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access1-Bromomethyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide
aUniversity of Illinois, School of Chemical Sciences, Box 77-5, 600 South Mathews Avenue, Urbana, Illinois 61801, USA, bUniversity of Illinois, School of Chemical Sciences, Box 59-1, 505 South Mathews Avenue, Urbana, Illinois 61801, USA, and cUniversity of Illinois, School of Chemical Sciences, Box 55-5, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
*Correspondence e-mail: jsmoore@illinois.edu
The title compound, C7H14BrN2+·Br−, was prepared by nucleophilic substitution of DABCO (systematic name: 1,4-diazabicyclo[2.2.2]octane) with dibromomethane in acetone. The structure features Br⋯H close contacts (2.79 and 2.90 Å) as well as a weak bromine–bromide interaction [3.6625 (6) Å].
Related literature
For use of DABCO as an organocatalyst, see Basaviah et al. (2003![[Basaviah, D., Rao, A. J. & Satyanarayana, T. (2003). Chem. Rev. 103, 811-891.]](../../../../../../logos/arrows/e_arr.gif "Basaviah, D., Rao, A. J. & Satyanarayana, T. (2003). Chem. Rev. 103, 811-891.")
). For related haloalkylations of DABCO, see: Almarzoqi et al. (1986); Fronczek et al. (1990); Gustafsson et al. (2005); Banks et al. (1993); Batsanov et al. (2005); Fletcher Claville et al. (2007). For inversion see: Flack & Bernardinelli (2000).
![[Scheme 1]](pk2223scheme1.gif)
Experimental
Crystal data
|
Data collection: APEX2 (Bruker, 2004); cell SAINT (Bruker, 2005); data reduction: SAINT and XPREP (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and CrystalMaker (CrystalMaker, 1994); software used to prepare material for publication: XCIF (Bruker, 2005).
Supporting information
contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536810000292/pk2223sup1.cif
Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810000292/pk2223Isup2.hkl
Dibromomethane (10 mmol) was added to a solution of DABCO (10 mmol) in acetone (100 ml). Colorless plates of poor quality evolve almost immediately, which after 1 h are filtered. The filtrate is sealed in a flask and left to sit for 1 week, after which prisms suitable for X-ray analysis form on the side of the flask.
A structural model consisting of one symmetrically independent molecule was developed. All non-hydrogen atoms were refined with anisotropic displacement parameters. All hydrogen atoms were placed in ideal positions and refined as riding atoms. The ideally calculated H atoms on C1, C2, and C5 are related by the (1 - x, y, z). For these H atoms the special position constraints were suppressed to allow for the correct calculation of the idealized H atom positions. For all H atoms the Uiso values were assigned as 1.2 times the carrier Ueq. On the basis of 468 unmerged Friedel opposites, the likelihood of inversion is negligible (Flack, 1983; Flack& Bernardinelli, 2000).
The nucleophilicity of 1,4-diazabicyclo[2.2.2]octane (DABCO) has enabled it to be an excellent organocatalyst for a variety of reactions, in particular the Baylis-Hillman reaction (Basaviah et al., 2003). Furthermore, DABCO can undergo substitution with even relatively unreactive electrophiles such as dichloromethane (Almarzoqi et al., 1986).
We have isolated crystals of the title compound of sufficient quality for crystallographic analysis. Typically, the reaction between dibromomethane and DABCO proceeds quickly in acetone, resulting in the immediate precipitation of the monoalkylated bromide salt that is insoluble in acetone. However, at sufficiently low concentrations of reactants, slow crystallization of the product occurs.
The title molecule crystallizes in a non-centrosymmetric Cmc21. One notable feature of this structure is a close contact between free bromide and the bromomethyl hydrogen (Br2···H5A) of 2.794 (3) Å. Another close contact for H4B···Br2 (2.899 (3) Å) was found. There is also a relatively close contact between the covalently-bound bromine and bromide anion (Br1···Br2 3.6625 (6) Å). However, this distance is significantly longer than the Br···Br interaction seen in a related structure, (bromomethyl)trimethylammonium bromide (Br···Br = 3.369 Å) (Fletcher Claville et al. 2007).
For use of DABCO as an organocatalyst, see Basaviah et al. (2003). For related haloalkylations of DABCO, see: Almarzoqi et al. (1986); Fronczek et al. (1990); Gustafsson et al. (2005); Banks et al. (1993); Batsanov et al. (2005); Fletcher Claville et al. (2007). For inversion see: Flack & Bernardinelli (2000).
Data collection: APEX2 (Bruker, 2004); cell SAINT (Bruker, 2005); data reduction: SAINT and XPREP (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and CrystalMaker (CrystalMaker, 1994); software used to prepare material for publication: XCIF (Bruker, 2005).
![[Figure 1]](./pk2223fig1thm.gif) | Fig. 1. Thermal ellipsoid plot showing non-H atoms at 35% probability and H atoms as arbitrary small spheres. The atoms labeled A are related by the symmetry operator (1 - x, y, z). |
![[Figure 2]](./pk2223fig2thm.gif) | Fig. 2. A packing plot of the unit cell as viewed down the a-axis showing 35% probability ellipsoids for non-H atoms. H atoms have been removed to improve clarity. |
| C7H14BrN2+·Br− | F(000) = 560 |
| Mr = 286.02 | Dx = 1.922 Mg m−3 |
| Orthorhombic, Cmc21 | Mo Kα radiation, λ = 0.71073 Å |
| Hall symbol: C 2c -2 | Cell parameters from 3160 reflections |
| a = 7.1100 (3) Å | θ = 3.3–26.3° |
| b = 11.8085 (5) Å | µ = 8.15 mm−1 |
| c = 11.7702 (5) Å | T = 193 K |
| V = 988.21 (7) Å3 | Plate, colourless |
| Z = 4 | 0.36 × 0.35 × 0.06 mm |
| Bruker Kappa APEXII CCD diffractometer | 991 independent reflections |
| Radiation source: fine-focus sealed tube | 954 reflections with I > 2σ(I) |
| Graphite monochromator | Rint = 0.050 |
| φ and ω scans | θmax = 25.4°, θmin = 3.3° |
| Absorption correction: integration (SHELXTL and XPREP; Bruker, 2005) | h = −8→8 |
| Tmin = 0.151, Tmax = 0.744 | k = −14→14 |
| 7347 measured reflections | l = −14→14 |
| 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)] = 0.022 | H-atom parameters constrained |
| wR(F2) = 0.052 | w = 1/[σ2(Fo2) + (0.0248P)2] where P = (Fo2 + 2Fc2)/3 |
| S = 1.10 | (Δ/σ)max < 0.001 |
| 991 reflections | Δρmax = 0.42 e Å−3 |
| 61 parameters | Δρmin = −0.44 e Å−3 |
| 1 restraint | Absolute structure: Flack (1983), 468 Friedel pairs |
| Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.004 (17) |
| C7H14BrN2+·Br− | V = 988.21 (7) Å3 |
| Mr = 286.02 | Z = 4 |
| Orthorhombic, Cmc21 | Mo Kα radiation |
| a = 7.1100 (3) Å | µ = 8.15 mm−1 |
| b = 11.8085 (5) Å | T = 193 K |
| c = 11.7702 (5) Å | 0.36 × 0.35 × 0.06 mm |
| Bruker Kappa APEXII CCD diffractometer | 991 independent reflections |
| Absorption correction: integration (SHELXTL and XPREP; Bruker, 2005) | 954 reflections with I > 2σ(I) |
| Tmin = 0.151, Tmax = 0.744 | Rint = 0.050 |
| 7347 measured reflections |
| R[F2 > 2σ(F2)] = 0.022 | H-atom parameters constrained |
| wR(F2) = 0.052 | Δρmax = 0.42 e Å−3 |
| S = 1.10 | Δρmin = −0.44 e Å−3 |
| 991 reflections | Absolute structure: Flack (1983), 468 Friedel pairs |
| 61 parameters | Absolute structure parameter: −0.004 (17) |
| 1 restraint |
Experimental. One distinct cell was identified using APEX2 (Bruker, 2004). Seven frame series were integrated and filtered for statistical outliers using SAINT (Bruker, 2005) then corrected for absorption by integration using SHELXTL/XPREP V2005/2 (Bruker, 2005) before using SAINT/SADABS (Bruker, 2005) to sort, merge, and scale the combined data. No decay correction was applied. |
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. Structure was phased by direct methods (Sheldrick, 2008). Systematic conditions suggested the ambiguous space group. The space group choice was confirmed by successful convergence of the full-matrix least-squares refinement on F2. The highest peaks in the final difference Fourier map were in the vicinity of atoms Br1 and Br2; the final map had no other significant features. A final analysis of variance between observed and calculated structure factors showed some dependence on amplitude and resolution. |
| x | y | z | Uiso*/Ueq | Occ. (<1) | |
| Br1 | 0.5000 | 0.14054 (4) | −0.05638 (4) | 0.03174 (19) | |
| Br2 | 0.0000 | 0.65245 (4) | 0.34152 (3) | 0.02920 (17) | |
| N1 | 0.5000 | 0.5040 (4) | 0.1977 (4) | 0.0281 (9) | |
| N2 | 0.5000 | 0.3707 (3) | 0.0253 (3) | 0.0188 (8) | |
| C1 | 0.5000 | 0.5692 (5) | 0.0917 (5) | 0.0360 (13) | |
| H1A | 0.6126 | 0.6185 | 0.0898 | 0.043* | 0.50 |
| H1B | 0.3874 | 0.6185 | 0.0898 | 0.043* | 0.50 |
| C2 | 0.5000 | 0.4932 (4) | −0.0128 (4) | 0.0291 (12) | |
| H2A | 0.3871 | 0.5086 | −0.0595 | 0.035* | 0.50 |
| H2B | 0.6129 | 0.5086 | −0.0595 | 0.035* | 0.50 |
| C3 | 0.3326 (5) | 0.4320 (3) | 0.1979 (3) | 0.0369 (9) | |
| H3A | 0.2189 | 0.4804 | 0.1960 | 0.044* | |
| H3B | 0.3294 | 0.3875 | 0.2691 | 0.044* | |
| C4 | 0.3283 (5) | 0.3507 (3) | 0.0964 (3) | 0.0264 (8) | |
| H4A | 0.3263 | 0.2714 | 0.1236 | 0.032* | |
| H4B | 0.2137 | 0.3640 | 0.0506 | 0.032* | |
| C5 | 0.5000 | 0.3026 (4) | −0.0825 (4) | 0.0234 (10) | |
| H5A | 0.6125 | 0.3229 | −0.1278 | 0.028* | 0.50 |
| H5B | 0.3875 | 0.3229 | −0.1278 | 0.028* | 0.50 |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Br1 | 0.0285 (4) | 0.0282 (3) | 0.0385 (4) | 0.000 | 0.000 | −0.0120 (3) |
| Br2 | 0.0230 (3) | 0.0325 (3) | 0.0321 (4) | 0.000 | 0.000 | 0.0042 (3) |
| N1 | 0.037 (2) | 0.027 (2) | 0.021 (2) | 0.000 | 0.000 | −0.0071 (18) |
| N2 | 0.021 (2) | 0.023 (2) | 0.013 (2) | 0.000 | 0.000 | −0.0006 (16) |
| C1 | 0.046 (3) | 0.024 (3) | 0.038 (3) | 0.000 | 0.000 | −0.005 (2) |
| C2 | 0.042 (3) | 0.023 (3) | 0.022 (3) | 0.000 | 0.000 | 0.006 (2) |
| C3 | 0.039 (2) | 0.037 (2) | 0.034 (2) | −0.0058 (18) | 0.0135 (16) | −0.0103 (18) |
| C4 | 0.0189 (18) | 0.035 (2) | 0.0254 (17) | −0.0029 (15) | 0.0062 (12) | −0.0040 (13) |
| C5 | 0.032 (3) | 0.025 (2) | 0.013 (2) | 0.000 | 0.000 | −0.0048 (18) |
| Br1—C5 | 1.938 (5) | C3—C4 | 1.532 (4) |
| N1—C3i | 1.463 (4) | C3—H3A | 0.9900 |
| N1—C3 | 1.464 (4) | C3—H3B | 0.9900 |
| N1—C1 | 1.466 (6) | C4—H4A | 0.9900 |
| N2—C4 | 1.499 (4) | C4—H4B | 0.9900 |
| N2—C4i | 1.499 (4) | C5—H5A | 0.9900 |
| N2—C5 | 1.502 (6) | C5—H5B | 0.9900 |
| N2—C2 | 1.514 (6) | Br1—Br2ii | 3.6625 (6) |
| C1—C2 | 1.522 (7) | Br2—H5Aiii | 2.79 |
| C1—H1A | 0.9900 | Br2—H5Biv | 2.79 |
| C1—H1B | 0.9900 | Br2—H4Bv | 2.90 |
| C2—H2A | 0.9900 | Br2—H4Biv | 2.90 |
| C2—H2B | 0.9900 | ||
| C3i—N1—C3 | 108.9 (4) | H2A—C2—H2B | 108.3 |
| C3i—N1—C1 | 107.8 (3) | N1—C3—C4 | 112.3 (3) |
| C3—N1—C1 | 107.8 (3) | N1—C3—H3A | 109.1 |
| C4—N2—C4i | 109.1 (4) | C4—C3—H3A | 109.1 |
| C4—N2—C5 | 112.8 (2) | N1—C3—H3B | 109.1 |
| C4i—N2—C5 | 112.8 (2) | C4—C3—H3B | 109.1 |
| C4—N2—C2 | 108.4 (2) | H3A—C3—H3B | 107.9 |
| C4i—N2—C2 | 108.4 (2) | N2—C4—C3 | 108.7 (3) |
| C5—N2—C2 | 105.2 (3) | N2—C4—H4A | 109.9 |
| N1—C1—C2 | 112.2 (4) | C3—C4—H4A | 109.9 |
| N1—C1—H1A | 109.2 | N2—C4—H4B | 109.9 |
| C2—C1—H1A | 109.2 | C3—C4—H4B | 109.9 |
| N1—C1—H1B | 109.2 | H4A—C4—H4B | 108.3 |
| C2—C1—H1B | 109.2 | N2—C5—Br1 | 113.2 (3) |
| H1A—C1—H1B | 107.9 | N2—C5—H5A | 108.9 |
| N2—C2—C1 | 108.9 (4) | Br1—C5—H5A | 108.9 |
| N2—C2—H2A | 109.9 | N2—C5—H5B | 108.9 |
| C1—C2—H2A | 109.9 | Br1—C5—H5B | 108.9 |
| N2—C2—H2B | 109.9 | H5A—C5—H5B | 107.7 |
| C1—C2—H2B | 109.9 | ||
| C3i—N1—C1—C2 | 58.7 (2) | C4i—N2—C4—C3 | 59.3 (4) |
| C3—N1—C1—C2 | −58.7 (2) | C5—N2—C4—C3 | −174.6 (3) |
| C4—N2—C2—C1 | 59.1 (2) | C2—N2—C4—C3 | −58.6 (3) |
| C4i—N2—C2—C1 | −59.1 (2) | N1—C3—C4—N2 | −0.5 (4) |
| C5—N2—C2—C1 | 180.0 | C4—N2—C5—Br1 | −62.1 (2) |
| N1—C1—C2—N2 | 0.0 | C4i—N2—C5—Br1 | 62.1 (2) |
| C3i—N1—C3—C4 | −57.5 (5) | C2—N2—C5—Br1 | 180.0 |
| C1—N1—C3—C4 | 59.2 (4) |
| Symmetry codes: (i) −x+1, y, z; (ii) −x+1/2, −y+1/2, z−1/2; (iii) −x+1, −y+1, z+1/2; (iv) −x, −y+1, z+1/2; (v) x, −y+1, z+1/2. |
Experimental details
| Crystal data | |
| Chemical formula | C7H14BrN2+·Br− |
| Mr | 286.02 |
| Crystal system, space group | Orthorhombic, Cmc21 |
| Temperature (K) | 193 |
| a, b, c (Å) | 7.1100 (3), 11.8085 (5), 11.7702 (5) |
| V (Å3) | 988.21 (7) |
| Z | 4 |
| Radiation type | Mo Kα |
| µ (mm−1) | 8.15 |
| Crystal size (mm) | 0.36 × 0.35 × 0.06 |
| Data collection | |
| Diffractometer | Bruker Kappa APEXII CCD |
| Absorption correction | Integration (SHELXTL and XPREP; Bruker, 2005) |
| Tmin, Tmax | 0.151, 0.744 |
| No. of measured, independent and observed [I > 2σ(I)] reflections | 7347, 991, 954 |
| Rint | 0.050 |
| (sin θ/λ)max (Å−1) | 0.603 |
| Refinement | |
| R[F2 > 2σ(F2)], wR(F2), S | 0.022, 0.052, 1.10 |
| No. of reflections | 991 |
| No. of parameters | 61 |
| No. of restraints | 1 |
| H-atom treatment | H-atom parameters constrained |
| Δρmax, Δρmin (e Å−3) | 0.42, −0.44 |
| Absolute structure | Flack (1983), 468 Friedel pairs |
| Absolute structure parameter | −0.004 (17) |
Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2005), SAINT and XPREP (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and CrystalMaker (CrystalMaker, 1994), XCIF (Bruker, 2005).
Acknowledgements
This work was supported by the National Science Foundation under NSF Award Nos. CBET-0730667 and CHE-0642413. The Materials Chemistry Laboratory at the University of Illinois was supported in part by grants NSF CHE 95–03145 and NSF CHE 03–43032 from the National Science Foundation.
References
Almarzoqi, B., George, A. V. & Isaacs, N. S. (1986). Tetrahedron Lett. 42, 601–607. CrossRef CAS Google Scholar
Banks, R. E., Sharif, I. & Pritchard, R. G. (1993). Acta Cryst. C49, 492–495. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Basaviah, D., Rao, A. J. & Satyanarayana, T. (2003). Chem. Rev. 103, 811–891. Web of Science PubMed Google Scholar
Batsanov, A. S., Trmcic, J. & Sandford, G. (2005). Acta Cryst. E61, o681–o682. Web of Science CSD CrossRef IUCr Journals Google Scholar
Bruker (2004). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2005). SAINT, XCIF and XPREP. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
CrystalMaker (1994). CrystalMaker. CrystalMaker Software Ltd, Oxford, England. www.CrystalMaker.com. Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Flack, H. D. & Bernardinelli, G. (2000). J. Appl. Cryst. 33, 1143–1148. Web of Science CrossRef CAS IUCr Journals Google Scholar
Fletcher Claville, M. O., Payne, R. J., Parker, B. C. & Fronczek, F. R. (2007). Acta Cryst. E63, o2601. Web of Science CSD CrossRef IUCr Journals Google Scholar
Fronczek, F. R., Ivie, M. L. & Maverick, A. W. (1990). Acta Cryst. C46, 2057–2062. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Gustafsson, B., Håkansson, M. & Jagner, S. (2005). Inorg. Chim. Acta, 358, 1309–1312. 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
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| CRYSTALLOGRAPHIC COMMUNICATIONS |
The nucleophilicity of 1,4-diazabicyclo[2.2.2]octane (DABCO) has enabled it to be an excellent organocatalyst for a variety of reactions, in particular the Baylis-Hillman reaction (Basaviah et al., 2003). Furthermore, DABCO can undergo substitution with even relatively unreactive electrophiles such as dichloromethane (Almarzoqi et al., 1986).
We have isolated crystals of the title compound of sufficient quality for crystallographic analysis. Typically, the reaction between dibromomethane and DABCO proceeds quickly in acetone, resulting in the immediate precipitation of the monoalkylated bromide salt that is insoluble in acetone. However, at sufficiently low concentrations of reactants, slow crystallization of the product occurs.
The title molecule crystallizes in a non-centrosymmetric space group, Cmc21. One notable feature of this structure is a close contact between free bromide and the bromomethyl hydrogen (Br2···H5A) of 2.794 (3) Å. Another close contact for H4B···Br2 (2.899 (3) Å) was found. There is also a relatively close contact between the covalently-bound bromine and bromide anion (Br1···Br2 3.6625 (6) Å). However, this distance is significantly longer than the Br···Br interaction seen in a related structure, (bromomethyl)trimethylammonium bromide (Br···Br = 3.369 Å) (Fletcher Claville et al. 2007).