3-Carboxy­methyl-1,3-benzimidazolium-1-acetate monohydrate

Jinling Miao; Yong Nie; Hongwei Chen; Jingtao Li; Daqi Wang

doi:10.1107/S1600536809027391

. 2009 Jul 25;65(Pt 8):o2005. doi: 10.1107/S1600536809027391

3-Carboxymethyl-1,3-benzimidazolium-1-acetate monohydrate

Jinling Miao ^a,^*, Yong Nie ^a, Hongwei Chen ^a, Jingtao Li ^a, Daqi Wang ^b

PMCID: PMC2977158 PMID: 21583676

Abstract

The title compound, C₁₁H₁₀N₂O₄·H₂O, has a zwitterionic structure, in which the benzimidazole ring system is planar, with a maximum deviation of 0.007 (3) Å. The carboxyl/carboxylate groups adopt a trans configuration. In the crystal structure, intermolecular O—H⋯O hydrogen bonds involving the hydroxy/oxide O atoms link the molecules into a one-dimensional chain. These chains are further linked by O—H⋯O hydrogen bonds involving the water molecules into a two-dimensional network. π–π contacts between the benzimidazole rings [centroid–centroid distance = 3.5716 (4) Å] lead to the formation of a three-dimensional supramolecular structure.

Related literature

For a related structure, see: Chen & Huang (2006 ▶).

Experimental

Crystal data

C₁₁H₁₀N₂O₄·H₂O
M _r = 252.23
Monoclinic,
a = 16.0731 (15) Å
b = 8.1619 (11) Å
c = 18.8678 (17) Å
β = 113.3680 (10)°
V = 2272.2 (4) Å³
Z = 8
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 298 (2) K
0.50 × 0.40 × 0.20 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.943, T _max = 0.977
5875 measured reflections
2213 independent reflections
1495 reflections with I > 2σ(I)
R _int = 0.048

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.120
S = 1.00
2213 reflections
173 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); 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 datablocks I, global. DOI: 10.1107/S1600536809027391/hk2729sup1.cif

e-65-o2005-sup1.cif^{(16.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809027391/hk2729Isup2.hkl

e-65-o2005-Isup2.hkl^{(98.5KB, hkl)}

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
O3—H3⋯O2ⁱ	0.925 (17)	1.592 (18)	2.487 (2)	162 (2)
O5—H5⋯O1	0.88 (3)	1.95 (3)	2.825 (2)	172 (3)
O6—H6⋯O1	0.84 (3)	2.11 (3)	2.943 (2)	173 (3)

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors thank the University of Jinan (grant No. B0604) for support of this work.

supplementary crystallographic information

Comment

Benzimidazole carboxylic acids have received much attention because of their application in the design of therapeutic agents and in construction of supramolecular metal complexes. Previously, the synthesis and crystal structure of 1-(carboxymethyl)-1,3-benzimidazol-3-ium-3-acetate, (II), have been described (Chen & Huang, 2006). We report herein the crystal struture of the title compound, (I).

In the molecule of the title compound (Fig. 1), the benzimidazole ring system is planar with a maximum deviation of 0.007 (3) Å for atom N1, and the two carboxyl groups adopt a trans configuration with respect to the benzimidazole ring plane. The C—N bonds on the imidazolium rings are found to be within 1.323 (2)–1.391 (2) Å, which are between the C—N single and C=N double bonds, suggesting charge delocalization on the imidazolium rings. The torsion angles of C5—N1—C2—C1 [95.5 (2)°] and C6—N2—C4—C3 [-89.5 (2)°] are much smaller than the corresponding values in (II). The lattice water molecules have site symmetries 2.

In the crystal structure, intermolecular O-H···O hydrogen bonds involving the hydroxy O atoms (Table 1) link the molecules into a one-dimensional chain (Fig. 2), in which they are further linked by O-H···O hydrogen bonds of lattice water molecules (Table 1) into a two-dimensional network (Fig. 3). The π···π contacts between the benzene rings of the benzimidazole groups (Fig. 4), Cg2···Cg2ⁱ [symmetry code: (i) -x, 2 - y, -z, where Cg2 is centroid of the ring (C6-C11)] may further stabilize the structure, with centroid-centroid distance of 3.5716 (4) Å and lead to the formation of a three-dimensional supramolecular structure (Fig. 5).

Experimental

For the preparation of the title compound, benzimidazole (0.714 g,6 mmol) was added to an aqueous solution (35 ml) of iodoacetic acid (1.859 g, 10 mmol) and NaOH (0.405 g, 10 mmol). The resulting mixture was heated at reflux during which benzimidazole was gradually dissolved and the colorless solution changed to yellow. The pH was adjusted using saturated NaOH solution at 20 min intervals, keeping in the range of 8–9. When no pH change was detected, the solution was further refluxed for 30 min, cooled, acidified with hydrochloric acid until pH = 2–3. The brown precipitate formed was filtered and recrystallized using water during which the deep yellow solution changed to colorless. The colorless plate crystals were formed after 5 d.