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Acta Crystallogr Sect E Struct Rep Online. 2008 July 1; 64(Pt 7): o1338–o1339.
Published online 2008 June 25. doi:  10.1107/S1600536808018643
PMCID: PMC2961761

1-Hydroxy­ethyl-2-methyl-5-nitro­imidazolium 3-carb­oxy-4-hydroxy­benzene­sulfonate

Abstract

Cocrystallization of 1-hydroxy­ethyl-2-methyl-5-nitroimidazole (metronidazole) and 5-sulfosalicylic acid (5-H2SSA) from methanol solution yields the title salt, C6H10N3O3 +·C7H5O6S. In the crystal structure, the ions are linked by a combination of inter­molecular O—H(...)O, N—H(...)O and C—H(...)O hydrogen bonds, forming a three-dimensional framework. The hydroxyl group of the cation is disordered over two sites in a 0.860 (4):0.140 (4) ratio.

Related literature

For related literature, see: Athar et al. (2005 [triangle]); Bharti et al. (2002 [triangle]); Castelli et al. (2000 [triangle]); Cohen-Jonathan et al. (2001 [triangle]); Crozet et al. (2002 [triangle]); Galván-Tejada et al. (2002 [triangle]); Hodgkiss (1998 [triangle]); Kennedy et al. (2006 [triangle]); Meng et al. (2007 [triangle]); Skupin et al. (1997 [triangle]); Wu et al. (2003 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-o1338-scheme1.jpg

Experimental

Crystal data

  • C6H10N3O3 +·C7H5O6S
  • M r = 389.34
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-o1338-efi1.jpg
  • a = 8.8438 (3) Å
  • b = 13.0249 (4) Å
  • c = 14.148 (5) Å
  • β = 100.413 (1)°
  • V = 1602.9 (6) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.26 mm−1
  • T = 294 (2) K
  • 0.35 × 0.26 × 0.20 mm

Data collection

  • Bruker SMART APEX CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1997 [triangle]) T min = 0.904, T max = 0.950
  • 17399 measured reflections
  • 3503 independent reflections
  • 3156 reflections with I > 2σ(I)
  • R int = 0.020

Refinement

  • R[F 2 > 2σ(F 2)] = 0.042
  • wR(F 2) = 0.118
  • S = 1.06
  • 3503 reflections
  • 262 parameters
  • 4 restraints
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.32 e Å−3
  • Δρmin = −0.30 e Å−3

Data collection: SMART (Bruker, 2001 [triangle]); cell refinement: SAINT (Bruker, 2001 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: PLATON (Spek, 2003 [triangle]); software used to prepare material for publication: PLATON.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808018643/lh2643sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808018643/lh2643Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

This work was supported by Wuhan Grand Pharmaceutical Group Co. Ltd.

supplementary crystallographic information

Comment

1-Hydroxyethyl-2-methyl-5-nitrimidazole (metronidazole) is often used in the treatment of anaerobic protozoan and bacterial infections (Castelli et al., 2000; Cohen-Jonathan et al., 2001; Hodgkiss et al., 1998). However, the low solubility in water makes its absorption in human body much less than expected. Recently, many efforts have been devoted to developing some new substitutes for the medicine, i.e. i) metal-organic coordination compounds (Kennedy et al., 2006; Galván-Tejada et al., 2002; Athar et al., 2005; Bharti et al., 2002; Wu et al., 2003), ii) organic substitute derivatives (Crozet et al., 2002, Skupin et al., 1997) and iii) pharmaceutical co-crystals. In this paper, we report the 1:1 molecular adduct formed by metronidazole 5-sulfosalicylic acid (5-H2SSA), (I).

In (I), the H atom is transferred from the sulfonic acid group to the imidazole N atom (Fig.1) forming an 1:1 organic adduct, which is similar to the analogous organic adducts reported (Meng et al., 2007). The hydroxyl O atom is disordered at two sites with occupancy being 0.86 (1)/0.14 (1) for the major and minor components, respectively.

In the crystal packing, the component ions are linked by a combination of O—H···O, N—H···O and C—H···O hydrogen bonds (Table 1), forming a three-dimensional network (Fig.2). There are no other interactions (e.g. C—H···π and π-π) observed in the crystal structure by using PLATON (Spek, 2003).

Experimental

All the reagents and solvents were used as obtained without further purification. Equivalent molar amount of metronidazole and 5-sulfosalicylic acid dihydrate were dissolved in methanol (10 ml). The mixture was stirred for ten minutes at 300 K and then filtered. Block colorless crystals of (I) suitable for single-crystal X-ray diffraction analysis were grown by slow evaporation of the solution at the bottom of the vessel in two days.

Refinement

H atoms bonded to C atoms were positioned geometrically [C–H = 0.93Å (aromatic), 0.97(methylene) and 0.96(methyl)] and refined in riding modes [Uiso(H) = 1.2Ueq(aromatic and methylene C) and 1.5U~eq~(methyl C]. H atoms bonded to N and O atoms were found in Fourier difference maps with the constraints of N—H = 0.86 (2) Å,O—H = 0.82 (2) Å, and Uiso(H) = 1.2Ueq(N) or 1.5Ueq(O)]. The hydroxyl O atom is disordered at two sites with the occupancy being 0.86 (1):0.14 (1) for the major and minor components, respectively.

Figures

Fig. 1.
Molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H-bonds are shown in dashed lines.
Fig. 2.
Part of the crystal structure of (I), showing the formation of the three-dimensional framework structure. Hydrogen bonds are shown as dashed lines. For the sake of clarity, H atoms not involved in the motif have been omitted from the drawing.

Crystal data

C6H10N3O3+·C7H5O6SF000 = 808
Mr = 389.34Dx = 1.613 Mg m3
Monoclinic, P21/nMo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 9747 reflections
a = 8.8438 (3) Åθ = 2.5–28.2º
b = 13.0249 (4) ŵ = 0.26 mm1
c = 14.148 (5) ÅT = 294 (2) K
β = 100.4130 (10)ºBlock, colorless
V = 1602.9 (6) Å30.35 × 0.26 × 0.20 mm
Z = 4

Data collection

Bruker SMART APEX CCD area-detector diffractometer3503 independent reflections
Radiation source: fine focus sealed Siemens Mo tube3156 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.020
T = 294(2) Kθmax = 27.0º
0.3° wide ω exposures scansθmin = 2.1º
Absorption correction: multi-scan(SADABS; Sheldrick, 1997)h = −11→11
Tmin = 0.905, Tmax = 0.950k = −16→16
17399 measured reflectionsl = −18→18

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.042H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.118  w = 1/[σ2(Fo2) + (0.0695P)2 + 0.4716P] where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max < 0.001
3503 reflectionsΔρmax = 0.32 e Å3
262 parametersΔρmin = −0.30 e Å3
4 restraintsExtinction correction: none
Primary atom site location: structure-invariant direct methods

Special details

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)

xyzUiso*/UeqOcc. (<1)
C10.26714 (18)0.68882 (13)0.68052 (11)0.0389 (3)
C20.3234 (2)0.78986 (13)0.68903 (12)0.0441 (4)
C30.4814 (2)0.80629 (14)0.69525 (14)0.0520 (4)
H30.51980.87290.70070.062*
C40.5807 (2)0.72533 (14)0.69348 (13)0.0462 (4)
H40.68510.73760.69650.055*
C50.52498 (18)0.62468 (13)0.68713 (11)0.0380 (3)
C60.36914 (18)0.60747 (13)0.68103 (11)0.0380 (3)
H60.33200.54050.67720.046*
C70.1012 (2)0.67003 (14)0.67435 (13)0.0433 (4)
C80.1649 (2)0.27776 (14)0.56001 (12)0.0443 (4)
C90.2283 (2)0.36913 (14)0.54592 (13)0.0474 (4)
H90.17820.43180.53420.057*
C100.41167 (19)0.25196 (13)0.56990 (11)0.0405 (4)
C110.5662 (2)0.20700 (17)0.58081 (16)0.0591 (5)
H11A0.63760.25840.56800.089*
H11B0.56500.15120.53630.089*
H11C0.59690.18200.64520.089*
C120.2655 (3)0.09157 (14)0.58498 (13)0.0546 (5)
H12A0.19350.07640.62730.065*
H12B0.36470.06330.61370.065*
C130.2110 (3)0.04186 (16)0.48829 (16)0.0625 (6)
H13A0.2000−0.03150.49650.075*0.860 (4)
H13B0.11130.06940.45970.075*0.860 (4)
H13C0.29600.04040.45350.075*0.140 (4)
H13D0.1834−0.02880.49870.075*0.140 (4)
N10.27916 (17)0.20437 (10)0.57531 (10)0.0415 (3)
N20.38028 (18)0.35061 (12)0.55237 (11)0.0441 (3)
H20.447 (3)0.3933 (19)0.5509 (15)0.055 (6)*
N30.0052 (2)0.26065 (16)0.56153 (12)0.0582 (4)
O10.06220 (15)0.57238 (10)0.66817 (11)0.0551 (4)
H1−0.029 (3)0.567 (2)0.6806 (19)0.083*
O20.00803 (16)0.73868 (11)0.67490 (13)0.0644 (4)
O30.23266 (19)0.87220 (10)0.69337 (12)0.0612 (4)
H3A0.144 (4)0.849 (3)0.688 (2)0.092*
O40.80111 (14)0.55223 (12)0.72322 (11)0.0577 (4)
O50.59335 (15)0.44064 (11)0.74685 (10)0.0552 (4)
O60.62653 (14)0.48356 (9)0.58626 (9)0.0447 (3)
O7−0.0358 (2)0.17473 (15)0.58045 (15)0.0874 (6)
O8−0.0796 (2)0.33520 (18)0.54514 (15)0.0865 (6)
O90.3138 (2)0.06004 (17)0.42931 (13)0.0725 (7)0.860 (4)
H9A0.260 (4)0.065 (3)0.3759 (14)0.109*0.860 (4)
O9'0.1003 (12)0.0853 (9)0.4339 (7)0.066 (4)0.140 (4)
H9'0.13 (3)0.135 (12)0.408 (15)0.099*0.140 (4)
S10.64580 (4)0.51687 (3)0.68609 (3)0.03782 (14)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.0401 (8)0.0393 (8)0.0371 (8)−0.0030 (7)0.0064 (6)−0.0011 (6)
C20.0514 (10)0.0369 (8)0.0437 (9)−0.0007 (7)0.0078 (7)0.0033 (7)
C30.0565 (11)0.0377 (9)0.0610 (11)−0.0127 (8)0.0084 (9)0.0039 (8)
C40.0425 (9)0.0445 (9)0.0514 (10)−0.0126 (7)0.0077 (7)0.0038 (7)
C50.0367 (8)0.0395 (8)0.0381 (8)−0.0048 (6)0.0070 (6)0.0012 (6)
C60.0380 (8)0.0358 (8)0.0404 (8)−0.0065 (6)0.0075 (6)−0.0027 (6)
C70.0412 (8)0.0417 (9)0.0472 (9)0.0003 (7)0.0088 (7)−0.0034 (7)
C80.0451 (9)0.0486 (10)0.0391 (8)−0.0103 (7)0.0073 (7)−0.0059 (7)
C90.0491 (9)0.0401 (9)0.0517 (10)−0.0048 (7)0.0058 (8)−0.0027 (7)
C100.0464 (9)0.0394 (8)0.0343 (8)−0.0087 (7)0.0036 (6)−0.0016 (6)
C110.0510 (10)0.0617 (12)0.0620 (12)0.0035 (9)0.0035 (9)0.0017 (10)
C120.0836 (14)0.0359 (9)0.0447 (9)−0.0151 (9)0.0128 (9)0.0021 (7)
C130.0888 (16)0.0447 (10)0.0561 (12)−0.0255 (11)0.0188 (11)−0.0107 (9)
N10.0520 (8)0.0365 (7)0.0351 (7)−0.0120 (6)0.0060 (6)−0.0017 (5)
N20.0465 (8)0.0371 (7)0.0480 (8)−0.0133 (6)0.0066 (6)−0.0014 (6)
N30.0501 (9)0.0760 (12)0.0500 (9)−0.0176 (9)0.0134 (7)−0.0135 (8)
O10.0359 (6)0.0428 (7)0.0875 (10)−0.0024 (5)0.0135 (6)−0.0028 (6)
O20.0482 (7)0.0479 (8)0.0985 (12)0.0063 (6)0.0172 (7)−0.0104 (7)
O30.0614 (8)0.0360 (7)0.0852 (11)0.0023 (6)0.0104 (8)0.0021 (7)
O40.0333 (6)0.0637 (9)0.0728 (9)−0.0072 (6)0.0014 (6)−0.0126 (7)
O50.0534 (7)0.0544 (8)0.0578 (8)0.0007 (6)0.0105 (6)0.0214 (6)
O60.0486 (7)0.0396 (6)0.0456 (7)−0.0045 (5)0.0079 (5)−0.0006 (5)
O70.0759 (11)0.0821 (12)0.1140 (15)−0.0409 (10)0.0429 (10)−0.0266 (11)
O80.0517 (9)0.1110 (16)0.0978 (13)0.0069 (10)0.0161 (9)0.0071 (11)
O90.0805 (13)0.0892 (14)0.0503 (10)−0.0317 (11)0.0186 (9)−0.0189 (9)
O9'0.082 (8)0.066 (7)0.047 (6)0.001 (6)0.006 (5)−0.013 (5)
S10.0307 (2)0.0400 (2)0.0417 (2)−0.00536 (14)0.00351 (15)0.00333 (15)

Geometric parameters (Å, °)

C1—C61.391 (2)C11—H11B0.9600
C1—C21.405 (2)C11—H11C0.9600
C1—C71.475 (2)C12—N11.482 (2)
C2—O31.348 (2)C12—C131.512 (3)
C2—C31.400 (3)C12—H12A0.9700
C3—C41.376 (3)C12—H12B0.9700
C3—H30.9300C13—O9'1.265 (8)
C4—C51.398 (2)C13—O91.361 (3)
C4—H40.9300C13—H13A0.9700
C5—C61.384 (2)C13—H13B0.9700
C5—S11.7662 (17)C13—H13C0.9700
C6—H60.9300C13—H13D0.9700
C7—O21.217 (2)N2—H20.81 (2)
C7—O11.317 (2)N3—O71.221 (3)
C8—C91.346 (2)N3—O81.223 (3)
C8—N11.379 (2)O1—H10.86 (3)
C8—N31.434 (2)O3—H3A0.83 (3)
C9—N21.352 (2)O4—S11.4539 (12)
C9—H90.9300O5—S11.4437 (13)
C10—N21.328 (2)O6—S11.4579 (14)
C10—N11.340 (2)O9—H13C0.4764
C10—C111.469 (3)O9—H9A0.82 (1)
C11—H11A0.9600O9'—H9'0.82 (1)
C6—C1—C2119.60 (15)C13—C12—H12B109.4
C6—C1—C7120.76 (15)H12A—C12—H12B108.0
C2—C1—C7119.61 (15)O9'—C13—O994.5 (6)
O3—C2—C3118.11 (16)O9'—C13—C12116.4 (5)
O3—C2—C1123.01 (16)O9—C13—C12109.93 (18)
C3—C2—C1118.87 (16)O9'—C13—H13A115.5
C4—C3—C2120.97 (16)O9—C13—H13A109.7
C4—C3—H3119.5C12—C13—H13A109.7
C2—C3—H3119.5O9—C13—H13B109.7
C3—C4—C5120.09 (16)C12—C13—H13B109.7
C3—C4—H4120.0H13A—C13—H13B108.2
C5—C4—H4120.0O9'—C13—H13C106.6
C6—C5—C4119.46 (16)C12—C13—H13C108.5
C6—C5—S1117.90 (12)H13A—C13—H13C98.3
C4—C5—S1122.63 (13)H13B—C13—H13C121.6
C5—C6—C1120.98 (15)O9'—C13—H13D109.2
C5—C6—H6119.5O9—C13—H13D118.2
C1—C6—H6119.5C12—C13—H13D108.4
O2—C7—O1122.75 (17)H13B—C13—H13D100.4
O2—C7—C1123.05 (17)H13C—C13—H13D107.4
O1—C7—C1114.20 (15)C10—N1—C8107.09 (14)
C9—C8—N1108.85 (15)C10—N1—C12123.38 (16)
C9—C8—N3125.28 (18)C8—N1—C12129.19 (16)
N1—C8—N3125.85 (17)C10—N2—C9110.91 (15)
C8—C9—N2105.54 (16)C10—N2—H2122.7 (16)
C8—C9—H9127.2C9—N2—H2126.1 (16)
N2—C9—H9127.2O7—N3—O8124.99 (19)
N2—C10—N1107.62 (16)O7—N3—C8118.5 (2)
N2—C10—C11124.35 (17)O8—N3—C8116.46 (19)
N1—C10—C11128.03 (17)C7—O1—H1108 (2)
C10—C11—H11A109.5C2—O3—H3A105 (2)
C10—C11—H11B109.5C13—O9—H9A104 (3)
H11A—C11—H11B109.5H13C—O9—H9A119.2
C10—C11—H11C109.5C13—O9'—H9'109 (10)
H11A—C11—H11C109.5O5—S1—O4112.76 (9)
H11B—C11—H11C109.5O5—S1—O6112.23 (8)
N1—C12—C13111.03 (16)O4—S1—O6112.44 (8)
N1—C12—H12A109.4O5—S1—C5106.37 (8)
C13—C12—H12A109.4O4—S1—C5106.18 (8)
N1—C12—H12B109.4O6—S1—C5106.24 (7)
C6—C1—C2—O3−176.99 (16)C11—C10—N1—C8−179.79 (17)
C7—C1—C2—O31.0 (3)N2—C10—N1—C12174.03 (15)
C6—C1—C2—C31.7 (2)C11—C10—N1—C12−6.0 (3)
C7—C1—C2—C3179.71 (16)C9—C8—N1—C10−0.29 (19)
O3—C2—C3—C4178.52 (17)N3—C8—N1—C10−178.63 (16)
C1—C2—C3—C4−0.2 (3)C9—C8—N1—C12−173.61 (17)
C2—C3—C4—C5−1.2 (3)N3—C8—N1—C128.0 (3)
C3—C4—C5—C61.1 (3)C13—C12—N1—C10−96.5 (2)
C3—C4—C5—S1−179.15 (14)C13—C12—N1—C875.8 (2)
C4—C5—C6—C10.4 (2)N1—C10—N2—C9−0.10 (19)
S1—C5—C6—C1−179.38 (12)C11—C10—N2—C9179.92 (17)
C2—C1—C6—C5−1.8 (2)C8—C9—N2—C10−0.1 (2)
C7—C1—C6—C5−179.78 (15)C9—C8—N3—O7−175.94 (19)
C6—C1—C7—O2179.04 (18)N1—C8—N3—O72.1 (3)
C2—C1—C7—O21.1 (3)C9—C8—N3—O82.8 (3)
C6—C1—C7—O1−1.0 (2)N1—C8—N3—O8−179.15 (17)
C2—C1—C7—O1−178.93 (16)C6—C5—S1—O5−42.03 (15)
N1—C8—C9—N20.23 (19)C4—C5—S1—O5138.20 (15)
N3—C8—C9—N2178.58 (16)C6—C5—S1—O4−162.37 (13)
N1—C12—C13—O9'−44.9 (7)C4—C5—S1—O417.86 (17)
N1—C12—C13—O961.0 (3)C6—C5—S1—O677.73 (14)
N2—C10—N1—C80.23 (18)C4—C5—S1—O6−102.04 (15)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O3—H3A···O20.83 (3)1.86 (3)2.618 (2)151 (3)
N2—H2···O60.81 (2)1.97 (2)2.7557 (19)163 (2)
C13—H13D···O7i0.972.463.280 (3)142
C11—H11C···O4ii0.962.553.457 (3)157
O9—H9A···O5iii0.82 (1)2.129 (13)2.940 (2)170 (4)
O9'—H9'···O2iv0.82 (1)2.258 (13)2.830 (2)127 (2)
O1—H1···O4v0.86 (3)1.73 (3)2.5801 (19)171 (3)

Symmetry codes: (i) −x, −y, −z+1; (ii) −x+3/2, y−1/2, −z+3/2; (iii) x−1/2, −y+1/2, z−1/2; (iv) −x, −y+1, −z+1; (v) x−1, y, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH2643).

References

  • Athar, F., Husain, K., Abid, M., Agarwal, S. M., Coles, S. J., Hursthouse, M. B., Maurya, M. R. & Azam, A. (2005). Chem. Biodivers 2, 1220–1330. [PubMed]
  • Bharti, N., Shailendra, Coles, S. J., Hursthouse, M. B., Mayer, T. A., Gonzalez Garza, M. T., Cruz-Vega, D. E., Mata-Cardenas, B. D., Naqvi, F., Maurya, M. R. & Azam, A. (2002). Helv. Chim. Acta, 85, 2704–2712.
  • Bruker (2001). SAINT and SMART Bruker AXS, Inc., Madison, Wisconsin, USA.
  • Castelli, M., Malagoli, M., Lupo, L., Bofia, S., Paolucci, F., Cermelli, C., Zanca, A. & Baggio, G. (2000). J. Antimicrob. Chemother.46, 541–550. [PubMed]
  • Cohen-Jonathan, E., Evans, S. M., Koch, C. J., Muschel, R. J., McKenna, W. J., Wu, J. & Bernhard, E. J. (2001). Cancer Res.161, 2289–2293. [PubMed]
  • Crozet, M. D., Vanelle, P., Giorgi, M. & Gellis, A. (2002). Acta Cryst. C58, o496–o498. [PubMed]
  • Galván-Tejada, N., Bernès, S., Castillo-Blum, S. E., Nöth, H., Vicente, R. & Barba-Behrens, N. (2002). J. Inorg. Biochem.91, 339–348. [PubMed]
  • Hodgkiss, R. J. (1998). Anti-Cancer Drug Des.13, 687–702. [PubMed]
  • Kennedy, D. C., Wu, A., Patrick, B. O. & James, B. R. (2006). J. Inorg. Biochem.100, 1974–1982. [PubMed]
  • Meng, X.-G., Zhou, C.-S., Wang, L. & Liu, C.-L. (2007). Acta Cryst. C63, o667–o670. [PubMed]
  • Sheldrick, G. M. (1997). SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Skupin, S., Cooper, T. G., Frohlich, R., Prigge, J. & Haufe, G. (1997). Tetrahedron Asymm.8, 2453–2464.
  • Spek, A. L. (2003). J. Appl. Cryst.36, 7–13.
  • Wu, A., Kennedy, D. C., Patrick, B. O. & James, B. R. (2003). Inorg. Chem.42, 7579–7586. [PubMed]

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