Crystal structure of 1,3-bis­(4-methyl­benz­yl)-1H-1,3-benzimidazol-3-ium bromide monohydrate

Sevim Türktekin Çelikesir; Ömer Çelik; Senem Akkoç; İlhan Özer İlhan; Yetkin Gök; Mehmet Akkurt

doi:10.1107/S2056989014025857

. 2015 Jan 1;71(Pt 1):o10–o11. doi: 10.1107/S2056989014025857

Crystal structure of 1,3-bis(4-methylbenzyl)-1H-1,3-benzimidazol-3-ium bromide monohydrate

Sevim Türktekin Çelikesir ^a, Ömer Çelik ^b, Senem Akkoç ^c, İlhan Özer İlhan ^c, Yetkin Gök ^d, Mehmet Akkurt ^a,^*

PMCID: PMC4331869 PMID: 25705478

Abstract

In the title hydrated symetrically substituted 1,3-bis(4-methylbenzyl)benzimidazolium salt, C₂₃H₂₃N₂ ⁺·Br⁻·H₂O, the dihedral angles between the benzimidazole ring system (r.m.s. deviation = 0.003 Å) and the pendant benzene rings are 73.18 (16) and 77.52 (16)°. Both benzene rings lie to the same side of the benzimidazole ring system, giving the cation an overall U-shape. In the crystal, the cation is linked to the water molecule by a short C—H⋯O hydrogen bond and the water molecule forms O—H⋯Br hydrogen bonds. Together, these interactions lead to [010] chains. The packing is consolidated by C—H⋯Br hydrogen bonds and aromatic π–π stacking interactions [centroid–centroid distances = 3.5401 (17) and 3.8815 (18) Å], generating a three-dimensional network.

Keywords: crystal structure; 1,3-bis(4-methylbenzyl)-1H-3,1-benzimidazol-3-ium bromide monohydrate; benzimidazolium salts; N-heterocyclic carbenes; hydrogen bonds; aromatic π–π stacking interactions

Related literature

For general background to N-heterocyclic carbenes (NHCs), which have been frequently used as ligands in organometallic and coordination chemistry, see: Arduengo et al. (1991 ▸); Akkoç & Gök (2013 ▸); Akkoç et al. (2014 ▸); Berding et al. (2009 ▸); Gök et al. (2014 ▸). For related structures, see: Akkurt et al. (2011 ▸, 2012 ▸). graphic file with name e-71-00o10-scheme1.jpg

Experimental

Crystal data

C₂₃H₂₃N₂ ⁺·Br⁻·H₂O
M _r = 425.35
Triclinic,
a = 9.3846 (3) Å
b = 9.7174 (3) Å
c = 12.5603 (4) Å
α = 76.405 (2)°
β = 84.739 (2)°
γ = 72.696 (2)°
V = 1062.65 (6) Å³
Z = 2
Mo Kα radiation
μ = 1.95 mm⁻¹
T = 296 K
0.15 × 0.10 × 0.06 mm

Data collection

Bruker APEXII CCD diffractometer
22302 measured reflections
4342 independent reflections
3144 reflections with I > 2σ(I)
R _int = 0.035

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.135
S = 1.06
4342 reflections
252 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 1.15 e Å⁻³
Δρ_min = −0.49 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▸); cell refinement: SAINT (Bruker, 2007 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS2014 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2008 ▸); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▸); software used to prepare material for publication: PLATON (Spek, 2009 ▸).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989014025857/hb7325sup1.cif

e-71-00o10-sup1.cif^{(28.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989014025857/hb7325Isup2.hkl

e-71-00o10-Isup2.hkl^{(238.1KB, hkl)}

Click here for additional data file.^{(7.6KB, cml)}

Supporting information file. DOI: 10.1107/S2056989014025857/hb7325Isup3.cml

Click here for additional data file.^{(1.9MB, tif)}

. DOI: 10.1107/S2056989014025857/hb7325fig1.tif

Perspective view of the molecular structure of the title compound with displacement ellipsoids drawn at the 30% probability level.

Click here for additional data file.^{(2MB, tif)}

a . DOI: 10.1107/S2056989014025857/hb7325fig2.tif

View of the hydrogen bonding and molecular packing of the title compound along a axis. Only H atoms involved in H bonding are shown.

CCDC reference: 1036037

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
O1H1WBr1ⁱ	0.83(5)	2.47(5)	3.261(3)	162(5)
O1H2WBr1	0.82(5)	2.51(5)	3.318(3)	171(4)
C7H7O1	0.93	2.30	3.210(4)	166
C8H8BBr1	0.97	2.79	3.730(3)	163
C16H16ABr1ⁱ	0.97	2.91	3.875(4)	173
C16H16BBr1ⁱⁱ	0.97	2.79	3.741(4)	167

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

Acknowledgments

The authors are indebted to the X-ray laboratory of Dicle University Scientific and Technological Applied and Research Center, Diyarbakir, Turkey, for use of the X-ray diffractometer. This study was supported financially by the Erciyes University Research Fund (FBA-2013–4307).

supplementary crystallographic information

S1. Comment

N-heterocyclic carbenes (NHCs), on which many studies have been conducted over the past 40 years, have been frequently used as ligands in organometallic and coordination chemistry (Arduengo et al., 1991; Akkoç & Gök, 2013; Akkoç et al. 2014; Berding et al., 2009; Gök et al., 2014). These ligands have such properties as being strong-donors, weak-acceptors, of low toxicity, easily-synthesized and able to control the steric and electronic effects of substituents on the nitrogen atom, and being more stable against air and moisture compared to phosphine types.

In the title compound (Fig. 1), the benzene rings (C9–C14 and C17–C22) which form a dihedral angle of 75.4 (2)° make dihedral angles of 73.18 (16) and 77.52 (16)° with respect to the central benzimidazole ring system (N1/N2/C1–C7). All bond lengths and bond angles in Table 1 are in normal range, and they are in a good agreement with those found in related compounds (Akkurt et al., 2011; Akkurt et al., 2012).

The crystal packing features C—H···O, O—H···Br and C—H···Br hydrogen bonds (Table 2, Fig. 2) together with π-π stacking interactions between the benzene and imidazolium rings (Cg1: C1–C6 and Cg2: N1/N2/C1/C6/C7) [Cg1···Cg2 (1 - x, -y, 1 - z) = 3.5401 (17) Å] and between the benzene rings of the benzimidazole ring system [Cg2···Cg2 (1 - x, -y, 1 - z) = 3.8815 (18) Å].

S2. Experimental

To a solution of benzimidazole and potassium hidroxide in ethyl alcohol, 4-methylbenzyl bromide was added slowly. This mixture was refluxed at 18 h. Then, it was filtered and was dried under vacuum. 4-Methylbenzyl bromide (1.0 mmol) was added slowly to a solution of the obtained N-4-methylbenzylbenzimidazole (1.0 mmol) in DMF (4 ml) at room temperature and the resulting mixture was heated up to 353 K for 12 h. Diethyl ether (15 ml) was added to obtain a crystalline solid which was filtered off. The solid was washed with diethyl ether (2x15 ml) and dried under vacuum. The crude product was recrystallized from ethyl alcohol/diethyl ether at room temperature to yield colourless blocks.