Hydrogen-bonded sheet structures in methyl 4-(4-chloro­anilino)-3-nitro­benzoate and methyl 1-benzyl-2-(4-chloro­phen­yl)-1H-benzimidazole-5-carboxyl­ate

In methyl 4-(4-chloro­anilino)-3-nitro­benzoate, C₁₄H₁₁ClN₂O₄, (I), there is an intra­molecular N-H...O hydrogen bond and the intra­molecular distances provide evidence for electronic polarization of the o-quinonoid type. The mol­ecules are linked into sheets built from N-H...O, C-H...O and C-H...[pi](arene) hydrogen bonds, together with an aromatic [pi]-[pi] stacking inter­action. The mol­ecules of methyl 1-benzyl-2-(4-chloro­phenyl)-1H-benzimidazole-5-carboxyl­ate, C₂₂H₁₇ClN₂O₂, (II), are also linked into sheets, this time by a combination of C-H...[pi](arene) hydrogen bonds and aromatic [pi]-[pi] stacking inter­actions.

S1. Comment

We report here the molecular structures and the supramolecular assembly of the two title compounds, (I) (Fig. 1) and (II) (Fig. 2). Benzimidazoles are compounds of wide interest because of their diverse biological activities and clinical applications (Ansari & Lal, 2009). They are regarded as a promising class of bioactive heterocyclic compounds, exhibiting a wide range of biological properties such as antifungal, antiparasitic and antiviral activity. They are also active as analgesics, anticoagulants, anticonvulsants, antihistamines and anti-inflammatory agents, and they show anticancer, antihypertensive and anti-ulcer activity, as well as acting as proton-pump inhibitors (Bansal & Silakari, 2012). Consequently, substituted benzimidazoles have attracted interest, especially since it has been reported that the influence of the substitution at the 1-, 2- and 5-positions of the benzimidazole framework is important for their pharmacological effects (Kılcıgil & Altanlar, 2006). We have recently reported the design of a four-step synthesis of novel 1,2,5-trisubstituted benzimidazoles bearing the 4-chlorophenyl or quinolin-2-one pharmacophores at position 2, which exhibit high activity against a range of cancer cell lines (Abonía et al., 2011). As part of our current synthetic programme aimed at the development of potential antitumour agents, we have now prepared the benzimidazole derivative (II) using a two-step synthesis involving the in situ reduction of the nitroaniline precursor, (I), followed by cyclocondensation with 4-chlorobenzaldehyde

Within the molecule of (I), the nitro group makes a dihedral angle of only 9.4 (2)° with the adjacent aryl ring, and this may be associated with the presence of an intramolecular N—H···O hydrogen bond (Fig. 1, Table 2) which gives rise to an S(6) motif (Bernstein et al., 1995). On the other hand, the two rings within the molecule make a dihedral angle of 49.8 (2)°.

The bond distances in the molecule of (I) provide evidence for polarization of the electronic structure. Thus, the distances C12—C13 and C15—C16 are significantly shorter than the other C—C distances in the C11–C16 ring (Table 1); the bond C13—N31 is short for its type [mean value (Allen et al., 1987) = 1.468 Å, lower quartile value = 1.460 Å], while the C14—N41 bond is significantly shorter than the N41—C41 bond; and the N31—O31 and N31—O32 bonds are both long for their type (mean value = 1.217 Å, upper quartile value = 1.225 Å). These observations, taken as a whole, indicate that the polarized form, (Ia) (see scheme), makes a significant contribution to the overall electronic structure, alongside the classically delocalized form, (I). Polarization of this type has been observed previously in both simple 2-nitroanilines containing unsubstituted amino groups (Cannon et al., 2001; Glidewell et al., 2001) and N-(2-nitrophenyl)phenylamine (McWilliam et al., 2001).

As noted above, the molecules of (I) contain an intramolecular N—H···O hydrogen bond. In addition, the molecules are linked by a combination of intermolecular N—H···O, C—H···O and C—H···π(arene) hydrogen bonds (Table 2), augmented by an aromatic π–π stacking interaction. The resulting rather complex sheet structure can be readily analysed in terms of two one-dimensional substructures (Ferguson et al., 1998a,b; Gregson et al., 2000).

The first substructure is built from a combination of N—H···O and C—H···O hydrogen bonds, which link molecules related by inversion to form a chain of rings running parallel to the [010] direction. Pairs of inversion-related N—H···O hydrogen bonds generate R₂²(4) rings centred at (1/2, n, 1/2), where n represents an integer, and pairs of inversion-related C—H···O hydrogen bonds generate R₂²(10) rings centred at (1/2, n + 1/2, 1/2), where n again represents an integer (Fig. 3).

The second substructure in (I) is built from the combination of a C—H···π(Arene) hydrogen bond and an aromatic π–π stacking interaction. Aryl atom C46 in the molecule at (x, y, z) acts as hydrogen-bond donor to the C41–C46 aryl ring in the molecule at (x, -y + 1/2, z - 1/2), so linking molecules related by the c-glide plane at y = 1/4 into a chain running parallel to the [001] direction (Fig. 4). In addition, the trisubstituted C11–C16 ring in the molecule at (x, y, z) makes a dihedral angle of only 2.0 (2)° with the corresponding rings of the two molecules at (x, -y + 1/2, z - 1/2) and (x, -y + 1/2, z + 1/2). The shortest ring-centroid separation is 3.722 (2) Å and the shortest perpendicular distance between the ring planes is ca 3.34 Å, corresponding to a ring-centroid offset of ca 1.64 Å. The effect of this stacking interaction is to reinforce the chain formation along [001] generated by the C—H···π(arene) hydrogen bond (Fig. 4). The combination of the [010] and [001] chains generates a complex sheet lying parallel to (100).

The crystal structure of (I) also contains a rather short intermolecular Cl···O contact of 2.924 (3) Å between atom Cl44 in the molecule at (x, y, z) and atom O31 in the molecule at (x + 1, y + 1, z + 1). This contact distance is certainly shorter than the sum of the van der Waals radii (3.2 Å; Bondi, 1964), but it is unclear whether this contact is attractive, or, as seems more likely, repulsive.

In the molecule of (II) (Fig. 2), the bond distances within the fused bicyclic system (Table 3) indicate strong bond fixation in the imidazole portion, with typical aromatic delocalization in the carbocyclic ring. The chlorinated aryl ring makes a dihedral angle of 50.2 (2)° with the adjacent imidazole ring, while the benzyl ring is almost orthogonal to the imidazole ring, with a dihedral angle of 81.7 (2)°.

The supramolecular assembly in (II) depends on the combination of a C—H···π(arene) hydrogen bond (Table 4) and an aromatic π–π stacking interaction, both of which involve the fused aryl ring. In the π-stacking interaction, the fused rings of the molecules at (x, y, z) and (-x + 1, -y + 1, -z + 1), which are strictly parallel, have an interplanar spacing of 3.481 (2) Å, with a ring-centroid separation of 3.568 (2) Å corresponding to a ring-centroid offset of ca 0.78 Å (Fig 5). The C—H···π(arene) hydrogen bond links molecules related by the 2₁ screw axis along (0, 3/4, z) to form a chain running parallel to the [001] direction (Fig. 6).

The combination of these two interactions generates a sheet structure in which, for example, the reference π-stacked dimer centred at (1/2, 1/2, 1/2) is directly linked by C—H···π(arene) hydrogen bonds to the four symmetry-related dimers centred at (1/2, 0, 0), (1/2, 1, 0), (1/2, 0, 1) and (1/2, 1, 1), so forming a sheet lying parallel to (100) (Fig. 7).

The details of the supramolecular assembly in (I) and (II) provide some interesting comparisons. In each compound, the supramolecular assembly leads to the formation of a sheet parallel to (100) in space group P2₁/c, and in both compounds it is the ring carrying the ester function which participates in the π–π stacking interaction. However, the acceptor in the C—H···π(arene) hydrogen bond is the chlorinated aryl ring in (I) but the fused aryl ring in (II), while the donor in this interaction forms part of the chlorinated aryl ring in (I) as opposed to the benzyl ring in (II). Finally, the ester function participates in the assembly in (I), where the ester carbonyl O atom acts as the acceptor in the C—H···O hydrogen bond, while in (II) the ester function plays no part in the supramolecular assembly.

Related literature

For related literature, see: Abonía et al. (2011); Allen et al. (1987); Ansari & Lal (2009); Bansal & Silakari (2012); Bernstein et al. (1995); Bondi (1964); Cannon et al. (2001); Ferguson et al. (1998a, 1998b); Glidewell et al. (2001); Gregson et al. (2000); Kılcıgil & Altanlar (2006); McWilliam et al. (2001).

S2. Experimental

For the synthesis of (I), a mixture of methyl 4-fluoro-3-nitrobenzoate (0.199 g, 1 mmol) and 4-chloroaniline (1 mmol) in dimethylsulfoxide (2 ml) was stirred at ambient temperature for 2 h. After complete disappearance of the starting materials [as monitored by thin-layer chromatography (TLC)], the solid thus formed was collected by filtration and washed with a methanol–water mixture (1:2 v/v; 3 × 2 ml), to afford (I) (yield 84%; orange crystals, m.p. 421 K). Spectroscopic analysis: FT–IR (KBr, ν, cm^-1): 3312 (NH), 1770 (C═O), 1718 (C═C), 1622 (C═N), 1524, 1324 (NO₂). MS (70 eV) m/z (%): 308/306 (100/34) [M⁺], 277/275 (15/5) [M - OCH₃], 243/241 (29/9), 230/228 (38/13), 201 (30), 111 (3).

For the synthesis of (II), a mixture of the intermediate (A) (see scheme) (0.306 g, 1 mmol), which had been prepared in a manner analogous to that for (I) but using benzylamine in place of 4-choloroaniline, acetic acid (2 ml) and zinc powder (5 equivalents) was stirred at ambient temperature for 15 min. After complete disappearance of the starting compound, (I) (as monitored by TLC), the by-product zinc acetate and excess zinc were removed by filtration. The resulting solution was then heated with 4-chlorobenzaldehyde (1.05 mmol) at 373 K for 1 h. After complete disappearance of the starting materials (as monitored by TLC), the solution was allowed to cool to ambient temperature and the excess of acetic acid was removed under reduced pressure. The solid product was washed with ethanol (2 × 1 ml) to afford (II) (yield 88%; colourless crystals, m.p. 437 K). Spectroscopic analysis: FT–IR (KBr, ν, cm^-1): 3028, 2951, 1719 (C═O), 1612 (C═C), 1521 (C═N), 1438, 1287 (C—O). MS (70 eV) m/z (%): 378/376 (3/12) [M⁺], 345 (1) [M - 28], 137 (3), 91 (28).

Crystals of (I) and (II) suitable for single-crystal X-ray diffraction were grown by slow evaporation, at ambient temperature and in air, from solutions in ethanol.

S3. Refinement

All H atoms were located in difference maps and subsequently treated as riding atoms in geometrically idealized positions, with C—H = 0.95 (aromatic), 0.98 (CH₃) or 0.99 Å (CH₂) and N—H = 0.88 Å, and with U_iso(H) = kU_eq(carrier), where k = 1.5 for the methyl groups, which were permitted to rotate but not to tilt, and 1.2 for all other H atoms.

Computing details

For both compounds, data collection: COLLECT (Nonius, 1999); cell refinement: DIRAX/LSQ (Duisenberg et al., 2000); data reduction: EVALCCD (Duisenberg et al., 2003); 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 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures

Fig. 1. The molecular structure of (I), showing the atom-labelling scheme and the intramolecular N—H···O hydrogen bond (dashed line). Displacement ellipsoids are drawn at the 30% probability level.

Fig. 2. The molecular structure of (II), showing the atom-labelling scheme Displacement ellipsoids are drawn at the 30% probability level.

Fig. 3. A stereoview of part of the crystal structure of (I), showing the formation of a chain of alternating R₂²(4) and R₂²(10) rings running parallel to the [010] direction. For the sake of clarity, H atoms not involved in the motifs shown have been omitted.

Fig. 4. A stereoview of part of the crystal structure of (I), showing the formation of a chain running parallel to the [001] direction and built from C—H···π(arene) hydrogen bonds augmented by aromatic π–π stacking interactions. For the sake of clarity, H atoms not involved in the motifs shown have been omitted.

Fig. 5. Part of the crystal structure of (II), showing the formation of a π-stacked dimer centred at (1/2, 1/2, 1/2). For the sake of clarity, all H atoms have been omitted. The atom marked with an asterisk (*) is at the symmetry position (-x + 1, -y + 1, -z + 1).

Fig. 6. A stereoview of part of the crystal structure of (II), showing the formation of a chain running parallel to the [001] direction and built from C—H···π(arene) hydrogen bonds. For the sake of clarity, H atoms not involved in the motif shown have been omitted.

Fig. 7. A stereoview of part of the crystal structure of (II), showing the formation of a sheet lying parallel to (100). For the sake of clarity, H atoms not involved in the motifs shown have been omitted.

(I) Methyl 4-(4-chloroanilino)-3-nitrobenzoate

Crystal data

C14H11ClN2O4	F(000) = 632
Mr = 306.70	Dx = 1.480 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3170 reflections
a = 12.4413 (10) Å	θ = 3.1–27.5°
b = 15.8116 (18) Å	µ = 0.30 mm^−1
c = 7.1805 (10) Å	T = 120 K
β = 103.037 (9)°	Plate, orange
V = 1376.1 (3) Å^3	0.32 × 0.16 × 0.08 mm
Z = 4

Data collection

Bruker Nonius KappaCCD area-detector diffractometer	2572 independent reflections
Radiation source: Bruker–Nonius FR591 rotating anode	1600 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.111
Detector resolution: 9.091 pixels mm^-1	θmax = 25.6°, θmin = 3.1°
ϕ and ω scans	h = −15→15
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −19→19
Tmin = 0.912, Tmax = 0.977	l = −8→8
20301 measured 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)] = 0.059	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.163	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0792P)^2 + 1.1147P] where P = (Fo^2 + 2Fc^2)/3
2572 reflections	(Δ/σ)max = 0.001
191 parameters	Δρmax = 0.37 e Å^−3
0 restraints	Δρmin = −0.35 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.3117 (3)	0.4227 (2)	0.2714 (5)	0.0278 (8)
O1	0.3299 (2)	0.49519 (15)	0.3259 (4)	0.0347 (7)
O2	0.22506 (19)	0.39896 (15)	0.1329 (3)	0.0303 (6)
C2	0.1486 (3)	0.4650 (2)	0.0504 (6)	0.0367 (10)
H2A	0.1074	0.4837	0.1444	0.055*
H2B	0.0970	0.4431	−0.0632	0.055*
H2C	0.1895	0.5129	0.0141	0.055*
C11	0.3824 (3)	0.3493 (2)	0.3463 (5)	0.0238 (8)
C12	0.3467 (3)	0.2672 (2)	0.3069 (5)	0.0252 (8)
H12	0.2753	0.2568	0.2298	0.030*
C13	0.4153 (3)	0.1993 (2)	0.3798 (5)	0.0225 (8)
C14	0.5244 (3)	0.2110 (2)	0.4889 (5)	0.0235 (8)
C15	0.5571 (3)	0.2966 (2)	0.5303 (5)	0.0238 (8)
H15	0.6284	0.3080	0.6072	0.029*
C16	0.4887 (3)	0.3627 (2)	0.4624 (5)	0.0245 (8)
H16	0.5133	0.4188	0.4939	0.029*
N31	0.3685 (2)	0.11608 (18)	0.3335 (4)	0.0259 (7)
O31	0.2797 (2)	0.10904 (15)	0.2170 (4)	0.0323 (6)
O32	0.41931 (19)	0.05350 (15)	0.4133 (4)	0.0343 (7)
N41	0.5935 (2)	0.14530 (18)	0.5553 (4)	0.0250 (7)
H41	0.5645	0.0944	0.5351	0.030*
C41	0.7062 (3)	0.1486 (2)	0.6529 (5)	0.0236 (8)
C42	0.7405 (3)	0.0972 (2)	0.8112 (5)	0.0246 (8)
H42	0.6881	0.0635	0.8553	0.029*
C43	0.8501 (3)	0.0945 (2)	0.9056 (5)	0.0274 (8)
H43	0.8732	0.0589	1.0137	0.033*
C44	0.9259 (3)	0.1438 (2)	0.8419 (5)	0.0271 (8)
Cl44	1.06412 (7)	0.14155 (6)	0.96463 (14)	0.0371 (3)
C45	0.8938 (3)	0.1960 (2)	0.6835 (5)	0.0289 (9)
H45	0.9466	0.2300	0.6413	0.035*
C46	0.7837 (3)	0.1978 (2)	0.5876 (5)	0.0280 (8)
H46	0.7609	0.2323	0.4775	0.034*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.029 (2)	0.025 (2)	0.030 (2)	0.0033 (16)	0.0075 (16)	0.0026 (16)
O1	0.0418 (17)	0.0223 (14)	0.0385 (16)	0.0026 (12)	0.0057 (12)	−0.0007 (12)
O2	0.0268 (13)	0.0261 (14)	0.0360 (15)	0.0050 (11)	0.0027 (11)	0.0025 (11)
C2	0.032 (2)	0.032 (2)	0.042 (2)	0.0094 (18)	0.0003 (18)	0.0092 (18)
C11	0.0295 (19)	0.0183 (18)	0.0257 (19)	0.0031 (15)	0.0107 (15)	0.0004 (14)
C12	0.0232 (18)	0.030 (2)	0.0229 (19)	0.0002 (16)	0.0055 (15)	−0.0001 (15)
C13	0.0185 (17)	0.0260 (19)	0.0223 (18)	0.0004 (15)	0.0032 (14)	0.0016 (15)
C14	0.0236 (18)	0.0241 (19)	0.0234 (19)	0.0011 (15)	0.0070 (14)	0.0009 (15)
C15	0.0218 (18)	0.0257 (19)	0.0246 (19)	−0.0033 (15)	0.0070 (15)	−0.0023 (15)
C16	0.0274 (18)	0.0187 (17)	0.0286 (19)	−0.0022 (15)	0.0087 (15)	0.0000 (15)
N31	0.0249 (16)	0.0231 (16)	0.0289 (17)	0.0007 (13)	0.0040 (13)	−0.0018 (13)
O31	0.0258 (14)	0.0272 (14)	0.0379 (15)	−0.0013 (11)	−0.0052 (12)	−0.0001 (11)
O32	0.0287 (14)	0.0186 (13)	0.0500 (17)	0.0010 (11)	−0.0030 (12)	0.0048 (12)
N41	0.0240 (15)	0.0180 (15)	0.0307 (17)	−0.0003 (13)	0.0013 (12)	−0.0028 (12)
C41	0.0191 (17)	0.0212 (18)	0.0292 (19)	0.0006 (15)	0.0025 (14)	−0.0003 (15)
C42	0.0275 (18)	0.0182 (18)	0.029 (2)	0.0026 (15)	0.0078 (15)	−0.0004 (15)
C43	0.0288 (19)	0.0221 (19)	0.029 (2)	0.0062 (16)	0.0012 (16)	0.0003 (15)
C44	0.0218 (18)	0.0251 (19)	0.031 (2)	0.0035 (16)	−0.0004 (15)	−0.0069 (16)
Cl44	0.0222 (5)	0.0411 (6)	0.0439 (6)	0.0045 (4)	−0.0013 (4)	−0.0023 (5)
C45	0.0264 (19)	0.026 (2)	0.035 (2)	−0.0026 (16)	0.0100 (16)	−0.0005 (16)
C46	0.0268 (19)	0.028 (2)	0.027 (2)	−0.0013 (16)	0.0028 (15)	0.0028 (16)

Geometric parameters (Å, º)

C1—O1	1.216 (4)	N31—O32	1.242 (4)
C1—O2	1.344 (4)	C14—N41	1.364 (4)
C1—C11	1.482 (5)	N41—C41	1.420 (4)
O2—C2	1.446 (4)	N41—H41	0.8800
C2—H2A	0.9800	C16—H16	0.9500
C2—H2B	0.9800	C41—C42	1.384 (5)
C2—H2C	0.9800	C41—C46	1.399 (5)
C11—C12	1.380 (5)	C42—C43	1.380 (5)
C12—C13	1.397 (5)	C42—H42	0.9500
C12—H12	0.9500	C43—C44	1.379 (5)
C13—C14	1.418 (5)	C43—H43	0.9500
C14—C15	1.426 (5)	C44—C45	1.389 (5)
C15—C16	1.366 (5)	C44—Cl44	1.747 (3)
C15—H15	0.9500	C45—C46	1.388 (5)
C16—C11	1.412 (5)	C45—H45	0.9500
C13—N31	1.447 (4)	C46—H46	0.9500
N31—O31	1.231 (4)
O1—C1—O2	124.1 (3)	C15—C16—H16	119.3
O1—C1—C11	124.7 (3)	C11—C16—H16	119.3
O2—C1—C11	111.2 (3)	O31—N31—O32	121.8 (3)
C1—O2—C2	116.4 (3)	O31—N31—C13	119.4 (3)
O2—C2—H2A	109.5	O32—N31—C13	118.8 (3)
O2—C2—H2B	109.5	C14—N41—C41	128.2 (3)
H2A—C2—H2B	109.5	C14—N41—H41	115.9
O2—C2—H2C	109.5	C41—N41—H41	115.9
H2A—C2—H2C	109.5	C42—C41—C46	119.6 (3)
H2B—C2—H2C	109.5	C42—C41—N41	118.1 (3)
C12—C11—C16	118.5 (3)	C46—C41—N41	122.2 (3)
C12—C11—C1	121.7 (3)	C43—C42—C41	120.6 (3)
C16—C11—C1	119.8 (3)	C43—C42—H42	119.7
C11—C12—C13	120.3 (3)	C41—C42—H42	119.7
C11—C12—H12	119.8	C44—C43—C42	119.6 (3)
C13—C12—H12	119.8	C44—C43—H43	120.2
C12—C13—C14	122.3 (3)	C42—C43—H43	120.2
C12—C13—N31	115.6 (3)	C43—C44—C45	121.1 (3)
C14—C13—N31	122.1 (3)	C43—C44—Cl44	119.3 (3)
N41—C14—C13	122.9 (3)	C45—C44—Cl44	119.6 (3)
N41—C14—C15	121.5 (3)	C46—C45—C44	119.2 (3)
C13—C14—C15	115.6 (3)	C46—C45—H45	120.4
C16—C15—C14	121.7 (3)	C44—C45—H45	120.4
C16—C15—H15	119.1	C45—C46—C41	120.0 (3)
C14—C15—H15	119.1	C45—C46—H46	120.0
C15—C16—C11	121.5 (3)	C41—C46—H46	120.0
O1—C1—O2—C2	−1.9 (5)	C12—C13—N31—O31	8.9 (5)
C11—C1—O2—C2	178.9 (3)	C14—C13—N31—O31	−170.0 (3)
O1—C1—C11—C12	167.0 (4)	C12—C13—N31—O32	−171.0 (3)
O2—C1—C11—C12	−13.9 (5)	C14—C13—N31—O32	10.2 (5)
O1—C1—C11—C16	−12.5 (5)	C13—C14—N41—C41	174.9 (3)
O2—C1—C11—C16	166.6 (3)	C15—C14—N41—C41	−7.0 (5)
C16—C11—C12—C13	−0.4 (5)	C14—N41—C41—C42	135.8 (4)
C1—C11—C12—C13	−179.9 (3)	C14—N41—C41—C46	−48.3 (5)
C11—C12—C13—C14	−2.7 (5)	C46—C41—C42—C43	0.5 (5)
C11—C12—C13—N31	178.5 (3)	N41—C41—C42—C43	176.6 (3)
C12—C13—C14—N41	−177.7 (3)	C41—C42—C43—C44	0.3 (5)
N31—C13—C14—N41	1.0 (5)	C42—C43—C44—C45	−0.3 (5)
C12—C13—C14—C15	4.1 (5)	C42—C43—C44—Cl44	178.8 (3)
N31—C13—C14—C15	−177.2 (3)	C43—C44—C45—C46	−0.4 (5)
N41—C14—C15—C16	179.3 (3)	Cl44—C44—C45—C46	−179.6 (3)
C13—C14—C15—C16	−2.4 (5)	C44—C45—C46—C41	1.2 (5)
C14—C15—C16—C11	−0.5 (5)	C42—C41—C46—C45	−1.2 (5)
C12—C11—C16—C15	2.0 (5)	N41—C41—C46—C45	−177.2 (3)
C1—C11—C16—C15	−178.5 (3)

Hydrogen-bond geometry (Å, º)

Cg1 represents the centroid of the C41–C46 ring.

D—H···A	D—H	H···A	D···A	D—H···A
N41—H41···O32	0.88	1.93	2.617 (4)	133
N41—H41···O32^i	0.88	2.37	3.158 (4)	149
C16—H16···O1^ii	0.95	2.49	3.302 (4)	144
C46—H46···Cg1^iii	0.95	2.72	3.560 (4)	147

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

(II) Methyl 1-benzyl-2-(4-chlorophenyl)-1H-benzimidazole-5-carboxylate

Crystal data

C22H17ClN2O2	F(000) = 784
Mr = 376.83	Dx = 1.373 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4183 reflections
a = 14.214 (2) Å	θ = 2.8–27.5°
b = 11.7391 (10) Å	µ = 0.23 mm^−1
c = 11.0580 (14) Å	T = 120 K
β = 98.908 (10)°	Block, colourless
V = 1822.9 (4) Å^3	0.31 × 0.28 × 0.20 mm
Z = 4

Data collection

Bruker Nonius KappaCCD area-detector diffractometer	4183 independent reflections
Radiation source: Bruker Nonius FR591 rotating anode	3040 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.065
Detector resolution: 9.091 pixels mm^-1	θmax = 27.5°, θmin = 2.8°
ϕ and ω scans	h = −18→18
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −15→15
Tmin = 0.932, Tmax = 0.956	l = −14→14
24459 measured 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)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.117	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0449P)^2 + 1.0641P] where P = (Fo^2 + 2Fc^2)/3
4183 reflections	(Δ/σ)max = 0.001
245 parameters	Δρmax = 0.32 e Å^−3
0 restraints	Δρmin = −0.43 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
N1	0.69848 (11)	0.57451 (13)	0.45316 (14)	0.0219 (3)
C2	0.73360 (13)	0.46478 (15)	0.46699 (17)	0.0215 (4)
N3	0.69613 (11)	0.40547 (13)	0.54929 (14)	0.0240 (4)
C3a	0.63269 (13)	0.48000 (15)	0.59228 (16)	0.0218 (4)
C4	0.57395 (13)	0.46255 (15)	0.68054 (17)	0.0230 (4)
H4	0.5718	0.3907	0.7196	0.028*
C5	0.51849 (13)	0.55328 (15)	0.70979 (17)	0.0225 (4)
C6	0.52074 (14)	0.65955 (16)	0.64954 (17)	0.0240 (4)
H6	0.4823	0.7202	0.6712	0.029*
C7	0.57724 (14)	0.67767 (15)	0.56017 (17)	0.0241 (4)
H7	0.5779	0.7487	0.5192	0.029*
C7a	0.63340 (13)	0.58599 (15)	0.53325 (16)	0.0218 (4)
C17	0.71419 (14)	0.66023 (15)	0.36200 (16)	0.0239 (4)
H17A	0.6517	0.6839	0.3166	0.029*
H17B	0.7508	0.6249	0.3025	0.029*
C11	0.76685 (13)	0.76488 (15)	0.41551 (16)	0.0217 (4)
C12	0.82367 (15)	0.76704 (17)	0.52964 (18)	0.0269 (4)
H12	0.8296	0.7007	0.5795	0.032*
C13	0.87194 (16)	0.86605 (18)	0.57100 (19)	0.0324 (5)
H13	0.9107	0.8669	0.6491	0.039*
C14	0.86405 (16)	0.96298 (18)	0.4997 (2)	0.0345 (5)
H14	0.8977	1.0301	0.5282	0.041*
C15	0.80687 (16)	0.96185 (17)	0.3867 (2)	0.0343 (5)
H15	0.8008	1.0286	0.3375	0.041*
C16	0.75846 (15)	0.86392 (16)	0.34512 (18)	0.0274 (4)
H16	0.7189	0.8641	0.2675	0.033*
C21	0.80203 (14)	0.41651 (16)	0.39352 (17)	0.0234 (4)
C22	0.88719 (14)	0.47085 (17)	0.37947 (18)	0.0274 (4)
H22	0.9031	0.5414	0.4195	0.033*
C23	0.94890 (15)	0.42279 (18)	0.30757 (19)	0.0301 (5)
H23	1.0072	0.4593	0.2993	0.036*
C24	0.92384 (15)	0.32070 (17)	0.24829 (18)	0.0281 (4)
Cl24	0.99602 (4)	0.26432 (5)	0.14922 (5)	0.03969 (17)
C25	0.84068 (15)	0.26460 (17)	0.26202 (18)	0.0285 (4)
H25	0.8247	0.1945	0.2210	0.034*
C26	0.78075 (15)	0.31173 (16)	0.33641 (18)	0.0271 (4)
H26	0.7246	0.2722	0.3486	0.032*
C51	0.45824 (14)	0.53386 (16)	0.80648 (17)	0.0235 (4)
O51	0.44658 (10)	0.44172 (11)	0.85107 (12)	0.0300 (3)
O52	0.41778 (10)	0.62973 (11)	0.84006 (12)	0.0288 (3)
C52	0.35773 (16)	0.61510 (18)	0.93410 (19)	0.0329 (5)
H52A	0.3075	0.5597	0.9062	0.049*
H52B	0.3288	0.6883	0.9500	0.049*
H52C	0.3964	0.5875	1.0095	0.049*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0277 (9)	0.0146 (7)	0.0236 (8)	−0.0007 (6)	0.0046 (6)	0.0011 (6)
C2	0.0247 (10)	0.0140 (8)	0.0252 (9)	−0.0001 (7)	0.0020 (7)	−0.0006 (7)
N3	0.0284 (9)	0.0156 (8)	0.0286 (8)	−0.0008 (6)	0.0064 (7)	0.0002 (6)
C3a	0.0257 (10)	0.0136 (8)	0.0253 (9)	−0.0008 (7)	0.0013 (7)	−0.0003 (7)
C4	0.0273 (10)	0.0144 (8)	0.0270 (9)	−0.0021 (8)	0.0033 (8)	−0.0001 (7)
C5	0.0255 (10)	0.0156 (9)	0.0257 (9)	−0.0023 (7)	0.0015 (8)	−0.0021 (7)
C6	0.0282 (10)	0.0162 (9)	0.0271 (10)	0.0011 (8)	0.0021 (8)	−0.0025 (7)
C7	0.0302 (11)	0.0132 (9)	0.0280 (10)	0.0011 (8)	0.0017 (8)	0.0005 (7)
C7a	0.0256 (10)	0.0164 (9)	0.0233 (9)	−0.0021 (7)	0.0031 (8)	−0.0004 (7)
C17	0.0319 (11)	0.0168 (9)	0.0226 (9)	0.0000 (8)	0.0028 (8)	0.0032 (7)
C11	0.0249 (10)	0.0167 (9)	0.0243 (9)	−0.0005 (7)	0.0065 (8)	−0.0004 (7)
C12	0.0343 (11)	0.0213 (10)	0.0253 (10)	0.0002 (8)	0.0055 (8)	0.0028 (8)
C13	0.0371 (12)	0.0313 (11)	0.0281 (10)	−0.0036 (9)	0.0028 (9)	−0.0045 (9)
C14	0.0391 (13)	0.0229 (11)	0.0420 (12)	−0.0084 (9)	0.0079 (10)	−0.0074 (9)
C15	0.0420 (13)	0.0184 (10)	0.0425 (12)	−0.0020 (9)	0.0068 (10)	0.0063 (9)
C16	0.0325 (11)	0.0197 (10)	0.0287 (10)	0.0000 (8)	0.0010 (8)	0.0036 (8)
C21	0.0281 (10)	0.0188 (9)	0.0231 (9)	0.0028 (8)	0.0034 (8)	0.0024 (7)
C22	0.0304 (11)	0.0206 (10)	0.0310 (10)	−0.0044 (8)	0.0044 (8)	−0.0004 (8)
C23	0.0272 (11)	0.0294 (11)	0.0345 (11)	−0.0030 (9)	0.0069 (8)	0.0062 (9)
C24	0.0323 (11)	0.0241 (10)	0.0294 (10)	0.0077 (9)	0.0092 (8)	0.0072 (8)
Cl24	0.0467 (3)	0.0333 (3)	0.0443 (3)	0.0125 (2)	0.0234 (3)	0.0071 (2)
C25	0.0363 (12)	0.0187 (9)	0.0316 (10)	0.0033 (8)	0.0081 (9)	0.0019 (8)
C26	0.0310 (11)	0.0188 (9)	0.0322 (10)	−0.0016 (8)	0.0075 (8)	0.0023 (8)
C51	0.0253 (10)	0.0169 (9)	0.0269 (10)	−0.0009 (8)	−0.0003 (8)	−0.0043 (7)
O51	0.0382 (8)	0.0177 (7)	0.0361 (8)	−0.0006 (6)	0.0120 (6)	0.0000 (6)
O52	0.0358 (8)	0.0201 (7)	0.0330 (7)	0.0042 (6)	0.0135 (6)	0.0006 (6)
C52	0.0393 (12)	0.0293 (11)	0.0328 (11)	0.0074 (9)	0.0141 (9)	0.0025 (9)

Geometric parameters (Å, º)

N1—C2	1.381 (2)	C13—H13	0.9500
C2—N3	1.322 (2)	C14—C15	1.381 (3)
N3—C3a	1.392 (2)	C14—H14	0.9500
C3a—C4	1.394 (3)	C15—C16	1.382 (3)
C4—C5	1.393 (3)	C15—H15	0.9500
C4—H4	0.9500	C16—H16	0.9500
C5—C6	1.417 (3)	C21—C26	1.394 (3)
C6—H6	0.9500	C21—C22	1.398 (3)
C6—C7	1.383 (3)	C22—C23	1.391 (3)
C7—C7a	1.399 (3)	C22—H22	0.9500
C7—H7	0.9500	C23—C24	1.386 (3)
C7a—N1	1.383 (2)	C23—H23	0.9500
C3a—C7a	1.406 (2)	C24—C25	1.382 (3)
N1—C17	1.466 (2)	C24—Cl24	1.743 (2)
C2—C21	1.474 (3)	C25—C26	1.388 (3)
C5—C51	1.487 (3)	C25—H25	0.9500
C17—C11	1.511 (3)	C26—H26	0.9500
C17—H17A	0.9900	C51—O51	1.211 (2)
C17—H17B	0.9900	C51—O52	1.342 (2)
C11—C12	1.389 (3)	O52—C52	1.454 (2)
C11—C16	1.394 (3)	C52—H52A	0.9800
C12—C13	1.391 (3)	C52—H52B	0.9800
C12—H12	0.9500	C52—H52C	0.9800
C13—C14	1.379 (3)
C2—N1—C7a	106.63 (15)	C12—C13—H13	119.7
C2—N1—C17	128.71 (16)	C13—C14—C15	119.58 (19)
C7a—N1—C17	124.19 (15)	C13—C14—H14	120.2
N3—C2—N1	112.97 (16)	C15—C14—H14	120.2
N3—C2—C21	123.22 (16)	C14—C15—C16	120.15 (19)
N1—C2—C21	123.75 (16)	C14—C15—H15	119.9
C2—N3—C3a	104.80 (15)	C16—C15—H15	119.9
N3—C3a—C4	129.53 (17)	C15—C16—C11	120.86 (18)
N3—C3a—C7a	110.26 (16)	C15—C16—H16	119.6
C4—C3a—C7a	120.21 (17)	C11—C16—H16	119.6
C5—C4—C3a	118.17 (17)	C26—C21—C22	118.89 (18)
C5—C4—H4	120.9	C26—C21—C2	118.25 (18)
C3a—C4—H4	120.9	C22—C21—C2	122.86 (17)
C4—C5—C6	120.62 (18)	C23—C22—C21	120.78 (18)
C4—C5—C51	117.35 (16)	C23—C22—H22	119.6
C6—C5—C51	122.03 (17)	C21—C22—H22	119.6
C7—C6—C5	121.96 (17)	C24—C23—C22	118.84 (19)
C7—C6—H6	119.0	C24—C23—H23	120.6
C5—C6—H6	119.0	C22—C23—H23	120.6
C6—C7—C7a	116.57 (17)	C25—C24—C23	121.45 (19)
C6—C7—H7	121.7	C25—C24—Cl24	119.00 (16)
C7a—C7—H7	121.7	C23—C24—Cl24	119.50 (16)
N1—C7a—C7	132.19 (17)	C24—C25—C26	119.29 (19)
N1—C7a—C3a	105.34 (16)	C24—C25—H25	120.4
C7—C7a—C3a	122.46 (17)	C26—C25—H25	120.4
N1—C17—C11	114.08 (15)	C25—C26—C21	120.67 (19)
N1—C17—H17A	108.7	C25—C26—H26	119.7
C11—C17—H17A	108.7	C21—C26—H26	119.7
N1—C17—H17B	108.7	O51—C51—O52	123.02 (18)
C11—C17—H17B	108.7	O51—C51—C5	124.06 (17)
H17A—C17—H17B	107.6	O52—C51—C5	112.92 (16)
C12—C11—C16	118.65 (17)	C51—O52—C52	115.02 (15)
C12—C11—C17	123.62 (17)	O52—C52—H52A	109.5
C16—C11—C17	117.72 (16)	O52—C52—H52B	109.5
C11—C12—C13	120.12 (18)	H52A—C52—H52B	109.5
C11—C12—H12	119.9	O52—C52—H52C	109.5
C13—C12—H12	119.9	H52A—C52—H52C	109.5
C14—C13—C12	120.63 (19)	H52B—C52—H52C	109.5
C14—C13—H13	119.7
C7a—N1—C2—N3	0.0 (2)	C16—C11—C12—C13	−0.9 (3)
C17—N1—C2—N3	−172.18 (17)	C17—C11—C12—C13	178.22 (19)
C7a—N1—C2—C21	177.12 (17)	C11—C12—C13—C14	0.1 (3)
C17—N1—C2—C21	4.9 (3)	C12—C13—C14—C15	0.6 (3)
N1—C2—N3—C3a	0.0 (2)	C13—C14—C15—C16	−0.4 (3)
C21—C2—N3—C3a	−177.07 (17)	C14—C15—C16—C11	−0.4 (3)
C2—N3—C3a—C4	−179.70 (19)	C12—C11—C16—C15	1.1 (3)
C2—N3—C3a—C7a	−0.1 (2)	C17—C11—C16—C15	−178.08 (19)
N3—C3a—C4—C5	178.13 (18)	N3—C2—C21—C26	47.9 (3)
C7a—C3a—C4—C5	−1.5 (3)	N1—C2—C21—C26	−128.9 (2)
C3a—C4—C5—C6	1.1 (3)	N3—C2—C21—C22	−131.7 (2)
C3a—C4—C5—C51	−178.42 (17)	N1—C2—C21—C22	51.5 (3)
C4—C5—C6—C7	0.1 (3)	C26—C21—C22—C23	1.4 (3)
C51—C5—C6—C7	179.60 (17)	C2—C21—C22—C23	−178.98 (18)
C5—C6—C7—C7a	−0.9 (3)	C21—C22—C23—C24	1.0 (3)
C2—N1—C7a—C7	178.9 (2)	C22—C23—C24—C25	−1.9 (3)
C17—N1—C7a—C7	−8.4 (3)	C22—C23—C24—Cl24	175.46 (15)
C2—N1—C7a—C3a	−0.09 (19)	C23—C24—C25—C26	0.3 (3)
C17—N1—C7a—C3a	172.58 (16)	Cl24—C24—C25—C26	−177.09 (15)
C6—C7—C7a—N1	−178.33 (19)	C24—C25—C26—C21	2.3 (3)
C6—C7—C7a—C3a	0.6 (3)	C22—C21—C26—C25	−3.1 (3)
N3—C3a—C7a—N1	0.1 (2)	C2—C21—C26—C25	177.30 (17)
C4—C3a—C7a—N1	179.77 (16)	C4—C5—C51—O51	−8.5 (3)
N3—C3a—C7a—C7	−179.04 (17)	C6—C5—C51—O51	171.99 (18)
C4—C3a—C7a—C7	0.6 (3)	C4—C5—C51—O52	171.38 (17)
C2—N1—C17—C11	−115.9 (2)	C6—C5—C51—O52	−8.2 (3)
C7a—N1—C17—C11	73.1 (2)	O51—C51—O52—C52	−0.4 (3)
N1—C17—C11—C12	21.2 (3)	C5—C51—O52—C52	179.72 (16)
N1—C17—C11—C16	−159.68 (17)

Hydrogen-bond geometry (Å, º)

Cg2 represents the centroid of the C3a/C4–C7/C7a ring.

D—H···A	D—H	H···A	D···A	D—H···A
C16—H16···Cg2^i	0.95	2.52	3.388 (2)	153

Symmetry code: (i) x, −y+3/2, z−1/2.