Crystal structure of benzimidazolium salicylate

M Amudha; P Praveen Kumar; G Chakkaravarthi

doi:10.1107/S2056989015017764

. 2015 Sep 26;71(Pt 10):o794–o795. doi: 10.1107/S2056989015017764

Crystal structure of benzimidazolium salicylate

M Amudha ^a,^b, P Praveen Kumar ^a,^*, G Chakkaravarthi ^c,^*

PMCID: PMC4647433 PMID: 26594483

Abstract

In the anion of the title molecular salt, C₇H₇N₂ ⁺·C₇H₅O₃ ⁻ (systematic name: 1H-benzimidazol-3-ium 2-hydroxybenzoate), there is an intramolecular O—H⋯O hydrogen bond that generates an S(6) ring motif. The CO₂ group makes a dihedral angle of 5.33 (15)° with its attached ring. In the crystal, the dihedral angle between the benzimidazolium ring and the anion benzene ring is 75.88 (5)°. Two cations bridge two anions via two pairs of N—H⋯O hydrogen bonds, enclosing an R ⁴ ₄(16) ring motif, forming a four-membered centrosymmetric arrangement. These units are linked via C—H⋯O hydrogen bonds, forming chains propagating along the b-axis direction. The chains are linked by C—H⋯π and π–π interactions [inter-centroid distances = 3.4156 (7) and 3.8196 (8) Å], forming a three-dimensional structure.

Keywords: crystal structure, benzimidazolium, salicylate, hydrogen bonding

Related literature

For biological applications of benzimidazole derivatives, see: Narasimhan et al. (2012 ▸). For related structures, see: Ennajih et al. (2010 ▸); Haque et al. (2012 ▸); Mani et al. (2015 ▸). graphic file with name e-71-0o794-scheme1.jpg

Experimental

Crystal data

C₇H₇N₂ ⁺·C₇H₅O₃ ⁻
M _r = 256.26
Monoclinic,
a = 7.4776 (3) Å
b = 6.7002 (2) Å
c = 24.9017 (9) Å
β = 94.445 (2)°
V = 1243.86 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 295 K
0.34 × 0.30 × 0.25 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▸) T _min = 0.967, T _max = 0.976
23125 measured reflections
4606 independent reflections
3020 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.142
S = 1.03
4606 reflections
176 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▸); cell refinement: SAINT (Bruker, 2004 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▸); molecular graphics: PLATON (Spek, 2009 ▸); software used to prepare material for publication: SHELXL97 and PLATON.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989015017764/su5212sup1.cif

e-71-0o794-sup1.cif^{(22.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015017764/su5212Isup2.hkl

e-71-0o794-Isup2.hkl^{(221.1KB, hkl)}

Click here for additional data file.^{(5KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015017764/su5212Isup3.cml

Click here for additional data file.^{(1.1MB, tif)}

. DOI: 10.1107/S2056989015017764/su5212fig1.tif

The molecular structure of the title salt, with atom labelling. The displacement ellipsoids are drawn at the 30% probability level.

Click here for additional data file.^{(1.3MB, tif)}

b . DOI: 10.1107/S2056989015017764/su5212fig2.tif

The crystal packing of the title molecular salt, viewed along the b axis. The N—H⋯O and C—H⋯O hydrogen bonds are shown as dashed lines (see Table 1). H atoms not involved in these interactions have been omitted for clarity.

CCDC reference: 1426331

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

Cg3 is the centroid of the C1C6 ring.

DHA	DH	HA	D A	DHA
O3H3AO2	0.83(1)	1.78(1)	2.5425(14)	152(2)
N1H1AO1ⁱ	0.86	1.81	2.6139(13)	155
N2H2AO2ⁱⁱ	0.86	1.81	2.6448(13)	164
C14H14O1ⁱⁱⁱ	0.93	2.22	3.1161(16)	161
C3H3Cg3^iv	0.93	2.81	3.5779(15)	141
C10H10Cg3^v	0.93	2.88	3.6302(17)	139

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) .

Acknowledgments

The authors wish to acknowledge the SAIF, IIT Madras, for the data collection.

supplementary crystallographic information

S1. Structural commentary

Benzimidazoles and their derivatives have diverse biological and clinical applications (Narasimhan et al., 2012).

The molecular structure of the title salt is illustrated in Fig. 1. The geometric parameters are comparable with those reported for similar structures (Ennajih et al., 2010; Haque et al., 2012; Mani et al., 2015). The molecular structure of the anion is stabilized by an intramolecular O—H···O hydrogen bond which generates an S(6) ring motif (Table 1 and Fig. 1).

In the crystal, the dihedral angle between the nine-membered benzimidazolium ring (C8—C13/N2/C14/N1) and the anion benzene ring (C1—C6) is 75.88 (5)°. Two cations bridge two anions via two pairs of N—H···O hydrogen bonds, enclosing an R⁴₄(16) ring motif, forming a four-membered centrosymmetric arrangement (Table 1 and Fig. 2). These units are linked via C—H···O hydrogen bonds forming chains along the b axis direction. The chains are linked by C—H···π (Table 1) and π···π interactions [Cg1···Cg1ⁱ = 3.4156 (7) Å; Cg1···Cg2ⁱⁱ = 3.8196 (8) Å; Cg1 and Cg2 are the centroids of rings (N1/C8/C13/N2/C14) and (C8—C13), respectively; symmetry codes: (i) x+2, y+2, -z; (ii) -x+3, -y+2, -z], forming a three-dimensional structure.

S2. Synthesis and crystallization

Benzimidazole (6 g) and salicylic acid (7.002 g) were dissolved in an equimolar ratio in methanol and stirred well for ca 6 h. The saturated solution was filtered and allowed to evaporate slowly at room temperature. Colourless block-shaped crystals of the title compound were obtained within seven days.

S3. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The hydroxyl H atom was located in a difference Fourier map and refined with a distance restraint: O—H = 0.82 (1) Å with U_iso(H) = 1.5U_eq(O). The NH and C-bound H atoms were positioned geometrically and refined using a riding model: N—H = 0.86 Å, C—H = 0.93 Å with U_iso(H) = 1.2U_eq(N,C).