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Acta Crystallogr Sect E Struct Rep Online. 2010 June 1; 66(Pt 6): o1438–o1439.
Published online 2010 May 22. doi:  10.1107/S1600536810018581
PMCID: PMC2979370

1,3-Bis(4-bromo­phen­yl)imidazolium chloride dihydrate

Abstract

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 carbenes, see: Nolan (2006 [triangle]); Diez-Gonzalez & Nolan (2007 [triangle]); Glorius (2007 [triangle]); Leuthaeusser et al. (2007 [triangle]); Alcarazo et al. (2010 [triangle]). For related structures, see: Luger & Ruban (1975 [triangle]); Cole & Junk (2004 [triangle]); Wan et al. (2008 [triangle]).

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Object name is e-66-o1438-scheme1.jpg

Experimental

Crystal data

  • C15H11Br2N2 +·Cl·2H2O
  • M r = 450.56
  • Tetragonal, An external file that holds a picture, illustration, etc.
Object name is e-66-o1438-efi1.jpg
  • a = 17.8377 (7) Å
  • c = 5.1270 (1) Å
  • V = 1631.33 (10) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 5.14 mm−1
  • T = 120 K
  • 0.40 × 0.03 × 0.02 mm

Data collection

  • Nonius KappaCCD diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2007 [triangle]) T min = 0.665, T max = 1.000
  • 13675 measured reflections
  • 1885 independent reflections
  • 1654 reflections with I > 2σ(I)
  • R int = 0.048

Refinement

  • R[F 2 > 2σ(F 2)] = 0.032
  • wR(F 2) = 0.075
  • S = 1.06
  • 1885 reflections
  • 108 parameters
  • 2 restraints
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.40 e Å−3
  • Δρmin = −0.69 e Å−3
  • Absolute structure: Flack (1983 [triangle]), 742 Friedel pairs
  • Flack parameter: 0.01 (2)

Data collection: COLLECT (Hooft, 1998 [triangle]); cell refinement: DENZO (Otwinowski & Minor, 1997 [triangle]) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 (Farrugia, 1997 [triangle]) and DIAMOND (Brandenburg, 2006 [triangle]); software used to prepare material for publication: publCIF (Westrip, 2010 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810018581/hb5456sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810018581/hb5456Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

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).

supplementary crystallographic information

Comment

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].

Experimental

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.

Refinement

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).

Figures

Fig. 1.
The molecular structure of the cation in (I) showing displacement ellipsoids at the 50% probability level. The C1 atom lies on a two-fold axis. Symmetry operation i: y, x, 2-z.
Fig. 2.
A view highlighting the eight-membered {···HOH···Cl}2 synthons aligned along the c axis in (I). The O–H···O hydrogen bonding and C–H···O interactions ...
Fig. 3.
A view in projection down the c axis of the crystal packing in (I). The O–H···O hydrogen bonding and C–H···O interactions are shown as orange and blue dashed lines, respectively. Colour code: ...

Crystal data

C15H11Br2N2+·Cl·2H2ODx = 1.835 Mg m3
Mr = 450.56Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P42212Cell parameters from 2084 reflections
Hall symbol: P 4n 2nθ = 2.9–27.5°
a = 17.8377 (7) ŵ = 5.14 mm1
c = 5.1270 (1) ÅT = 120 K
V = 1631.33 (10) Å3Needle, colourless
Z = 40.40 × 0.03 × 0.02 mm
F(000) = 888

Data collection

Nonius KappaCCD diffractometer1885 independent reflections
Radiation source: Enraf Nonius FR591 rotating anode1654 reflections with I > 2σ(I)
10 cm confocal mirrorsRint = 0.048
Detector resolution: 9.091 pixels mm-1θmax = 27.5°, θmin = 3.2°
[var phi] and ω scansh = −23→23
Absorption correction: multi-scan (SADABS; Sheldrick, 2007)k = −14→23
Tmin = 0.665, Tmax = 1.000l = −6→6
13675 measured reflections

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.032H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.075w = 1/[σ2(Fo2) + (0.0285P)2 + 2.7306P] where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max = 0.001
1885 reflectionsΔρmax = 0.40 e Å3
108 parametersΔρmin = −0.69 e Å3
2 restraintsAbsolute structure: Flack (1983), 742 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: 0.01 (2)

Special details

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.

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

xyzUiso*/Ueq
Br10.100493 (18)0.463088 (18)0.00124 (12)0.02761 (11)
Cl10.13502 (7)0.13502 (7)0.50000.0552 (4)
O10.20493 (17)0.20493 (17)1.00000.0681 (15)
H1O0.186 (5)0.181 (5)1.125 (8)0.102*
O20.0584 (3)0.0584 (3)1.00000.0794 (16)
H2O0.067 (5)0.087 (4)0.867 (10)0.119*
N10.32639 (19)0.38584 (18)0.8472 (7)0.0274 (7)
C10.32553 (19)0.32553 (19)1.00000.0270 (9)
H10.28790.28791.00000.032*
C20.3893 (3)0.4253 (3)0.9090 (14)0.083 (3)
H20.40440.47140.83220.100*
C30.2714 (2)0.4041 (2)0.6525 (7)0.0252 (8)
C40.2720 (2)0.4748 (2)0.5411 (11)0.0382 (13)
H40.30750.51110.59740.046*
C50.2207 (3)0.4925 (3)0.3464 (9)0.0369 (10)
H50.22090.54080.26850.044*
C60.1696 (2)0.4391 (2)0.2680 (7)0.0267 (9)
C70.1683 (2)0.3694 (2)0.3799 (8)0.0265 (9)
H70.13250.33340.32410.032*
C80.2194 (2)0.3512 (2)0.5749 (8)0.0289 (10)
H80.21850.30300.65360.035*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br10.02725 (18)0.0350 (2)0.02061 (17)0.00424 (13)−0.0019 (3)0.0025 (3)
Cl10.0652 (6)0.0652 (6)0.0352 (8)−0.0031 (8)0.0037 (10)−0.0037 (10)
O10.079 (2)0.079 (2)0.046 (3)−0.049 (3)−0.009 (4)0.009 (4)
O20.080 (2)0.080 (2)0.078 (4)0.008 (3)0.018 (4)−0.018 (4)
N10.0252 (17)0.0274 (18)0.0296 (19)0.0075 (14)−0.0003 (15)0.0059 (15)
C10.0298 (14)0.0298 (14)0.021 (2)0.0017 (19)−0.005 (3)0.005 (3)
C20.056 (3)0.061 (3)0.132 (7)−0.030 (3)−0.064 (4)0.064 (4)
C30.0245 (19)0.030 (2)0.021 (2)0.0066 (16)0.0005 (15)0.0017 (16)
C40.038 (2)0.033 (2)0.044 (4)−0.0073 (16)−0.011 (2)0.011 (2)
C50.038 (2)0.033 (2)0.039 (3)−0.0040 (19)−0.013 (2)0.014 (2)
C60.0221 (19)0.036 (2)0.0219 (19)0.0067 (16)0.0002 (15)0.0025 (16)
C70.0219 (19)0.027 (2)0.030 (2)0.0039 (16)0.0048 (17)−0.0021 (17)
C80.026 (2)0.029 (2)0.032 (3)0.0052 (16)0.0026 (15)0.0037 (15)

Geometric parameters (Å, °)

Br1—C61.890 (4)C3—C81.383 (6)
O1—H1O0.84 (6)C3—C41.383 (6)
O2—H2O0.87 (6)C4—C51.391 (6)
N1—C11.331 (4)C4—H40.9500
N1—C21.362 (6)C5—C61.378 (6)
N1—C31.437 (5)C5—H50.9500
C1—N1i1.331 (4)C6—C71.370 (6)
C1—H10.9500C7—C81.391 (6)
C2—C2i1.303 (10)C7—H70.9500
C2—H20.9500C8—H80.9500
C1—N1—C2106.9 (4)C5—C4—H4120.1
C1—N1—C3125.8 (4)C6—C5—C4119.2 (4)
C2—N1—C3127.3 (4)C6—C5—H5120.4
N1—C1—N1i109.1 (5)C4—C5—H5120.4
N1—C1—H1125.4C7—C6—C5121.1 (4)
N1i—C1—H1125.4C7—C6—Br1119.8 (3)
C2i—C2—N1108.5 (3)C5—C6—Br1119.1 (3)
C2i—C2—H2125.7C6—C7—C8120.2 (4)
N1—C2—H2125.7C6—C7—H7119.9
C8—C3—C4120.6 (4)C8—C7—H7119.9
C8—C3—N1120.2 (4)C3—C8—C7119.1 (4)
C4—C3—N1119.2 (4)C3—C8—H8120.5
C3—C4—C5119.9 (4)C7—C8—H8120.5
C3—C4—H4120.1
C2—N1—C1—N1i−0.2 (4)N1—C3—C4—C5177.9 (4)
C3—N1—C1—N1i178.9 (4)C3—C4—C5—C60.2 (7)
C1—N1—C2—C2i0.7 (10)C4—C5—C6—C70.5 (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—C8166.4 (5)Br1—C6—C7—C8179.5 (3)
C1—N1—C3—C4168.5 (4)C4—C3—C8—C71.0 (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 codes: (i) y, x, −z+2.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O1—H1o···Cl1ii0.84 (6)2.28 (6)3.1116 (19)170 (8)
O2—H2o···Cl10.87 (6)2.40 (6)3.211 (3)157 (7)
C1—H1···O10.952.093.042 (5)180
C2—H2···O2iii0.952.403.302 (7)159

Symmetry codes: (ii) x, y, z+1; (iii) −y+1/2, x+1/2, z−1/2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB5456).

References

  • Alcarazo, M., Stork, T., Anoop, A., Thiel, W. & Fürstner, A. (2010). Angew. Chem. Int. Ed 49, 2542–2546. [PubMed]
  • Brandenburg, K. (2006). DIAMOND Crystal Impact GbR, Bonn, Germany.
  • Cole, M. L. & Junk, P. C. (2004). CrystEngComm, 6, 173–176.
  • Diez-Gonzalez, S. & Nolan, S. P. (2007). Coord. Chem. Rev 251, 874–883.
  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Flack, H. D. (1983). Acta Cryst. A39, 876–881.
  • Glorius, F. (2007). N-Heterocyclic Carbenes in Transition Metal Catalysis. In Topics Organometallic Chemistry, Vol. 21, pp. 1–218. Berlin: Springer.
  • Hooft, R. W. W. (1998). COLLECT Nonius BV, Delft, The Netherlands.
  • Leuthaeusser, S., Schwarz, D. & Plenio, H. (2007). Chem. Eur. J 13, 7195–7203. [PubMed]
  • Luger, P. & Ruban, G. (1975). Z. Kristallogr 142, 177–185.
  • Nolan, S. P. (2006). N-Heterocyclic Carbenes in Synthesis, pp. 1–304. Weinheim: Wiley–VCH.
  • Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.
  • Sheldrick, G. M. (2007). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Wan, Y., Xin, H., Chen, X., Xu, H. & Wu, H. (2008). Acta Cryst. E64, o2159. [PMC free article] [PubMed]
  • Westrip, S. P. (2010). J. Appl. Cryst.43 Submitted.

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