3-(2-Hy­droxy­eth­yl)-1-(4-nitro­phen­yl)-1H-imidazol-3-ium bromide

Ibrahim, H.; Zamisa, S.J.; Bala, M.D.; Ntola, P.; Friedrich, H.B.

doi:10.1107/S2414314624011386

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 9| Part 11| November 2024| x241138

https://doi.org/10.1107/S2414314624011386

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3-(2-Hydroxyethyl)-1-(4-nitrophenyl)-1H-imidazol-3-ium bromide

Halliru Ibrahim,^a Sizwe J. Zamisa,^b ^* Muhammad D. Bala,^b Pinkie Ntola ^a and Holger B. Friedrich ^b

^aDepartment of Chemistry, Durban University of Technology, PO Box 1334, Durban, 4000, South Africa, and ^bSchool of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Durban, 4000, South Africa
^*Correspondence e-mail: Zamisas@ukzn.ac.za

(Received 13 November 2024; accepted 22 November 2024; online 28 November 2024)

The molecular structure of the title salt, C₁₁H₁₂N₃O₃⁺·Br⁻, reveals near co-planarity between the the imidazole and 4-nitrobenzene moieties with a dihedral angle of 8.99 (14)° between their planes. A prominent feature in the molecular packing is the bromide anion acting as a double acceptor for O—H⋯Br and C—H⋯Br hydrogen-bonds, leading to a linear chain propagating along [110]. The crystal studied was refined as an inversion twin, with the minor component = 0.081 (8).

Keywords: crystal structure; imidazolium salt; hydrogen-bonding.

CCDC reference: 2404555

Structure description

The title crystal is an imidazolium bromide salt based on a 1-(4-nitrophenyl)-1H-imidazol-3-yl moiety (Ibrahim & Bala, 2016 ; Illam et al., 2021 ), which is functionalized at the 1,3-diazole wingtip with a 2-hydroxyethyl group. Unlike analogues with a fused 1H-benzo[d] backbone (Kumar et al., 2015 ), derivatives of the title salt with the 1H-imidazol-3-yl moiety do not show any potential as chemodosimeters. The incorporation of oxygen-containing functionalities in the design of these imidazolium salts is motivated by the desire to increase the solubility of the ligand/precursor in common solvents (Garrison & Young, 2005 ), and, upon coordination, to enhance the electron density around the metal, thereby stabilizing the metal center during a catalytic cycle (Simpson et al., 2015 ). We recently explored the potential of such NO₂-functionalized imidazolylidene–Co^II/Ni^II complexes as viable green catalysts for aryl C—N coupling reactions of aryl amines with aryl bromides (Ibrahim & Bala, 2016). In a continuation of this work designed to develop new derivatives with superior catalytic abilities, the title compound was synthesized and analyzed by X-ray crystallography.

The asymmetric unit of the title salt comprises an imidazolyl cation and a bromide anion (Fig. 1). The conformation of the cationic species is such that the dihedral angle between the imidazole and 4-nitrobenzene planes is 8.99 (14)° while the orientation of the ethanolyl side is almost orthogonal with respect to the imidazole plane [C7—N3—C10—C11 torsion angle = 95.1 (4)°]. A prominent feature of the molecular packing relates to the bromide anion acting as a double acceptorm with the hydroxyl-H1 atom and the H3 atom of a neighboring 4-nitrophenyl moiety to form a linear supramolecular chain propagatingalong [ $[\overline{1}]$ 10] (Table 1; Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯Br1	0.84	2.42	3.2509 (19)	171
C3—H3⋯Br1ⁱ	0.95	2.71	3.572 (2)	151
Symmetry code: (i) $[x+{\script{1\over 2}}, y-{\script{1\over 2}}, z]$ .

Figure 1
The asymmetric unit of the title compound showing the atom-labeling scheme and displacement ellipsoids at the 50% probability level.

Figure 2
Representation of intermolecular O1—H1⋯Br1 and C3—H3⋯Br1 hydrogen bonds (brown dotted bonds) within the crystal of the title compound.

Synthesis and crystallization

The title compound was synthesized with a slight modification of the reported protocol (Ibrahim & Bala, 2016). A mixture of N-p-nitrophenyl imidazole (0.5 g, 0.003 mol) and 2-bromoethanol (0.56 g, 0.005 mol; 0.35 ml, ρ = 1.76 g cm⁻³, 95%) was refluxed overnight in acetonitrile under an inert dinitrogen atmosphere. Removal of the solvent followed by washing with ethyl acetate afforded a yellow precipitate, which yielded the title salt as an air-stable yellow solid after drying in vacuo. Slow diffusion of diethyl ether into a methanolic solution of the isolated title salt afforded suitable single crystals for the X-ray diffraction analysis. Yield: 0.70 g, 0.002 mol, 85.7%. m.p. 475–477 K. ¹H NMR (400 MHz, DMSO-d₆): δ 10.03 (s, 1H, NCHN), 8.52 (d, J = 9.0 Hz, 2H, CH_(phenyl)), 8.47 (d, J = 1.6 Hz, 1H, CH_(imidazolyl)), 8.11 (d, J = 9.1 Hz, 2H, CH_(benzyl)), 8.06 (s, 1H, CH_(imidazolyl)), 4.33 (t, J = 10.0 Hz, 2H, CH_2(ethanoyl)), 3.84 (t, J = 10.0 Hz, 2H, CH₂(hydroxyethy), 3.35 (s, b, 1H, OH(hydroxyethyl)). ¹³C NMR (100 MHz, DMSO-d₆): δ 147.5 (NCN), 139.2, 136.4, 125.6, 124.1, 122.9, 120.9, 59.1 (CH₂), 52.4 (CH₂). FTIR (ν(O—H) 3243, ν(aryl C—H) 3090, ν(alkyl C—H) 2958, ν(C=N) 1552, ν(NO₂) 1522 & 1341, ν(C—O) 1222, ν(phenyl) 854 cm⁻¹. LRMS-ES⁺: m/z (%) 234.0550 (100) [(M − Br)]⁺.

Refinement

Table 2 provides a summary of the crystal data, data collection and structure refinement details. The structure was refined as an inversion twin, with the minor component = 0.081 (8).

Table 2
Experimental details

Crystal data
Chemical formula	C₁₁H₁₂N₃O₃⁺·Br⁻
M_r	314.15
Crystal system, space group	Monoclinic, Cc
Temperature (K)	100
a, b, c (Å)	6.4352 (4), 12.2697 (11), 15.5936 (10)
β (°)	90.290 (3)
V (Å³)	1231.22 (16)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	3.34
Crystal size (mm)	0.38 × 0.21 × 0.14

Data collection
Diffractometer	Bruker SMART APEXII area detector
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.661, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	9019, 3051, 2930
R_int	0.019
(sin θ/λ)_max (Å⁻¹)	0.673

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.017, 0.037, 1.03
No. of reflections	3051
No. of parameters	165
No. of restraints	2
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.36, −0.23
Absolute structure	Refined as an inversion twin
Absolute structure parameter	0.081 (8)
Computer programs: COSMO and SAINT (Bruker, 2010 ), SHELXT2013 (Sheldrick, 2015a ), SHELXL2018/3 (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 2404555

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314624011386/tk4113sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314624011386/tk4113Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314624011386/tk4113Isup3.cml

checkCIF report

Computing details top

(I) top

Crystal data top

C₁₁H₁₂N₃O³⁺·Br⁻	F(000) = 632
M_r = 314.15	D_x = 1.695 Mg m⁻³
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
a = 6.4352 (4) Å	Cell parameters from 6616 reflections
b = 12.2697 (11) Å	θ = 3.3–28.5°
c = 15.5936 (10) Å	µ = 3.34 mm⁻¹
β = 90.290 (3)°	T = 100 K
V = 1231.22 (16) Å³	Slab, light yellow
Z = 4	0.38 × 0.21 × 0.14 mm

Data collection top

Bruker SMART APEXII area detector diffractometer	2930 reflections with I > 2σ(I)
Detector resolution: 7.9 pixels mm^-1	R_int = 0.019
ω and φ scans	θ_max = 28.6°, θ_min = 2.6°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −8→8
T_min = 0.661, T_max = 0.746	k = −16→16
9019 measured reflections	l = −20→20
3051 independent reflections

Refinement top

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)] = 0.017	H-atom parameters constrained
wR(F²) = 0.037	w = 1/[σ²(F_o²) + (0.0076P)²] where P = (F_o² + 2F_c²)/3
S = 1.03	(Δ/σ)_max < 0.001
3051 reflections	Δρ_max = 0.36 e Å⁻³
165 parameters	Δρ_min = −0.22 e Å⁻³
2 restraints	Absolute structure: Refined as an inversion twin
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.081 (8)

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refined as a 2-component inversion twin.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Br1	0.52235 (5)	0.56771 (2)	0.24805 (3)	0.01782 (6)
C2	0.6133 (4)	0.2573 (2)	0.12029 (17)	0.0170 (5)
H2	0.588284	0.236441	0.177996	0.020*
O2	1.1242 (3)	0.15187 (18)	−0.01212 (14)	0.0336 (6)
O1	0.2180 (3)	0.45365 (14)	0.38751 (12)	0.0204 (4)
H1	0.298129	0.475858	0.348926	0.031*
C11	0.0084 (5)	0.4666 (3)	0.3601 (2)	0.0178 (7)
H11A	−0.007513	0.538803	0.332540	0.021*
H11B	−0.083443	0.464705	0.410782	0.021*
C10	−0.0603 (5)	0.3781 (2)	0.29685 (18)	0.0165 (6)
H10A	−0.035231	0.305423	0.322381	0.020*
H10B	−0.211178	0.385282	0.285381	0.020*
N3	0.0538 (4)	0.38742 (19)	0.21627 (15)	0.0140 (5)
C7	0.2242 (4)	0.33242 (19)	0.19668 (16)	0.0160 (5)
H7	0.287958	0.278530	0.231755	0.019*
N2	0.2926 (3)	0.36462 (15)	0.11964 (13)	0.0141 (4)
C1	0.4742 (4)	0.32634 (19)	0.07739 (15)	0.0145 (5)
C3	0.7879 (4)	0.2196 (2)	0.07779 (17)	0.0185 (5)
H3	0.883162	0.171970	0.105583	0.022*
C4	0.8207 (3)	0.2526 (2)	−0.00536 (18)	0.0164 (5)
N1	1.0073 (4)	0.21336 (18)	−0.05093 (16)	0.0229 (5)
O3	1.0345 (4)	0.24477 (17)	−0.12456 (14)	0.0306 (5)
C8	0.0106 (6)	0.4587 (3)	0.1501 (2)	0.0178 (7)
H8	−0.102340	0.508493	0.147718	0.021*
C6	0.5101 (4)	0.3571 (2)	−0.00708 (17)	0.0182 (6)
H6	0.414163	0.403271	−0.035965	0.022*
C5	0.6850 (4)	0.3206 (2)	−0.04886 (17)	0.0193 (5)
H5	0.711834	0.341669	−0.106364	0.023*
C9	0.1575 (4)	0.44526 (18)	0.08943 (17)	0.0168 (5)
H9	0.166987	0.483219	0.036499	0.020*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.01789 (10)	0.01860 (10)	0.01696 (10)	−0.00135 (15)	−0.00015 (7)	0.00074 (15)
C2	0.0190 (14)	0.0193 (12)	0.0127 (12)	0.0002 (11)	−0.0003 (11)	0.0011 (9)
O2	0.0239 (12)	0.0384 (13)	0.0386 (14)	0.0131 (10)	0.0002 (10)	−0.0074 (10)
O1	0.0181 (9)	0.0268 (9)	0.0163 (9)	−0.0040 (7)	0.0012 (7)	0.0031 (7)
C11	0.0188 (16)	0.0178 (14)	0.0169 (15)	−0.0021 (12)	0.0021 (12)	−0.0041 (12)
C10	0.0163 (14)	0.0203 (14)	0.0130 (13)	−0.0032 (11)	0.0056 (11)	−0.0004 (11)
N3	0.0143 (12)	0.0110 (10)	0.0167 (11)	−0.0017 (9)	0.0034 (9)	−0.0022 (8)
C7	0.0169 (13)	0.0154 (11)	0.0157 (12)	−0.0011 (9)	0.0011 (9)	0.0000 (9)
N2	0.0153 (10)	0.0128 (9)	0.0144 (10)	−0.0004 (8)	0.0006 (8)	−0.0001 (7)
C1	0.0143 (12)	0.0127 (11)	0.0165 (13)	−0.0017 (9)	0.0018 (10)	−0.0033 (9)
C3	0.0176 (13)	0.0158 (12)	0.0219 (13)	0.0014 (10)	−0.0021 (10)	−0.0017 (10)
C4	0.0134 (15)	0.0148 (10)	0.0211 (12)	−0.0034 (12)	0.0045 (12)	−0.0060 (9)
N1	0.0181 (12)	0.0186 (11)	0.0320 (14)	−0.0028 (9)	0.0050 (10)	−0.0081 (10)
O3	0.0319 (13)	0.0271 (11)	0.0329 (12)	0.0010 (9)	0.0190 (10)	0.0008 (9)
C8	0.0196 (16)	0.0170 (14)	0.0170 (15)	−0.0008 (12)	0.0011 (12)	−0.0026 (11)
C6	0.0178 (14)	0.0189 (13)	0.0180 (14)	0.0042 (11)	0.0007 (11)	0.0037 (10)
C5	0.0226 (14)	0.0194 (12)	0.0159 (12)	−0.0037 (10)	0.0034 (10)	0.0009 (10)
C9	0.0182 (12)	0.0143 (11)	0.0179 (13)	0.0018 (9)	−0.0006 (10)	0.0022 (9)

Geometric parameters (Å, º) top

C2—H2	0.9500	C7—N2	1.341 (3)
C2—C1	1.400 (3)	N2—C1	1.424 (3)
C2—C3	1.387 (4)	N2—C9	1.398 (3)
O2—N1	1.224 (3)	C1—C6	1.391 (3)
O1—H1	0.8400	C3—H3	0.9500
O1—C11	1.421 (4)	C3—C4	1.376 (4)
C11—H11A	0.9900	C4—N1	1.479 (3)
C11—H11B	0.9900	C4—C5	1.383 (4)
C11—C10	1.530 (4)	N1—O3	1.225 (3)
C10—H10A	0.9900	C8—H8	0.9500
C10—H10B	0.9900	C8—C9	1.351 (5)
C10—N3	1.463 (3)	C6—H6	0.9500
N3—C7	1.325 (3)	C6—C5	1.378 (4)
N3—C8	1.379 (4)	C5—H5	0.9500
C7—H7	0.9500	C9—H9	0.9500

C1—C2—H2	120.3	C2—C1—N2	120.2 (2)
C3—C2—H2	120.3	C6—C1—C2	120.5 (2)
C3—C2—C1	119.4 (2)	C6—C1—N2	119.3 (2)
C11—O1—H1	109.5	C2—C3—H3	120.6
O1—C11—H11A	109.1	C4—C3—C2	118.7 (2)
O1—C11—H11B	109.1	C4—C3—H3	120.6
O1—C11—C10	112.7 (3)	C3—C4—N1	119.1 (2)
H11A—C11—H11B	107.8	C3—C4—C5	122.7 (2)
C10—C11—H11A	109.1	C5—C4—N1	118.2 (2)
C10—C11—H11B	109.1	O2—N1—C4	117.5 (2)
C11—C10—H10A	109.5	O2—N1—O3	124.6 (3)
C11—C10—H10B	109.5	O3—N1—C4	117.9 (2)
H10A—C10—H10B	108.1	N3—C8—H8	126.0
N3—C10—C11	110.7 (2)	C9—C8—N3	107.9 (3)
N3—C10—H10A	109.5	C9—C8—H8	126.0
N3—C10—H10B	109.5	C1—C6—H6	120.0
C7—N3—C10	125.3 (2)	C5—C6—C1	120.0 (2)
C7—N3—C8	108.3 (3)	C5—C6—H6	120.0
C8—N3—C10	126.3 (3)	C4—C5—H5	120.7
N3—C7—H7	125.3	C6—C5—C4	118.6 (2)
N3—C7—N2	109.4 (2)	C6—C5—H5	120.7
N2—C7—H7	125.3	N2—C9—H9	126.7
C7—N2—C1	126.3 (2)	C8—C9—N2	106.7 (2)
C7—N2—C9	107.7 (2)	C8—C9—H9	126.7
C9—N2—C1	126.0 (2)

C2—C1—C6—C5	−0.8 (4)	N2—C1—C6—C5	−179.9 (2)
C2—C3—C4—N1	179.6 (2)	C1—C2—C3—C4	0.8 (4)
C2—C3—C4—C5	−1.0 (4)	C1—N2—C9—C8	−178.1 (2)
O1—C11—C10—N3	−66.2 (3)	C1—C6—C5—C4	0.6 (4)
C11—C10—N3—C7	95.1 (4)	C3—C2—C1—N2	179.2 (2)
C11—C10—N3—C8	−80.8 (3)	C3—C2—C1—C6	0.0 (4)
C10—N3—C7—N2	−177.1 (2)	C3—C4—N1—O2	0.6 (3)
C10—N3—C8—C9	177.1 (2)	C3—C4—N1—O3	−179.2 (2)
N3—C7—N2—C1	178.5 (2)	C3—C4—C5—C6	0.2 (4)
N3—C7—N2—C9	0.4 (3)	N1—C4—C5—C6	179.7 (2)
N3—C8—C9—N2	−0.3 (3)	C8—N3—C7—N2	−0.6 (3)
C7—N3—C8—C9	0.6 (3)	C5—C4—N1—O2	−178.9 (2)
C7—N2—C1—C2	−7.5 (3)	C5—C4—N1—O3	1.4 (4)
C7—N2—C1—C6	171.7 (2)	C9—N2—C1—C2	170.3 (2)
C7—N2—C9—C8	−0.1 (3)	C9—N2—C1—C6	−10.6 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···Br1	0.84	2.42	3.2509 (19)	171
C3—H3···Br1ⁱ	0.95	2.71	3.572 (2)	151

Symmetry code: (i) x+1/2, y−1/2, z.

Acknowledgements

The authors would like to thank the University of KwaZulu-Natal for the research facilities. DUT/HANT is acknowledged for funding the postdoctoral fellowship of HI.

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