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Acta Cryst. (2009). E65, o499    [ doi:10.1107/S1600536809004103 ]

2-Methylimidazolium hydrogen maleate

Z.-X. Liu

Abstract top

Molecules in the title compound, C4H7N2+·C4H3O4-, are linked by intermolecular N-H...O hydrogen bonds into one-dimensional chains parallel to [101]. These chains are in turn linked by an R22(8) motif, formed by weak C-H...O hydrogen bonds, into corrugated sheets running parallel to (10\overline{1}). These sheets are further linked by weak intermolecular C-H...O hydrogen bonds, forming a three-dimensional network. Intramolecular N-H...O and O-H...O interactions are also present.

Comment top

As part of the continuing studies on the synthesis of co-crystal or organic salts involving imidazole (Liu & Meng, 2006), the crystal structure of title compound (I) is reported. It was obtained by mixing a 2:1 molar amounts of 2-methylimidazole and 2-maleic acid and in 95% methanol solution at room temperature.

According to Aakeröy and Salmon (2005) complex (I) is an organic salt. In (I), one of the carboxyl protons is transferred to the imidazole N atom, forming a 1:1 anhydrous organic adduct. The two carboxyl groups in the maleate anion are hydrogen-bonded to each other via atom H3A located approximately at the mid-point of atoms O1 and O3 (Fig.1).

In the crystal structure, by a combination of N1-H1···O2, N2-H2A···O4i and C4-H4A···O3i hydrogen bonds (symmetry codes as in Table 1) molecules in (I) are linked into a one-dimensional chain parallel to the [101] direction (Fig.2). These adjacent chains are linked by a R22(8) hydrogen motif (Bernstein et al., 1995) originating from two weak centrosymmetric C6-H6···O2 (3/2-x, 5/2-y, 1-z) hydrogen bonds, into a corrugated sheet running parallel to the (101) plane (Fig.3). These sheets are further linked by weak C3-H3···O3 (1-x, 1-y, 1-z) hydrogen bonds, forming a three-dimensional network.

Related literature top

For related structures, see: Aakeröy & Salmon (2005); Liu & Meng (2006). For hydrogen-bond motifs, see: Bernstein et al. (1995).

Experimental top

All the reagents and solvents were used as obtained without further purification. A 1:2 molar amounts of maleic acid (0.1 mmol, 11.6 mg) and 2-methylimidazole (0.2 mmol, 16.4 mg) were dissolved in 95% methanol (10 ml). The mixture was stirred for half an hour at room temperature and then filtered. The resulting solution was kept in air for one week. Block-shaped crystals suitable for single-crystal X-ray diffraction analysis were grown by slow evaporation of a solution of (I).

Refinement top

H atoms bonded to C atoms were located in difference maps and subsequently treated as riding modes, with C–H=0.93 Å, Uiso(H) = 1.2Ueq(C) and C–H=0.96 Å, 1.5Ueq(C) for methyl H atoms. H atoms bonded to N and O atoms were also found in the difference maps and their distances were refined freely (see Table 1 for the distances), and the Uiso(H) values being set k times of their carrier atoms (k=1.2 for N and 1.5 for O atoms)

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. Molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H-bonds are shown in dashed lines.
[Figure 2] Fig. 2. Part of the crystal structure of (I), showing the formation of the one-dimensional chain linked by intermolecular N-H···O hydrogen bonds parallel to the [101] direction. (symmetry code: i = 1/2+x, 3/2-y, 1/2+z)
[Figure 3] Fig. 3. Part of the crystal structure of (I), showing the formation of the two-dimensional corrugated sheet linked by intermolecular N-H···O and C-H···O hydrogen bonds (a) view perpendicular to the (101) plane and (b) view along to the (101) plane, respectively. Only H atoms involved in hydrogen bonds are shown.
2-Methylimidazolium hydrogen maleate top
Crystal data top
C4H7N2+·C4H3O4−F(000) = 832
Mr = 198.18Dx = 1.336 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 1457 reflections
a = 13.9897 (14) Åθ = 3.1–21.4°
b = 7.2274 (7) ŵ = 0.11 mm−1
c = 20.533 (2) ÅT = 295 K
β = 108.310 (2)°Block, colorless
V = 1970.9 (3) Å30.10 × 0.10 × 0.08 mm
Z = 8
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer		2143 independent reflections
Radiation source: fine focus sealed Siemens Mo tube1273 reflections with I > 2σ(I)
graphiteRint = 0.027
0.3° wide ω exposures scansθmax = 27.0°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2001)		h = −17→17
Tmin = 0.979, Tmax = 0.991k = −9→9
7461 measured reflectionsl = −26→24
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.046Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.130H atoms treated by a mixture of independent and constrained refinement
S = 0.99 w = 1/[σ2(Fo2) + (0.0703P)2]
where P = (Fo2 + 2Fc2)/3
2143 reflections(Δ/σ)max = 0.001
137 parametersΔρmax = 0.17 e Å−3
0 restraintsΔρmin = −0.13 e Å−3
Crystal data top
C4H7N2+·C4H3O4−V = 1970.9 (3) Å3
Mr = 198.18Z = 8
Monoclinic, C2/cMo Kα radiation
a = 13.9897 (14) ŵ = 0.11 mm−1
b = 7.2274 (7) ÅT = 295 K
c = 20.533 (2) Å0.10 × 0.10 × 0.08 mm
β = 108.310 (2)°
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer		2143 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2001)		1273 reflections with I > 2σ(I)
Tmin = 0.979, Tmax = 0.991Rint = 0.027
7461 measured reflectionsθmax = 27.0°
Refinement top
R[F2 > 2σ(F2)] = 0.046H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.130Δρmax = 0.17 e Å−3
S = 0.99Δρmin = −0.13 e Å−3
2143 reflectionsAbsolute structure: ?
137 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

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 > 2sigma(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) top
xyzUiso*/Ueq
C10.77143 (12)0.6738 (2)0.65115 (8)0.0603 (4)
C20.64878 (15)0.5430 (3)0.57064 (11)0.0810 (6)
H20.59570.52640.53030.097*
C30.68665 (14)0.4163 (3)0.61863 (11)0.0812 (6)
H30.66540.29430.61830.097*
C40.84501 (15)0.8105 (3)0.69038 (10)0.0855 (6)
H4A0.86990.77310.73760.128*
H4B0.81310.92930.68720.128*
H4C0.90000.81830.67200.128*
C50.61393 (13)1.0269 (2)0.46763 (9)0.0630 (5)
C60.59800 (13)1.1982 (2)0.42603 (9)0.0641 (5)
H60.64461.29150.44400.077*
C70.52819 (11)1.2406 (2)0.36726 (9)0.0643 (5)
H70.53271.36010.35170.077*
C80.44457 (13)1.1297 (3)0.32255 (9)0.0652 (5)
N10.70226 (11)0.7022 (2)0.59149 (8)0.0687 (4)
H10.6924 (14)0.811 (3)0.5686 (9)0.082*
N20.76299 (11)0.4998 (2)0.66877 (8)0.0665 (4)
H2A0.8074 (14)0.439 (3)0.7076 (10)0.080*
O10.55899 (10)0.88414 (17)0.44508 (7)0.0830 (4)
O20.68111 (10)1.02685 (18)0.52321 (7)0.0844 (4)
O30.43419 (11)0.96097 (18)0.33767 (7)0.0885 (5)
H3A0.495 (2)0.916 (3)0.3917 (15)0.133*
O40.38675 (9)1.20541 (19)0.27165 (6)0.0826 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0574 (10)0.0627 (11)0.0610 (10)0.0021 (8)0.0187 (8)−0.0008 (8)
C20.0663 (11)0.0887 (15)0.0787 (13)−0.0016 (10)0.0093 (10)−0.0184 (11)
C30.0727 (12)0.0667 (12)0.0994 (15)−0.0082 (10)0.0202 (11)−0.0139 (11)
C40.0861 (13)0.0770 (14)0.0872 (14)−0.0151 (10)0.0186 (11)−0.0040 (10)
C50.0611 (10)0.0644 (11)0.0618 (11)−0.0024 (8)0.0169 (9)−0.0047 (8)
C60.0662 (10)0.0583 (10)0.0644 (11)−0.0138 (8)0.0158 (9)−0.0052 (8)
C70.0649 (10)0.0580 (10)0.0660 (11)−0.0100 (8)0.0147 (9)−0.0006 (8)
C80.0631 (11)0.0734 (12)0.0588 (11)−0.0047 (9)0.0188 (9)−0.0052 (9)
N10.0679 (9)0.0715 (10)0.0631 (9)0.0079 (8)0.0154 (8)0.0042 (7)
N20.0633 (9)0.0610 (9)0.0712 (10)0.0041 (7)0.0156 (8)0.0035 (7)
O10.0929 (9)0.0625 (8)0.0787 (9)−0.0138 (7)0.0056 (8)0.0039 (6)
O20.0830 (9)0.0878 (10)0.0658 (8)−0.0080 (7)−0.0005 (7)0.0060 (6)
O30.0962 (10)0.0716 (9)0.0768 (9)−0.0281 (7)−0.0028 (7)−0.0017 (7)
O40.0748 (8)0.0894 (9)0.0693 (8)−0.0015 (7)0.0021 (7)0.0008 (7)
Geometric parameters (Å, °) top
C1—N11.317 (2)C5—O11.283 (2)
C1—N21.324 (2)C5—C61.481 (2)
C1—C41.471 (2)C6—C71.328 (2)
C2—C31.327 (3)C6—H60.9300
C2—N11.366 (2)C7—C81.476 (2)
C2—H20.9300C7—H70.9300
C3—N21.369 (2)C8—O41.2307 (19)
C3—H30.9300C8—O31.278 (2)
C4—H4A0.9600N1—H10.901 (19)
C4—H4B0.9600N2—H2A0.95 (2)
C4—H4C0.9600O1—H3A1.20 (3)
C5—O21.230 (2)O3—H3A1.21 (3)
N1—C1—N2107.46 (16)C7—C6—C5130.67 (15)
N1—C1—C4125.99 (16)C7—C6—H6114.7
N2—C1—C4126.55 (16)C5—C6—H6114.7
C3—C2—N1107.26 (17)C6—C7—C8130.74 (16)
C3—C2—H2126.4C6—C7—H7114.6
N1—C2—H2126.4C8—C7—H7114.6
C2—C3—N2106.84 (18)O4—C8—O3122.41 (17)
C2—C3—H3126.6O4—C8—C7117.90 (17)
N2—C3—H3126.6O3—C8—C7119.69 (16)
C1—C4—H4A109.5C1—N1—C2109.26 (16)
C1—C4—H4B109.5C1—N1—H1124.6 (12)
H4A—C4—H4B109.5C2—N1—H1126.1 (12)
C1—C4—H4C109.5C1—N2—C3109.18 (16)
H4A—C4—H4C109.5C1—N2—H2A125.4 (11)
H4B—C4—H4C109.5C3—N2—H2A125.1 (11)
O2—C5—O1122.12 (17)C5—O1—H3A111.7 (11)
O2—C5—C6117.90 (15)C5—O2—H1113.4 (6)
O1—C5—C6119.98 (16)C8—O3—H3A112.4 (11)
N1—C2—C3—N20.3 (2)C4—C1—N1—C2179.34 (16)
O2—C5—C6—C7−175.16 (18)C3—C2—N1—C1−0.1 (2)
O1—C5—C6—C75.4 (3)N1—C1—N2—C30.27 (19)
C5—C6—C7—C8−1.9 (3)C4—C1—N2—C3−179.18 (16)
C6—C7—C8—O4176.67 (17)C2—C3—N2—C1−0.3 (2)
C6—C7—C8—O3−3.0 (3)O1—C5—O2—H1−0.7 (7)
N2—C1—N1—C2−0.11 (19)C6—C5—O2—H1179.9 (6)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O1—H3A···O31.20 (3)1.21 (3)2.4085 (18)174 (2)
N1—H1···O20.901 (19)1.80 (2)2.701 (2)176.3 (17)
N2—H2A···O4i0.95 (2)1.77 (2)2.713 (2)171.2 (17)
C3—H3···O3ii0.932.643.471 (2)150
C4—H4A···O3i0.962.593.490 (2)155
C6—H6···O2iii0.932.663.544 (2)158
Symmetry codes: (i) x+1/2, −y+3/2, z+1/2; (ii) −x+1, −y+1, −z+1; (iii) −x+3/2, −y+5/2, −z+1.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O1—H3A···O31.20 (3)1.21 (3)2.4085 (18)174 (2)
N1—H1···O20.901 (19)1.80 (2)2.701 (2)176.3 (17)
N2—H2A···O4i0.95 (2)1.77 (2)2.713 (2)171.2 (17)
C3—H3···O3ii0.932.643.471 (2)150
C4—H4A···O3i0.962.593.490 (2)155
C6—H6···O2iii0.932.663.544 (2)158
Symmetry codes: (i) x+1/2, −y+3/2, z+1/2; (ii) −x+1, −y+1, −z+1; (iii) −x+3/2, −y+5/2, −z+1.
Acknowledgements top

This work received financial support mainly from Yangtze University.

references
References top

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Liu, Z.-X. & Meng, X.-G. (2006). Acta Cryst. E62, o1286–o1288.

Sheldrick, G. M. (2001). SADABS. University of Göttingen, Germany.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13.