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

Han, J.; Zhao, M.; Zhang, J.; Ma, L.; Fan, G.

doi:10.1107/S1600536812046594

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 (C-C) = 0.003 Å
R = 0.038
wR = 0.114
Data-to-parameter ratio = 13.2
Details

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

Jie Han,^a ^* Ming-gao Zhao,^b Jun Zhang,^b Lan Ma ^b and Guang Fan ^c

^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). For a related structure, see: Sun et al. (2010).

Experimental

Crystal data

C₁₈H₁₈N₄²⁺·2Cl^-·2H₂O
M_r = 397.30
Monoclinic, P 2₁ /c
a = 8.1080 (12) Å
b = 9.0857 (14) Å
c = 12.9188 (19) Å
= 94.426 (2)°
V = 948.8 (2) Å³
Z = 2
Mo K radiation
= 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) T_min = 0.876, T_max = 0.943
4604 measured reflections
1681 independent reflections
1371 reflections with I > 2(I)
R_int = 0.021

Refinement

R[F² > 2(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
_max = 0.16 e Å^-3
_min = -0.20 e Å^-3

Table 1
Hydrogen-bond geometry (Å, °)

D-HA	D-H	HA	DA	D-HA
O1-H1CCl1ⁱ	0.83	2.33	3.1558 (19)	170
O1-H1DCl1ⁱⁱ	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); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); 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.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Sun, T., Li, K., Lai, Y., Chen, R. & Wu, H. (2010). Acta Cryst. E66, m1058.

organic compounds