organic compounds
1-(4-Nitrophenyl)-1H-imidazol-3-ium chloride
aSchool of Chemistry & Physics, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000, South Africa
*Correspondence e-mail: bala@ukzn.ac.za
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 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).
Experimental
Crystal data
|
Refinement
Data collection: APEX2 (Bruker, 2008); cell 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).
Supporting information
https://doi.org/10.1107/S1600536812050878/nr2034sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812050878/nr2034Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536812050878/nr2034Isup3.cml
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.
Carbon-bound H-atoms were placed in calculated positions [C—H = 0.93 Å for aromatic H atoms; Uiso(H) = 1.2Ueq(C)] and were included in the
in the riding model. The nitrogen-bound H atom was located on a difference Fourier map and refined freely with isotropic parameters.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
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 x = 0.00 (6). These results in conjunction with a of 0.997 for the Bijvoet normal probability plot indicate that the 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.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).
Data collection: APEX2 (Bruker, 2008); cell
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).C9H8N3O2+·Cl− | F(000) = 464 |
Mr = 225.64 | Dx = 1.503 Mg m−3 |
Orthorhombic, Pna21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2c -2n | Cell parameters from 9896 reflections |
a = 14.6042 (8) Å | θ = 2.2–28.3° |
b = 12.1781 (7) Å | µ = 0.37 mm−1 |
c = 5.6070 (3) Å | T = 173 K |
V = 997.21 (10) Å3 | Block, colourless |
Z = 4 | 0.54 × 0.16 × 0.15 mm |
Bruker SMART APEXII CCD diffractometer | 2217 independent reflections |
Radiation source: fine-focus sealed tube | 2120 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.060 |
φ and ω scans | θmax = 28.3°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | h = −17→19 |
Tmin = 0.524, Tmax = 0.746 | k = −16→16 |
20153 measured reflections | l = −7→6 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.029 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.076 | w = 1/[σ2(Fo2) + (0.0354P)2 + 0.3302P] where P = (Fo2 + 2Fc2)/3 |
S = 1.09 | (Δ/σ)max < 0.001 |
2217 reflections | Δρmax = 0.30 e Å−3 |
140 parameters | Δρmin = −0.22 e Å−3 |
8 restraints | Absolute structure: Flack (1983), Hooft et al. (2010) and Spek (2009); Hooft parameter = 0.03(2), 856 Bijvoet pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.00 (6) |
C9H8N3O2+·Cl− | V = 997.21 (10) Å3 |
Mr = 225.64 | Z = 4 |
Orthorhombic, Pna21 | Mo Kα radiation |
a = 14.6042 (8) Å | µ = 0.37 mm−1 |
b = 12.1781 (7) Å | T = 173 K |
c = 5.6070 (3) Å | 0.54 × 0.16 × 0.15 mm |
Bruker SMART APEXII CCD diffractometer | 2217 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | 2120 reflections with I > 2σ(I) |
Tmin = 0.524, Tmax = 0.746 | Rint = 0.060 |
20153 measured reflections |
R[F2 > 2σ(F2)] = 0.029 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.076 | Δρmax = 0.30 e Å−3 |
S = 1.09 | Δρmin = −0.22 e Å−3 |
2217 reflections | Absolute structure: Flack (1983), Hooft et al. (2010) and Spek (2009); Hooft parameter = 0.03(2), 856 Bijvoet pairs |
140 parameters | Absolute structure parameter: 0.00 (6) |
8 restraints |
Experimental. Carbon-bound H-atoms were placed in calculated positions [C—H = 0.93 Å for aromatic H atoms; Uiso(H) = 1.2Ueq(C)] and were included in the refinement in the riding model. The nitrogen-bound H atom was located on a difference Fourier map and refined freely with isotropic parameters. |
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. |
x | y | z | Uiso*/Ueq | ||
C2 | 0.61881 (11) | 0.39839 (13) | −0.1020 (3) | 0.0241 (5) | |
H2 | 0.5556 | 0.4068 | −0.0918 | 0.029* | |
C4 | 0.76184 (13) | 0.41464 (15) | −0.2179 (4) | 0.0308 (5) | |
H4 | 0.8131 | 0.4368 | −0.3039 | 0.037* | |
C3 | 0.76136 (12) | 0.34674 (15) | −0.0291 (4) | 0.0303 (4) | |
H3 | 0.8120 | 0.3132 | 0.0402 | 0.036* | |
N3 | 0.54484 (10) | 0.08365 (11) | 0.8199 (3) | 0.0274 (3) | |
N2 | 0.67050 (9) | 0.33611 (11) | 0.0429 (3) | 0.0210 (3) | |
N1 | 0.67229 (10) | 0.44554 (12) | −0.2608 (3) | 0.0251 (3) | |
O1 | 0.46671 (9) | 0.09724 (10) | 0.8910 (3) | 0.0323 (4) | |
O2 | 0.59895 (10) | 0.01721 (12) | 0.9069 (3) | 0.0406 (4) | |
H1 | 0.6548 (14) | 0.4898 (17) | −0.386 (4) | 0.030 (5)* | |
Cl1 | 0.88518 (2) | 0.09410 (3) | 0.84010 (10) | 0.02647 (12) | |
C8 | 0.57713 (11) | 0.14961 (13) | 0.6161 (3) | 0.0217 (3) | |
C9 | 0.66889 (12) | 0.14545 (14) | 0.5571 (4) | 0.0303 (4) | |
H9 | 0.7093 | 0.1022 | 0.6443 | 0.036* | |
C10 | 0.69939 (11) | 0.20704 (13) | 0.3655 (4) | 0.0300 (4) | |
H10 | 0.7608 | 0.2048 | 0.3216 | 0.036* | |
C5 | 0.63843 (11) | 0.27213 (12) | 0.2387 (3) | 0.0204 (3) | |
C6 | 0.54623 (11) | 0.27679 (13) | 0.3038 (4) | 0.0264 (4) | |
H6 | 0.5058 | 0.3212 | 0.2196 | 0.032* | |
C7 | 0.51553 (11) | 0.21484 (13) | 0.4943 (4) | 0.0260 (4) | |
H7 | 0.4543 | 0.2170 | 0.5397 | 0.031* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C2 | 0.0202 (8) | 0.0223 (7) | 0.0297 (13) | 0.0005 (6) | −0.0001 (7) | 0.0027 (7) |
C4 | 0.0233 (9) | 0.0369 (9) | 0.0323 (13) | 0.0006 (7) | 0.0030 (8) | 0.0051 (8) |
C3 | 0.0172 (8) | 0.0356 (10) | 0.0380 (12) | 0.0008 (7) | 0.0036 (8) | 0.0068 (8) |
N3 | 0.0293 (7) | 0.0286 (6) | 0.0242 (9) | −0.0071 (5) | −0.0034 (8) | 0.0010 (6) |
N2 | 0.0173 (6) | 0.0196 (6) | 0.0262 (8) | −0.0004 (5) | 0.0005 (6) | −0.0007 (6) |
N1 | 0.0247 (7) | 0.0232 (6) | 0.0274 (8) | −0.0002 (5) | −0.0003 (6) | 0.0013 (6) |
O1 | 0.0286 (7) | 0.0373 (6) | 0.0311 (9) | −0.0060 (5) | 0.0047 (6) | 0.0014 (6) |
O2 | 0.0347 (7) | 0.0438 (8) | 0.0432 (10) | −0.0032 (6) | −0.0100 (6) | 0.0205 (7) |
Cl1 | 0.01823 (18) | 0.02836 (18) | 0.0328 (2) | −0.00189 (13) | −0.00026 (19) | 0.0061 (2) |
C8 | 0.0231 (8) | 0.0202 (7) | 0.0219 (9) | −0.0046 (6) | −0.0016 (7) | 0.0000 (6) |
C9 | 0.0231 (8) | 0.0295 (9) | 0.0382 (12) | 0.0013 (7) | −0.0040 (8) | 0.0089 (8) |
C10 | 0.0161 (7) | 0.0326 (8) | 0.0415 (12) | 0.0018 (6) | −0.0002 (8) | 0.0085 (9) |
C5 | 0.0210 (8) | 0.0190 (6) | 0.0214 (8) | −0.0021 (6) | −0.0001 (6) | −0.0009 (6) |
C6 | 0.0202 (7) | 0.0256 (7) | 0.0333 (12) | 0.0044 (6) | −0.0007 (8) | 0.0034 (7) |
C7 | 0.0196 (8) | 0.0278 (8) | 0.0307 (10) | 0.0016 (6) | 0.0022 (7) | −0.0005 (7) |
C2—N1 | 1.316 (2) | N1—H1 | 0.92 (2) |
C2—N2 | 1.343 (2) | C8—C7 | 1.381 (2) |
C2—H2 | 0.9300 | C8—C9 | 1.381 (2) |
C4—C3 | 1.343 (3) | C9—C10 | 1.384 (3) |
C4—N1 | 1.382 (2) | C9—H9 | 0.9300 |
C4—H4 | 0.9300 | C10—C5 | 1.388 (2) |
C3—N2 | 1.393 (2) | C10—H10 | 0.9300 |
C3—H3 | 0.9300 | C5—C6 | 1.396 (2) |
N3—O1 | 1.220 (2) | C6—C7 | 1.382 (3) |
N3—O2 | 1.232 (2) | C6—H6 | 0.9300 |
N3—C8 | 1.474 (2) | C7—H7 | 0.9300 |
N2—C5 | 1.425 (2) | ||
N1—C2—N2 | 108.78 (15) | C7—C8—C9 | 122.31 (17) |
N1—C2—H2 | 125.6 | C7—C8—N3 | 119.25 (15) |
N2—C2—H2 | 125.6 | C9—C8—N3 | 118.43 (16) |
C3—C4—N1 | 107.45 (16) | C8—C9—C10 | 118.58 (16) |
C3—C4—H4 | 126.3 | C8—C9—H9 | 120.7 |
N1—C4—H4 | 126.3 | C10—C9—H9 | 120.7 |
C4—C3—N2 | 106.90 (16) | C9—C10—C5 | 120.04 (15) |
C4—C3—H3 | 126.5 | C9—C10—H10 | 120.0 |
N2—C3—H3 | 126.5 | C5—C10—H10 | 120.0 |
O1—N3—O2 | 124.04 (17) | C10—C5—C6 | 120.53 (17) |
O1—N3—C8 | 118.59 (14) | C10—C5—N2 | 119.73 (15) |
O2—N3—C8 | 117.37 (15) | C6—C5—N2 | 119.73 (15) |
C2—N2—C3 | 107.90 (15) | C7—C6—C5 | 119.50 (15) |
C2—N2—C5 | 126.14 (14) | C7—C6—H6 | 120.2 |
C3—N2—C5 | 125.95 (15) | C5—C6—H6 | 120.2 |
C2—N1—C4 | 108.96 (16) | C8—C7—C6 | 119.02 (16) |
C2—N1—H1 | 127.3 (13) | C8—C7—H7 | 120.5 |
C4—N1—H1 | 123.7 (13) | C6—C7—H7 | 120.5 |
N1—C4—C3—N2 | 0.1 (2) | C8—C9—C10—C5 | 0.7 (3) |
N1—C2—N2—C3 | 0.8 (2) | C9—C10—C5—C6 | 0.4 (3) |
N1—C2—N2—C5 | 179.69 (15) | C9—C10—C5—N2 | 179.43 (17) |
C4—C3—N2—C2 | −0.6 (2) | C2—N2—C5—C10 | 176.61 (17) |
C4—C3—N2—C5 | −179.45 (15) | C3—N2—C5—C10 | −4.7 (3) |
N2—C2—N1—C4 | −0.7 (2) | C2—N2—C5—C6 | −4.4 (3) |
C3—C4—N1—C2 | 0.4 (2) | C3—N2—C5—C6 | 174.27 (17) |
O1—N3—C8—C7 | −7.6 (2) | C10—C5—C6—C7 | −0.8 (3) |
O2—N3—C8—C7 | 171.90 (17) | N2—C5—C6—C7 | −179.81 (15) |
O1—N3—C8—C9 | 171.10 (16) | C9—C8—C7—C6 | 1.1 (3) |
O2—N3—C8—C9 | −9.4 (2) | N3—C8—C7—C6 | 179.81 (16) |
C7—C8—C9—C10 | −1.5 (3) | C5—C6—C7—C8 | 0.0 (3) |
N3—C8—C9—C10 | 179.81 (16) |
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 |
Symmetry codes: (i) −x+3/2, y+1/2, z−3/2; (ii) x−1/2, −y+1/2, z−1. |
Experimental details
Crystal data | |
Chemical formula | C9H8N3O2+·Cl− |
Mr | 225.64 |
Crystal system, space group | Orthorhombic, Pna21 |
Temperature (K) | 173 |
a, b, c (Å) | 14.6042 (8), 12.1781 (7), 5.6070 (3) |
V (Å3) | 997.21 (10) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.37 |
Crystal size (mm) | 0.54 × 0.16 × 0.15 |
Data collection | |
Diffractometer | Bruker SMART APEXII CCD |
Absorption correction | Multi-scan (SADABS; Bruker, 2008) |
Tmin, Tmax | 0.524, 0.746 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 20153, 2217, 2120 |
Rint | 0.060 |
(sin θ/λ)max (Å−1) | 0.668 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.029, 0.076, 1.09 |
No. of reflections | 2217 |
No. of parameters | 140 |
No. of restraints | 8 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.30, −0.22 |
Absolute structure | Flack (1983), Hooft et al. (2010) and Spek (2009); Hooft parameter = 0.03(2), 856 Bijvoet pairs |
Absolute structure parameter | 0.00 (6) |
Computer programs: APEX2 (Bruker, 2008), SAINT-Plus (Bruker, 2008), SAINT-Plus and XPREP (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 2012), WinGX (Farrugia, 2012).
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) | 144.1 |
C2—H2···Cl1ii | 0.93 | 2.52 | 3.4286 (17) | 166.1 |
C4—H4···O2i | 0.93 | 2.29 | 3.181 (2) | 160.6 |
Symmetry codes: (i) −x+3/2, y+1/2, z−3/2; (ii) x−1/2, −y+1/2, z−1. |
Acknowledgements
We thank the NRF and the University of KwaZulu-Natal for financial support.
References
Bruker (2008). APEX2, SAINT-Plus, XPREP and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.. Google Scholar
Coberan, R. & Peris, E. (2008). Organometallics, 27, 1954–1958. Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Gayathri, P., Thiruvalluvar, A., Srinivasan, N., Jayabharathi, J. & Butcher, R. J. (2010). Acta Cryst. E66, o2519. Web of Science CSD CrossRef IUCr Journals Google Scholar
Gnanamgari, D., Sauer, E. L. O., Schley, N. D., Butler, C., Incarvito, C. D. & Crabtree, R. H. (2009). Organometallics, 28, 321–325. Web of Science CSD CrossRef CAS Google Scholar
Hooft, R. W. W., Straver, L. H. & Spek, A. L. (2010). J. Appl. Cryst. 43, 665–668. Web of Science CrossRef CAS IUCr Journals Google Scholar
Ibrahim, H., Bala, M. D. & Omondi, B. (2012). Acta Cryst. E68, o2305. CSD CrossRef IUCr Journals Google Scholar
Ishihara, M., Tonogaki, M., Ohba, S., Saito, Y., Okazaki, M., Katoh, T. & Kamiyama, K. (1992). Acta Cryst. C48, 184–188. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Scheele, U. J., Meyer, F. & Dechert, S. (2007). Tetrahedron Lett. 48, 8366–8370. Web of Science CSD CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Singh, A. K., Kumar, P., Yadav, M. & Pandey, D. S. (2010). J. Organomet. Chem. 695, 567–573. Web of Science CSD CrossRef CAS Google Scholar
Singh, A. K., Kumar, P., Yadav, M. & Pandey, D. S. (2011). Bull. Chem. Soc. Jpn, 84, 205–210. Web of Science CSD CrossRef CAS Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Zheng, Z., Geng, W.-Q., Wu, Z.-C. & Zhou, H.-P. (2011). Acta Cryst. E67, o524. Web of Science CSD CrossRef IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
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.