3-(3-Meth­oxy­phen­yl)benzo[d]thia­zolo[3,2-a]imidazol-9-ium hydrogen sulfate

In the title mol­ecular salt, C₁₆H₁₃N₂OS⁺·HSO₄⁻, the thia­zolo[3,2-a]benzimidazolium ring system is roughly planar [maximum deviation = 0.046 (3) Å] and makes a dihedral angle of 58.22 (11)° with the benzene ring. The meth­oxy group is almost coplanar with its attached benzene ring [C_meth­yl—O—C—C = −1.6 (5)°]. In the crystal, the cation is linked to the anion by a bifurcated N—H...(O,O) hydrogen bond, generating an R₁²(4) ring motif. The ion pairs are then connected by a C—H...O hydrogen bond into inversion dimers and these dimers are further linked by O—H...O hydrogen bonds into an infinite tape along [100]. A π–π stacking inter­action [centroid-to-centroid distance = 3.5738 (18) Å] and a short inter­molecular contact [S...O = 2.830 (3) Å] are also observed.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.058
• wR factor = 0.170
• Data-to-parameter ratio = 16.0

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT430_ALERT_2_B Short Inter D...A Contact  S1     ..  O4      ..       2.83 Ang.

Alert level C
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....        2.4
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         21

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT007_ALERT_5_G Note: Number of Unrefined D-H Atoms ............          1
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          2

   0 ALERT level A = Most likely a serious problem - resolve or explain
   1 ALERT level B = A potentially serious problem, consider carefully
   2 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   3 ALERT level G = General information/check it is not something unexpected

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   2 ALERT type 5 Informative message, check

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S1. Comment

Various biological properties of thiazolo[3,2-a]benzimidazole derivatives have been reported, including antibacterial, antifungal, anti-inflammatory, antiulcer, antiviral, anthelmintic and anticancer activities (Chimirri et al., 1988; Al-Rashood & Abdel-Aziz, 2010). In continuation of our interest in this area (Hamdy et al., 2007; Abdel-Aziz et al., 2007, 2008; Farag et al., 2011), we report herein the crystal structure of the title compound.

The molecular structure of the title compound is shown in Fig. 1. The asymmetric unit of the title compound, C₁₆H₁₃N₂OS⁺, HSO₄^-, contains a 3-(3-methoxyphenyl)benzo[d]thiazolo[3,2-a]imidazol-9-ium cation and a hydrogen sulfate anion. The thiazolo[3,2-a]benzimidazole ring system is roughly planar [S1/N1/N2/C1–C9; maximum deviation = 0.046 (3) Å at atom C8] and makes a dihedral angle of 58.22 (11)° with the C10–C15 benzene ring. The O1—C16 methoxy group is almost coplanar with the C10–C15 benzene ring as indicated by the C16—O1—C12—C11 torsion angle of -1.6 (5)°.

In the crystal (Fig. 2), the cation and anion are linked to each other by bifurcated N1—H1N1···(O3,O4) hydrogen bonds, generating an R₁²(4) ring motif (Bernstein et al., 1995). The asymmetric units are then connected by C11—H11A···O5 hydrogen bond into inversion dimers and the dimers are further linked by O2—H1O2···O3 hydrogen bond into an infinite tape, propagating along the a-axis. A π–π interaction [Cg1···Cg2 = 3.5738 (18) Å; Cg1 and Cg2 are the centroids of N1/C6/C1/N2/C7 and C1–C6 rings, respectively; symmetry code = -1 + x, y, z] and a short intermolecular contact [S1···O4 = 2.830 (3) Å; symmetry code = -x, 1 - y, 1 - z] are also observed.

Related literature

For the biological activities of thiazolo[3,2-a]benzimidazoles, see: Chimirri et al. (1988); Al-Rashood & Abdel-Aziz (2010); Hamdy et al. (2007); Abdel-Aziz et al. (2007, 2008); Farag et al. (2011). For hydrogen-bond motifs, see: Bernstein et al. (1995). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986).

S2. Experimental

A mixture of 2-mercaptobenzimidazole (1.52 g, 10 mmol) and 3-methoxyacetophenone (1.52 g, 10 mmol) in boiling AcOH/H₂SO₄ (50 ml; 10:1, v/v) was refluxed for 5 h. The reaction mixture was then left to cool at room temperature. The colourless blocks formed were filtered off, washed with ethanol and dried to afford the title compound.

S3. Refinement

Atoms H1O2 and H1N1 were located in a difference Fourier map and the atom H1O2 was then fixed at its found location [O2—H1O2 = 0.9734 Å] and refined using a riding model with U_iso(H) = 1.5U_eq(O), whereas the atom H1N1 was refined freely [N1—H1N1 = 0.93 (4) Å]. The remaining H atoms were positioned geometrically [C—H = 0.93 and 0.96 Å] and refined with U_iso(H) = 1.2 or 1.5U_eq(C). A rotating group model was applied to the methyl group.

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures

	Fig. 1. The molecular structure of the title compound with 50% probability displacement ellipsoids. Hydrogen bonds are indicated by dashed lines.
	Fig. 2. The crystal packing of the title compound. The dashed lines represent the hydrogen bonds. For clarity sake, hydrogen atoms not involved in hydrogen bonding have been omitted.

3-(3-Methoxyphenyl)benzo[d]thiazolo[3,2-a]imidazol-9-ium hydrogen sulfate

Crystal data

C16H13N2OS^+·HSO4^−	F(000) = 784
Mr = 378.41	Dx = 1.550 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4717 reflections
a = 4.5428 (8) Å	θ = 2.3–29.3°
b = 20.096 (4) Å	µ = 0.36 mm^−1
c = 17.788 (3) Å	T = 100 K
β = 93.003 (4)°	Block, colourless
V = 1621.6 (5) Å^3	0.31 × 0.15 × 0.12 mm
Z = 4

Data collection

Bruker APEX DUO CCD diffractometer	3699 independent reflections
Radiation source: fine-focus sealed tube	2904 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.050
φ and ω scans	θmax = 27.5°, θmin = 1.5°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −5→5
Tmin = 0.898, Tmax = 0.959	k = −26→24
12491 measured reflections	l = −19→23

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)] = 0.058	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.170	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0882P)^2 + 3.0462P] where P = (Fo^2 + 2Fc^2)/3
3699 reflections	(Δ/σ)max = 0.001
231 parameters	Δρmax = 0.99 e Å^−3
0 restraints	Δρmin = −0.68 e Å^−3

Special details

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

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
S1	0.21267 (17)	0.46487 (4)	0.42583 (4)	0.0192 (2)
S2	0.24639 (17)	0.37855 (4)	0.66173 (4)	0.0214 (2)
O1	0.7757 (6)	0.47885 (11)	0.06026 (13)	0.0313 (6)
O2	0.0440 (5)	0.31645 (11)	0.67548 (13)	0.0281 (5)
H1O2	−0.1640	0.3283	0.6741	0.042*
O3	0.5152 (6)	0.34615 (13)	0.63785 (13)	0.0325 (6)
O4	0.1087 (6)	0.41582 (12)	0.59898 (14)	0.0315 (6)
O5	0.2805 (7)	0.41374 (13)	0.73091 (15)	0.0416 (7)
N1	0.5806 (6)	0.36239 (12)	0.48611 (14)	0.0176 (5)
N2	0.5187 (5)	0.37532 (11)	0.36286 (13)	0.0154 (5)
C1	0.7199 (6)	0.32219 (14)	0.37436 (16)	0.0162 (6)
C2	0.8648 (7)	0.28056 (14)	0.32574 (16)	0.0185 (6)
H2A	0.8406	0.2849	0.2737	0.022*
C3	1.0472 (7)	0.23229 (15)	0.35886 (17)	0.0217 (6)
H3A	1.1477	0.2035	0.3282	0.026*
C4	1.0841 (7)	0.22567 (15)	0.43704 (17)	0.0209 (6)
H4A	1.2093	0.1927	0.4569	0.025*
C5	0.9397 (7)	0.26676 (14)	0.48591 (17)	0.0195 (6)
H5A	0.9654	0.2624	0.5379	0.023*
C6	0.7538 (6)	0.31496 (14)	0.45269 (16)	0.0173 (6)
C7	0.4426 (6)	0.39749 (14)	0.43096 (16)	0.0168 (6)
C8	0.2254 (7)	0.46239 (14)	0.32772 (16)	0.0198 (6)
H8A	0.1249	0.4926	0.2961	0.024*
C9	0.3934 (6)	0.41295 (14)	0.30187 (15)	0.0167 (6)
C10	0.4589 (6)	0.39786 (14)	0.22327 (16)	0.0171 (6)
C11	0.5788 (7)	0.44837 (14)	0.18026 (16)	0.0186 (6)
H11A	0.6104	0.4906	0.2006	0.022*
C12	0.6502 (7)	0.43475 (15)	0.10674 (16)	0.0212 (6)
C13	0.6007 (7)	0.37120 (15)	0.07654 (17)	0.0226 (6)
H13A	0.6500	0.3621	0.0275	0.027*
C14	0.4790 (7)	0.32211 (15)	0.11920 (17)	0.0212 (6)
H14A	0.4460	0.2801	0.0986	0.025*
C15	0.4049 (6)	0.33474 (14)	0.19277 (16)	0.0188 (6)
H15A	0.3207	0.3016	0.2212	0.023*
C16	0.8306 (10)	0.54428 (17)	0.0891 (2)	0.0367 (9)
H16A	0.9177	0.5709	0.0513	0.055*
H16B	0.9628	0.5418	0.1329	0.055*
H16C	0.6481	0.5641	0.1023	0.055*
H1N1	0.540 (8)	0.3670 (18)	0.537 (2)	0.022 (9)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0257 (4)	0.0124 (4)	0.0195 (4)	0.0041 (3)	0.0020 (3)	−0.0003 (3)
S2	0.0273 (4)	0.0140 (4)	0.0233 (4)	0.0020 (3)	0.0053 (3)	−0.0002 (3)
O1	0.0577 (17)	0.0144 (11)	0.0228 (11)	−0.0097 (10)	0.0120 (11)	0.0003 (9)
O2	0.0312 (13)	0.0176 (11)	0.0352 (13)	−0.0015 (9)	−0.0016 (10)	0.0050 (9)
O3	0.0345 (14)	0.0369 (15)	0.0262 (12)	0.0089 (10)	0.0037 (10)	0.0035 (10)
O4	0.0381 (14)	0.0203 (12)	0.0365 (13)	0.0082 (10)	0.0046 (10)	0.0096 (10)
O5	0.067 (2)	0.0288 (14)	0.0294 (13)	−0.0083 (12)	0.0063 (12)	−0.0110 (11)
N1	0.0243 (13)	0.0119 (12)	0.0165 (12)	0.0029 (9)	0.0011 (9)	−0.0007 (9)
N2	0.0198 (12)	0.0094 (11)	0.0169 (11)	0.0001 (8)	−0.0001 (9)	0.0004 (9)
C1	0.0178 (14)	0.0089 (13)	0.0219 (14)	−0.0009 (10)	0.0012 (10)	0.0031 (10)
C2	0.0228 (15)	0.0137 (14)	0.0190 (13)	−0.0015 (11)	0.0013 (11)	−0.0008 (11)
C3	0.0260 (16)	0.0132 (14)	0.0262 (15)	0.0016 (11)	0.0047 (12)	−0.0031 (12)
C4	0.0249 (16)	0.0125 (14)	0.0252 (15)	0.0027 (11)	−0.0014 (11)	0.0020 (11)
C5	0.0242 (16)	0.0138 (14)	0.0203 (14)	0.0003 (11)	0.0001 (11)	0.0020 (11)
C6	0.0224 (15)	0.0123 (13)	0.0172 (13)	−0.0009 (10)	0.0024 (10)	0.0005 (11)
C7	0.0190 (14)	0.0119 (13)	0.0196 (14)	−0.0017 (10)	0.0011 (10)	−0.0004 (10)
C8	0.0269 (16)	0.0105 (14)	0.0218 (14)	0.0022 (11)	0.0005 (11)	0.0022 (11)
C9	0.0217 (15)	0.0102 (13)	0.0179 (14)	−0.0007 (10)	−0.0015 (10)	0.0029 (10)
C10	0.0204 (15)	0.0114 (13)	0.0192 (13)	0.0005 (10)	−0.0011 (10)	0.0012 (11)
C11	0.0254 (16)	0.0093 (13)	0.0209 (14)	−0.0018 (10)	−0.0005 (11)	0.0000 (11)
C12	0.0312 (17)	0.0132 (14)	0.0194 (14)	−0.0026 (11)	0.0024 (11)	0.0028 (11)
C13	0.0334 (18)	0.0165 (15)	0.0181 (14)	−0.0027 (12)	0.0027 (12)	−0.0036 (11)
C14	0.0261 (16)	0.0116 (14)	0.0256 (15)	−0.0029 (11)	−0.0021 (12)	−0.0018 (11)
C15	0.0236 (15)	0.0114 (13)	0.0214 (14)	−0.0038 (10)	0.0001 (11)	0.0000 (11)
C16	0.066 (3)	0.0121 (16)	0.0334 (19)	−0.0074 (15)	0.0170 (17)	0.0012 (13)

Geometric parameters (Å, º)

S1—C7	1.710 (3)	C4—C5	1.388 (4)
S1—C8	1.750 (3)	C4—H4A	0.9300
S2—O5	1.421 (3)	C5—C6	1.396 (4)
S2—O4	1.458 (2)	C5—H5A	0.9300
S2—O3	1.466 (3)	C8—C9	1.348 (4)
S2—O2	1.577 (2)	C8—H8A	0.9300
O1—C12	1.358 (4)	C9—C10	1.476 (4)
O1—C16	1.428 (4)	C10—C15	1.396 (4)
O2—H1O2	0.9734	C10—C11	1.399 (4)
N1—C7	1.337 (4)	C11—C12	1.391 (4)
N1—C6	1.389 (4)	C11—H11A	0.9300
N1—H1N1	0.93 (4)	C12—C13	1.399 (4)
N2—C7	1.353 (4)	C13—C14	1.378 (4)
N2—C1	1.413 (4)	C13—H13A	0.9300
N2—C9	1.417 (3)	C14—C15	1.392 (4)
C1—C2	1.393 (4)	C14—H14A	0.9300
C1—C6	1.401 (4)	C15—H15A	0.9300
C2—C3	1.387 (4)	C16—H16A	0.9600
C2—H2A	0.9300	C16—H16B	0.9600
C3—C4	1.398 (4)	C16—H16C	0.9600
C3—H3A	0.9300
C7—S1—C8	88.78 (14)	N1—C7—N2	110.6 (2)
O5—S2—O4	115.49 (16)	N1—C7—S1	135.9 (2)
O5—S2—O3	114.67 (17)	N2—C7—S1	113.4 (2)
O4—S2—O3	109.68 (14)	C9—C8—S1	114.2 (2)
O5—S2—O2	107.32 (15)	C9—C8—H8A	122.9
O4—S2—O2	107.17 (14)	S1—C8—H8A	122.9
O3—S2—O2	101.22 (15)	C8—C9—N2	110.1 (2)
C12—O1—C16	117.0 (2)	C8—C9—C10	128.3 (3)
S2—O2—H1O2	112.1	N2—C9—C10	121.5 (2)
C7—N1—C6	107.6 (2)	C15—C10—C11	120.8 (3)
C7—N1—H1N1	123 (2)	C15—C10—C9	121.0 (3)
C6—N1—H1N1	129 (2)	C11—C10—C9	118.2 (3)
C7—N2—C1	108.2 (2)	C12—C11—C10	119.2 (3)
C7—N2—C9	113.5 (2)	C12—C11—H11A	120.4
C1—N2—C9	138.1 (2)	C10—C11—H11A	120.4
C2—C1—C6	121.6 (3)	O1—C12—C11	124.8 (3)
C2—C1—N2	133.4 (3)	O1—C12—C13	115.2 (3)
C6—C1—N2	105.0 (2)	C11—C12—C13	120.0 (3)
C3—C2—C1	116.6 (3)	C14—C13—C12	120.2 (3)
C3—C2—H2A	121.7	C14—C13—H13A	119.9
C1—C2—H2A	121.7	C12—C13—H13A	119.9
C2—C3—C4	121.8 (3)	C13—C14—C15	120.7 (3)
C2—C3—H3A	119.1	C13—C14—H14A	119.6
C4—C3—H3A	119.1	C15—C14—H14A	119.6
C5—C4—C3	122.0 (3)	C14—C15—C10	119.0 (3)
C5—C4—H4A	119.0	C14—C15—H15A	120.5
C3—C4—H4A	119.0	C10—C15—H15A	120.5
C4—C5—C6	116.3 (3)	O1—C16—H16A	109.5
C4—C5—H5A	121.9	O1—C16—H16B	109.5
C6—C5—H5A	121.9	H16A—C16—H16B	109.5
N1—C6—C5	129.7 (3)	O1—C16—H16C	109.5
N1—C6—C1	108.6 (2)	H16A—C16—H16C	109.5
C5—C6—C1	121.7 (3)	H16B—C16—H16C	109.5
C7—N2—C1—C2	178.7 (3)	C8—S1—C7—N2	−0.4 (2)
C9—N2—C1—C2	−6.0 (6)	C7—S1—C8—C9	0.3 (2)
C7—N2—C1—C6	0.2 (3)	S1—C8—C9—N2	−0.1 (3)
C9—N2—C1—C6	175.4 (3)	S1—C8—C9—C10	−178.0 (2)
C6—C1—C2—C3	−0.8 (4)	C7—N2—C9—C8	−0.2 (3)
N2—C1—C2—C3	−179.2 (3)	C1—N2—C9—C8	−175.2 (3)
C1—C2—C3—C4	0.0 (4)	C7—N2—C9—C10	177.9 (3)
C2—C3—C4—C5	0.3 (5)	C1—N2—C9—C10	2.8 (5)
C3—C4—C5—C6	0.3 (4)	C8—C9—C10—C15	−125.6 (3)
C7—N1—C6—C5	179.7 (3)	N2—C9—C10—C15	56.7 (4)
C7—N1—C6—C1	0.4 (3)	C8—C9—C10—C11	54.9 (4)
C4—C5—C6—N1	179.6 (3)	N2—C9—C10—C11	−122.8 (3)
C4—C5—C6—C1	−1.2 (4)	C15—C10—C11—C12	−1.3 (4)
C2—C1—C6—N1	−179.1 (3)	C9—C10—C11—C12	178.2 (3)
N2—C1—C6—N1	−0.4 (3)	C16—O1—C12—C11	−1.6 (5)
C2—C1—C6—C5	1.5 (4)	C16—O1—C12—C13	−179.9 (3)
N2—C1—C6—C5	−179.8 (3)	C10—C11—C12—O1	−177.9 (3)
C6—N1—C7—N2	−0.3 (3)	C10—C11—C12—C13	0.3 (5)
C6—N1—C7—S1	−176.2 (3)	O1—C12—C13—C14	178.9 (3)
C1—N2—C7—N1	0.0 (3)	C11—C12—C13—C14	0.5 (5)
C9—N2—C7—N1	−176.5 (2)	C12—C13—C14—C15	−0.3 (5)
C1—N2—C7—S1	176.94 (19)	C13—C14—C15—C10	−0.8 (5)
C9—N2—C7—S1	0.4 (3)	C11—C10—C15—C14	1.6 (4)
C8—S1—C7—N1	175.4 (3)	C9—C10—C15—C14	−177.9 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N1···O3	0.94 (4)	1.85 (4)	2.750 (3)	160 (3)
N1—H1N1···O4	0.94 (4)	2.50 (4)	3.199 (4)	132 (3)
O2—H1O2···O3^i	0.97	1.60	2.531 (4)	158
C11—H11A···O5^ii	0.93	2.32	3.237 (4)	170

Symmetry codes: (i) x−1, y, z; (ii) −x+1, −y+1, −z+1.