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Crystal structure of di­methyl­ammonium hydrogen oxalate hemi(oxalic acid)

aLaboratoire de Chimie Minérale et Analytique (LACHIMIA), Département de Chimie, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal, bDepartment of Chemistry, University of Fribourg, Chemin des Musée 9, CH-1700 Fribourg, Switzerland, and cICMUB UMR 6302, Université de Bourgogne, Faculté des Sciences, 9 avenue Alain Savary, 21000 Dijon, France
*Correspondence e-mail: hcattey@u-bourgogne.fr, diallo_waly@yahoo.fr

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 18 March 2015; accepted 24 March 2015; online 11 April 2015)

Single crystals of the title salt, Me2NH2+·HC2O4·0.5H2C2O4, were isolated as a side product from the reaction involving Me2NH, H2C2O4 and Sn(n-Bu)3Cl in a 1:2 ratio in methanol or by the reaction of the (Me2NH2)2C2O4 salt and Sn(CH3)3Cl in a 2:1 ratio in ethanol. The asymmetric unit comprises a di­methyl­ammonium cation (Me2NH2+), an hydrogenoxalate anion (HC2O4), and half a mol­ecule of oxalic acid (H2C2O4) situated about an inversion center. From a supra­molecular point of view, the three components inter­act together via hydrogen bonding. The Me2NH2+ cations and the HC2O4 anions are in close proximity through bifurcated N—H⋯(O,O) hydrogen bonds, while the HC2O4 anions are organized into infinite chains via O—H⋯O hydrogen bonds, propagating along the a-axis direction. In addition, the oxalic acid (H2C2O4) mol­ecules play the role of connectors between these chains. Both the carbonyl and hydroxyl groups of each diacid are involved in four inter­molecular inter­actions with two Me2NH2+ and two HC2O4 ions of four distinct polymeric chains, via two N—H⋯O and two O—H⋯O hydrogen bonds, respectively. The resulting mol­ecular assembly can be viewed as a two-dimensional bilayer-like arrangement lying parallel to (010), and reinforced by a C—H⋯O hydrogen bond.

1. Chemical context

Within the scope of our research on the crystal structure determination of new organotin compounds containing dialkyammonium, we recently reported the structures of bis­(di­methyl­ammonium) tetra­chlorido­dimethyl­stannate(IV) [Diop et al., 2011[Diop, T., Diop, L. & Michaud, F. (2011). Acta Cryst. E67, m696.]] and di­methyl­ammonium di­chlorido­tri­phenyl­stannate(IV) [Sow et al., 2012[Sow, Y., Diop, L., Kociok-Kohn, G. & Molloy, K. C. (2012). Acta Cryst. E68, m1015-m1016.]]. Continuing our quest in this field, we report herein on the crystal structure of the title salt, Me2NH2+·HC2O4·0.5H2C2O4, isolated from two distinct reaction pathways, viz. mixing Me2NH, H2C2O4 and SnBu3Cl in methanol or the reaction of the (Me2NH2)2C2O4 salt and Sn(CH3)3Cl in ethanol.

[Scheme 1]

The title salt constitutes a new example of di­alkyl­ammonium hydrogenoxalates and thus supplements the number of crystal structures resolved to date for this type of salt (Birnbaum, 1972[Birnbaum, K. B. (1972). Acta Cryst. B28, 1551-1560.]; Thomas & Pramatus, 1975[Thomas, J. O. & Pramatus, S. (1975). Acta Cryst. B31, 2159-2161.]; Thomas, 1977[Thomas, J. O. (1977). Acta Cryst. B33, 2867-2876.]; Gündisch et al., 2001[Gündisch, D., Harms, K., Schwarz, S., Seitz, G., Stubbs, M. T. & Wegge, T. (2001). Bioorg. Med. Chem. 9, 2683-2691.]; Warden et al., 2005[Warden, A. C., Warren, M., Hearn, M. T. W. & Spiccia, L. (2005). Cryst. Growth Des. 5, 713-720.]). In addition, and because of their capacity to easily develop hydrogen-bonding networks, carb­oxy­lic acids and their deriv­atives are of great inter­est in the field of crystal engineering, leading to a large diversity of supra­molecular topologies (Ivasenko & Perepichka, 2011[Ivasenko, O. & Perepichka, D. F. (2011). Chem. Soc. Rev. 40, 191-206.]).

2. Structural comments

In the asymmetric unit of the title salt there are three components: one di­methyl­ammonium cation (Me2NH2+), one hydrogenoxalate anion (HC2O4), and half a mol­ecule of oxalic acid (H2C2O4) which possess inversion symmetry (Fig. 1[link]). All three entities are linked by inter­molecular inter­actions (Table 1[link] and Fig. 2[link]). The Me2NH2+ cation is in close proximity with the HC2O4 anion through bifurcated N—H⋯(O,O) hydrogen bonds [N1—H1A⋯O1 = 2.854 (1) Å and N1—H1A⋯O4 = 2.964 (1) Å]. The lengths of the N–C bonds [N1—C4 = 1.4822 (12) and N1—C5 = 1.4842 (12) Å] are nearly identical of those reported previously for Me2NH2+·HC2O4 (Thomas, 1977[Thomas, J. O. (1977). Acta Cryst. B33, 2867-2876.]). The Me2NH2+ cation is also involved in hydrogen bonding with one of the two carbonyl groups of the oxalic acid mol­ecule [N1—H1B⋯O6 = 2.846 (1) Å]. The HC2O4 hydrogenoxalate anions form a one-dimensional chain along the a-axis direction via the formation of O—H⋯O hydrogen bonds [O3—H3⋯O1 = 2.564 (1) Å]. Furthermore, the HC2O4 anion is also involved in hydrogen bonding with one of the two hydroxyl groups of the oxalic acid mol­ecule [O5—H5⋯O2 = 2.565 (1) Å].

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O3—H3⋯O1i 0.84 1.73 2.564 (1) 174
O5—H5⋯O2 0.84 1.73 2.565 (1) 170
N1—H1A⋯O1ii 0.91 2.08 2.854 (1) 143
N1—H1A⋯O4ii 0.91 2.23 2.964 (1) 137
N1—H1B⋯O6 0.91 2.05 2.846 (1) 146
C5—H5C⋯O4iii 0.98 2.41 3.346 (1) 159
Symmetry codes: (i) x-1, y, z; (ii) -x+1, -y+1, -z+1; (iii) -x, -y+1, -z+1.
[Figure 1]
Figure 1
A view of the mol­ecular structure of the title salt, with the atom labelling. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2]
Figure 2
Crystal packing of the title salt, viewed along the a axis, showing the two-dimensional bilayer-like arrangement formed through N—H⋯O and O—H⋯O hydrogen bonds (dashed lines; details are given in Table 1[link]). H atoms not involved in hydrogen bonding have been omitted for clarity.

3. Supra­molecular features

From a supra­molecular point of view, the combination of these inter­molecular inter­actions leads to the formation of a mol­ecular assembly which can be described as a two-dimensional bilayer-like arrangement, parallel to (010), consisting of anti­parallel infinite chains of Me2NH2+·HC2O4 (Table 1[link] and Fig. 3[link]), with an inter-chain distance of ca 3.0 Å. The oxalic acid mol­ecules are organized in a parallel offset fashion, and act as hydrogen-bond connectors between the chains, involving both the carbonyl and hydroxyl groups (Table 1[link] and Figs. 2[link] and 3[link]).

[Figure 3]
Figure 3
Crystal packing of the title salt viewed along the b axis. The hydrogen bonds are shown as dashed lines (see Table 1[link] for details) and H atoms not involved in hydrogen bonding have been omitted for clarity.

4. Database survey

The crystal structure of Me2NH2+·HC2O4, first reported by Thomas & Pramatus (1975[Thomas, J. O. & Pramatus, S. (1975). Acta Cryst. B31, 2159-2161.]) and then completed in 1977 (Thomas, 1977[Thomas, J. O. (1977). Acta Cryst. B33, 2867-2876.]), shows a supra­molecular structure qualified as a puckered layer. In particular, the HC2O4 ions are linked via O—H⋯O hydrogen bonds [2.533 (1) Å], leading to an infinite chain along [100]. In the title salt, the HC2O4 ions inter­act in the same manner but through slightly longer O—H⋯O hydrogen bonds [2.564 (1) Å]. In addition, the oxalic acid mol­ecules that co-crystallize with Me2NH2+·HC2O4 act both as donors and acceptors of hydrogen bonds through N—H⋯O and O—H⋯O bonds with the Me2NH2+ cation and HC2O4 anion, respectively. Consequently, the degree of supra­molecularity is increased here, resulting in a two-dimensional architecture parallel to (010), which is reinforced by a C—H⋯O hydrogen bond (Table 1[link] and Figs. 2[link] and 3[link]).

5. Synthesis and crystallization

Crystals of the title compound were obtained by mixing in 20 ml methanol (98% purity) Me2NH (0.30 g, 6.67 mmol), H2C2O4 (0.60 g, 6.67 mmol) and Sn(n-Bu)3Cl (4.39 g, 13.33 mmol). Another experimental method is the reaction between the (Me2NH2)2C2O4 salt (0.50 g, 2.77 mmol), previously synthesized from oxalic acid and di­methyl­amine, and Sn(CH3)3Cl (0.28 g, 1.39 mmol) in 15 ml of ethanol (98% purity). In both cases, the reaction mixture was stirred for ca 2 h at room temperature. Colourless crystals were obtained after one week by slow evaporation of the solvent.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. All the H atoms were placed in calculated positions and refined as riding: O—H = 0.84 Å, N—H = 0.91 Å, and C—H = 0.98 Å with Uiso(H) = 1.5Ueq(C,O) and 1.2Ueq(N).

Table 2
Experimental details

Crystal data
Chemical formula C2H8N+·C2HO4·0.5C2H2O4
Mr 180.14
Crystal system, space group Triclinic, P[\overline{1}]
Temperature (K) 100
a, b, c (Å) 5.6519 (3), 7.5809 (4), 10.3100 (6)
α, β, γ (°) 75.467 (2), 88.120 (2), 69.487 (2)
V3) 399.76 (4)
Z 2
Radiation type Mo Kα
μ (mm−1) 0.14
Crystal size (mm) 0.5 × 0.3 × 0.1
 
Data collection
Diffractometer Bruker D8 Venture triumph Mo
Absorption correction Multi-scan (SADABS; Bruker, 2014[Bruker (2014). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.693, 0.746
No. of measured, independent and observed [I ≥ 2σ(I)] reflections 10413, 1840, 1655
Rint 0.023
(sin θ/λ)max−1) 0.651
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.028, 0.075, 1.07
No. of reflections 1840
No. of parameters 113
H-atom treatment H-atom parameters not refined
Δρmax, Δρmin (e Å−3) 0.38, −0.26
Computer programs: APEX2 and SAINT (Bruker, 2014[Bruker (2014). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]), SUPERFLIP (Palatinus & Chapuis, 2007[Palatinus, L. & Chapuis, G. (2007). J. Appl. Cryst. 40, 786-790.]), SHELXL2014 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]) and Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.].

Supporting information


Computing details top

Data collection: APEX2 (Bruker, 2014); cell refinement: SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: Olex2 (Dolomanov et al., 2009) and Mercury (Macrae et al., 2008; software used to prepare material for publication: Olex2 (Dolomanov et al., 2009).

Dimethylammonium hydrogen oxalate hemi(oxalic acid) top
Crystal data top
C2H8N+·C2HO4·0.5C2H2O4Z = 2
Mr = 180.14F(000) = 190.1598
Triclinic, P1Dx = 1.497 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 5.6519 (3) ÅCell parameters from 7049 reflections
b = 7.5809 (4) Åθ = 3.0–27.6°
c = 10.3100 (6) ŵ = 0.14 mm1
α = 75.467 (2)°T = 100 K
β = 88.120 (2)°Prism, colourless
γ = 69.487 (2)°0.5 × 0.3 × 0.1 mm
V = 399.76 (4) Å3
Data collection top
Bruker D8 Venture triumph Mo
diffractometer
1840 independent reflections
Radiation source: X-ray tube, Siemens KFF Mo 2K-90C1655 reflections with I 2σ(I)
TRIUMPH curved crystal monochromatorRint = 0.023
φ and ω scansθmax = 27.6°, θmin = 3.0°
Absorption correction: multi-scan
(SADABS; Bruker, 2014)
h = 77
Tmin = 0.693, Tmax = 0.746k = 99
10413 measured reflectionsl = 1313
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.028H-atom parameters not refined
wR(F2) = 0.075 w = 1/[σ2(Fo2) + (0.0375P)2 + 0.1325P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max = 0.001
1840 reflectionsΔρmax = 0.38 e Å3
113 parametersΔρmin = 0.26 e Å3
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.75407 (12)0.32103 (10)0.47166 (7)0.01407 (16)
O20.57685 (12)0.40754 (10)0.26360 (7)0.01329 (16)
O30.14369 (12)0.38767 (11)0.36954 (7)0.01625 (17)
H30.02150.36320.40830.024*
O40.36051 (14)0.20987 (11)0.56626 (7)0.02010 (17)
O50.29036 (13)0.37192 (10)0.09144 (7)0.01471 (16)
H50.36830.39440.14970.022*
O60.01961 (13)0.67729 (10)0.07499 (7)0.01568 (16)
C10.57857 (16)0.34999 (13)0.38821 (9)0.01061 (18)
C20.34558 (17)0.30728 (13)0.45205 (9)0.01216 (19)
C30.08336 (17)0.52128 (13)0.04793 (9)0.01171 (19)
N10.22327 (15)0.83866 (11)0.24521 (8)0.01223 (17)
H1A0.30340.78520.32840.015*
H1B0.16970.74900.22360.015*
C40.40571 (19)0.88277 (15)0.14735 (10)0.0182 (2)
H4A0.32240.93590.05690.027*
H4B0.55000.76300.15000.027*
H4C0.46530.97850.17050.027*
C50.00007 (19)1.01362 (14)0.24892 (11)0.0177 (2)
H5A0.08861.07110.15980.027*
H5B0.05571.10910.27510.027*
H5C0.11490.97610.31430.027*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0100 (3)0.0212 (4)0.0119 (3)0.0072 (3)0.0008 (2)0.0031 (3)
O20.0113 (3)0.0178 (3)0.0107 (3)0.0060 (3)0.0004 (2)0.0024 (3)
O30.0089 (3)0.0274 (4)0.0131 (3)0.0087 (3)0.0002 (3)0.0030 (3)
O40.0162 (4)0.0286 (4)0.0148 (3)0.0123 (3)0.0008 (3)0.0022 (3)
O50.0134 (3)0.0149 (3)0.0150 (3)0.0021 (3)0.0044 (3)0.0059 (3)
O60.0178 (3)0.0130 (3)0.0166 (3)0.0046 (3)0.0040 (3)0.0051 (3)
C10.0087 (4)0.0105 (4)0.0127 (4)0.0028 (3)0.0003 (3)0.0039 (3)
C20.0103 (4)0.0154 (4)0.0126 (4)0.0057 (3)0.0004 (3)0.0050 (3)
C30.0127 (4)0.0138 (4)0.0091 (4)0.0059 (3)0.0003 (3)0.0018 (3)
N10.0145 (4)0.0118 (4)0.0107 (4)0.0050 (3)0.0005 (3)0.0028 (3)
C40.0166 (5)0.0202 (5)0.0186 (5)0.0074 (4)0.0050 (4)0.0055 (4)
C50.0152 (5)0.0148 (4)0.0211 (5)0.0037 (4)0.0033 (4)0.0034 (4)
Geometric parameters (Å, º) top
O1—C11.2573 (11)N1—H1A0.9100
O2—C11.2480 (11)N1—H1B0.9100
O3—H30.8400N1—C41.4822 (12)
O3—C21.3089 (11)N1—C51.4842 (12)
O4—C21.2105 (12)C4—H4A0.9800
O5—H50.8400C4—H4B0.9800
O5—C31.3051 (11)C4—H4C0.9800
O6—C31.2111 (12)C5—H5A0.9800
C1—C21.5515 (13)C5—H5B0.9800
C3—C3i1.5501 (17)C5—H5C0.9800
C2—O3—H3109.5C5—N1—H1A109.0
C3—O5—H5109.5C5—N1—H1B109.0
O1—C1—C2114.27 (8)N1—C4—H4A109.5
O2—C1—O1126.60 (8)N1—C4—H4B109.5
O2—C1—C2119.13 (8)N1—C4—H4C109.5
O3—C2—C1112.45 (8)H4A—C4—H4B109.5
O4—C2—O3126.54 (9)H4A—C4—H4C109.5
O4—C2—C1121.01 (8)H4B—C4—H4C109.5
O5—C3—C3i111.64 (10)N1—C5—H5A109.5
O6—C3—O5126.87 (8)N1—C5—H5B109.5
O6—C3—C3i121.48 (10)N1—C5—H5C109.5
H1A—N1—H1B107.8H5A—C5—H5B109.5
C4—N1—H1A109.0H5A—C5—H5C109.5
C4—N1—H1B109.0H5B—C5—H5C109.5
C4—N1—C5112.87 (8)
O1—C1—C2—O3162.31 (8)O2—C1—C2—O317.79 (12)
O1—C1—C2—O417.45 (13)O2—C1—C2—O4162.45 (9)
Symmetry code: (i) x, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3···O1ii0.841.732.564 (1)174
O5—H5···O20.841.732.565 (1)170
N1—H1A···O1iii0.912.082.854 (1)143
N1—H1A···O4iii0.912.232.964 (1)137
N1—H1B···O60.912.052.846 (1)146
C5—H5C···O4iv0.982.413.346 (1)159
Symmetry codes: (ii) x1, y, z; (iii) x+1, y+1, z+1; (iv) x, y+1, z+1.
 

Acknowledgements

The authors gratefully acknowledge support from the Cheikh Anta Diop University of Dakar (Senegal), the Centre National de la Recherche Scientifique (CNRS, France) and the University of Burgundy (Dijon, France).

References

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