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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 69| Part 12| December 2013| Pages m667-m668

Imidazolium trans-di­aqua­dioxalato­chromate(III) dihydrate

aLaboratoire de Matériaux et Cristallochimie, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Manar II Tunis, Tunisia
*Correspondence e-mail: cherif.ichraf@yahoo.fr

(Received 3 November 2013; accepted 8 November 2013; online 16 November 2013)

In the title hydrated mol­ecular salt, (C3H5N2)[Cr(C2O4)2(H2O)2]·2H2O, the complete cation is generated by a crystallographic twofold rotation axis, with one C atom lying on the rotation axis. The complete anion is generated by crystallographic inversion symmetry (CrIII site symmetry -1), to generate a slightly distorted CrO6 octa­hedron with trans water mol­ecules and chelating oxalate dianions. The oxalate ion is almost planar (r.m.s. deviation = 0.017 Å) and the five-membered chelate ring is a shallow envelope with the metal ion displaced by 0.126 (1) Å from the ligand atoms. The crystal structure features O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, which link the components into a three-dimensional network.

Related literature

For a related structure and background to oxalate complexes, see: Chérif et al. (2012[Chérif, I., Zid, M. F., El-Ghozzi, M. & Avignant, D. (2012). Acta Cryst. E68, m900-m901.]). For the structures of salts containing the [Cr(C2O4)2(H2O)2] anion with various cations, see: Bélombé et al. (2009[Bélombé, M. M., Nenwa, J. & Emmerling, F. (2009). Z. Kristallogr. 224, 239-240.]); Nenwa et al. (2010[Nenwa, J., Belombe, M. M., Ngoune, J. & Fokwa, B. P. T. (2010). Acta Cryst. E66, m1410.]); Chérif et al. (2011[Chérif, I., Abdelhak, J., Zid, M. F. & Driss, A. (2011). Acta Cryst. E67, m1648-m1649.]); Kahlenberg et al. (2011[Kahlenberg, V., Wertl, W., Többens, D. M. & Schottenberger, H. (2011). Z. Anorg. Allg. Chem. 637, 1371-1377.]). For geometric parameters of the imidazolium cation, see: Zhu (2012[Zhu, R.-Q. (2012). Acta Cryst. E68, m389.]); Smith & Wermuth (2010[Smith, G. & Wermuth, U. D. (2010). Acta Cryst. E66, o2399.]).

[Scheme 1]

Experimental

Crystal data
  • (C3H5N2)[Cr(C2O4)2(H2O)2]·2H2O

  • Mr = 369.19

  • Monoclinic, C 2/c

  • a = 10.836 (1) Å

  • b = 7.5409 (7) Å

  • c = 16.349 (3) Å

  • β = 93.52 (1)°

  • V = 1333.4 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.93 mm−1

  • T = 298 K

  • 0.6 × 0.4 × 0.3 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • Absorption correction: ψ scan (North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.647, Tmax = 0.757

  • 1848 measured reflections

  • 1452 independent reflections

  • 1369 reflections with I > 2σ(I)

  • Rint = 0.011

  • 2 standard reflections every 120 min intensity decay: 2.2%

Refinement
  • R[F2 > 2σ(F2)] = 0.029

  • wR(F2) = 0.086

  • S = 1.12

  • 1452 reflections

  • 124 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.55 e Å−3

  • Δρmin = −0.39 e Å−3

Table 1
Selected bond lengths (Å)

Cr—O3 1.963 (1)
Cr—O2 1.967 (1)
Cr—O1 1.979 (2)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O6—H1⋯O4i 0.80 (3) 2.20 (3) 2.984 (2) 168 (3)
O6—H4⋯O4ii 0.72 (3) 2.16 (3) 2.878 (2) 174 (4)
O1—H2⋯O5iii 0.79 (3) 1.93 (3) 2.717 (2) 173 (3)
O1—H3⋯O6iv 0.85 (3) 1.75 (3) 2.601 (2) 176 (3)
N1—H5⋯O3 1.04 (4) 2.07 (3) 2.926 (2) 137 (2)
C3—H7⋯O2iv 0.93 2.25 3.088 (3) 150
Symmetry codes: (i) x, y+1, z; (ii) [-x+{\script{3\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (iii) [x-{\script{1\over 2}}, y+{\script{1\over 2}}, z]; (iv) [-x+{\script{3\over 2}}, -y+{\script{1\over 2}}, -z+1].

Data collection: CAD-4 EXPRESS (Duisenberg, 1992[Duisenberg, A. J. M. (1992). J. Appl. Cryst. 25, 92-96.]; Macíček & Yordanov, 1992[Macíček, J. & Yordanov, A. (1992). J. Appl. Cryst. 25, 73-80.]); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: DIAMOND (Brandenburg & Putz, 1999[Brandenburg, K. & Putz, H. (1999). DIAMOND. Crystal Impact GbR. Bonn, Germany.]); software used to prepare material for publication: WinGX (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]).

Supporting information


Comment top

As part of our ongoing studies of new bis(oxalato)chromate(III) species of general formula (organic cation)[Cr(C2O4)2(H2O)2].nH2O (Chérif et al., 2012), we now describe the synthesis and structure of the title compound, (I).

The asymmetric unit of (I) is formed by one-half cation, one half anion and one water molecule of crystallization (Fig. 1). The Cr+III ion lies on an inversion center and the C and H atoms of C(4)—H(6) groups lie on twofold rotation axis. In the anionic complex, the coordination environment of Cr+III ion involves six oxygen atoms (two from trans water molecules and four from two chelating oxalate dianion) in a slightly distorted octahedral geometry. The main distortion of the CrO6 octahedron is associated to the reduction from the ideal 90° value of some bond angles [83.11 (5)° for O(3)—Cr—O(2) and O(3)i—Cr—O(2)i]. The equatorial Cr—O(ox) distances are very similar, 1.963 (1) Å [Cr—O(3), Cr—O(3)i] and 1.967 (1) Å [Cr—O(2), Cr—O(2)i], and they are comparable with the values reported for similar compounds containing the [Cr(C2O4)2(H2O)2]- motif completed with various uncoordinated cations including quinolinium: [C9H8N][Cr(H2O)2(C2O4)2] (Bélombé et al., 2009), 4-dimethylaminopyridinium: [C7H11N2][Cr(C2O4)2(H2O)2] (Nenwa et al., 2010), 4-aminopyridinium: [C5H7N2][Cr(C2O4)2(H2O)2]·H2O (Chérif et al., 2011), 1-ethyl-3-methylimidazolium: [EMIm][Cr(C2O4)2(H2O)2] (Kahlenberg et al., 2011) and 3-aminopyridinium (C5H7N2)[Cr(C2O4)2(H2O)2] (Chérif et al., 2012). The axial Cr—O(water) distances of 1.979 (2) Å are somewhat longer than the Cr—O(ox) ones but significantly shorter than those for compounds already mentioned. As far as the imidazolium cations are concerned, the C—N [1.363 (3) Å for N(1)—C(4) and N(1)ii—C(4), 1.295 (3) Å for N(1)—C(3) and N(1)ii—C(3)ii] and C—C bond lengths of 1.315 (4) Å for C(3)—C(3)ii, agree with those reported for similar compounds (Zhu, 2012; Smith & Wermuth, 2010).

Within the crystal structure, hydrogen bonds consisting of O—H···O, N—H···O and C—H···O interactions contribute to the cohesion of the packing (Fig. 2). In fact, for the O—H···O hydrogen bonds, the uncoordinated water molecules [O(6)] play a role as both acceptors and donors while the coordinated one [O(1)] act only as donors. Finally, the [Cr(C2O4)2(H2O)2]- anions and (C3H5N2)+ cations are linked through N(1)—H(5)···O(3) and C(3)—H(7)···O(2) interactions. As a consequence, the overall hydrogen-bonded scheme can be described as a three-dimensional network.

Related literature top

For a related structure and background to oxalate complexes, see: Chérif et al. (2012). For the structures of salts containing the [Cr(C2O4)2(H2O)2]- anion with various cations, see: Bélombé et al. (2009); Nenwa et al. (2010); Chérif et al. (2011); Kahlenberg et al. (2011). For geometric parameters of the imidazolium cation, see: Zhu (2012); Smith & Wermuth (2010).

Experimental top

A mixture of imidazole (1 mmol), oxalic acid dihydrate (2 mmol) and Cr(NO3)3·9H2O (1 mmol) was dissolved in 40 ml of water. The resulting solution was then stirred for 2 h and allowed to evaporate at room temperature. After two months, violet prisms of (I) were obtained.

Refinement top

All non hydrogen atoms were treated anisotropically and the H atoms were refined isotropically. After several cycles of refinement, the hydrogen atoms were found in a difference Fourier map and the H(7) was placed in calculated position with C—H distance of 0.93 Å and constrained to ride on his parent atom [C(3)] with Uiso(H)=1.2Ueq(C).

Computing details top

Data collection: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); cell refinement: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 1999); software used to prepare material for publication: WinGX (Farrugia, 2012).

Figures top
[Figure 1] Fig. 1. : A view of the title compound with displacement ellipsoids drawn at the 50% probability level for non-H atoms. [Symmetry codes: (i) -x + 3/2,-y + 1/2,-z + 1; (ii) -x + 2,y,-z + 3/2].
[Figure 2] Fig. 2. : Structure projection along b axis showing O—H···O (red dashed lines) and N—H···O (blue dashed lines) hydrogen bonds.
Imidazolium trans-diaquadioxalatochromate(III) dihydrate top
Crystal data top
(C3H5N2)[Cr(C2O4)2(H2O)2]·2H2OF(000) = 756
Mr = 369.19Dx = 1.839 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 25 reflections
a = 10.836 (1) Åθ = 10–15°
b = 7.5409 (7) ŵ = 0.93 mm1
c = 16.349 (3) ÅT = 298 K
β = 93.52 (1)°Prism, violet
V = 1333.4 (3) Å30.6 × 0.4 × 0.3 mm
Z = 4
Data collection top
Enraf–Nonius CAD-4
diffractometer
1369 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.011
Graphite monochromatorθmax = 27.0°, θmin = 2.5°
ω/2θ scansh = 1313
Absorption correction: ψ scan
(North et al., 1968)
k = 19
Tmin = 0.647, Tmax = 0.757l = 201
1848 measured reflections2 standard reflections every 120 min
1452 independent reflections intensity decay: 2.2%
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)] = 0.029Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.086H atoms treated by a mixture of independent and constrained refinement
S = 1.12 w = 1/[σ2(Fo2) + (0.0456P)2 + 1.7165P]
where P = (Fo2 + 2Fc2)/3
1452 reflections(Δ/σ)max < 0.001
124 parametersΔρmax = 0.55 e Å3
0 restraintsΔρmin = 0.39 e Å3
Crystal data top
(C3H5N2)[Cr(C2O4)2(H2O)2]·2H2OV = 1333.4 (3) Å3
Mr = 369.19Z = 4
Monoclinic, C2/cMo Kα radiation
a = 10.836 (1) ŵ = 0.93 mm1
b = 7.5409 (7) ÅT = 298 K
c = 16.349 (3) Å0.6 × 0.4 × 0.3 mm
β = 93.52 (1)°
Data collection top
Enraf–Nonius CAD-4
diffractometer
1369 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.011
Tmin = 0.647, Tmax = 0.7572 standard reflections every 120 min
1848 measured reflections intensity decay: 2.2%
1452 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0290 restraints
wR(F2) = 0.086H atoms treated by a mixture of independent and constrained refinement
S = 1.12Δρmax = 0.55 e Å3
1452 reflectionsΔρmin = 0.39 e Å3
124 parameters
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
Cr0.75000.25000.50000.02258 (15)
O20.70111 (13)0.12749 (18)0.39687 (8)0.0324 (3)
O30.83676 (12)0.02646 (17)0.52566 (8)0.0276 (3)
O40.73747 (15)0.12361 (19)0.33002 (9)0.0387 (4)
O60.86780 (17)0.5293 (2)0.31972 (10)0.0402 (4)
C10.83297 (15)0.0860 (2)0.46642 (11)0.0242 (4)
O10.59861 (14)0.1644 (2)0.54913 (11)0.0424 (4)
O50.88681 (13)0.22844 (18)0.46604 (9)0.0334 (3)
C20.75010 (16)0.0264 (2)0.38993 (11)0.0264 (4)
C30.9690 (2)0.1333 (3)0.71415 (13)0.0372 (5)
H70.94250.23370.68510.045*
N10.95088 (19)0.0291 (4)0.69055 (13)0.0575 (6)
C41.00000.1396 (5)0.75000.0518 (9)
H10.832 (3)0.618 (4)0.3298 (18)0.051 (8)*
H20.535 (3)0.199 (4)0.5285 (19)0.055 (8)*
H30.606 (3)0.101 (4)0.592 (2)0.056 (8)*
H40.837 (3)0.493 (5)0.283 (2)0.072 (12)*
H50.910 (4)0.078 (5)0.636 (2)0.085 (11)*
H61.00000.257 (7)0.75000.087 (18)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cr0.0263 (2)0.0204 (2)0.0200 (2)0.00213 (14)0.00693 (15)0.00055 (13)
O20.0411 (7)0.0286 (7)0.0257 (6)0.0078 (6)0.0137 (5)0.0039 (5)
O30.0326 (7)0.0246 (6)0.0242 (6)0.0035 (5)0.0095 (5)0.0005 (5)
O40.0485 (8)0.0352 (8)0.0306 (7)0.0058 (6)0.0109 (6)0.0097 (6)
O60.0554 (10)0.0333 (8)0.0311 (8)0.0038 (7)0.0030 (7)0.0006 (6)
C10.0222 (8)0.0235 (8)0.0262 (8)0.0013 (6)0.0029 (6)0.0014 (7)
O10.0296 (8)0.0528 (10)0.0441 (9)0.0015 (7)0.0030 (7)0.0219 (8)
O50.0326 (7)0.0260 (7)0.0408 (8)0.0062 (5)0.0053 (6)0.0010 (6)
C20.0277 (8)0.0267 (9)0.0242 (8)0.0009 (7)0.0045 (7)0.0010 (7)
C30.0401 (11)0.0382 (11)0.0335 (10)0.0124 (9)0.0040 (8)0.0118 (9)
N10.0402 (10)0.0946 (19)0.0362 (10)0.0027 (11)0.0099 (8)0.0193 (11)
C40.0457 (18)0.0294 (16)0.080 (3)0.0000.0024 (17)0.000
Geometric parameters (Å, º) top
Cr—O3i1.963 (1)C1—O51.223 (2)
Cr—O31.963 (1)C1—C21.560 (2)
Cr—O21.967 (1)O1—H20.79 (4)
Cr—O2i1.967 (1)O1—H30.85 (3)
Cr—O1i1.979 (2)C3—N11.295 (3)
Cr—O11.979 (2)C3—C3ii1.315 (4)
O2—C21.284 (2)C3—H70.9300
O3—C11.286 (2)N1—C41.363 (3)
O4—C21.224 (2)N1—H51.04 (4)
O6—H10.80 (3)C4—N1ii1.363 (3)
O6—H40.73 (4)C4—H60.89 (5)
O3i—Cr—O3180.0O5—C1—O3126.15 (16)
O3i—Cr—O296.89 (5)O5—C1—C2120.02 (16)
O3—Cr—O283.11 (5)O3—C1—C2113.83 (14)
O3i—Cr—O2i83.11 (5)Cr—O1—H2116 (2)
O3—Cr—O2i96.89 (5)Cr—O1—H3119 (2)
O2—Cr—O2i180.0H2—O1—H3125 (3)
O3i—Cr—O1i91.78 (7)O4—C2—O2125.83 (17)
O3—Cr—O1i88.22 (7)O4—C2—C1119.95 (16)
O2—Cr—O1i89.52 (7)O2—C2—C1114.21 (15)
O2i—Cr—O1i90.48 (7)N1—C3—C3ii108.99 (13)
O3i—Cr—O188.22 (7)N1—C3—H7125.5
O3—Cr—O191.78 (7)C3ii—C3—H7125.5
O2—Cr—O190.48 (7)C3—N1—C4108.7 (2)
O2i—Cr—O189.52 (7)C3—N1—H5130 (2)
O1i—Cr—O1180.0C4—N1—H5122 (2)
C2—O2—Cr114.16 (11)N1ii—C4—N1104.7 (3)
C1—O3—Cr114.36 (11)N1ii—C4—H6127.67 (16)
H1—O6—H4107 (3)N1—C4—H6127.67 (15)
Symmetry codes: (i) x+3/2, y+1/2, z+1; (ii) x+2, y, z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O6—H1···O4iii0.80 (3)2.20 (3)2.984 (2)168 (3)
O6—H4···O4iv0.72 (3)2.16 (3)2.878 (2)174 (4)
O1—H2···O5v0.79 (3)1.93 (3)2.717 (2)173 (3)
O1—H3···O6i0.85 (3)1.75 (3)2.601 (2)176 (3)
N1—H5···O31.04 (4)2.07 (3)2.926 (2)137 (2)
C3—H7···O2i0.932.253.088 (3)150
Symmetry codes: (i) x+3/2, y+1/2, z+1; (iii) x, y+1, z; (iv) x+3/2, y+1/2, z+1/2; (v) x1/2, y+1/2, z.
Selected bond lengths (Å) top
Cr—O31.963 (1)Cr—O11.979 (2)
Cr—O21.967 (1)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O6—H1···O4i0.80 (3)2.20 (3)2.984 (2)168 (3)
O6—H4···O4ii0.72 (3)2.16 (3)2.878 (2)174 (4)
O1—H2···O5iii0.79 (3)1.93 (3)2.717 (2)173 (3)
O1—H3···O6iv0.85 (3)1.75 (3)2.601 (2)176 (3)
N1—H5···O31.04 (4)2.07 (3)2.926 (2)137 (2)
C3—H7···O2iv0.932.253.088 (3)150
Symmetry codes: (i) x, y+1, z; (ii) x+3/2, y+1/2, z+1/2; (iii) x1/2, y+1/2, z; (iv) x+3/2, y+1/2, z+1.
 

References

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ISSN: 2056-9890
Volume 69| Part 12| December 2013| Pages m667-m668
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