4-(1H-Benzimidazol-3-ium-2-yl)­benzoate dihydrate

In the title compound, C₁₄H₁₀N₂O₂·2H₂O, the water mol­ecules are involved in hydrogen bonds and interactions. Intermolecular and intramolecular O-H...O hydrogen bonds connect the complex into chains along the a axis, whereas N-H...O intermolecular hydrogen bonds and C-H...O interactions interconnect these layers forming a three-dimensional network.

S1. Comment

Benzimidazole is an interesting heterocyclic ring because it is present in various naturally occurring drugs such as omeprazole, astemizole and emedastine difumarate (Sakai et al., 1989). The efficacy of substituted benzimidazoles in the treatment of parasitic infections is well known (Brown et al., 1961; Preston, 1974; Sarkar et al., 1984). Substituted benzimidazole moieties are established pharmacophores in parasitic chemotherapy. Furthermore, proton tranfer, accompanied by a configurational change of the pi-electron structure, is one of the key reactions in many proposals for molecular-electronic devices (Xu et al., 1994). The electrical properties depend heavily on the intermolecular interactions. Thus, the title compound, (I), may be a candidate for construction of a novel type of conductive organic material in which the proton motion is essentially correlated to the electron conduction (Inabe, 1991). \sch

The benzimidazole moiety is planar, with the maximum deviation of 0.008 (2)° for the N1 atom with protonation occurring at the other imidazole N atom. The dihedral angle between this benzimidazole moiety and the phenyl ring is 11.33 (12)°. The C—O bond lengths are comparable to those of a –COO^- group (Leban & Rupnik, 1992; Aakeroy & Hitchcock, 1994). The carboxyl group makes a dihedral angle of 4.4 (2) Å with the mean plane of the phenyl ring. In the asymmetric unit, both water molecules are linked to the carboxyl group through O—H···O hydrogen bonds.

In the crystal, all the hydrogen bondings and interactions (Table 2) involved the water molecules. The water molecules are involved in O—H···O intramolecular and intermolecular hydrogen bonds with the O atoms in the COO^- group. These hydrogen bonds connect those water molecules into infinite chains in the [100] direction in which the O atoms of the COO^- group act as a bridge. This results in the molecules of the title compound being stacked along the same axis to form layers. The water molecules are also involved in N—H···O intermolecular hydrogen bonds and C—H···O interactions. These hydrogen bonds and interactions interconnect these layers. The O—H···O, N—H···O hydrogen bonds and the C—H···O interactions in which all are involving the water molecules form a three-dimensional network of the title compound throughout the structure.

Related literature

For related literature, see: Aakeroy & Hitchcock (1994); Addison & Burke (1981); Addison et al. (1983); Brown et al. (1961); Flack (1983); Inabe (1991); Leban & Rupnik (1992); Preston (1974); Sakai et al. (1989); Sarkar et al. (1984); Xu et al. (1994).

S2. Experimental

The title compound is prepared from benzene-1,4-dicarboxylic acid and 1,2-diaminobenzene in 36% yield using a modified Phillips reaction (Addison & Burke, 1981; Addison et al., 1983) and is recrystallized from water. The single crystals suitable for X-ray analysis were obtained by slow evaporation at room temperature from the EtOH/H₂O solvent.

S3. Refinement

Friedel pairs were averaged in view of the inconclusive Flack parameter (Flack, 1983) value and s.u. After checking their presence in the difference map, all H atoms were geometrically fixed and allowed to ride on their attached atoms except the H atoms of N1, N2, O1W and O2W which were involved in hydrogen bonding and were refined isotropically.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 1990).

Figures

Fig. 1. The structure of (I) showing 50% probability displacement ellipsoids and the atom-numbering scheme.

4-[1H-Benzimidazolium]-Benzene Carbonic Acid dihydrate solvate

Crystal data

C14H10N2O2·2H2O	F(000) = 576
Mr = 274.27	Dx = 1.408 Mg m^−3
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
a = 4.5541 (2) Å	Cell parameters from 2836 reflections
b = 16.3140 (8) Å	θ = 2.3–29.4°
c = 17.5245 (9) Å	µ = 0.11 mm^−1
β = 96.234 (2)°	T = 293 K
V = 1294.29 (11) Å^3	Rectangular slab, colourless
Z = 4	0.48 × 0.30 × 0.08 mm

Data collection

Siemens SMART CCD area detector diffractometer	1150 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.058
Graphite monochromator	θmax = 27.5°, θmin = 2.3°
Detector resolution: 8.33 pixels mm^-1	h = −5→5
ω scans	k = −13→20
4352 measured reflections	l = −22→20
1474 independent reflections

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)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.111	See text
S = 0.97	w = 1/[σ^2(Fo^2) + (0.0593P)^2] where P = (Fo^2 + 2Fc^2)/3
1474 reflections	(Δ/σ)max < 0.001
205 parameters	Δρmax = 0.18 e Å^−3
6 restraints	Δρmin = −0.25 e Å^−3

Special details

Experimental. The data collection covered over a hemisphere of reciprocal space by a combination of three sets of exposures; each set had a different ϕ angle (0, 88 and 180°) for the crystal and each exposure of 30 s covered 0.3° in ω. The crystal-to-detector distance was 4 cm and the detector swing angle was -35°. Crystal decay was monitored by repeating fifty initial frames at the end of data collection and analysing the duplicate reflections, and was found to be negligible.

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
N2	0.5276 (5)	0.26258 (17)	0.14519 (15)	0.0335 (6)
O1	1.4317 (6)	0.49797 (19)	−0.07722 (16)	0.0544 (7)
O2	1.4672 (6)	0.59464 (18)	0.01262 (17)	0.0554 (7)
O1W	0.9502 (6)	0.69114 (18)	0.00665 (16)	0.0517 (7)
O2W	1.8698 (7)	0.5413 (2)	−0.15967 (16)	0.0593 (8)
N1	0.6511 (5)	0.34087 (18)	0.24503 (15)	0.0350 (6)
C1	0.3826 (6)	0.2317 (2)	0.20484 (18)	0.0351 (7)
C2	0.1938 (8)	0.1653 (2)	0.2078 (2)	0.0457 (8)
H2A	0.1420	0.1320	0.1653	0.055*
C3	0.0862 (8)	0.1516 (3)	0.2783 (2)	0.0525 (10)
H3A	−0.0405	0.1077	0.2833	0.063*
C4	0.1644 (8)	0.2021 (3)	0.3412 (2)	0.0546 (10)
H4A	0.0875	0.1906	0.3871	0.065*
C5	0.3507 (8)	0.2683 (3)	0.3385 (2)	0.0475 (9)
H5A	0.4005	0.3019	0.3808	0.057*
C6	0.4598 (7)	0.2815 (2)	0.26800 (18)	0.0380 (8)
C7	0.6851 (6)	0.3278 (2)	0.17099 (18)	0.0313 (7)
C8	0.8679 (6)	0.3777 (2)	0.12518 (16)	0.0310 (6)
C9	0.9271 (8)	0.3509 (2)	0.05292 (19)	0.0417 (8)
H9A	0.8532	0.3009	0.0340	0.050*
C10	1.0959 (8)	0.3988 (2)	0.00925 (19)	0.0412 (8)
H10A	1.1345	0.3805	−0.0389	0.049*
C11	1.2077 (6)	0.4733 (2)	0.03591 (19)	0.0341 (7)
C12	1.1456 (8)	0.4997 (2)	0.10781 (19)	0.0433 (8)
H12A	1.2178	0.5501	0.1263	0.052*
C13	0.9798 (8)	0.4529 (2)	0.15210 (19)	0.0426 (8)
H13A	0.9420	0.4716	0.2002	0.051*
C14	1.3868 (7)	0.5255 (2)	−0.0130 (2)	0.0392 (8)
H1N2	0.503 (10)	0.237 (3)	0.093 (3)	0.066 (13)*
H1N1	0.730 (12)	0.386 (3)	0.279 (3)	0.086 (18)*
H1W1	1.105 (14)	0.656 (4)	0.005 (5)	0.15 (3)*
H2W1	0.804 (8)	0.656 (2)	0.007 (2)	0.052 (12)*
H1W2	2.032 (11)	0.519 (4)	−0.145 (4)	0.12 (3)*
H2W2	1.739 (10)	0.527 (3)	−0.128 (3)	0.078 (16)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N2	0.0338 (13)	0.0357 (14)	0.0317 (14)	−0.0038 (11)	0.0076 (11)	0.0013 (12)
O1	0.0501 (16)	0.0737 (19)	0.0422 (13)	−0.0125 (13)	0.0175 (11)	0.0041 (13)
O2	0.0510 (15)	0.0530 (16)	0.0648 (16)	−0.0167 (13)	0.0182 (12)	0.0037 (14)
O1W	0.0574 (17)	0.0459 (15)	0.0543 (16)	−0.0161 (14)	0.0175 (13)	−0.0129 (13)
O2W	0.0465 (15)	0.083 (2)	0.0486 (15)	0.0035 (15)	0.0082 (12)	0.0269 (15)
N1	0.0333 (13)	0.0449 (16)	0.0269 (12)	−0.0057 (13)	0.0040 (10)	0.0021 (12)
C1	0.0300 (14)	0.0427 (18)	0.0336 (16)	0.0013 (13)	0.0078 (12)	0.0079 (14)
C2	0.0441 (18)	0.0426 (19)	0.050 (2)	−0.0046 (16)	0.0052 (15)	0.0030 (17)
C3	0.0433 (19)	0.055 (2)	0.061 (2)	−0.0054 (18)	0.0122 (16)	0.017 (2)
C4	0.045 (2)	0.078 (3)	0.042 (2)	−0.001 (2)	0.0117 (15)	0.018 (2)
C5	0.0458 (18)	0.069 (3)	0.0286 (17)	−0.0008 (18)	0.0080 (13)	0.0059 (17)
C6	0.0287 (15)	0.052 (2)	0.0331 (16)	−0.0002 (15)	0.0013 (12)	0.0045 (14)
C7	0.0260 (13)	0.0342 (16)	0.0333 (16)	−0.0007 (13)	0.0014 (11)	0.0017 (13)
C8	0.0270 (14)	0.0369 (17)	0.0294 (15)	−0.0007 (13)	0.0044 (11)	0.0048 (13)
C9	0.0452 (18)	0.042 (2)	0.0386 (19)	−0.0123 (16)	0.0093 (14)	−0.0030 (16)
C10	0.0436 (17)	0.049 (2)	0.0324 (17)	−0.0075 (17)	0.0126 (13)	−0.0033 (16)
C11	0.0238 (13)	0.0407 (18)	0.0378 (16)	−0.0013 (13)	0.0027 (11)	0.0042 (14)
C12	0.049 (2)	0.0437 (19)	0.0378 (18)	−0.0157 (16)	0.0071 (14)	−0.0036 (15)
C13	0.0487 (19)	0.047 (2)	0.0333 (17)	−0.0142 (17)	0.0106 (14)	−0.0063 (16)
C14	0.0293 (16)	0.047 (2)	0.0414 (18)	−0.0056 (15)	0.0044 (13)	0.0088 (16)

Geometric parameters (Å, º)

N2—C7	1.334 (4)	C3—H3A	0.9300
N2—C1	1.390 (4)	C4—C5	1.377 (6)
N2—H1N2	0.99 (5)	C4—H4A	0.9300
O1—C14	1.249 (4)	C5—C6	1.398 (4)
O2—C14	1.254 (5)	C5—H5A	0.9300
O1W—H1W1	0.91 (4)	C7—C8	1.465 (4)
O1W—H2W1	0.88 (3)	C8—C13	1.392 (5)
O2W—H1W2	0.84 (4)	C8—C9	1.393 (4)
O2W—H2W2	0.89 (3)	C9—C10	1.384 (5)
N1—C7	1.340 (4)	C9—H9A	0.9300
N1—C6	1.391 (4)	C10—C11	1.379 (5)
N1—H1N1	0.98 (6)	C10—H10A	0.9300
C1—C2	1.387 (5)	C11—C12	1.390 (5)
C1—C6	1.387 (5)	C11—C14	1.510 (4)
C2—C3	1.396 (5)	C12—C13	1.372 (5)
C2—H2A	0.9300	C12—H12A	0.9300
C3—C4	1.391 (6)	C13—H13A	0.9300
C7—N2—C1	108.4 (3)	N1—C6—C5	131.1 (3)
C7—N2—H1N2	130 (3)	N2—C7—N1	109.9 (3)
C1—N2—H1N2	121 (3)	N2—C7—C8	125.0 (3)
H1W1—O1W—H2W1	101 (6)	N1—C7—C8	125.0 (3)
H1W2—O2W—H2W2	109 (6)	C13—C8—C9	119.0 (3)
C7—N1—C6	108.1 (3)	C13—C8—C7	120.9 (3)
C7—N1—H1N1	129 (3)	C9—C8—C7	120.1 (3)
C6—N1—H1N1	123 (3)	C10—C9—C8	120.0 (3)
C2—C1—C6	122.2 (3)	C10—C9—H9A	120.0
C2—C1—N2	131.1 (3)	C8—C9—H9A	120.0
C6—C1—N2	106.7 (3)	C11—C10—C9	121.1 (3)
C1—C2—C3	115.9 (4)	C11—C10—H10A	119.4
C1—C2—H2A	122.1	C9—C10—H10A	119.4
C3—C2—H2A	122.1	C10—C11—C12	118.4 (3)
C4—C3—C2	121.5 (4)	C10—C11—C14	120.5 (3)
C4—C3—H3A	119.3	C12—C11—C14	121.0 (3)
C2—C3—H3A	119.3	C13—C12—C11	121.3 (3)
C5—C4—C3	122.9 (3)	C13—C12—H12A	119.4
C5—C4—H4A	118.5	C11—C12—H12A	119.4
C3—C4—H4A	118.5	C12—C13—C8	120.2 (3)
C4—C5—C6	115.5 (4)	C12—C13—H13A	119.9
C4—C5—H5A	122.2	C8—C13—H13A	119.9
C6—C5—H5A	122.2	O1—C14—O2	125.2 (3)
C1—C6—N1	106.8 (3)	O1—C14—C11	117.4 (3)
C1—C6—C5	122.1 (3)	O2—C14—C11	117.3 (3)
C7—N2—C1—C2	−180.0 (4)	N2—C7—C8—C13	167.9 (3)
C7—N2—C1—C6	0.1 (3)	N1—C7—C8—C13	−12.1 (5)
C6—C1—C2—C3	−0.1 (5)	N2—C7—C8—C9	−10.8 (5)
N2—C1—C2—C3	180.0 (3)	N1—C7—C8—C9	169.2 (3)
C1—C2—C3—C4	0.3 (6)	C13—C8—C9—C10	0.3 (5)
C2—C3—C4—C5	0.0 (6)	C7—C8—C9—C10	178.9 (3)
C3—C4—C5—C6	−0.5 (6)	C8—C9—C10—C11	0.0 (5)
C2—C1—C6—N1	179.6 (3)	C9—C10—C11—C12	−0.4 (5)
N2—C1—C6—N1	−0.4 (3)	C9—C10—C11—C14	−178.9 (3)
C2—C1—C6—C5	−0.4 (5)	C10—C11—C12—C13	0.7 (5)
N2—C1—C6—C5	179.6 (3)	C14—C11—C12—C13	179.1 (3)
C7—N1—C6—C1	0.6 (4)	C11—C12—C13—C8	−0.5 (6)
C7—N1—C6—C5	−179.4 (3)	C9—C8—C13—C12	0.0 (5)
C4—C5—C6—C1	0.7 (5)	C7—C8—C13—C12	−178.6 (3)
C4—C5—C6—N1	−179.4 (4)	C10—C11—C14—O1	−1.1 (4)
C1—N2—C7—N1	0.3 (3)	C12—C11—C14—O1	−179.5 (3)
C1—N2—C7—C8	−179.7 (3)	C10—C11—C14—O2	175.9 (3)
C6—N1—C7—N2	−0.6 (3)	C12—C11—C14—O2	−2.5 (5)
C6—N1—C7—C8	179.4 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1W1···O2	0.91 (6)	1.92 (6)	2.825 (4)	171 (7)
O1W—H2W1···O2^i	0.88 (4)	1.84 (4)	2.716 (4)	172 (3)
O2W—H2W2···O1	0.89 (5)	1.80 (5)	2.682 (4)	171 (5)
O2W—H1W2···O1^ii	0.84 (6)	2.09 (6)	2.887 (4)	158 (6)
N1—H1N1···O2W^iii	0.99 (5)	1.68 (5)	2.667 (4)	177 (5)
N2—H1N2···O1W^iv	1.00 (5)	1.68 (5)	2.682 (4)	177 (4)
C9—H9A···O1W^iv	0.93	2.57	3.433 (4)	154
C13—H13A···O2W^iii	0.93	2.52	3.391 (4)	156

Symmetry codes: (i) x−1, y, z; (ii) x+1, y, z; (iii) x−1, −y+1, z+1/2; (iv) x−1/2, y−1/2, z.