) + (0.03P)2 + 2.31P],
where P = [max(Fo2,0) + 2Fc2]/3
wR(F2) = 0.121(Δ/σ)max < 0.001
S = 1.08Δρmax = 0.47 e Å−3
5125 reflectionsΔρmin = −0.42 e Å−3
380 parametersExtinction correction: None
Primary atom site location: structure-invariant direct methods
Crystal data top
2C16H13NO·C4H8O2V = 2850.32 (15) Å3
Mr = 558.68Z = 4
Monoclinic, P21/cMo Kα
a = 24.0888 (7) ŵ = 0.09 mm−1
b = 5.6066 (2) ÅT = 160 K
c = 21.1050 (6) Å0.48 × 0.09 × 0.03 mm
β = 90.313 (3)º
Data collection top
Area
diffractometer		5125 independent reflections
Absorption correction: multi-scan
(ABSPACK; Oxford Diffraction, 2007)		3677 reflections with I > 2σ(I)
Tmin = 0.84, Tmax = 1.00Rint = 0.057
23004 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.068380 parameters
wR(F2) = 0.121H-atom parameters constrained
S = 1.08Δρmax = 0.47 e Å−3
5125 reflectionsΔρmin = −0.42 e Å−3
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.30658 (11)0.7244 (5)0.22235 (12)0.0230
C20.34609 (11)0.5089 (5)0.22501 (12)0.0212
C30.38005 (11)0.4805 (5)0.16566 (12)0.0223
C40.36884 (12)0.2923 (5)0.12509 (12)0.0258
C50.39561 (13)0.2692 (6)0.06774 (13)0.0325
C60.43397 (12)0.4386 (6)0.04947 (14)0.0345
C70.44599 (12)0.6265 (6)0.08979 (13)0.0319
C80.42064 (11)0.6495 (5)0.14882 (12)0.0236
C90.43795 (11)0.8470 (5)0.18941 (13)0.0273
C100.43627 (11)0.8646 (5)0.25275 (13)0.0278
C110.41740 (11)0.6923 (5)0.29951 (12)0.0248
C120.43986 (12)0.7061 (6)0.36058 (13)0.0312
C130.42709 (13)0.5401 (6)0.40640 (14)0.0363
C140.39126 (14)0.3563 (6)0.39233 (13)0.0362
C150.36716 (12)0.3447 (5)0.33299 (13)0.0291
C160.37863 (11)0.5125 (5)0.28643 (12)0.0225
C170.19387 (11)0.2237 (5)0.72423 (12)0.0211
C180.15359 (11)0.0105 (5)0.72796 (11)0.0217
C190.11962 (11)0.0120 (5)0.78837 (12)0.0227
C200.13026 (12)−0.1573 (5)0.83494 (12)0.0281
C210.10561 (13)−0.1443 (6)0.89365 (13)0.0342
C220.07002 (13)0.0420 (6)0.90707 (14)0.0361
C230.05789 (12)0.2069 (6)0.86079 (13)0.0305
C240.08117 (11)0.1940 (5)0.80018 (12)0.0241
C250.06348 (11)0.3688 (5)0.75313 (13)0.0270
C260.06267 (11)0.3504 (5)0.68996 (13)0.0277
C270.08061 (11)0.1544 (5)0.64959 (12)0.0235
C280.05571 (11)0.1337 (6)0.58956 (13)0.0301
C290.06815 (12)−0.0532 (6)0.54957 (13)0.0341
C300.10567 (12)−0.2249 (6)0.56844 (13)0.0300
C310.13153 (12)−0.2035 (5)0.62664 (12)0.0262
C320.12027 (11)−0.0156 (5)0.66747 (12)0.0221
C330.24356 (17)1.1206 (7)0.52906 (16)0.0547
C340.20870 (16)1.1411 (8)0.47152 (17)0.0612
C350.26150 (18)0.8437 (9)0.42284 (16)0.0654
C360.29643 (16)0.8250 (8)0.47959 (16)0.0576
O20.20878 (8)0.3034 (4)0.67272 (9)0.0319
O10.29456 (9)0.8317 (4)0.27135 (9)0.0416
N10.28447 (10)0.7810 (4)0.16701 (10)0.0276
O40.26727 (11)0.8892 (5)0.53470 (11)0.0601
N20.21372 (10)0.3049 (4)0.77846 (10)0.0301
O30.23813 (13)1.0729 (6)0.41616 (11)0.0766
H120.29290.70050.13310.0337*
H130.23880.41670.77780.0346*
H140.20140.24920.81430.0341*
H110.26040.89280.16580.0335*
H210.32200.36800.22720.0227*
H410.34220.17720.13710.0304*
H510.38770.13580.04180.0373*
H610.45160.42560.01000.0391*
H710.47240.74210.07740.0366*
H910.45210.97690.16690.0320*
H1010.44951.00700.26950.0308*
H1210.46460.83120.37040.0366*
H1310.44200.55530.44660.0428*
H1410.38330.24080.42290.0431*
H1510.34300.22070.32350.0324*
H1810.1771−0.12950.73040.0252*
H2010.1550−0.28180.82560.0321*
H2110.1138−0.26130.92440.0401*
H2210.05400.05800.94780.0424*
H2310.03300.33200.86990.0339*
H2510.04910.51420.77000.0313*
H2610.04730.47940.66830.0327*
H2810.03080.24940.57660.0346*
H2910.0505−0.06290.50880.0391*
H3010.1144−0.35360.54220.0347*
H3110.1579−0.31820.63930.0303*
H3310.27321.23960.52580.0635*
H3320.22021.15440.56570.0653*
H3410.19591.30560.46700.0711*
H3420.17751.03330.47570.0712*
H3510.28220.80020.38570.0752*
H3520.23100.72960.42680.0756*
H3610.32900.93320.47500.0676*
H3620.31000.66060.48510.0684*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0193 (15)0.0282 (17)0.0216 (15)−0.0031 (12)0.0011 (12)−0.0002 (13)
C20.0250 (16)0.0174 (14)0.0214 (14)−0.0029 (12)0.0021 (11)0.0015 (12)
C30.0228 (16)0.0243 (16)0.0199 (14)0.0055 (12)−0.0029 (11)0.0048 (12)
C40.0286 (17)0.0256 (16)0.0232 (15)0.0019 (13)−0.0001 (12)0.0003 (13)
C50.0371 (19)0.0352 (19)0.0250 (16)0.0071 (15)−0.0039 (13)−0.0070 (14)
C60.0273 (17)0.055 (2)0.0216 (15)0.0101 (16)0.0024 (12)−0.0003 (15)
C70.0238 (16)0.043 (2)0.0288 (16)−0.0002 (14)0.0043 (13)0.0074 (15)
C80.0194 (15)0.0283 (17)0.0232 (15)0.0031 (13)−0.0003 (11)0.0045 (13)
C90.0250 (16)0.0251 (17)0.0317 (17)−0.0027 (13)0.0000 (12)0.0041 (14)
C100.0270 (16)0.0234 (17)0.0330 (17)−0.0035 (13)−0.0029 (13)−0.0060 (14)
C110.0219 (15)0.0273 (17)0.0251 (15)0.0055 (13)0.0005 (12)−0.0048 (13)
C120.0288 (17)0.0322 (18)0.0325 (17)0.0017 (14)−0.0046 (13)−0.0073 (15)
C130.0364 (19)0.048 (2)0.0246 (16)0.0080 (16)−0.0066 (13)−0.0019 (16)
C140.049 (2)0.039 (2)0.0212 (16)0.0063 (16)−0.0025 (14)0.0051 (14)
C150.0314 (17)0.0287 (18)0.0274 (16)−0.0003 (14)0.0018 (12)−0.0007 (14)
C160.0264 (16)0.0234 (16)0.0178 (14)0.0052 (13)0.0015 (11)−0.0037 (12)
C170.0189 (15)0.0242 (16)0.0203 (15)0.0013 (12)−0.0009 (11)−0.0041 (13)
C180.0228 (15)0.0232 (16)0.0190 (14)0.0038 (12)−0.0011 (11)0.0007 (12)
C190.0216 (15)0.0259 (16)0.0207 (14)−0.0044 (12)−0.0013 (11)−0.0032 (13)
C200.0337 (17)0.0283 (17)0.0224 (15)0.0004 (14)−0.0002 (12)0.0015 (14)
C210.0423 (19)0.040 (2)0.0199 (15)−0.0100 (16)0.0002 (13)0.0071 (14)
C220.0344 (18)0.049 (2)0.0244 (16)−0.0085 (16)0.0078 (13)−0.0044 (16)
C230.0261 (17)0.0343 (18)0.0313 (17)−0.0009 (14)0.0046 (13)−0.0086 (15)
C240.0242 (16)0.0266 (16)0.0215 (15)−0.0038 (13)0.0022 (12)−0.0040 (13)
C250.0235 (16)0.0228 (16)0.0347 (17)−0.0001 (12)0.0048 (12)−0.0026 (14)
C260.0268 (16)0.0253 (17)0.0310 (17)0.0042 (13)−0.0026 (13)0.0048 (14)
C270.0221 (15)0.0254 (17)0.0231 (15)−0.0036 (13)0.0001 (11)0.0018 (13)
C280.0227 (16)0.0399 (19)0.0277 (16)−0.0010 (14)−0.0035 (12)0.0099 (15)
C290.0321 (18)0.049 (2)0.0207 (15)−0.0079 (16)−0.0020 (13)−0.0008 (15)
C300.0341 (18)0.0319 (18)0.0241 (15)−0.0064 (14)0.0025 (13)−0.0048 (13)
C310.0289 (17)0.0266 (16)0.0231 (15)−0.0003 (13)−0.0010 (12)0.0017 (13)
C320.0195 (15)0.0243 (16)0.0225 (15)−0.0037 (12)0.0033 (11)0.0039 (13)
C330.072 (3)0.060 (3)0.0321 (19)−0.001 (2)−0.0018 (18)−0.0009 (19)
C340.059 (3)0.075 (3)0.049 (2)−0.005 (2)−0.0066 (19)0.007 (2)
C350.069 (3)0.097 (4)0.031 (2)0.008 (3)−0.0032 (18)−0.009 (2)
C360.057 (3)0.070 (3)0.046 (2)−0.009 (2)0.0046 (18)0.002 (2)
O20.0365 (13)0.0357 (12)0.0235 (11)−0.0099 (10)0.0011 (9)0.0034 (10)
O10.0443 (14)0.0513 (15)0.0292 (12)0.0234 (12)−0.0061 (10)−0.0082 (11)
N10.0272 (14)0.0302 (14)0.0256 (13)0.0092 (11)−0.0009 (10)−0.0014 (11)
O40.0769 (19)0.073 (2)0.0303 (13)0.0053 (16)−0.0001 (12)0.0113 (13)
N20.0307 (14)0.0366 (15)0.0231 (13)−0.0155 (12)0.0048 (10)−0.0024 (11)
O30.088 (2)0.109 (3)0.0327 (15)0.010 (2)−0.0051 (14)0.0206 (16)
Geometric parameters (Å, °) top
C1—C21.539 (4)C20—H2010.940
C1—O11.232 (3)C21—C221.382 (4)
C1—N11.320 (3)C21—H2110.944
C2—C31.508 (4)C22—C231.375 (4)
C2—C161.511 (4)C22—H2210.948
C2—H210.981C23—C241.401 (4)
C3—C41.385 (4)C23—H2310.944
C3—C81.408 (4)C24—C251.457 (4)
C4—C51.381 (4)C25—C261.337 (4)
C4—H410.946C25—H2510.955
C5—C61.382 (4)C26—C271.457 (4)
C5—H510.945C26—H2610.932
C6—C71.384 (4)C27—C281.404 (4)
C6—H610.940C27—C321.400 (4)
C7—C81.397 (4)C28—C291.379 (4)
C7—H710.946C28—H2810.924
C8—C91.460 (4)C29—C301.378 (4)
C9—C101.341 (4)C29—H2910.959
C9—H910.935C30—C311.379 (4)
C10—C111.456 (4)C30—H3010.934
C10—H1010.929C31—C321.389 (4)
C11—C121.397 (4)C31—H3110.942
C11—C161.400 (4)C33—C341.477 (5)
C12—C131.378 (4)C33—O41.423 (4)
C12—H1210.943C33—H3310.980
C13—C141.376 (4)C33—H3320.977
C13—H1310.924C34—O31.422 (4)
C14—C151.379 (4)C34—H3410.976
C14—H1410.934C34—H3420.969
C15—C161.389 (4)C35—C361.464 (5)
C15—H1510.928C35—O31.410 (5)
C17—C181.542 (4)C35—H3510.963
C17—O21.231 (3)C35—H3520.979
C17—N21.319 (3)C36—O41.409 (4)
C18—C191.519 (4)C36—H3610.997
C18—C321.511 (3)C36—H3620.984
C18—H1810.969N1—H120.871
C19—C201.389 (4)N1—H110.855
C19—C241.401 (4)N2—H130.870
C20—C211.379 (4)N2—H140.873
C2—C1—O1120.0 (2)C20—C21—H211119.5
C2—C1—N1117.9 (2)C22—C21—H211120.8
O1—C1—N1122.0 (3)C21—C22—C23119.5 (3)
C1—C2—C3113.0 (2)C21—C22—H221120.9
C1—C2—C16109.8 (2)C23—C22—H221119.6
C3—C2—C16115.6 (2)C22—C23—C24122.0 (3)
C1—C2—H21105.5C22—C23—H231119.2
C3—C2—H21106.1C24—C23—H231118.9
C16—C2—H21106.0C19—C24—C23117.9 (3)
C2—C3—C4119.3 (3)C19—C24—C25124.0 (2)
C2—C3—C8121.3 (2)C23—C24—C25118.0 (3)
C4—C3—C8119.3 (2)C24—C25—C26129.0 (3)
C3—C4—C5121.5 (3)C24—C25—H251115.1
C3—C4—H41119.0C26—C25—H251115.8
C5—C4—H41119.5C25—C26—C27129.7 (3)
C4—C5—C6119.8 (3)C25—C26—H261115.7
C4—C5—H51119.2C27—C26—H261114.6
C6—C5—H51121.0C26—C27—C28117.6 (3)
C5—C6—C7119.3 (3)C26—C27—C32124.0 (2)
C5—C6—H61120.0C28—C27—C32118.3 (3)
C7—C6—H61120.7C27—C28—C29121.5 (3)
C6—C7—C8121.9 (3)C27—C28—H281118.9
C6—C7—H71119.4C29—C28—H281119.7
C8—C7—H71118.8C28—C29—C30119.9 (3)
C3—C8—C7118.1 (3)C28—C29—H291119.7
C3—C8—C9124.0 (2)C30—C29—H291120.4
C7—C8—C9118.0 (3)C29—C30—C31119.3 (3)
C8—C9—C10129.1 (3)C29—C30—H301121.2
C8—C9—H91113.3C31—C30—H301119.6
C10—C9—H91117.6C30—C31—C32122.0 (3)
C9—C10—C11129.7 (3)C30—C31—H311119.5
C9—C10—H101115.4C32—C31—H311118.5
C11—C10—H101114.9C18—C32—C27121.4 (2)
C10—C11—C12117.9 (3)C18—C32—C31119.5 (2)
C10—C11—C16123.7 (2)C27—C32—C31119.0 (2)
C12—C11—C16118.4 (3)C34—C33—O4111.5 (3)
C11—C12—C13121.5 (3)C34—C33—H331107.5
C11—C12—H121119.0O4—C33—H331109.5
C13—C12—H121119.4C34—C33—H332107.9
C12—C13—C14119.8 (3)O4—C33—H332110.1
C12—C13—H131119.7H331—C33—H332110.3
C14—C13—H131120.5C33—C34—O3111.8 (3)
C13—C14—C15119.5 (3)C33—C34—H341109.3
C13—C14—H141120.1O3—C34—H341109.4
C15—C14—H141120.4C33—C34—H342108.3
C14—C15—C16121.7 (3)O3—C34—H342107.3
C14—C15—H151119.5H341—C34—H342110.8
C16—C15—H151118.8C36—C35—O3112.0 (3)
C2—C16—C11121.4 (2)C36—C35—H351110.5
C2—C16—C15119.6 (3)O3—C35—H351111.0
C11—C16—C15118.9 (2)C36—C35—H352108.2
C18—C17—O2120.9 (2)O3—C35—H352107.7
C18—C17—N2116.7 (2)H351—C35—H352107.2
O2—C17—N2122.3 (3)C35—C36—O4111.7 (3)
C17—C18—C19112.4 (2)C35—C36—H361109.1
C17—C18—C32111.3 (2)O4—C36—H361108.7
C19—C18—C32115.1 (2)C35—C36—H362110.6
C17—C18—H181105.2O4—C36—H362108.0
C19—C18—H181106.1H361—C36—H362108.7
C32—C18—H181105.9C1—N1—H12120.5
C18—C19—C20119.5 (3)C1—N1—H11118.2
C18—C19—C24120.9 (2)H12—N1—H11121.2
C20—C19—C24119.4 (2)C33—O4—C36111.5 (3)
C19—C20—C21121.4 (3)C17—N2—H13118.9
C19—C20—H201118.2C17—N2—H14120.4
C21—C20—H201120.4H13—N2—H14120.7
C20—C21—C22119.7 (3)C34—O3—C35111.3 (3)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H11···O2i0.852.112.962 (3)171
N1—H12···O4i0.872.222.978 (3)145
N2—H13···O1ii0.871.952.823 (3)177
N2—H14···O3ii0.872.533.040 (3)119
Symmetry codes: (i) x, −y+3/2, z−1/2; (ii) x, −y+3/2, z+1/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H11···O2i0.852.112.962 (3)171
N1—H12···O4i0.872.222.978 (3)145
N2—H13···O1ii0.871.952.823 (3)177
N2—H14···O3ii0.872.533.040 (3)119
Symmetry codes: (i) x, −y+3/2, z−1/2; (ii) x, −y+3/2, z+1/2.
Acknowledgements top

The authors thank the Basic Technology programme of the UK Research Councils for funding this work under the project Control and Prediction of the Organic Solid State (www.cposs.org.uk).

references
References top

Altomare, A., Cascarano, G., Giacovazzo, G., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.

Bandoli, G., Nicolini, M., Ongaro, A., Volpe, G. & Rubello, A. (1992). J. Chem. Crystallogr. 22, 177–183.

Betteridge, P. W., Carruthers, J. R., Cooper, R. I., Prout, K. & Watkin, D. J. (2003). J. Appl. Cryst. 36, 1487.

Blessing, R. H. (1997). J. Appl. Cryst. 30, 421–426.

Cyr, T. D., Matsui, F., Sears, R. W., Curran, N. M. & Lovering, E. G. (1987). J. Assoc. Off. Anal. Chem. 70, 836–840.

Davis, M. A., Winthrop, S. O., Thomas, R. A., Herr, F., Charest, M.-P. & Gaudry, R. (1964). J. Med. Chem. 7, 88–94.

Etter, M. C. (1990). Acc. Chem. Res. 23, 120–126.

Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.

Fleischman, S. G., Kuduva, S. S., McMahon, J. A., Moulton, B., Walsh, R. D. B., Rodriguez-Hornedo, N. & Zaworotko, M. J. (2003). Cryst. Growth Des. 3, 909–919.

Florence, A. J., Baumgartner, B., Weston, C., Shankland, N., Kennedy, A. R., Shankland, K. & David, W. I. F. (2003). J. Pharm. Sci. 92, 1930–1938.

Florence, A. J., Bedford, C. T., Fabbiani, F. P. A., Shankland, K., Gelbrich, T., Hursthouse, M. B., Shankland, N., johnston, A. & Fernandes, P. (2008). CrystEngComm, DOI: 10.1039/b719717a

Florence, A. J., Johnston, A., Fernandes, P., Shankland, N. & Shankland, K. (2006). J. Appl. Cryst. 39, 922–924.

Florence, A. J., Johnston, A., Price, S. L., Nowell, H., Kennedy, A. R. & Shankland, N. (2006). J. Pharm. Sci. 95, 1918–1930.

Florence, A. J., Leech, C. K., Shankland, N., Shankland, K. & Johnston, A. (2006). CrystEngComm, 8, 746–747.

Florence, A. J., Shankland, K., Gelbrich, T., Hursthouse, M. B., Shankland, N., Johnston, A., Fernandes, P. & Leech, C. K. (2008). CrystEngComm, 10, 26–28.

Harrison, W. T. A., Yathirajan, H. S. & Anilkumar, H. G. (2006). Acta Cryst. C62, o240–o242.

Leech, C. K., Florence, A. J., Shankland, K., Shankland, N. & Johnston, A. (2007). Acta Cryst. E63, o675–o677.

Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.

Oxford Diffraction (2007). CrysAlis CCD, CrysAlis RED and ABSPACK. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.

Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13.