1-(4-Nitro­phen­yl)-1H-imidazol-3-ium chloride

Halliru Ibrahim; Muhammad D Bala

doi:10.1107/S1600536812050878

. 2012 Dec 19;69(Pt 1):o114. doi: 10.1107/S1600536812050878

1-(4-Nitrophenyl)-1H-imidazol-3-ium chloride

Halliru Ibrahim ^a, Muhammad D Bala ^a,^*

PMCID: PMC3588291 PMID: 23476377

Abstract

In the title salt, C₉H₈N₃O₂ ⁺·Cl⁻, the least-squares planes of the imidazolium and benzene rings are almost coplanar, making a dihedral angle of 4.59 (1)°. In the crystal, the chloride anion links the organic molecules through N—H⋯Cl hydrogen bonds, forming chains that run diagonally across the bc face, which compliment strong C—H⋯O hydrogen bonds between neighbouring molecules. These chains are connected to adjacent chains through two weak C—H⋯Cl interactions, resulting in hydrogen-bonded sheets extending along the b and c axes. The absolute structure of the title compound was determined using a Flack x parameter of 0.00 (6) and a Hooft y parameter of 0.03 (2).

Related literature

For the synthesis of the title compound, see: Gnanamgari et al. (2009 ▶); Coberan & Peris (2008 ▶); Singh et al., (2011 ▶). For the structure of imidazole with a bond to phenyl via carbon, see: Gayathri et al. (2010 ▶). For structure of imidazole with a bond to phenyl via nitrogen, see: Zheng et al. (2011 ▶). For the structure of nitrophenyl imidazole as a ligand in a complex, see: Singh et al. (2010 ▶, 2011 ▶). For related structures, see: Ishihara et al. (1992 ▶); Scheele et al., (2007 ▶). For our related work in this area, see: Ibrahim et al. (2012 ▶). graphic file with name e-69-0o114-scheme1.jpg

Experimental

Crystal data

C₉H₈N₃O₂ ⁺·Cl⁻
M _r = 225.64
Orthorhombic,
a = 14.6042 (8) Å
b = 12.1781 (7) Å
c = 5.6070 (3) Å
V = 997.21 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.37 mm⁻¹
T = 173 K
0.54 × 0.16 × 0.15 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.524, T _max = 0.746
20153 measured reflections
2217 independent reflections
2120 reflections with I > 2σ(I)
R _int = 0.060

Refinement

R[F ² > 2σ(F ²)] = 0.029
wR(F ²) = 0.076
S = 1.09
2217 reflections
140 parameters
8 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.22 e Å⁻³
Absolute structure: Flack (1983 ▶), Hooft et al. (2010 ▶), Spek (2009 ▶); Hooft parameter = 0.03 (2), 856 Bijvoet pairs
Flack parameter: 0.00 (6)

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT-Plus (Bruker, 2008 ▶); data reduction: SAINT-Plus and XPREP (Bruker, 2008 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 2012 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶).

Supplementary Material

Click here for additional data file.^{(20.3KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812050878/nr2034sup1.cif

e-69-0o114-sup1.cif^{(20.3KB, cif)}

Click here for additional data file.^{(106.8KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812050878/nr2034Isup2.hkl

e-69-0o114-Isup2.hkl^{(106.8KB, hkl)}

Click here for additional data file.^{(3.9KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536812050878/nr2034Isup3.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
N1—H1⋯Cl1ⁱ	0.92 (2)	2.08 (2)	2.9976 (17)	178 (2)
C9—H9⋯Cl1	0.93	2.80	3.5898 (19)	144
C2—H2⋯Cl1ⁱⁱ	0.93	2.52	3.4286 (17)	166
C4—H4⋯O2ⁱ	0.93	2.29	3.181 (2)	161

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

Acknowledgments

We thank the NRF and the University of KwaZulu-Natal for financial support.

supplementary crystallographic information

Comment

Since the isolation of the first stable free carbene, imidazolium based N-heterocyclic carbene ligands (NHC) ligands have recieved wide interest from researchers because substituted imidazolium salts are major precursors to the NHCs commonly employed in organometallic chemistry and catalysis for the stabilization of metal centers. Recently Gayathri et al., (2010) have reported structural analogues of the title compound with imidazole bond to phenyl via carbon, while Zheng et al., (2011) have reported the structure with imidazole bond to phenyl via nitrogen. For the structure of nitrophenyl imidazole as a ligand in a metal complex, see: (Singh et al., 2010 and 2011). Structures of related compounds were reported by Ishihara et al., (1992), Scheele et al., (2007) and Ibrahim et al., (2012). Hence, the title compound was obtained in an attempt to synthesize an imidazolium salt by the coupling of 2-chloromethylpyridine hydrochloride with p-nitrophenyl imidazole using the method reported by Gnanamgari et al., (2009). Coberan & Peris (2008) and Singh et al., (2011) have also reported synthesis of similar compounds. The grey solid obtained was recrystallized from methanol:ethyl acetate (1:1) solvent system. The planes of the imidazolium and phenyl rings in (I) are almost coplanar. Analysis of the absolute structure using likelihood methods (Hooft et al., 2010) was performed using PLATON (Spek, 2009). The Hooft y-parameter was determined to be 0.03 (2) which corroborated the Flack parameter x = 0.00 (6). These results in conjunction with a correlation coefficient of 0.997 for the Bijvoet normal probability plot indicate that the absolute structure is correctly assigned. In the title compound, C₉H₈N₃O₂.Cl, the L.S. planes of the imidazolium (N1—C4) and phenyl (C5—C10) rings are almost coplanar with a dihedral angle of 4.59 (1)°. In the crystal, the chloride atom links the organic molecules through N—H···Cl hydrogen bonds forming chains that run diagonally across the bc face which compliment strong intermolecular C—H···O hydrogen bonds between neighbouring molecules. These chains are connected to adjacent chains through two weak C—H···Cl interactions resulting in hydrogen bonded sheets extending along the b and c axes.

Experimental

To a 150 ml round bottom flask containing DMSO (30 ml, MERCK) was added imidazole (0.01 mol, 0.68 g, Fluka AG) and KOH (0.015 mol, 0.84 g, MERCK) then stirred at room temperature for 2 h. This was followed by the dropwise addition of a solution of 1-chloro-4-nitrobenzene (Fluka, 0.01 mol, 1.57 g) in DMSO (5 ml), and refluxed at 100 °C for 24 h. The resulting solution was first chilled and then dilute with distilled water until neutral. The organic component was extracted using CH₂Cl₂/CHCl₃ (1:1, 3 x 20 ml) and then dried with anhydrous MgSO4 and concetrated under vacuum yielding 2.081 g of pure (I). ¹H NMR (400 MHz, CDCl₃): 8.36(d; 2H) 7.96(s; 1H), 7.57(d; 2H) and 7.25(1H) p.p.m.. ¹³C NMR (400 MHz, CDCl₃): 146.6, 142.3, 135.7, 132.04, 126.1, 121.4 and 117.9 p.p.m.. IR (ATR): 3112(=C—H), 2924(sp³ C—H), 1596(C=N), 1503 and 1370(aromatic NO₂), 1049 (C—N medium) and 845 (p-subsituted benzene) cm^-1.