1-Methyl-1H-imidazol-3-ium methane­sulfonate

The structure of the title salt, C₄H₇N₂⁺·CH₃O₃S⁻, has monoclinic (P2₁/n) symmetry. The 1-methyl­imidazolium cation and the methyl­sulfonate anion in the asymmetric unit are held together by a strong N—H⋯O hydrogen bond.

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Chemical scheme

Structure description

Ionic liquids (ILs) with fluoride anions possess high electrochemical stability and electrical conductivity (Hmissa et al., 2018). Fluoride ionic liquids were produced to serve as potential non-volatile replacements of VOCs for the development of IL electrolytes.

Electrolytes with stable solvents can be utilized for the production of innocuous rechargeable Al-ion and Li-ion batteries. The reported strategy for the synthesis of ILs with fluoride anions is autocatalytic, HF-free, and does not require chromatographic purification. HF-free synthesis of fluoride ionic liquids eradicates the need for corrosive acids. The exposure of the ionic liquid to water may serve as a technique to increase electrical conductivity (Li et al., 2007). Chemical stability studies indicate that water attacks the S^VI atom, which leads to the formation of a sulfate-based salt (Fig. 1).

Figure 1 Synthetic scheme for the synthesis of imidazolium-based salts, paired with sulfate anion via SuFEx click chemistry

Sulfur(VI) fluoride-exchange (SuFEx) chemistry possesses characteristics of click chemistry. Many of its potential applications have been investigated recently, including post-polymerization modification (Yatvin et al., 2015) and sulfonimidoyl fluorides synthesis (Gao et al., 2018). Fluoride salts have been reported to function as catalysts for the SuFEx reaction (Gao et al., 2017). The autocatalytic property of the sulfonyl-based ionic liquids allows the reaction to proceed in a time-efficient manner, opening the doors for potential industrial scale application. The chemical stability of these ionic liquids towards the hydrolysis reaction was studied in this work.

The title compound crystallizes in the monoclinic P2₁/n space group. The 1-methyl­imidazolium cation and the methyl­sulfonate anion in the asymmetric unit are linked by a strong O⋯H—N hydrogen bond [O⋯N distance = 2.775 (2) Å; Table 1 and (Fig. 2)] between the proton on N and one of the sulfonate oxygen atoms. The packing is shown in Fig. 3.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯O2	0.87	1.96	2.775 (2)	156

Figure 2 The asymmetric unit with displacement ellipsoids shown at the 35% probability level. The N—H⋯O hydrogen bond (Table 1) is indicated by a dashed line.

Figure 3 A view of the crystal packing of the title compound.

1-MeIm is a common cation found in as many as 48 crystal structures in the Cambridge Structural Database (Groom et al., 2016). The planar cation often displays π–π inter­actions with neighboring 1-MeIm cations (Wilkes & Zaworotko, 1993). Such inter­actions are not seen in the title compound. One of the methyl­sulfonate O atoms displays some degree of inter­action with the π-cation [O–centroid distance = 3.382 (1) Å].

Synthesis and crystallization

One molar equivalent of 1-methyl­imidazole and methane­sulfonyl fluoride were dissolved separately using 10 ml extra dry toluene. The two solutions were combined and stirred vigorously for 8 h at reflux temperature. Subsequent to reflux, 1 ml of deionized water was added to the reaction mixture dropwise and then stirred for 4 h at 60°C to allow for hydrolysis to occur. The solid phase of the reaction mixture was filtered. Colourless plate-like crystals formed after 29 days upon slow evaporation of the reaction solvent (toluene).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C4H7N2^+·CH3O3S^−
Mr	178.21
Crystal system, space group	Monoclinic, P21/n
Temperature (K)	230
a, b, c (Å)	10.1891 (5), 7.4627 (4), 11.4884 (6)
β (°)	111.635 (1)
V (Å^3)	812.02 (7)
Z	4
Radiation type	Mo Kα
μ (mm^−1)	0.36
Crystal size (mm)	0.58 × 0.4 × 0.36
Data collection
Diffractometer	Bruker D8 Quest CMOS
Absorption correction	Multi-scan (SADABS; Bruker, 2016)
Tmin, Tmax	0.707, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	11035, 2011, 1827
Rint	0.015
(sin θ/λ)max (Å^−1)	0.668
Refinement
R[F^2 > 2σ(F^2)], wR(F^2), S	0.031, 0.085, 1.08
No. of reflections	2011
No. of parameters	102
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å^−3)	0.23, −0.33
Computer programs: SAINT (Bruker, 2015), SHELXT2014 (Sheldrick, 2015a), SHELXL2018 (Sheldrick, 2015b) and OLEX2 (Dolomanov et al., 2009).

Structural data

Computing details

Data collection: SAINT (Bruker, 2015); cell refinement: SAINT (Bruker, 2015); data reduction: SAINT (Bruker, 2015); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

1-Methyl-1H-imidazol-3-ium methanesulfonate

Crystal data

C4H7N2^+·CH3O3S^−	F(000) = 376
Mr = 178.21	Dx = 1.458 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 10.1891 (5) Å	Cell parameters from 9900 reflections
b = 7.4627 (4) Å	θ = 3.3–28.3°
c = 11.4884 (6) Å	µ = 0.36 mm^−1
β = 111.635 (1)°	T = 230 K
V = 812.02 (7) Å^3	Block, colourless
Z = 4	0.58 × 0.4 × 0.36 mm

Data collection

Bruker D8 Quest CMOS diffractometer	2011 independent reflections
Radiation source: sealed tube	1827 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.015
Detector resolution: 10.42 pixels mm^-1	θmax = 28.4°, θmin = 3.3°
φ and ω shutterless scans	h = −13→13
Absorption correction: multi-scan (SADABS; Bruker, 2016)	k = −9→9
Tmin = 0.707, Tmax = 0.746	l = −15→15
11035 measured reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.031	H-atom parameters constrained
wR(F^2) = 0.085	w = 1/[σ^2(Fo^2) + (0.0399P)^2 + 0.3268P] where P = (Fo^2 + 2Fc^2)/3
S = 1.08	(Δ/σ)max = 0.001
2011 reflections	Δρmax = 0.23 e Å^−3
102 parameters	Δρmin = −0.33 e Å^−3

Special details

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.

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

	x	y	z	Uiso*/Ueq
S1	0.67678 (3)	0.74219 (4)	0.90924 (3)	0.02711 (11)
O1	0.72814 (12)	0.64890 (15)	0.82397 (10)	0.0424 (3)
O2	0.58946 (10)	0.62642 (13)	0.95480 (8)	0.0354 (2)
O3	0.78655 (11)	0.83115 (16)	1.01095 (10)	0.0468 (3)
N1	0.38601 (11)	0.26564 (14)	0.59635 (10)	0.0283 (2)
N2	0.43894 (12)	0.37124 (16)	0.78128 (11)	0.0384 (3)
H2	0.483452	0.427925	0.850900	0.046*
C1	0.47811 (14)	0.36423 (18)	0.68438 (13)	0.0349 (3)
H1	0.558245	0.420035	0.678699	0.042*
C2	0.28337 (14)	0.2092 (2)	0.63836 (13)	0.0347 (3)
H2A	0.204560	0.137987	0.594256	0.042*
C3	0.31699 (16)	0.2752 (2)	0.75517 (14)	0.0408 (3)
H3	0.266479	0.258443	0.808246	0.049*
C4	0.38835 (18)	0.2315 (2)	0.47203 (14)	0.0456 (4)
H4A	0.362591	0.107785	0.448925	0.068*
H4B	0.482460	0.253917	0.472837	0.068*
H4C	0.321550	0.310260	0.411695	0.068*
C5	0.56302 (18)	0.9098 (3)	0.81923 (19)	0.0552 (4)
H5A	0.484569	0.854603	0.752852	0.083*
H5B	0.614304	0.987198	0.782942	0.083*
H5C	0.527445	0.980152	0.872276	0.083*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.02786 (17)	0.02531 (17)	0.02782 (17)	−0.00194 (10)	0.00987 (13)	0.00137 (11)
O1	0.0502 (6)	0.0444 (6)	0.0383 (5)	0.0050 (5)	0.0228 (5)	−0.0008 (4)
O2	0.0419 (5)	0.0357 (5)	0.0285 (4)	−0.0136 (4)	0.0128 (4)	−0.0001 (4)
O3	0.0407 (6)	0.0527 (7)	0.0441 (6)	−0.0190 (5)	0.0121 (5)	−0.0124 (5)
N1	0.0306 (5)	0.0254 (5)	0.0270 (5)	−0.0018 (4)	0.0083 (4)	−0.0002 (4)
N2	0.0388 (6)	0.0354 (6)	0.0303 (5)	0.0046 (5)	0.0003 (5)	−0.0091 (5)
C1	0.0307 (6)	0.0276 (6)	0.0396 (7)	−0.0027 (5)	0.0051 (5)	−0.0006 (5)
C2	0.0318 (6)	0.0393 (7)	0.0323 (7)	−0.0074 (5)	0.0109 (5)	−0.0032 (6)
C3	0.0397 (7)	0.0510 (9)	0.0325 (7)	0.0027 (6)	0.0142 (6)	−0.0034 (6)
C4	0.0545 (9)	0.0541 (9)	0.0333 (7)	−0.0080 (7)	0.0220 (7)	−0.0044 (6)
C5	0.0492 (9)	0.0469 (9)	0.0735 (11)	0.0159 (7)	0.0271 (8)	0.0264 (9)

Geometric parameters (Å, º)

S1—O1	1.4478 (10)	C1—H1	0.9400
S1—O2	1.4680 (9)	C2—H2A	0.9400
S1—O3	1.4468 (10)	C2—C3	1.350 (2)
S1—C5	1.7590 (16)	C3—H3	0.9400
N1—C1	1.3210 (17)	C4—H4A	0.9700
N1—C2	1.3699 (17)	C4—H4B	0.9700
N1—C4	1.4596 (17)	C4—H4C	0.9700
N2—H2	0.8700	C5—H5A	0.9700
N2—C1	1.3149 (19)	C5—H5B	0.9700
N2—C3	1.369 (2)	C5—H5C	0.9700
O1—S1—O2	112.08 (6)	C3—C2—H2A	126.5
O1—S1—C5	105.57 (8)	N2—C3—H3	126.7
O2—S1—C5	105.88 (7)	C2—C3—N2	106.63 (13)
O3—S1—O1	113.73 (7)	C2—C3—H3	126.7
O3—S1—O2	111.83 (6)	N1—C4—H4A	109.5
O3—S1—C5	107.10 (9)	N1—C4—H4B	109.5
C1—N1—C2	108.71 (11)	N1—C4—H4C	109.5
C1—N1—C4	125.66 (12)	H4A—C4—H4B	109.5
C2—N1—C4	125.53 (12)	H4A—C4—H4C	109.5
C1—N2—H2	125.4	H4B—C4—H4C	109.5
C1—N2—C3	109.15 (12)	S1—C5—H5A	109.5
C3—N2—H2	125.4	S1—C5—H5B	109.5
N1—C1—H1	125.7	S1—C5—H5C	109.5
N2—C1—N1	108.58 (12)	H5A—C5—H5B	109.5
N2—C1—H1	125.7	H5A—C5—H5C	109.5
N1—C2—H2A	126.5	H5B—C5—H5C	109.5
C3—C2—N1	106.92 (12)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O2	0.87	1.96	2.775 (2)	156