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Acta Cryst. (2009). E65, m772    [ doi:10.1107/S160053680902176X ]

Diaquabis(2-methyl-1H-imidazol-3-ium-4,5-dicarboxylato-[kappa]2O,O')magnesium

Y. L. Li, X. Guo, J. X. Wang and Y. C. Wang

Abstract top

The title compound, [Mg(C6H5N2O4)2(H2O)2], was prepared by reaction of Mg(NO3)2 and 2-methyl-1H-imidazole-4,5-dicarboxylic acid under hydrothermal conditions. The MgII atom lies on an inversion centre and displays a distorted octahedral coordination geometry. An extended three-dimensional network of intermolecular O-H...O and N-H...O hydrogen bonds stabilizes the crystal structure.

Comment top

Recently, the study of metal complexes with N-heterocyclic carboxylic acids has been given considerable attention (Nie et al., 2007; Liang et al., 2002; Net et al., 1989; Zeng et al., 2008). In this paper, we report on the synthesis and crystal structure of the title compound, which was obtained by the hydrothermal reaction of Mg(NO3)2 with 2-methyl-1H-imidazole-4,5-dicarboxylic acid.

As shown in Fig. 1, the magnesium(II) atom, which lies on an inversion centre, adopts a distorted octahedral coordination, with the equatorial plane provided by four O atoms from two organic ligands [Mg1–O1 = 2.011 (2) Å; Mg1–O3 = 2.036 (2) Å] and the axial sites occupied by the O atoms of two water molecules [Mg1–O5 = 2.110 (3) Å]. The seven-membered chelate ring assumes an envelope-like conformation, with atom Mg1 displaced by 0.4353 (4) Å from the mean plane of the remaining atoms of the ring. The crystal structure is stabilized by intermolecular O—H···O and N—H···O hydrogen bonds (Table 1), forming an extended three-dimensional network (Fig. 2).

Related literature top

For the crystal structures of metal complexes with N-heterocyclic carboxylic acids, see: Nie et al. (2007); Liang et al. (2002); Net et al. (1989); Zeng et al. (2008).

Experimental top

Colourless single crystals of title compound were obtained by hydrothermal treatment of Mg(NO3)2 (1 mmol), 2-methyl-1H-imidazole-4,5-dicarboxylic acid (1 mmol) and water (5 ml) over 4 days at 368 K. Yield: 67% (based on Mg(NO3)2.

Refinement top

The water H atoms and H atoms connected to N were located from a difference Fourier map but not refined [Uiso(H)=1.5Ueq(O, N)]. The methyl H atoms were placed at calculated positions and refined as riding, with C—H = 0.96 Å, and with Uiso(H) = 1.5Ueq(C).

Computing details top

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL/PC (Sheldrick, 2008); software used to prepare material for publication: SHELXTL/PC (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Atoms with suffix A are related to atoms with no suffix by 1-x, 2-y, 2-z.
[Figure 2] Fig. 2. Packing diagram of the title compound viewed along the b axis. Intermolecular hydrogen bonds are shown as dashed lines.
Diaquabis(2-methyl-1H-imidazol-3-ium-4,5-dicarboxylato- κ2O,O')magnesium top
Crystal data top
[Mg(C6H5N2O4)2(H2O)2]Z = 1
Mr = 398.58F(000) = 206
Triclinic, P1Dx = 1.698 Mg m−3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 4.943 (2) ÅCell parameters from 1023 reflections
b = 8.750 (6) Åθ = 3.9–27.4°
c = 9.621 (6) ŵ = 0.18 mm−1
α = 109.18 (3)°T = 292 K
β = 95.142 (17)°Block, colourless
γ = 93.14 (2)°0.30 × 0.25 × 0.20 mm
V = 389.9 (4) Å3
Data collection top
Rigaku SCXmini
diffractometer		1767 independent reflections
Radiation source: fine-focus sealed tube1308 reflections with I > 2σ(I)
graphiteRint = 0.046
Detector resolution: 13.6612 pixels mm-1θmax = 27.4°, θmin = 2.7°
ω scansh = −6→6
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)		k = −11→11
Tmin = 0.948, Tmax = 0.967l = −12→12
4002 measured reflections
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)] = 0.061Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.213H-atom parameters constrained
S = 1.19 w = 1/[σ2(Fo2) + (0.1078P)2 + 0.1465P]
where P = (Fo2 + 2Fc2)/3
1767 reflections(Δ/σ)max < 0.001
125 parametersΔρmax = 0.39 e Å−3
0 restraintsΔρmin = −0.42 e Å−3
Crystal data top
[Mg(C6H5N2O4)2(H2O)2]γ = 93.14 (2)°
Mr = 398.58V = 389.9 (4) Å3
Triclinic, P1Z = 1
a = 4.943 (2) ÅMo Kα radiation
b = 8.750 (6) ŵ = 0.18 mm−1
c = 9.621 (6) ÅT = 292 K
α = 109.18 (3)°0.30 × 0.25 × 0.20 mm
β = 95.142 (17)°
Data collection top
Rigaku SCXmini
diffractometer		1767 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)		1308 reflections with I > 2σ(I)
Tmin = 0.948, Tmax = 0.967Rint = 0.046
4002 measured reflectionsθmax = 27.4°
Refinement top
R[F2 > 2σ(F2)] = 0.061H-atom parameters constrained
wR(F2) = 0.213Δρmax = 0.39 e Å−3
S = 1.19Δρmin = −0.42 e Å−3
1767 reflectionsAbsolute structure: ?
125 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

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. 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Mg10.50001.00001.00000.0250 (4)
C10.3793 (6)0.7562 (4)0.6015 (3)0.0229 (7)
C20.5912 (6)0.8628 (4)0.6010 (3)0.0223 (7)
C30.5089 (7)0.6811 (4)0.3730 (4)0.0267 (7)
C40.5167 (9)0.5941 (5)0.2137 (4)0.0385 (9)
H4A0.41780.64920.15690.058*
H4B0.43470.48510.18850.058*
H4C0.70260.59150.19220.058*
C50.1991 (7)0.7356 (4)0.7122 (3)0.0240 (7)
C60.7466 (6)1.0094 (4)0.7140 (3)0.0233 (7)
N10.3343 (6)0.6454 (3)0.4585 (3)0.0268 (6)
H10.20070.55540.43650.040*
N20.6676 (6)0.8120 (3)0.4581 (3)0.0258 (6)
H20.79140.87190.42130.039*
O10.6722 (5)1.0584 (3)0.8405 (2)0.0319 (6)
O20.9380 (5)1.0749 (3)0.6734 (3)0.0380 (7)
O30.2358 (5)0.8310 (3)0.8427 (2)0.0312 (6)
O40.0166 (6)0.6225 (3)0.6638 (3)0.0410 (7)
O50.2236 (5)1.1757 (3)1.0012 (3)0.0336 (6)
H5B0.13541.15720.90700.050*
H5A0.09401.18361.05740.050*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mg10.0230 (8)0.0287 (8)0.0195 (8)−0.0077 (6)0.0050 (6)0.0042 (6)
C10.0240 (15)0.0222 (15)0.0209 (15)−0.0021 (12)0.0033 (12)0.0055 (12)
C20.0213 (14)0.0243 (15)0.0216 (15)−0.0001 (12)0.0050 (12)0.0078 (12)
C30.0294 (17)0.0240 (16)0.0261 (16)−0.0019 (13)0.0057 (13)0.0076 (13)
C40.054 (2)0.0332 (19)0.0227 (18)−0.0042 (17)0.0105 (16)0.0014 (15)
C50.0232 (15)0.0254 (15)0.0224 (15)−0.0035 (12)0.0057 (12)0.0067 (12)
C60.0230 (15)0.0259 (16)0.0206 (15)−0.0033 (12)0.0031 (12)0.0081 (13)
N10.0277 (14)0.0253 (14)0.0248 (14)−0.0064 (11)0.0068 (11)0.0052 (11)
N20.0284 (14)0.0268 (14)0.0228 (14)−0.0031 (11)0.0060 (11)0.0092 (11)
O10.0353 (13)0.0336 (14)0.0227 (12)−0.0103 (11)0.0076 (10)0.0049 (10)
O20.0346 (14)0.0432 (16)0.0330 (14)−0.0165 (12)0.0112 (11)0.0098 (12)
O30.0319 (13)0.0347 (14)0.0208 (12)−0.0114 (10)0.0069 (10)0.0022 (10)
O40.0408 (15)0.0392 (15)0.0323 (14)−0.0239 (12)0.0092 (12)0.0008 (11)
O50.0280 (13)0.0385 (14)0.0326 (13)−0.0015 (10)0.0091 (10)0.0090 (11)
Geometric parameters (Å, °) top
Mg1—O1i2.010 (2)C3—C41.475 (5)
Mg1—O12.010 (2)C4—H4A0.9600
Mg1—O3i2.036 (2)C4—H4B0.9600
Mg1—O32.036 (2)C4—H4C0.9600
Mg1—O5i2.110 (3)C5—O41.238 (4)
Mg1—O52.110 (3)C5—O31.249 (4)
C1—C21.365 (4)C6—O21.237 (4)
C1—N11.388 (4)C6—O11.247 (4)
C1—C51.496 (4)N1—H10.9534
C2—N21.393 (4)N2—H20.9489
C2—C61.498 (5)O5—H5B0.9297
C3—N21.330 (4)O5—H5A0.8656
C3—N11.336 (4)
O1i—Mg1—O1180.000 (1)C3—C4—H4A109.5
O1i—Mg1—O3i89.92 (10)C3—C4—H4B109.5
O1—Mg1—O3i90.08 (10)H4A—C4—H4B109.5
O1i—Mg1—O390.08 (10)C3—C4—H4C109.5
O1—Mg1—O389.92 (10)H4A—C4—H4C109.5
O3i—Mg1—O3180.000 (1)H4B—C4—H4C109.5
O1i—Mg1—O5i87.90 (11)O4—C5—O3124.6 (3)
O1—Mg1—O5i92.10 (11)O4—C5—C1115.5 (3)
O3i—Mg1—O5i88.95 (11)O3—C5—C1119.9 (3)
O3—Mg1—O5i91.05 (11)O2—C6—O1124.7 (3)
O1i—Mg1—O592.10 (11)O2—C6—C2117.0 (3)
O1—Mg1—O587.90 (11)O1—C6—C2118.3 (3)
O3i—Mg1—O591.05 (11)C3—N1—C1110.7 (3)
O3—Mg1—O588.95 (11)C3—N1—H1129.8
O5i—Mg1—O5180.000 (1)C1—N1—H1119.3
C2—C1—N1105.8 (3)C3—N2—C2110.1 (3)
C2—C1—C5136.3 (3)C3—N2—H2123.8
N1—C1—C5117.9 (3)C2—N2—H2125.2
C1—C2—N2106.6 (3)C6—O1—Mg1147.0 (2)
C1—C2—C6135.2 (3)C5—O3—Mg1145.7 (2)
N2—C2—C6118.2 (3)Mg1—O5—H5B111.2
N2—C3—N1106.8 (3)Mg1—O5—H5A117.4
N2—C3—C4127.0 (3)H5B—O5—H5A104.9
N1—C3—C4126.2 (3)
N1—C1—C2—N2−0.3 (4)N1—C3—N2—C2−0.7 (4)
C5—C1—C2—N2−179.6 (4)C4—C3—N2—C2177.5 (4)
N1—C1—C2—C6−179.5 (3)C1—C2—N2—C30.7 (4)
C5—C1—C2—C61.2 (7)C6—C2—N2—C3−180.0 (3)
C2—C1—C5—O4176.8 (4)O2—C6—O1—Mg1−150.7 (3)
N1—C1—C5—O4−2.4 (5)C2—C6—O1—Mg130.6 (6)
C2—C1—C5—O3−2.0 (6)O3i—Mg1—O1—C6142.4 (4)
N1—C1—C5—O3178.8 (3)O3—Mg1—O1—C6−37.6 (4)
C1—C2—C6—O2177.8 (4)O5i—Mg1—O1—C653.4 (4)
N2—C2—C6—O2−1.3 (5)O5—Mg1—O1—C6−126.6 (4)
C1—C2—C6—O1−3.4 (6)O4—C5—O3—Mg1163.9 (3)
N2—C2—C6—O1177.5 (3)C1—C5—O3—Mg1−17.4 (6)
N2—C3—N1—C10.5 (4)O1i—Mg1—O3—C5−151.8 (4)
C4—C3—N1—C1−177.8 (3)O1—Mg1—O3—C528.2 (4)
C2—C1—N1—C3−0.1 (4)O5i—Mg1—O3—C5−63.9 (4)
C5—C1—N1—C3179.3 (3)O5—Mg1—O3—C5116.1 (4)
Symmetry codes: (i) −x+1, −y+2, −z+2.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O4ii0.951.782.696 (4)161
N2—H2···O2iii0.951.812.727 (4)162
O5—H5B···O2iv0.932.233.155 (4)172
O5—H5B···O1iv0.932.362.961 (4)122
O5—H5A···O3v0.871.982.841 (4)170
Symmetry codes: (ii) −x, −y+1, −z+1; (iii) −x+2, −y+2, −z+1; (iv) x−1, y, z; (v) −x, −y+2, −z+2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O4i0.951.782.696 (4)161
N2—H2···O2ii0.951.812.727 (4)162
O5—H5B···O2iii0.932.233.155 (4)172
O5—H5B···O1iii0.932.362.961 (4)122
O5—H5A···O3iv0.871.982.841 (4)170
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x+2, −y+2, −z+1; (iii) x−1, y, z; (iv) −x, −y+2, −z+2.
Acknowledgements top

# no acknowledgements required

references
References top

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Zeng, J.-Z., Yi, X.-G., Lin, J.-Y., Ying, S.-M. & Huang, G.-S. (2008). Acta Cryst. E64, m476.