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Acta Crystallogr Sect E Struct Rep Online. 2010 October 1; 66(Pt 10): o2647.
Published online 2010 September 30. doi:  10.1107/S1600536810038055
PMCID: PMC2983353

Metronidazolium perchlorate

Abstract

In the crystal structure of the title compound [systematic name: 1-(2-hy­droxy­eth­yl)-2-methyl-5-nitro-1H-imidazol-3-ium perchlorate], C6H10N3O3 +·ClO4 , the cations are linked by inter­molecular N—H(...)O hydrogen bonds into zigzag chains along the c axis. The cations and anions are connected by O—H(...)O and C—H(...)O hydrogen bonds. A weak intra­molecular C—H(...)O hydrogen bond is also observed.

Related literature

For metronidazole, see: Castelli et al. (2000 [triangle]); Contrerasa et al. (2009 [triangle]). For a related structure, see: Wang et al. (2006 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o2647-scheme1.jpg

Experimental

Crystal data

  • C6H10N3O3 +·ClO4
  • M r = 271.62
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o2647-efi1.jpg
  • a = 7.8541 (13) Å
  • b = 10.6791 (17) Å
  • c = 13.032 (2) Å
  • β = 93.904 (2)°
  • V = 1090.5 (3) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.38 mm−1
  • T = 296 K
  • 0.40 × 0.20 × 0.20 mm

Data collection

  • Bruker SMART CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.862, T max = 0.928
  • 9191 measured reflections
  • 2509 independent reflections
  • 2219 reflections with I > 2σ(I)
  • R int = 0.030

Refinement

  • R[F 2 > 2σ(F 2)] = 0.053
  • wR(F 2) = 0.159
  • S = 1.04
  • 2509 reflections
  • 155 parameters
  • H-atom parameters constrained
  • Δρmax = 0.60 e Å−3
  • Δρmin = −0.43 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: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810038055/is2601sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810038055/is2601Isup2.hkl

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

Acknowledgments

The authors thank the Project of Shandong Province Higher Educational Science and Technology Program (J09LB03) and the Starting Fund of Shandong Institute of Light Industry for financial support.

supplementary crystallographic information

Comment

Metronidazole is usually applied in the area of anaerobic protozoan and bacterial infections (Castelli et al., 2000). Its solubility is low in water, so that its absorption is not easy in human body. To solve this problem and to increase its solubility in water, a kind of new strategy of protonated metronidazole has been studied though other methods have been developed in the area of medicine, for example, metal complexes (Contrerasa et al., 2009) and pharmaceutical co-crystals. However, co-crystals containing metronidazole has rarely been investigated. In this paper, we report the 1:1 salt formed by metronidazole and perchloric acid, (I).

A view of the title structure is shown in Fig. 1. The H atom is transferred from the perchloric acid group to the imidazole N atom forming an 1:1 organic salt, which is similar to other organic salt published previously (Wang et al., 2006). In the crystal structure, one-dimensional chains are formed via intermolecular O—H···O and N—H···O hydrogen bonds (Table 1 and Fig. 2).

Experimental

Metronidazole (1.71 g, 10 mmol) and 75% aqueous HClO4 (2 ml) were mixed and dissolved in 10 ml water. The reaction mixture was stirred slowly to room temperature. The bar colourless crystals suitable for X-ray diffraction were obtained after two weeks. Analysis found: C 26.17, H 3.69, N 15.41%; calcd. : C 26.53, H 3.71, N 15.47%. IR (KBr, cm-1): 3394, 3078, 1610, 1546, 1527, 1502, 1411, 1373, 1319, 1251, 1193, 1143, 1111, 1085, 1080, 1062, 037, 867, 831, 736, 671, 630, 559, 516.

Refinement

All H atoms were located in a difference Fourier map. Oxygen- and nitrogen-bound H atoms were then refined as riding, with Uiso(H) = 1.5Ueq(O, N). Carbon-bound H atoms were positioned geometrically (C—H = 0.96 or 0.97 Å), and were included in the refinement in the riding-model approximation, with Uiso(H) = 1.2Ueq(C).

Figures

Fig. 1.
The molecular structure of (I), with the atom numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
Fig. 2.
One-dimensional chain running along the c axis.

Crystal data

C6H10N3O3+·ClO4F(000) = 560
Mr = 271.62Dx = 1.654 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 5428 reflections
a = 7.8541 (13) Åθ = 2.5–27.5°
b = 10.6791 (17) ŵ = 0.38 mm1
c = 13.032 (2) ÅT = 296 K
β = 93.904 (2)°Prism, colourless
V = 1090.5 (3) Å30.40 × 0.20 × 0.20 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer2509 independent reflections
Radiation source: fine-focus sealed tube2219 reflections with I > 2σ(I)
graphiteRint = 0.030
[var phi] and ω scansθmax = 27.5°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)h = −10→10
Tmin = 0.862, Tmax = 0.928k = −13→13
9191 measured reflectionsl = −16→16

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.053H-atom parameters constrained
wR(F2) = 0.159w = 1/[σ2(Fo2) + (0.085P)2 + 0.8145P] where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max = 0.001
2509 reflectionsΔρmax = 0.60 e Å3
155 parametersΔρmin = −0.43 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.190 (12)

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*/Ueq
O10.7469 (2)0.70762 (17)0.58597 (12)0.0486 (4)
H10.85990.71180.59450.073*
O20.4144 (3)0.4116 (2)0.66132 (15)0.0639 (6)
O30.2449 (3)0.4469 (2)0.78337 (19)0.0727 (6)
N10.6726 (2)0.55501 (15)0.76908 (12)0.0340 (4)
N20.6393 (3)0.64689 (18)0.91461 (14)0.0437 (5)
H20.65800.69520.96430.066*
N30.3813 (3)0.45742 (19)0.74353 (16)0.0487 (5)
C10.7048 (3)0.5773 (2)0.58035 (16)0.0451 (5)
H1A0.76110.53970.52400.054*
H1B0.58270.56860.56560.054*
C20.7567 (3)0.5070 (2)0.67880 (16)0.0404 (5)
H2A0.72830.41910.66940.048*
H2B0.87940.51310.69220.048*
C30.7495 (3)0.6272 (2)0.84260 (15)0.0384 (5)
C40.4896 (3)0.5882 (2)0.88970 (17)0.0441 (5)
H4A0.39280.58790.92700.053*
C50.5098 (3)0.53022 (19)0.79949 (16)0.0379 (5)
C60.9254 (3)0.6762 (3)0.8466 (2)0.0550 (6)
H6A0.97910.65070.78600.083*
H6B0.98870.64390.90650.083*
H6C0.92280.76600.85000.083*
Cl11.22616 (7)0.74741 (5)0.59693 (4)0.0442 (3)
O41.3343 (4)0.7477 (2)0.6879 (2)0.0994 (10)
O51.1033 (4)0.6500 (3)0.5984 (3)0.1022 (10)
O61.3237 (5)0.7180 (3)0.5116 (2)0.1074 (11)
O71.1515 (5)0.8663 (3)0.5795 (2)0.1214 (14)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0558 (10)0.0482 (10)0.0408 (8)−0.0064 (7)−0.0038 (7)0.0107 (7)
O20.0773 (14)0.0622 (12)0.0503 (11)−0.0159 (10)−0.0096 (9)−0.0110 (9)
O30.0564 (12)0.0751 (14)0.0870 (16)−0.0189 (10)0.0074 (11)0.0038 (12)
N10.0444 (9)0.0313 (8)0.0258 (8)0.0031 (7)−0.0008 (6)0.0019 (6)
N20.0642 (12)0.0368 (9)0.0302 (9)0.0026 (8)0.0033 (8)−0.0042 (7)
N30.0558 (12)0.0405 (10)0.0487 (11)−0.0059 (9)−0.0055 (9)0.0065 (8)
C10.0627 (14)0.0457 (12)0.0266 (9)−0.0026 (10)0.0012 (9)−0.0006 (8)
C20.0534 (12)0.0381 (11)0.0297 (9)0.0067 (9)0.0044 (8)−0.0019 (8)
C30.0510 (12)0.0356 (10)0.0279 (9)0.0016 (8)−0.0038 (8)0.0012 (7)
C40.0549 (13)0.0390 (11)0.0391 (11)0.0050 (9)0.0086 (9)0.0025 (9)
C50.0452 (11)0.0335 (10)0.0347 (10)0.0013 (8)−0.0006 (8)0.0037 (8)
C60.0545 (14)0.0615 (16)0.0476 (13)−0.0111 (12)−0.0074 (10)−0.0048 (11)
Cl10.0468 (4)0.0427 (4)0.0425 (4)−0.0003 (2)−0.0022 (2)−0.0002 (2)
O40.126 (2)0.0840 (18)0.0799 (17)0.0238 (15)−0.0504 (17)−0.0069 (13)
O50.0761 (16)0.097 (2)0.137 (3)−0.0317 (15)0.0297 (16)−0.0074 (18)
O60.137 (3)0.106 (2)0.0864 (19)−0.013 (2)0.0566 (19)0.0002 (16)
O70.157 (3)0.0654 (16)0.129 (2)0.0509 (17)−0.084 (2)−0.0367 (15)

Geometric parameters (Å, °)

O1—C11.431 (3)C1—H1B0.9700
O1—H10.8881C2—H2A0.9700
O2—N31.222 (3)C2—H2B0.9700
O3—N31.227 (3)C3—C61.475 (3)
N1—C31.341 (3)C4—C51.348 (3)
N1—C51.390 (3)C4—H4A0.9300
N1—C21.479 (3)C6—H6A0.9600
N2—C31.336 (3)C6—H6B0.9600
N2—C41.353 (3)C6—H6C0.9600
N2—H20.8328Cl1—O41.410 (3)
N3—C51.434 (3)Cl1—O71.411 (2)
C1—C21.518 (3)Cl1—O51.420 (3)
C1—H1A0.9700Cl1—O61.427 (3)
C1—O1—H1106.3N2—C3—N1108.12 (19)
C3—N1—C5106.50 (17)N2—C3—C6124.7 (2)
C3—N1—C2124.35 (18)N1—C3—C6127.2 (2)
C5—N1—C2129.02 (18)C5—C4—N2105.7 (2)
C3—N2—C4110.65 (18)C5—C4—H4A127.2
C3—N2—H2123.8N2—C4—H4A127.2
C4—N2—H2125.3C4—C5—N1109.1 (2)
O2—N3—O3125.3 (2)C4—C5—N3124.9 (2)
O2—N3—C5118.6 (2)N1—C5—N3126.03 (19)
O3—N3—C5116.1 (2)C3—C6—H6A109.5
O1—C1—C2112.96 (18)C3—C6—H6B109.5
O1—C1—H1A109.0H6A—C6—H6B109.5
C2—C1—H1A109.0C3—C6—H6C109.5
O1—C1—H1B109.0H6A—C6—H6C109.5
C2—C1—H1B109.0H6B—C6—H6C109.5
H1A—C1—H1B107.8O4—Cl1—O7110.68 (15)
N1—C2—C1113.07 (18)O4—Cl1—O5111.2 (2)
N1—C2—H2A109.0O7—Cl1—O5112.8 (2)
C1—C2—H2A109.0O4—Cl1—O6109.3 (2)
N1—C2—H2B109.0O7—Cl1—O6108.2 (2)
C1—C2—H2B109.0O5—Cl1—O6104.49 (19)
H2A—C2—H2B107.8

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O1—H1···O50.892.022.860 (4)157
N2—H2···O1i0.831.982.803 (3)169
C1—H1B···O20.972.523.126 (3)121
C6—H6B···O7i0.962.523.441 (4)161

Symmetry codes: (i) x, −y+3/2, z+1/2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: IS2601).

References

  • Bruker (2001). SMART and SAINT 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]
  • Contrerasa, R., Flores-Parraa, A., Mijangosa, E., Téllezb, F., López-Sandoval, H. & Barba-Behrens, N. (2009). Coord. Chem. Rev.253, 1979–1999.
  • Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Wang, Y.-T., Tang, G.-M., Qin, D.-W., Duan, H.-D. & Ng, S. W. (2006). Acta Cryst. E62, o3094–o3095.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography