2-Methyl­benzimidazolium thio­cyanate

In the crystal structure of the title compound, C₈H₉N₂⁺·SCN⁻, the nearly planar 2-methyl­benzimidazolium cation [r.m.s. deviation = 0.0123 (4) Å] is perpendicular to a mirror plane and the methyl H atoms are disordered about the mirror plane with equal occupancies. The thio­cyanate anion also lies on a mirror plane. N—H⋯N hydrogen bonds link the components into an infinite chain along the b axis.

Related literature

For related structures, see: Bhattacharya et al. (2004); Ding et al. (2004); Shaker et al. (2010); Huang et al. (2006). For the application of benzimidazole derivatives in crystal engineering, see: Cai et al. (2002). For the biological properties of benzimidazole derivatives, see: Refaat (2010); Ansari & Lal (2009).

Experimental

Crystal data

• C₈H₉N₂⁺·SCN⁻

• M_r = 191.25

• Orthorhombic, P n m a

• a = 9.879 (2) Å

• b = 7.2157 (15) Å

• c = 12.890 (3) Å

• V = 918.9 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 0.31 mm⁻¹

• T = 100 K

• 0.40 × 0.29 × 0.15 mm

Data collection

• Bruker APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996) T_min = 0.888, T_max = 0.956

• 10495 measured reflections

• 1133 independent reflections

• 1000 reflections with I > 2σ(I)

• R_int = 0.039

Refinement

• R[F² > 2σ(F²)] = 0.034

• wR(F²) = 0.090

• S = 1.01

• 1133 reflections

• 71 parameters

• 1 restraint

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

• Δρ_max = 0.39 e Å⁻³

• Δρ_min = −0.28 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯N1	0.88 (2)	2.00 (2)	2.8627 (16)	168 (2)

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: SHELXL97 and publCIF (Westrip, 2010).

Supporting information

S1. Comment

Benzimidazoles are a class of compounds with a wide variety of biological properties (Refaat, 2010; Ansari & Lal, 2009) and applications in crystal-engineering (Cai et al., 2002). During our studies on coordination behavior of 2-methylbenzimidazole, the title crystal was obtained unexpectedly as a by-product. The structures of several compounds similar to present structure have been reported (Bhattacharya et al., 2004; Ding et al., 2004; Shaker et al., 2010; Huang et al., 2006).

The asymmetric unit of the title compound, contains one-half molecule of each component. The nearly planar 2-methylbenzimidazolium moiety (r.m.s = 0.0123 Å) is perpendicular to, and the thiocyanate ion lies on a mirror plane. In the crystal structure, an N—H···N hydrogen bond links the molecules into an infinite chain along the b axis.

Related literature

For related structures, see: Bhattacharya et al. (2004); Ding et al. (2004); Shaker et al. (2010); Huang et al. (2006). For the application of benzimidazole derivatives in crystal engineering, see: Cai et al. (2002). For the biological properties of benzimidazole derivatives, see: Refaat (2010); Ansari & Lal (2009).

S2. Experimental

An ethanolic solution (12 ml) of 2-methylbenzimidazole (5 mmol, 0.78 g) was added to an aqueous solution (10 ml) of CuCl₂. 2H₂O (0.5 g, 2 mmol) followed by addition of an aqueous solution (10 ml) of KSCN (5 mmol).The resulting precipitates were filtered off. The colorless crystals of the title compound were obtained from the filtrate.

S3. Refinement

The C-bound hydrogen atoms were placed at calculated positions (C—H 0.95 or 0.98 Å) and were treated as riding on their parent atoms, with U_iso(H) set to 1.2 or 1.5 U_eq(C). The N-bound hydrogen atom was located in a difference Fourier map and refined with a distance restraint of N—H 0.88 (2) Å.

Computing details

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and publCIF (Westrip, 2010).

Figures

Fig. 1. Thermal ellipsoid plot of the title compound at the 50% probability level. Hydrogen atoms are drawn as spheres of arbitrary radius. The unlabelled atoms are generated by the symmetry operation (x, –y + 3/2, z).

2-Methylbenzimidazolium thiocyanate

Crystal data

C8H9N2^+·SCN^−	F(000) = 400
Mr = 191.25	Dx = 1.382 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 4285 reflections
a = 9.879 (2) Å	θ = 2.6–30.3°
b = 7.2157 (15) Å	µ = 0.31 mm^−1
c = 12.890 (3) Å	T = 100 K
V = 918.9 (3) Å^3	Block, colorless
Z = 4	0.40 × 0.29 × 0.15 mm

Data collection

Bruker APEXII CCD diffractometer	1133 independent reflections
Radiation source: fine-focus sealed tube	1000 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
φ and ω scans	θmax = 27.5°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −12→12
Tmin = 0.888, Tmax = 0.956	k = −9→9
10495 measured reflections	l = −16→16

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.090	H atoms treated by a mixture of independent and constrained refinement
S = 1.01	w = 1/[σ^2(Fo^2) + (0.0395P)^2 + 0.9286P] where P = (Fo^2 + 2Fc^2)/3
1133 reflections	(Δ/σ)max < 0.001
71 parameters	Δρmax = 0.39 e Å^−3
1 restraint	Δρmin = −0.28 e Å^−3

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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
S1	−0.11964 (6)	0.2500	0.31732 (5)	0.02094 (18)
N1	0.15210 (19)	0.2500	0.37930 (15)	0.0193 (4)
C1	0.0383 (2)	0.2500	0.35335 (17)	0.0162 (4)
H2	0.2584 (17)	0.485 (2)	0.3813 (13)	0.019*
N2	0.28838 (12)	0.60009 (17)	0.38143 (10)	0.0155 (3)
C2	0.0609 (2)	0.7500	0.38575 (17)	0.0191 (5)
H2A	0.0277	0.8779	0.3825	0.029*	0.50
H2B	0.0299	0.6922	0.4503	0.029*	0.50
H2BA	0.0258	0.6800	0.3264	0.029*	0.50
C3	0.2103 (2)	0.7500	0.38283 (15)	0.0156 (4)
C4	0.42343 (15)	0.6534 (2)	0.37939 (11)	0.0148 (3)
C5	0.54317 (15)	0.5525 (2)	0.37848 (11)	0.0179 (3)
H5	0.5432	0.4209	0.3774	0.022*
C6	0.66199 (15)	0.6529 (2)	0.37921 (11)	0.0189 (3)
H6	0.7460	0.5887	0.3797	0.023*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0159 (3)	0.0182 (3)	0.0287 (3)	0.000	−0.0020 (2)	0.000
N1	0.0179 (9)	0.0140 (9)	0.0260 (10)	0.000	0.0024 (7)	0.000
C1	0.0200 (10)	0.0105 (9)	0.0182 (10)	0.000	0.0034 (8)	0.000
N2	0.0169 (6)	0.0104 (6)	0.0191 (6)	−0.0018 (5)	0.0000 (5)	0.0004 (5)
C2	0.0170 (10)	0.0192 (11)	0.0211 (11)	0.000	0.0015 (8)	0.000
C3	0.0193 (10)	0.0151 (10)	0.0126 (9)	0.000	−0.0012 (8)	0.000
C4	0.0168 (7)	0.0141 (7)	0.0135 (6)	−0.0007 (6)	−0.0004 (5)	0.0004 (5)
C5	0.0215 (7)	0.0126 (7)	0.0197 (7)	0.0023 (6)	−0.0015 (6)	−0.0003 (6)
C6	0.0175 (7)	0.0200 (8)	0.0193 (7)	0.0026 (6)	−0.0007 (6)	0.0001 (6)

Geometric parameters (Å, º)

S1—C1	1.628 (2)	C2—H2BA	0.9800
N1—C1	1.173 (3)	C4—C5	1.389 (2)
N2—C3	1.3289 (18)	C4—C4^i	1.394 (3)
N2—C4	1.3888 (19)	C5—C6	1.379 (2)
N2—H2	0.881 (15)	C5—H5	0.9500
C2—C3	1.477 (3)	C6—C6^i	1.401 (3)
C2—H2A	0.9800	C6—H6	0.9500
C2—H2B	0.9800
N1—C1—S1	180.0 (2)	N2—C3—C2	125.52 (9)
C3—N2—C4	109.44 (13)	N2—C4—C5	132.32 (14)
C3—N2—H2	124.8 (12)	N2—C4—C4^i	106.08 (8)
C4—N2—H2	125.7 (12)	C5—C4—C4^i	121.60 (9)
C3—C2—H2A	109.5	C6—C5—C4	116.72 (15)
C3—C2—H2B	109.5	C6—C5—H5	121.6
H2A—C2—H2B	109.5	C4—C5—H5	121.6
C3—C2—H2BA	109.5	C5—C6—C6^i	121.67 (9)
H2A—C2—H2BA	109.5	C5—C6—H6	119.2
H2B—C2—H2BA	109.5	C6^i—C6—H6	119.2
N2—C3—N2^i	108.97 (18)

Symmetry code: (i) x, −y+3/2, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···N1	0.88 (2)	2.00 (2)	2.8627 (16)	168 (2)