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

The title hydrated salt, C18H18N4(2+)·2Cl(-)·2H2O, sits about an inversion centre, such that the asymmetric unit contains one half-mol-ecule. In the crystal, hydrogen bonds occur between the water mol-ecules and chloride anions, and there is π-π stacking of the benzene and imidazole rings of inversion-related pairs of mol-ecules, 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

C18H18N4 2+·2Cl−·2H2O

M = 397.30

Monoclinic,

a = 8.1080 (12) Å

b = 9.0857 (14) Å

c = 12.9188 (19) Å

β = 94.426 (2)°

V = 948.8 (2) Å3

Z = 2

Mo Kα radiation

μ = 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 > 2σ(I)

R int = 0.021

Refinement

R[F 2 > 2σ(F 2)] = 0.038

wR(F 2) = 0.114

S = 1.07

1681 reflections

127 parameters

2 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.16 e Å−3

Δρmin = −0.20 e Å−3

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.

Click here for additional data file.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812046594/pk2446sup1.cif

Click here for additional data file.

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812046594/pk2446Isup2.hkl

Click here for additional data file.

Supplementary material file. DOI: 10.1107/S1600536812046594/pk2446Isup3.cml

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

C18H18N42+·2Cl−·2H2O	F(000) = 416
Mr = 397.30	Dx = 1.391 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1814 reflections
a = 8.1080 (12) Å	θ = 2.5–26.8°
b = 9.0857 (14) Å	µ = 0.36 mm−1
c = 12.9188 (19) Å	T = 296 K
β = 94.426 (2)°	Block, white
V = 948.8 (2) Å3	0.38 × 0.28 × 0.17 mm
Z = 2

Bruker SMART APEXII CCD diffractometer	1681 independent reflections
Radiation source: fine-focus sealed tube	1371 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
φ and ω scans	θmax = 25.1°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −9→9
Tmin = 0.876, Tmax = 0.943	k = −10→10
4604 measured reflections	l = −10→15

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.114	H atoms treated by a mixture of independent and constrained refinement
S = 1.07	w = 1/[σ2(Fo2) + (0.0587P)2 + 0.1961P] where P = (Fo2 + 2Fc2)/3
1681 reflections	(Δ/σ)max < 0.001
127 parameters	Δρmax = 0.16 e Å−3
2 restraints	Δρmin = −0.20 e Å−3

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.

	x	y	z	Uiso*/Ueq
Cl1	0.49232 (8)	0.17546 (7)	0.85285 (4)	0.0755 (3)
N1	0.35268 (18)	0.00311 (15)	0.44209 (10)	0.0454 (4)
N2	0.2397 (2)	0.17478 (16)	0.53127 (12)	0.0521 (4)
O1	0.7107 (3)	0.0906 (2)	0.05725 (17)	0.0961 (6)
C1	0.4743 (2)	−0.0970 (2)	0.40528 (14)	0.0532 (5)
H1A	0.5002	−0.0687	0.3360	0.064*
H1B	0.4301	−0.1962	0.4021	0.064*
C2	0.3745 (2)	0.09265 (19)	0.52381 (13)	0.0462 (4)
C3	0.2198 (3)	0.2890 (2)	0.60909 (19)	0.0701 (6)
H3A	0.2912	0.2682	0.6701	0.105*
H3B	0.1069	0.2908	0.6268	0.105*
H3C	0.2482	0.3830	0.5815	0.105*
C4	0.1255 (2)	0.1382 (2)	0.44954 (16)	0.0557 (5)
C5	−0.0348 (3)	0.1869 (3)	0.4213 (2)	0.0725 (7)
H5	−0.0854	0.2590	0.4590	0.087*
C6	−0.1142 (3)	0.1222 (3)	0.3345 (2)	0.0825 (8)
H6	−0.2216	0.1515	0.3136	0.099*
C7	−0.0399 (3)	0.0149 (3)	0.2772 (2)	0.0805 (7)
H7	−0.0981	−0.0247	0.2188	0.097*
C8	0.1178 (3)	−0.0338 (2)	0.30476 (16)	0.0642 (6)
H8	0.1682	−0.1056	0.2667	0.077*
C9	0.1975 (2)	0.0297 (2)	0.39233 (14)	0.0509 (5)
H1C	0.653 (3)	0.101 (3)	0.0016 (12)	0.081 (8)*
H1D	0.667 (4)	0.021 (2)	0.087 (2)	0.105 (11)*

	U11	U22	U33	U12	U13	U23
Cl1	0.0922 (5)	0.0875 (5)	0.0477 (3)	0.0113 (3)	0.0113 (3)	−0.0030 (2)
N1	0.0513 (9)	0.0469 (8)	0.0380 (8)	0.0018 (6)	0.0036 (6)	0.0004 (6)
N2	0.0584 (10)	0.0490 (9)	0.0508 (9)	0.0069 (7)	0.0152 (7)	0.0038 (6)
O1	0.0995 (15)	0.1007 (15)	0.0839 (14)	−0.0151 (12)	−0.0199 (11)	0.0121 (12)
C1	0.0599 (12)	0.0587 (11)	0.0414 (9)	0.0051 (9)	0.0068 (8)	−0.0074 (8)
C2	0.0525 (11)	0.0475 (10)	0.0396 (9)	0.0030 (8)	0.0103 (8)	0.0028 (7)
C3	0.0826 (15)	0.0569 (12)	0.0742 (14)	0.0093 (10)	0.0278 (12)	−0.0077 (10)
C4	0.0539 (11)	0.0548 (10)	0.0593 (12)	0.0024 (9)	0.0102 (9)	0.0165 (9)
C5	0.0604 (13)	0.0688 (14)	0.0901 (17)	0.0111 (10)	0.0171 (12)	0.0306 (12)
C6	0.0567 (14)	0.0892 (17)	0.0993 (19)	−0.0038 (12)	−0.0093 (13)	0.0444 (16)
C7	0.0726 (16)	0.0880 (17)	0.0773 (16)	−0.0122 (13)	−0.0181 (13)	0.0283 (14)
C8	0.0688 (13)	0.0683 (13)	0.0538 (12)	−0.0082 (10)	−0.0063 (10)	0.0120 (10)
C9	0.0504 (11)	0.0549 (10)	0.0472 (10)	−0.0026 (8)	0.0023 (8)	0.0117 (8)

N1—C2	1.334 (2)	C3—H3B	0.9600
N1—C9	1.389 (2)	C3—H3C	0.9600
N1—C1	1.448 (2)	C4—C9	1.388 (3)
N2—C2	1.333 (2)	C4—C5	1.394 (3)
N2—C4	1.390 (3)	C5—C6	1.382 (4)
N2—C3	1.462 (3)	C5—H5	0.9300
O1—H1C	0.830 (10)	C6—C7	1.389 (4)
O1—H1D	0.827 (10)	C6—H6	0.9300
C1—C2i	1.473 (3)	C7—C8	1.374 (3)
C1—H1A	0.9700	C7—H7	0.9300
C1—H1B	0.9700	C8—C9	1.385 (3)
C2—C1i	1.473 (3)	C8—H8	0.9300
C3—H3A	0.9600
C2—N1—C9	108.69 (15)	H3A—C3—H3C	109.5
C2—N1—C1	126.20 (15)	H3B—C3—H3C	109.5
C9—N1—C1	124.93 (15)	C9—C4—N2	106.96 (16)
C2—N2—C4	108.25 (15)	C9—C4—C5	120.5 (2)
C2—N2—C3	125.56 (18)	N2—C4—C5	132.5 (2)
C4—N2—C3	126.12 (17)	C6—C5—C4	116.4 (2)
H1C—O1—H1D	104 (3)	C6—C5—H5	121.8
N1—C1—C2i	109.51 (14)	C4—C5—H5	121.8
N1—C1—H1A	109.8	C5—C6—C7	122.5 (2)
C2i—C1—H1A	109.8	C5—C6—H6	118.7
N1—C1—H1B	109.8	C7—C6—H6	118.7
C2i—C1—H1B	109.8	C8—C7—C6	121.4 (2)
H1A—C1—H1B	108.2	C8—C7—H7	119.3
N2—C2—N1	109.82 (16)	C6—C7—H7	119.3
N2—C2—C1i	125.99 (16)	C7—C8—C9	116.3 (2)
N1—C2—C1i	124.19 (15)	C7—C8—H8	121.8
N2—C3—H3A	109.5	C9—C8—H8	121.8
N2—C3—H3B	109.5	C8—C9—C4	122.85 (19)
H3A—C3—H3B	109.5	C8—C9—N1	130.88 (19)
N2—C3—H3C	109.5	C4—C9—N1	106.27 (16)
C2—N1—C1—C2i	3.6 (3)	N2—C4—C5—C6	−178.57 (19)
C9—N1—C1—C2i	178.11 (15)	C4—C5—C6—C7	−0.4 (3)
C4—N2—C2—N1	−0.86 (19)	C5—C6—C7—C8	0.6 (4)
C3—N2—C2—N1	−177.88 (17)	C6—C7—C8—C9	0.0 (3)
C4—N2—C2—C1i	179.73 (17)	C7—C8—C9—C4	−0.8 (3)
C3—N2—C2—C1i	2.7 (3)	C7—C8—C9—N1	178.01 (18)
C9—N1—C2—N2	1.22 (19)	N2—C4—C9—C8	179.65 (17)
C1—N1—C2—N2	176.48 (16)	C5—C4—C9—C8	1.1 (3)
C9—N1—C2—C1i	−179.35 (16)	N2—C4—C9—N1	0.56 (19)
C1—N1—C2—C1i	−4.1 (3)	C5—C4—C9—N1	−177.98 (17)
C2—N2—C4—C9	0.16 (19)	C2—N1—C9—C8	179.92 (19)
C3—N2—C4—C9	177.16 (17)	C1—N1—C9—C8	4.6 (3)
C2—N2—C4—C5	178.5 (2)	C2—N1—C9—C4	−1.08 (19)
C3—N2—C4—C5	−4.5 (3)	C1—N1—C9—C4	−176.42 (16)
C9—C4—C5—C6	−0.5 (3)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1C···Cl1ii	0.83	2.33	3.1558 (19)	170
O1—H1D···Cl1i	0.83	2.37	3.190 (2)	170

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) ; (ii) .