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Volume 68 
Part 12 
Page o3398  
December 2012  

Received 25 September 2012
Accepted 12 November 2012
Online 24 November 2012

Key indicators
Single-crystal X-ray study
T = 296 K
Mean [sigma](C-C) = 0.003 Å
R = 0.038
wR = 0.114
Data-to-parameter ratio = 13.2
Details
Open access

5,12-Dimethylpyrazino[1,2-a:4,5-a']dibenzimidazole-5,12-diium dichloride dihydrate

aResearch Institute of Shaanxi Yanchang Petroleum (Group) Co. Ltd, Ke Ji No. 2 Road 75, Xi'an 710075, Shaanxi, People's Republic of China,bDepartment of Pharmacology, School of Pharmacy, Forth Military Medical University, Chang-le West Road 17, Xi'an 710032, Shaanxi, People's Republic of China, and cCollege of Chemistry & Chemical Engineering, Xianyang Normal University, Xianyang 712000, Shaanxi, People's Republic of China
Correspondence e-mail: eota@163.com

The title hydrated salt, C18H18N42+·2Cl-·2H2O, sits about an inversion centre, such that the asymmetric unit contains one half-molecule. In the crystal, hydrogen bonds occur between the water molecules and chloride anions, and there is [pi]-[pi] stacking of the benzene and imidazole rings of inversion-related pairs of molecules, with a centroid-centroid distance of 3.704 (17) Å.

Related literature

For descriptions of clinical applications of the benzimidazole ring system, see: Harrell et al. (2004[Harrell, C. C., Kohli, P., Siwy, Z. & Martin, C. R. (2004). J. Am. Chem. Soc. 126, 15646-15647.]). For a related structure, see: Sun et al. (2010[Sun, T., Li, K., Lai, Y., Chen, R. & Wu, H. (2010). Acta Cryst. E66, m1058.]).

[Scheme 1]

Experimental

Crystal data
  • C18H18N42+·2Cl-·2H2O

  • Mr = 397.30

  • Monoclinic, P 21 /c

  • a = 8.1080 (12) Å

  • b = 9.0857 (14) Å

  • c = 12.9188 (19) Å

  • [beta] = 94.426 (2)°

  • V = 948.8 (2) Å3

  • Z = 2

  • Mo K[alpha] radiation

  • [mu] = 0.36 mm-1

  • T = 296 K

  • 0.38 × 0.28 × 0.17 mm

Data collection
  • Bruker SMART APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2002[Bruker (2002). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.876, Tmax = 0.943

  • 4604 measured reflections

  • 1681 independent reflections

  • 1371 reflections with I > 2[sigma](I)

  • Rint = 0.021

Refinement
  • R[F2 > 2[sigma](F2)] = 0.038

  • wR(F2) = 0.114

  • S = 1.07

  • 1681 reflections

  • 127 parameters

  • 2 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • [Delta][rho]max = 0.16 e Å-3

  • [Delta][rho]min = -0.20 e Å-3

Table 1
Hydrogen-bond geometry (Å, °)

D-H...A D-H H...A D...A D-H...A
O1-H1C...Cl1i 0.83 2.33 3.1558 (19) 170
O1-H1D...Cl1ii 0.83 2.37 3.190 (2) 170
Symmetry codes: (i) x, y, z-1; (ii) -x+1, -y, -z+1.

Data collection: APEX2 (Bruker, 2002[Bruker (2002). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2002[Bruker (2002). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; 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: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: PK2446 ).


Acknowledgements

The work was supported by 2009ZX09103-111, the China Postdoctoral Science Foundation (No. 2009041446), the Special Research Fund of the Education Department of Shaanxi Province (12 J K0631) and the Special Research Fund of Xianyang Normal University (11XSYK204). We thank the Instrumental Analysis Center of Northwest University for the data collection.

References

Bruker (2002). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
Harrell, C. C., Kohli, P., Siwy, Z. & Martin, C. R. (2004). J. Am. Chem. Soc. 126, 15646-15647.  [ISI] [CrossRef] [PubMed] [ChemPort]
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [details]
Sun, T., Li, K., Lai, Y., Chen, R. & Wu, H. (2010). Acta Cryst. E66, m1058.  [CSD] [CrossRef] [details]


Acta Cryst (2012). E68, o3398  [ doi:10.1107/S1600536812046594 ]

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