organic compounds
3-(1-Methyl-3-imidazolio)propanesulfonate: a precursor to a Brønsted acid ionic liquid
aDepartment of Chemistry, US Naval Academy, 572 M. Holloway Road, Annapolis, Maryland 21402, USA, and bAir Force Office of Scientific Research, 4015 Wilson Boulevard, Arlington, Virginia 22203, USA
*Correspondence e-mail: trulove@usna.edu
The title compound, C7H12N2O3S, is a zwitterion precursor to a Brønsted acid ionic liquid with potential as an acid catalyst. The C—N—C—C torsion angle of 100.05 (8)° allows the positively charged imidazolium head group and the negatively charged sulfonate group to interact with neighboring forming a C—H⋯O hydrogen-bonding network; the shortest among these interactions is 2.9512 (9) Å. The C—H⋯O interactions can be described by graph-set notation as two R22(16) and one R22(5) hydrogen-bonded rings.
Related literature
For the use of functionalized ionic liquids (ILs) as Brønsted acid catalysts for organic reactions, see: Cole et al. (2002); Yoshizawa et al. (2001). The local structure of ILs is often conserved on transition from the solid state to the liquid state, see: Henderson et al. (2007); Reichert et al. (2007); Triolo et al. (2006). For a related structure, see: Pringle et al. (2003). For polymorphs of ionic liquids, see: Holbrey et al. (2003) and for the applications of ionic liquids, see: Plechkova & Seddon (2008).
Experimental
Crystal data
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Refinement
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Data collection: SMART (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536810004344/kp2241sup1.cif
contains datablocks I, New_Global_Publ_Block. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536810004344/kp2241Isup2.hkl
Compound I was synthesized following the procedure for similar
published by (Yoshizawa et al., 2001). 1,3-Propane sultone (25 g, 0.122 mol) was added dropwise to a solution of 1-methylimidazole (10 g, 0.122 mol) in acetone (40 ml) and stirred, then cooled on an ice bath overnight. A white precipitate was recovered from the reaction solution through filtration and washing with acetone. The product was then dried under vacuum giving a white solid (m.p. 482 K). A colourless crystal suitable for single crystal X-ray diffraction was retrieved from the dried product.Data collection: SMART (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).Fig. 1. The thermal ellipsiod plot of the asymmetric unit of (I). The displacement ellipsiods are shown at the 50% probability level. | |
Fig. 2. Close contacts in compound I. | |
Fig. 3. Packing diagram along the b axis. | |
Fig. 4. Reaction scheme. |
C7H12N2O3S | F(000) = 432 |
Mr = 204.25 | Dx = 1.481 Mg m−3 |
Monoclinic, P21/c | Melting point: 482 K |
Hall symbol: -P 2ybc | Mo Kα radiation, λ = 0.71073 Å |
a = 9.8164 (4) Å | Cell parameters from 4851 reflections |
b = 11.7421 (5) Å | θ = 3.1–41.1° |
c = 7.9769 (3) Å | µ = 0.33 mm−1 |
β = 94.878 (2)° | T = 296 K |
V = 916.13 (6) Å3 | Plate, colourless |
Z = 4 | 0.29 × 0.28 × 0.13 mm |
Bruker SMART CCD area-detector diffractometer | 8299 independent reflections |
Radiation source: fine-focus sealed tube | 5726 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.033 |
phi and ω scans | θmax = 47.1°, θmin = 3.1° |
Absorption correction: for a sphere (SADABS; Bruker, 2007) | h = −20→13 |
Tmin = 0.910, Tmax = 0.958 | k = −19→24 |
21327 measured reflections | l = −16→16 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.120 | All H-atom parameters refined |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0574P)2 + 0.0483P] where P = (Fo2 + 2Fc2)/3 |
8299 reflections | (Δ/σ)max = 0.002 |
166 parameters | Δρmax = 0.55 e Å−3 |
0 restraints | Δρmin = −0.47 e Å−3 |
C7H12N2O3S | V = 916.13 (6) Å3 |
Mr = 204.25 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 9.8164 (4) Å | µ = 0.33 mm−1 |
b = 11.7421 (5) Å | T = 296 K |
c = 7.9769 (3) Å | 0.29 × 0.28 × 0.13 mm |
β = 94.878 (2)° |
Bruker SMART CCD area-detector diffractometer | 8299 independent reflections |
Absorption correction: for a sphere (SADABS; Bruker, 2007) | 5726 reflections with I > 2σ(I) |
Tmin = 0.910, Tmax = 0.958 | Rint = 0.033 |
21327 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 0 restraints |
wR(F2) = 0.120 | All H-atom parameters refined |
S = 1.03 | Δρmax = 0.55 e Å−3 |
8299 reflections | Δρmin = −0.47 e Å−3 |
166 parameters |
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. 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 | ||
S1 | 0.288447 (16) | 0.459431 (14) | 0.711035 (19) | 0.01929 (4) | |
O1 | 0.18103 (7) | 0.54452 (5) | 0.71911 (8) | 0.02993 (12) | |
O2 | 0.42331 (6) | 0.50523 (8) | 0.76230 (9) | 0.03616 (15) | |
O3 | 0.25705 (8) | 0.35528 (5) | 0.79823 (8) | 0.03407 (14) | |
N3 | 0.17238 (6) | 0.51000 (5) | 0.16133 (7) | 0.01989 (9) | |
N1 | 0.28516 (6) | 0.65793 (5) | 0.08981 (8) | 0.02208 (9) | |
C2 | 0.29151 (7) | 0.54584 (6) | 0.11322 (8) | 0.02096 (10) | |
H2A | 0.3704 (14) | 0.5037 (13) | 0.1080 (19) | 0.037 (3)* | |
C4 | 0.08588 (8) | 0.60254 (6) | 0.16753 (10) | 0.02580 (12) | |
H4A | −0.0036 (14) | 0.5991 (11) | 0.2077 (16) | 0.034 (3)* | |
C5 | 0.15675 (8) | 0.69513 (7) | 0.12222 (11) | 0.02724 (13) | |
H5A | 0.1323 (14) | 0.7688 (12) | 0.1137 (17) | 0.037 (3)* | |
C6 | 0.39573 (9) | 0.72763 (8) | 0.03336 (12) | 0.03149 (15) | |
H6A | 0.3932 (15) | 0.8024 (14) | 0.0813 (19) | 0.044 (4)* | |
H6B | 0.4809 (19) | 0.6923 (15) | 0.063 (2) | 0.061 (5)* | |
H6C | 0.3820 (17) | 0.7417 (17) | −0.081 (2) | 0.067 (5)* | |
C7 | 0.14604 (8) | 0.39419 (6) | 0.21968 (8) | 0.02303 (11) | |
H7A | 0.0552 (13) | 0.3717 (11) | 0.1696 (15) | 0.027 (3)* | |
H7B | 0.2156 (12) | 0.3490 (11) | 0.1741 (15) | 0.026 (3)* | |
C8 | 0.15267 (7) | 0.38976 (6) | 0.41105 (8) | 0.02112 (10) | |
H8A | 0.0853 (14) | 0.4389 (12) | 0.4510 (18) | 0.033 (3)* | |
H8B | 0.1301 (13) | 0.3105 (12) | 0.4405 (17) | 0.036 (3)* | |
C9 | 0.29159 (7) | 0.42456 (8) | 0.49418 (9) | 0.02574 (12) | |
H9A | 0.3243 (16) | 0.4859 (13) | 0.444 (2) | 0.043 (4)* | |
H9B | 0.3600 (16) | 0.3658 (13) | 0.4885 (18) | 0.043 (4)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.01791 (6) | 0.02075 (7) | 0.01894 (6) | −0.00086 (5) | 0.00002 (4) | 0.00099 (4) |
O1 | 0.0309 (3) | 0.0258 (2) | 0.0325 (3) | 0.0079 (2) | −0.0007 (2) | −0.00600 (19) |
O2 | 0.0218 (2) | 0.0569 (4) | 0.0287 (3) | −0.0109 (3) | −0.0044 (2) | −0.0016 (3) |
O3 | 0.0510 (4) | 0.0231 (2) | 0.0281 (2) | −0.0029 (2) | 0.0032 (2) | 0.00664 (19) |
N3 | 0.0201 (2) | 0.01929 (19) | 0.02006 (19) | 0.00022 (16) | 0.00055 (16) | −0.00017 (15) |
N1 | 0.0208 (2) | 0.0222 (2) | 0.0233 (2) | −0.00089 (18) | 0.00185 (17) | 0.00077 (17) |
C2 | 0.0201 (2) | 0.0225 (2) | 0.0204 (2) | 0.00164 (19) | 0.00209 (18) | 0.00037 (18) |
C4 | 0.0200 (3) | 0.0237 (3) | 0.0339 (3) | 0.0023 (2) | 0.0034 (2) | 0.0011 (2) |
C5 | 0.0245 (3) | 0.0214 (3) | 0.0361 (3) | 0.0030 (2) | 0.0042 (2) | 0.0014 (2) |
C6 | 0.0295 (4) | 0.0310 (3) | 0.0347 (4) | −0.0069 (3) | 0.0068 (3) | 0.0048 (3) |
C7 | 0.0289 (3) | 0.0190 (2) | 0.0207 (2) | −0.0029 (2) | −0.0008 (2) | −0.00147 (18) |
C8 | 0.0208 (2) | 0.0220 (2) | 0.0204 (2) | −0.00162 (19) | 0.00092 (18) | −0.00033 (18) |
C9 | 0.0180 (2) | 0.0392 (4) | 0.0200 (2) | 0.0002 (2) | 0.00188 (18) | −0.0015 (2) |
S1—O3 | 1.4529 (6) | C5—H5A | 0.899 (14) |
S1—O2 | 1.4550 (6) | C6—H6A | 0.959 (16) |
S1—O1 | 1.4580 (6) | C6—H6B | 0.945 (19) |
S1—C9 | 1.7805 (7) | C6—H6C | 0.924 (19) |
N3—C2 | 1.3298 (9) | C7—C8 | 1.5233 (9) |
N3—C4 | 1.3825 (9) | C7—H7A | 0.982 (13) |
N3—C7 | 1.4673 (9) | C7—H7B | 0.961 (12) |
N1—C2 | 1.3301 (9) | C8—C9 | 1.5207 (10) |
N1—C5 | 1.3791 (10) | C8—H8A | 0.952 (14) |
N1—C6 | 1.4607 (10) | C8—H8B | 0.990 (14) |
C2—H2A | 0.923 (14) | C9—H9A | 0.898 (16) |
C4—C5 | 1.3562 (11) | C9—H9B | 0.967 (16) |
C4—H4A | 0.961 (14) | ||
O3—S1—O2 | 113.68 (5) | H6A—C6—H6B | 110.8 (14) |
O3—S1—O1 | 111.84 (4) | N1—C6—H6C | 110.7 (11) |
O2—S1—O1 | 112.24 (5) | H6A—C6—H6C | 102.9 (15) |
O3—S1—C9 | 107.06 (4) | H6B—C6—H6C | 112.0 (15) |
O2—S1—C9 | 105.52 (4) | N3—C7—C8 | 110.85 (5) |
O1—S1—C9 | 105.84 (4) | N3—C7—H7A | 107.3 (7) |
C2—N3—C4 | 108.62 (6) | C8—C7—H7A | 111.0 (7) |
C2—N3—C7 | 124.60 (6) | N3—C7—H7B | 104.0 (7) |
C4—N3—C7 | 126.28 (6) | C8—C7—H7B | 112.9 (7) |
C2—N1—C5 | 108.65 (6) | H7A—C7—H7B | 110.4 (10) |
C2—N1—C6 | 124.78 (7) | C9—C8—C7 | 112.84 (6) |
C5—N1—C6 | 126.54 (7) | C9—C8—H8A | 108.3 (8) |
N3—C2—N1 | 108.77 (6) | C7—C8—H8A | 110.0 (8) |
N3—C2—H2A | 127.3 (9) | C9—C8—H8B | 111.1 (8) |
N1—C2—H2A | 123.6 (9) | C7—C8—H8B | 106.2 (8) |
C5—C4—N3 | 106.86 (7) | H8A—C8—H8B | 108.4 (11) |
C5—C4—H4A | 128.8 (8) | C8—C9—S1 | 113.36 (5) |
N3—C4—H4A | 124.1 (8) | C8—C9—H9A | 111.2 (10) |
C4—C5—N1 | 107.09 (7) | S1—C9—H9A | 106.8 (10) |
C4—C5—H5A | 130.7 (9) | C8—C9—H9B | 112.9 (9) |
N1—C5—H5A | 122.2 (9) | S1—C9—H9B | 106.2 (9) |
N1—C6—H6A | 110.2 (9) | H9A—C9—H9B | 105.9 (13) |
N1—C6—H6B | 110.1 (11) | ||
C2—N3—C7—C8 | 100.05 (8) | C4—N3—C7—C8 | −70.97 (8) |
N3—C7—C8—C9 | −60.48 (8) | N3—C7—C8—C9 | −60.48 (8) |
C7—C8—C9—S1 | 163.00 (5) |
D—H···A | D—H | H···A | D···A | D—H···A |
C2—H2A···O2i | 0.923 (14) | 2.197 (14) | 2.9512 (9) | 138.4 (12) |
C5—H5A···O1ii | 0.899 (14) | 2.381 (15) | 3.1573 (10) | 144.6 (12) |
C4—H4A···O1iii | 0.961 (14) | 2.528 (14) | 3.3268 (11) | 140.5 (11) |
C4—H4A···O3iii | 0.961 (14) | 2.541 (14) | 3.4364 (11) | 155.0 (11) |
C7—H7B···O3iv | 0.961 (12) | 2.613 (12) | 3.1693 (10) | 117.2 (9) |
C8—H8B···O3iv | 0.990 (14) | 2.621 (13) | 3.2086 (9) | 118.1 (9) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, −y+3/2, z−1/2; (iii) −x, −y+1, −z+1; (iv) x, −y+1/2, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C7H12N2O3S |
Mr | 204.25 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 296 |
a, b, c (Å) | 9.8164 (4), 11.7421 (5), 7.9769 (3) |
β (°) | 94.878 (2) |
V (Å3) | 916.13 (6) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.33 |
Crystal size (mm) | 0.29 × 0.28 × 0.13 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | For a sphere (SADABS; Bruker, 2007) |
Tmin, Tmax | 0.910, 0.958 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 21327, 8299, 5726 |
Rint | 0.033 |
(sin θ/λ)max (Å−1) | 1.030 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.120, 1.03 |
No. of reflections | 8299 |
No. of parameters | 166 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.55, −0.47 |
Computer programs: SMART (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C2—H2A···O2i | 0.923 (14) | 2.197 (14) | 2.9512 (9) | 138.4 (12) |
C5—H5A···O1ii | 0.899 (14) | 2.381 (15) | 3.1573 (10) | 144.6 (12) |
C4—H4A···O1iii | 0.961 (14) | 2.528 (14) | 3.3268 (11) | 140.5 (11) |
C4—H4A···O3iii | 0.961 (14) | 2.541 (14) | 3.4364 (11) | 155.0 (11) |
C7—H7B···O3iv | 0.961 (12) | 2.613 (12) | 3.1693 (10) | 117.2 (9) |
C8—H8B···O3iv | 0.990 (14) | 2.621 (13) | 3.2086 (9) | 118.1 (9) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, −y+3/2, z−1/2; (iii) −x, −y+1, −z+1; (iv) x, −y+1/2, z−1/2. |
Acknowledgements
Portions of this work were funded by the Office of Naval Research and the US Naval Academy Research Foundation. Any opinions, findings, and conclusion or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the US Navy.
References
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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.
Ionic liquids (ILs) have proven to be highly versatile materials with an ever expanding suite of chemical applications. An application that has recently shown great promise is the use of functionalized ILs as Brønsted acid catalysts for organic reactions (Cole et al., 2002). These IL catalysts are most commonly prepared by the reaction of 1-methylimidazolium-3-alkyl sulfonate zwitterion with an acid that has a pKa low enough to protonate the sulfonate group (Yoshizawa et al., 2001; Cole et al., 2002). The activity of the IL (e.g. the effectiveness of proton transfer) is significantly impacted by the structure and interactions of the zwitterion. It has been shown that the local structure of ILs is often conserved on transition from the solid state to the liquid state (Triolo et al., 2006; Henderson et al., 2007; Reichert et al., 2007). Thus, a structural analysis of the zwitterion, 1-methylimidaolium-3-propanesulfonate (I) might provide valuable insight into the activity of the Brønsted acid IL catalyst.
The asymmetric unit of the title compound is presented in Figure 1. The dominant intermolecular interactions are Coulombic in nature and are through the charged centers of the zwitterion: the imidazolium ring and the sulfonate group (Fig. 2). The negative charged sulfonate group is surrounded by four imidazolium head groups forming six close contacts (Table 1). The interactions of the imidazolium ring hydrogen atoms with the sulfonate group establish two three-dimensional R22(16) rings. The packing along the b axis (Fig. 3) shows the zwitterions arranged in columns along the c axis. The head-to-tail orientation maximizes the polar interaction and minimizes cation-cation and anion-anion repulsions.