organic compounds
1,3-Bis(4-bromophenyl)imidazolium chloride dihydrate
aInstituto de Química, Departamento de Quimica Orgânica, Universidade Federal do Rio de Janeiro, Ilha do Fundão, CT, Bloco A, Rio de Janeiro 21949-900, RJ, Brazil, bDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia, cCentro de Desenvolvimento Tecnológico em Saúde (CDTS), Fundação Oswaldo Cruz (FIOCRUZ), Casa Amarela, Campus de Manguinhos, Av. Brasil 4365, 21040-900 Rio de Janeiro, RJ, Brazil, dCHEMSOL, 1 Harcourt Road, Aberdeen AB15 5NY, Scotland, and eDepartment of Chemistry, University of Aberdeen, Old Aberdeen AB15 5NY, Scotland
*Correspondence e-mail: edward.tiekink@gmail.com
In the title hydrated salt, C15H11Br2N2+·Cl−·2H2O, the complete imidazolium cation is generated by a crystallographic twofold axis, with one C atom lying on the axis. The chloride ion and both water molecules of crystallization also lie on a crystallographic twofold axis of symmetry. The cation is non-planar, the dihedral angle formed between the central imidazolium and benzene rings being 12.9 (3)°; the dihedral angle between the symmetry-related benzene rings is 25.60 (13)°. In the crystal, O—H⋯Cl hydrogen bonds result in supramolecular chains along c mediated by eight-membered {⋯HOH⋯Cl}2 synthons. These are consolidated by C—H⋯O and π–π [centroid–centroid distance = 3.687 (3) Å] interactions.
Related literature
For the preparation of imidazolylidene ); Diez-Gonzalez & Nolan (2007); Glorius (2007); Leuthaeusser et al. (2007); Alcarazo et al. (2010). For related structures, see: Luger & Ruban (1975); Cole & Junk (2004); Wan et al. (2008).
see: Nolan (2006Experimental
Crystal data
|
Data collection: COLLECT (Hooft, 1998); cell DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).
Supporting information
https://doi.org/10.1107/S1600536810018581/hb5456sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810018581/hb5456Isup2.hkl
p-Bromoaniline (50 mmol) was solubilised in AcOH/H2O (3:1 V/V, 40 ml). Aqueous formaldehyde (37%, 2 ml) was added to the solution resulting in the precipitation of a solid. Following this, aqueous glyoxal (40%, 3 ml) was added and the reaction mixture was subsequently warmed (333 K) for 30 minutes. Finally, aqueous HCl (3M, 10 ml) was added resulting in the formation of a homogeneous solution. Heating was continued for a further 30 min. The crude product was precipitated from the reaction by diluting with water. The solid was isolated by filtration and allowed to air dry. The product was recrystallized from 2-propanol to generate colourless needles of (I). Melting point 581–583 K; 83% yield. 1H NMR (DMSO-d6/CDCl3): δ 10.48 [1H, s]; 8.55 [2H, s]; 7.90 [4H, s] p.p.m. 13C NMR (DMSO-d6/CDCl3): δ 122.1; 123.2; 124.3; 133.2; 134.0; 135.0 p.p.m. IR (cm-1): 3365, 3092, 3048, 1556, 1488, 1309, 1259, 1075, 1008, 824.
The C-bound H atoms were geometrically placed (C–H = 0.95 Å) and refined as riding with Uiso(H) = 1.2Ueq(C). The water-bound H atoms were refined with O–H = 0.84±0.01 Å, and with Uiso(H) = 1.5Ueq(O).
The deprotonation of N,N-disubstituted imidazolium salts has been extensively used to generate imidazolylidene
for use as ligands for metals or their salts in (Nolan, 2006; Glorius, 2007). The structural motif can be readily varied so as to modify the electronic properties of the carbene and their complexes (Alcarazo et al., 2010; Leuthaeusser et al., 2007; Diez-Gonzalez & Nolan, 2007). Whereas structural studies are available for a number of derivatives (Luger & Ruban, 1975; Cole & Junk, 2004; Wan et al., 2008), little is known about simple 1,3-diphenyl derivatives that do not posses substituents in the 2,6-positions of the phenyl rings. As part of a study into structural effects of these we have been able to prepare and crystallize for the first time the salt 1,3-di-(4-bromophenyl)imidazolium chloride, isolated as a dihydrate, (I).The crystallographic π–π contacts (along c) between the imidazolium and between rings [ring centroid···ring centroid distance = 3.687 (3) Å, angle of inclination = 12.9 (3) ° for i: x, y, 1+z].
of (I) comprises half a 1,3-di-(4-bromophenyl)imidazolium cation, Fig. 1, half a chloride, and two half water molecules, as each of the aforementioned species lies on a two-fold axis of symmetry. The cation is non-planar with the dihedral angle formed between the central imidazolium ring [r.m.s. deviation = 0.005 Å] and the benzene ring (C3–C8) being 12.9 (3) °; the dihedral angle formed between the symmetry related benzene rings is 25.60 (13) °. The twists between the rings allows for the close approach of a water molecule allowing the formation of a C1—H···O1 interaction, Table 1. This O1-water molecule also forms O–H···Cl interactions with the chloride which in turn is connected to the second water molecule leading to eight-membered {···HOH···Cl}2 synthons aligned along the c axis, Fig. 2 and Table 1. The three-dimensional packing is consolidated by further C–H···O2 interactions, Fig. 3, as well asFor the preparation of imidazolylidene
see: Nolan (2006); Diez-Gonzalez & Nolan (2007); Glorius (2007); Leuthaeusser et al. (2007); Alcarazo et al. (2010). For related structures, see: Luger & Ruban (1975); Cole & Junk (2004); Wan et al. (2008).Data collection: COLLECT (Hooft, 1998); cell
DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); data reduction: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).C15H11Br2N2+·Cl−·2H2O | Dx = 1.835 Mg m−3 |
Mr = 450.56 | Mo Kα radiation, λ = 0.71073 Å |
Tetragonal, P42212 | Cell parameters from 2084 reflections |
Hall symbol: P 4n 2n | θ = 2.9–27.5° |
a = 17.8377 (7) Å | µ = 5.14 mm−1 |
c = 5.1270 (1) Å | T = 120 K |
V = 1631.33 (10) Å3 | Needle, colourless |
Z = 4 | 0.40 × 0.03 × 0.02 mm |
F(000) = 888 |
Nonius KappaCCD diffractometer | 1885 independent reflections |
Radiation source: Enraf Nonius FR591 rotating anode | 1654 reflections with I > 2σ(I) |
10 cm confocal mirrors monochromator | Rint = 0.048 |
Detector resolution: 9.091 pixels mm-1 | θmax = 27.5°, θmin = 3.2° |
φ and ω scans | h = −23→23 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2007) | k = −14→23 |
Tmin = 0.665, Tmax = 1.000 | l = −6→6 |
13675 measured reflections |
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)] = 0.032 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.075 | w = 1/[σ2(Fo2) + (0.0285P)2 + 2.7306P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max = 0.001 |
1885 reflections | Δρmax = 0.40 e Å−3 |
108 parameters | Δρmin = −0.69 e Å−3 |
2 restraints | Absolute structure: Flack (1983), 742 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.01 (2) |
C15H11Br2N2+·Cl−·2H2O | Z = 4 |
Mr = 450.56 | Mo Kα radiation |
Tetragonal, P42212 | µ = 5.14 mm−1 |
a = 17.8377 (7) Å | T = 120 K |
c = 5.1270 (1) Å | 0.40 × 0.03 × 0.02 mm |
V = 1631.33 (10) Å3 |
Nonius KappaCCD diffractometer | 1885 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2007) | 1654 reflections with I > 2σ(I) |
Tmin = 0.665, Tmax = 1.000 | Rint = 0.048 |
13675 measured reflections |
R[F2 > 2σ(F2)] = 0.032 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.075 | Δρmax = 0.40 e Å−3 |
S = 1.06 | Δρmin = −0.69 e Å−3 |
1885 reflections | Absolute structure: Flack (1983), 742 Friedel pairs |
108 parameters | Absolute structure parameter: 0.01 (2) |
2 restraints |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 | ||
Br1 | 0.100493 (18) | 0.463088 (18) | 0.00124 (12) | 0.02761 (11) | |
Cl1 | 0.13502 (7) | 0.13502 (7) | 0.5000 | 0.0552 (4) | |
O1 | 0.20493 (17) | 0.20493 (17) | 1.0000 | 0.0681 (15) | |
H1O | 0.186 (5) | 0.181 (5) | 1.125 (8) | 0.102* | |
O2 | 0.0584 (3) | 0.0584 (3) | 1.0000 | 0.0794 (16) | |
H2O | 0.067 (5) | 0.087 (4) | 0.867 (10) | 0.119* | |
N1 | 0.32639 (19) | 0.38584 (18) | 0.8472 (7) | 0.0274 (7) | |
C1 | 0.32553 (19) | 0.32553 (19) | 1.0000 | 0.0270 (9) | |
H1 | 0.2879 | 0.2879 | 1.0000 | 0.032* | |
C2 | 0.3893 (3) | 0.4253 (3) | 0.9090 (14) | 0.083 (3) | |
H2 | 0.4044 | 0.4714 | 0.8322 | 0.100* | |
C3 | 0.2714 (2) | 0.4041 (2) | 0.6525 (7) | 0.0252 (8) | |
C4 | 0.2720 (2) | 0.4748 (2) | 0.5411 (11) | 0.0382 (13) | |
H4 | 0.3075 | 0.5111 | 0.5974 | 0.046* | |
C5 | 0.2207 (3) | 0.4925 (3) | 0.3464 (9) | 0.0369 (10) | |
H5 | 0.2209 | 0.5408 | 0.2685 | 0.044* | |
C6 | 0.1696 (2) | 0.4391 (2) | 0.2680 (7) | 0.0267 (9) | |
C7 | 0.1683 (2) | 0.3694 (2) | 0.3799 (8) | 0.0265 (9) | |
H7 | 0.1325 | 0.3334 | 0.3241 | 0.032* | |
C8 | 0.2194 (2) | 0.3512 (2) | 0.5749 (8) | 0.0289 (10) | |
H8 | 0.2185 | 0.3030 | 0.6536 | 0.035* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.02725 (18) | 0.0350 (2) | 0.02061 (17) | 0.00424 (13) | −0.0019 (3) | 0.0025 (3) |
Cl1 | 0.0652 (6) | 0.0652 (6) | 0.0352 (8) | −0.0031 (8) | 0.0037 (10) | −0.0037 (10) |
O1 | 0.079 (2) | 0.079 (2) | 0.046 (3) | −0.049 (3) | −0.009 (4) | 0.009 (4) |
O2 | 0.080 (2) | 0.080 (2) | 0.078 (4) | 0.008 (3) | 0.018 (4) | −0.018 (4) |
N1 | 0.0252 (17) | 0.0274 (18) | 0.0296 (19) | 0.0075 (14) | −0.0003 (15) | 0.0059 (15) |
C1 | 0.0298 (14) | 0.0298 (14) | 0.021 (2) | 0.0017 (19) | −0.005 (3) | 0.005 (3) |
C2 | 0.056 (3) | 0.061 (3) | 0.132 (7) | −0.030 (3) | −0.064 (4) | 0.064 (4) |
C3 | 0.0245 (19) | 0.030 (2) | 0.021 (2) | 0.0066 (16) | 0.0005 (15) | 0.0017 (16) |
C4 | 0.038 (2) | 0.033 (2) | 0.044 (4) | −0.0073 (16) | −0.011 (2) | 0.011 (2) |
C5 | 0.038 (2) | 0.033 (2) | 0.039 (3) | −0.0040 (19) | −0.013 (2) | 0.014 (2) |
C6 | 0.0221 (19) | 0.036 (2) | 0.0219 (19) | 0.0067 (16) | 0.0002 (15) | 0.0025 (16) |
C7 | 0.0219 (19) | 0.027 (2) | 0.030 (2) | 0.0039 (16) | 0.0048 (17) | −0.0021 (17) |
C8 | 0.026 (2) | 0.029 (2) | 0.032 (3) | 0.0052 (16) | 0.0026 (15) | 0.0037 (15) |
Br1—C6 | 1.890 (4) | C3—C8 | 1.383 (6) |
O1—H1O | 0.84 (6) | C3—C4 | 1.383 (6) |
O2—H2O | 0.87 (6) | C4—C5 | 1.391 (6) |
N1—C1 | 1.331 (4) | C4—H4 | 0.9500 |
N1—C2 | 1.362 (6) | C5—C6 | 1.378 (6) |
N1—C3 | 1.437 (5) | C5—H5 | 0.9500 |
C1—N1i | 1.331 (4) | C6—C7 | 1.370 (6) |
C1—H1 | 0.9500 | C7—C8 | 1.391 (6) |
C2—C2i | 1.303 (10) | C7—H7 | 0.9500 |
C2—H2 | 0.9500 | C8—H8 | 0.9500 |
C1—N1—C2 | 106.9 (4) | C5—C4—H4 | 120.1 |
C1—N1—C3 | 125.8 (4) | C6—C5—C4 | 119.2 (4) |
C2—N1—C3 | 127.3 (4) | C6—C5—H5 | 120.4 |
N1—C1—N1i | 109.1 (5) | C4—C5—H5 | 120.4 |
N1—C1—H1 | 125.4 | C7—C6—C5 | 121.1 (4) |
N1i—C1—H1 | 125.4 | C7—C6—Br1 | 119.8 (3) |
C2i—C2—N1 | 108.5 (3) | C5—C6—Br1 | 119.1 (3) |
C2i—C2—H2 | 125.7 | C6—C7—C8 | 120.2 (4) |
N1—C2—H2 | 125.7 | C6—C7—H7 | 119.9 |
C8—C3—C4 | 120.6 (4) | C8—C7—H7 | 119.9 |
C8—C3—N1 | 120.2 (4) | C3—C8—C7 | 119.1 (4) |
C4—C3—N1 | 119.2 (4) | C3—C8—H8 | 120.5 |
C3—C4—C5 | 119.9 (4) | C7—C8—H8 | 120.5 |
C3—C4—H4 | 120.1 | ||
C2—N1—C1—N1i | −0.2 (4) | N1—C3—C4—C5 | 177.9 (4) |
C3—N1—C1—N1i | 178.9 (4) | C3—C4—C5—C6 | 0.2 (7) |
C1—N1—C2—C2i | 0.7 (10) | C4—C5—C6—C7 | 0.5 (7) |
C3—N1—C2—C2i | −178.4 (6) | C4—C5—C6—Br1 | −179.4 (4) |
C1—N1—C3—C8 | −12.5 (5) | C5—C6—C7—C8 | −0.4 (6) |
C2—N1—C3—C8 | 166.4 (5) | Br1—C6—C7—C8 | 179.5 (3) |
C1—N1—C3—C4 | 168.5 (4) | C4—C3—C8—C7 | 1.0 (6) |
C2—N1—C3—C4 | −12.5 (7) | N1—C3—C8—C7 | −177.9 (3) |
C8—C3—C4—C5 | −1.0 (7) | C6—C7—C8—C3 | −0.3 (6) |
Symmetry code: (i) y, x, −z+2. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1o···Cl1ii | 0.84 (6) | 2.28 (6) | 3.1116 (19) | 170 (8) |
O2—H2o···Cl1 | 0.87 (6) | 2.40 (6) | 3.211 (3) | 157 (7) |
C1—H1···O1 | 0.95 | 2.09 | 3.042 (5) | 180 |
C2—H2···O2iii | 0.95 | 2.40 | 3.302 (7) | 159 |
Symmetry codes: (ii) x, y, z+1; (iii) −y+1/2, x+1/2, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C15H11Br2N2+·Cl−·2H2O |
Mr | 450.56 |
Crystal system, space group | Tetragonal, P42212 |
Temperature (K) | 120 |
a, c (Å) | 17.8377 (7), 5.1270 (1) |
V (Å3) | 1631.33 (10) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 5.14 |
Crystal size (mm) | 0.40 × 0.03 × 0.02 |
Data collection | |
Diffractometer | Nonius KappaCCD |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2007) |
Tmin, Tmax | 0.665, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13675, 1885, 1654 |
Rint | 0.048 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.032, 0.075, 1.06 |
No. of reflections | 1885 |
No. of parameters | 108 |
No. of restraints | 2 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.40, −0.69 |
Absolute structure | Flack (1983), 742 Friedel pairs |
Absolute structure parameter | 0.01 (2) |
Computer programs: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1o···Cl1i | 0.84 (6) | 2.28 (6) | 3.1116 (19) | 170 (8) |
O2—H2o···Cl1 | 0.87 (6) | 2.40 (6) | 3.211 (3) | 157 (7) |
C1—H1···O1 | 0.95 | 2.09 | 3.042 (5) | 180 |
C2—H2···O2ii | 0.95 | 2.40 | 3.302 (7) | 159 |
Symmetry codes: (i) x, y, z+1; (ii) −y+1/2, x+1/2, z−1/2. |
Footnotes
‡Additional correspondence author, e-mail: j.wardell@abdn.ac.uk.
Acknowledgements
The use of the EPSRC X-ray crystallographic service at the University of Southampton, England, and the valuable assistance of the staff there is gratefully acknowledged. SJG thanks CNPq and FAPERJ for financial support. JLW acknowledges support from CAPES and FAPEMIG (Brazil).
References
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The deprotonation of N,N-disubstituted imidazolium salts has been extensively used to generate imidazolylidene carbenes for use as ligands for metals or their salts in homogeneous catalysis (Nolan, 2006; Glorius, 2007). The structural motif can be readily varied so as to modify the electronic properties of the carbene and their complexes (Alcarazo et al., 2010; Leuthaeusser et al., 2007; Diez-Gonzalez & Nolan, 2007). Whereas structural studies are available for a number of derivatives (Luger & Ruban, 1975; Cole & Junk, 2004; Wan et al., 2008), little is known about simple 1,3-diphenyl derivatives that do not posses substituents in the 2,6-positions of the phenyl rings. As part of a study into structural effects of these carbenes, we have been able to prepare and crystallize for the first time the salt 1,3-di-(4-bromophenyl)imidazolium chloride, isolated as a dihydrate, (I).
The crystallographic asymmetric unit of (I) comprises half a 1,3-di-(4-bromophenyl)imidazolium cation, Fig. 1, half a chloride, and two half water molecules, as each of the aforementioned species lies on a two-fold axis of symmetry. The cation is non-planar with the dihedral angle formed between the central imidazolium ring [r.m.s. deviation = 0.005 Å] and the benzene ring (C3–C8) being 12.9 (3) °; the dihedral angle formed between the symmetry related benzene rings is 25.60 (13) °. The twists between the rings allows for the close approach of a water molecule allowing the formation of a C1—H···O1 interaction, Table 1. This O1-water molecule also forms O–H···Cl interactions with the chloride which in turn is connected to the second water molecule leading to eight-membered {···HOH···Cl}2 synthons aligned along the c axis, Fig. 2 and Table 1. The three-dimensional packing is consolidated by further C–H···O2 interactions, Fig. 3, as well as π–π contacts (along c) between the imidazolium and between rings [ring centroid···ring centroid distance = 3.687 (3) Å, angle of inclination = 12.9 (3) ° for i: x, y, 1+z].