Monoclinic polymorph of 4-[(1H-benz­imidazol-1-yl)meth­yl]benzoic acid

Hai-Wei Kuai; Xiao-Chun Cheng

doi:10.1107/S1600536811039043

. 2011 Sep 30;67(Pt 10):o2787. doi: 10.1107/S1600536811039043

Monoclinic polymorph of 4-[(1H-benzimidazol-1-yl)methyl]benzoic acid

Hai-Wei Kuai ^a,^*, Xiao-Chun Cheng ^a

PMCID: PMC3201311 PMID: 22058821

Abstract

Three polymorphs of the title compound, C₁₅H₁₂N₂O₂, were obtained accidentally as single crystals in the hydrothermal reaction of the title compound with manganese bromide in the presence of N,N′-dimethylformamide at 373 K. Here we report the structure of the first polymorph. The benzimidazole ring is almost planar, the maximum deviation from the mean plane being 0.016 (1) Å. The benzimidazole and benzene rings are approximately perpendicular, making a dihedral angle 85.56 (7)°, which is a reflection of the axial rotation of the flexible benzimidazolyl arm. In the crystal, adjacent molecules are connected through O—H⋯N hydrogen bonds into a chain along [100], and neighboring chains are further linked by via weak C—H⋯O hydrogen-bonding interactions, forming a two-dimensional network.

Related literature

For two other polymorphs of the title compound, see Kuai & Cheng (2011a ▶,b ▶). For the synthesis of 4-[(1H-benzo[d]imidazol-1-yl)methyl]benzoic acid, see: Hua et al. (2010 ▶). For background to metal-organic hybrid materials, see: Das & Bharadwaj (2009 ▶); Kuai et al. (2011 ▶).

Experimental

Crystal data

C₁₅H₁₂N₂O₂
M _r = 252.27
Monoclinic,
a = 10.435 (2) Å
b = 14.360 (3) Å
c = 8.2922 (17) Å
β = 96.925 (3)°
V = 1233.5 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.20 × 0.20 × 0.16 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.982, T _max = 0.985
6155 measured reflections
2157 independent reflections
1294 reflections with I > 2σ(I)
R _int = 0.065

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.082
S = 0.82
2157 reflections
160 parameters
H-atom parameters constrained
Δρ_max = 0.13 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SAINT (Bruker, 1998 ▶); 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 Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811039043/aa2023sup1.cif

e-67-o2787-sup1.cif^{(17.1KB, cif)}

Supplementary material file. DOI: 10.1107/S1600536811039043/aa2023Isup2.cdx

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811039043/aa2023Isup3.hkl

e-67-o2787-Isup3.hkl^{(106.1KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811039043/aa2023Isup4.cml

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H12⋯N12ⁱ	0.82	1.83	2.652 (2)	178
C12—H7⋯O2ⁱⁱ	0.93	2.49	3.213 (3)	135

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors gratefully acknowledge the Natural Science Foundation of Jiangsu Province of China (BK2008195) for financial support of this work.

supplementary crystallographic information

Comment

The title compound, 4-((1H-benzo[d]imidazol-1-yl)methyl)benzoic acid (HL), are usually regarded as an excellent candidate for building block in molecular self-assembly engineerings due to its variable conformations and coordination modes (Das et al., 2009). During assemblies of coordination polymers, we accidentally obtained three different kind of single crystals of the title compound, which can be proved by different unit cell parameters (or space group). Here, we will introduce one of them. The single crystals of the title compound, C₁₅H₁₂N₂O₂, were accidentally obtained by the hydrothermal reaction at 373 K of the HL with manganese bromide in the presence of N,N'-dimethylformamide as alkaline medium for the deprotonation. As shown in Fig. 1, the asymmetric unit consists of only one HL molecule. Interestingly, though crystallizing from alkaline solution, the HL remains the intact carboxylic group in the crystal structure. The flexible benzimidazolyl arm is apt to axially rotate. as a result, the benzimidazolyl ring and central benzene rings are approximately vertical, inclined at a dihedral angle of 85.56 (6) °; The torsion angles of N11-C11-C1-C2 and N11-C11-C1-C6 are -56.9 (3) ° and 125.4 (2) °, respectively. Adjacent molecules are connected through O-H···N hydrogen bonds into a one-dimensional chain along [100] deirction, and neighboring chains are further linked via C-H···O weak hydrogen bonding interaction to form a two-dimensional network (Fig. 2).

Experimental

Reaction mixture of MnBr₂ (21.5 mg, 0.1 mmol), 4-((1H-benzo[d]imidazol-1-yl)methyl)benzoic acid (25.2 mg, 0.1 mmol) and 2 ml N,N'-dimethylformamide (DMF) in 8 ml H₂O were sealed in a 16 ml Teflon-lined stainless steel container and keeped at 373 K for 3 days. After cooling to the room temperature, colourless block crystals of the title compound were obtained.