3,3′-[1,2-Phenyl­enebis(methyl­ene)]bis­(1-octylbenzimidazolium) dibromide monohydrate

Rosenani A Haque; Muhammad Adnan Iqbal; Hoong-Kun Fun; Suhana Arshad

doi:10.1107/S1600536812008331

. 2012 Mar 3;68(Pt 4):o924–o925. doi: 10.1107/S1600536812008331

3,3′-[1,2-Phenylenebis(methylene)]bis(1-octylbenzimidazolium) dibromide monohydrate

Rosenani A Haque ^a, Muhammad Adnan Iqbal ^a, Hoong-Kun Fun ^b,^*,^‡, Suhana Arshad ^b

PMCID: PMC3343909 PMID: 22589990

Abstract

In the title hydrated molecular salt, C₃₈H₅₂N₄ ²⁺·2Br⁻·H₂O, the central benzene ring of the dication makes dihedral angles of 89.47 (13) and 72.69 (12)° with the pendant benzimidazol-3-ium rings. The conformations of the octyl side chains are completely different. In the crystal, the components are linked by O—H⋯Br, C—H⋯Br and C—H⋯O hydrogen bonds into a two-dimensional network lying parallel to the ac plane. Aromatic π–π stacking interactions are also observed [shortest centroid-to-centroid separation = 3.5047 (16) Å].

Related literature

For related structures, see: Haque et al. (2012 ▶); Iqbal et al. (2012 ▶); Haque et al. (2011 ▶). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₃₈H₅₂N₄ ²⁺·2Br⁻·H₂O
M _r = 742.67
Triclinic,
a = 8.7203 (4) Å
b = 14.9342 (12) Å
c = 16.4090 (8) Å
α = 115.598 (3)°
β = 104.638 (2)°
γ = 92.358 (3)°
V = 1836.77 (19) Å³
Z = 2
Mo Kα radiation
μ = 2.24 mm⁻¹
T = 100 K
0.42 × 0.32 × 0.24 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.451, T _max = 0.614
44354 measured reflections
10659 independent reflections
8816 reflections with I > 2σ(I)
R _int = 0.047

Refinement

R[F ² > 2σ(F ²)] = 0.052
wR(F ²) = 0.161
S = 1.05
10659 reflections
416 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 2.62 e Å⁻³
Δρ_min = −1.68 e Å⁻³

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

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812008331/hb6650sup1.cif

e-68-0o924-sup1.cif^{(42.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812008331/hb6650Isup2.hkl

e-68-0o924-Isup2.hkl^{(521.2KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812008331/hb6650Isup3.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
O1W—H1W1⋯Br1	0.83 (5)	2.50 (5)	3.326 (3)	173 (4)
O1W—H2W1⋯Br2	0.83 (5)	2.52 (5)	3.343 (3)	177 (5)
C7—H7A⋯Br1	0.95	2.69	3.569 (3)	154
C15—H15A⋯Br1	0.99	2.92	3.672 (3)	134
C16—H16A⋯Br1	0.95	2.79	3.594 (3)	143
C2—H2A⋯Br2ⁱ	0.95	2.81	3.698 (3)	155
C4—H4A⋯O1Wⁱⁱ	0.95	2.49	3.218 (4)	133
C8—H8A⋯Br1ⁱⁱⁱ	0.99	2.80	3.779 (3)	169
C8—H8B⋯Br2ⁱⁱⁱ	0.99	2.71	3.655 (3)	159
C19—H19A⋯Br2^iv	0.95	2.84	3.770 (3)	167
C21—H21A⋯Br2^v	0.95	2.90	3.785 (3)	155
C31—H31A⋯Br2^v	0.99	2.87	3.786 (3)	154

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

Acknowledgments

RAH thanks the Universiti Sains Malaysia (USM) for Research University (RU) grants Nos. 1001/PKI MIA/811157 and 1001/PKIMIA/823082. MAI is grateful to (IPS) USM for financial support [a fellowship, grant No. USM.IPS/JWT/1/19 (JLD 6), and a research attachment fund, grant No. P-KM0018/10(R)-308/AIPS/415401]. HKF and SA thank the Universiti Sains Malaysia (USM) for Research University Grant No. 1001/PFIZIK/811160. SA also thanks the Malaysian government and USM for an award through the Academic Staff Training Scheme (ASTS).

supplementary crystallographic information

Comment

As a part of our ongoing studies, we have previously reported crystal structures of ortho-xylyl linked bis-benzimidazolium salts with ethyl (Haque et al., 2012), propyl (Iqbal et al., 2012), and heptyl (Haque et al., 2011) substitutions. In this paper we describe single-crystal X-ray diffraction study of the title compound, (I) (Fig. 1).

Bond lengths and angles are comparable to the related structure (Haque et al., 2011). The central benzene (C9–C14) ring makes dihedral angles of 89.47 (13) and 72.69 (12)° with the terminal 1H-benzo[d]imidazol-3-ium (N1/N2/C1–C7) and (N3/N4/C16–C22) rings, respectively.

The crystal structure is shown in Fig. 2. The cations, anions and water molecules are linked by intermolecular O—H···Br, C—H···Br and C—H···O hydrogen bonds (Table 1) into a two-dimensional network parallel to the ac plane. π–π interactions of Cg1···Cg3 = 3.5622 (18) Å (symmetry code: 3 - x, 1 - y, 1 - z), Cg3···Cg3 = 3.7158 (18) Å (symmetry code: 3 - x, 1 - y, 1 - z), Cg2···Cg4 = 3.6206 (17) Å (symmetry code: 2 - x, 1 - y, -z) and Cg4···Cg4 = 3.5047 (16) Å (symmetry code: 2 - x, 1 - y, -z) further stabilized the structure. [Cg1, Cg2, Cg3 and Cg4 is the centroid of the N1/N2/C1/C6/C7, N3/N4/C16/C17/C22, C1–C6 and C17–C22 rings, respectively].

Experimental

A mixture of benzimidazole (5.90 g, 50 mmol) and finely ground potassium hydroxide (4.50 g, 80 mmol) in 50 ml of DMSO was stirred at room temperature (27–28 °C) for 30 min. 1-Bromoctane (8.70 ml, 50 mmol) was added drop-wise into this consistently stirred mixture with further stirring for 2 h at the same temperature. The mixture was then poured into water (700 ml) and was extracted by chloroform (5 × 30 ml). The extract was dried by filtering through five plies of Whatman filter papers. This process was repeated twice to collect crystal a clear solution which was evaporated under reduced pressure to get N-octylbenzimidazole (1) as a thick yellowish fluid. Furthermore, a mixture of 1 (4.04 g, 20 mmol) and 1,2-bis(bromomethyl)benzene (2.64 g, 10 mmol) in 1,4-dioxane (50 ml) was refluxed at 100 °C for 18 h. After cooling the reaction mixture to room temperature, the desired compound (2.2Br) appeared as white crystalline powder. The salt was filtered and washed by fresh 1,4-dioxane (3 × 5 ml), dried at room temperature for 24 h. The product was collected as white crystalline powder (7.42 g, 97.76%). Saturated solution of 2.2Br in methanol (0.5 ml) was exposed to diethyl ether vapours (vapour diffusion) at room temperature to get colourless blocks of (I). Single crystals were also obtained by slow evaporation of saturated solution of 2.2Br in MeOH/CH₃CN (70:30) and by evaporating saturated solution of title compound in d₆-DMSO at room temperature.