Crystal structure of di­methyl­ammonium hydrogen oxalate hemi(oxalic acid)

Diallo, W.; Gueye, N.; Crochet, A.; Plasseraud, L.; Cattey, H.

doi:10.1107/S2056989015005964

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Volume 71| Part 5| May 2015| Pages 473-475

https://doi.org/10.1107/S2056989015005964

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Crystal structure of dimethylammonium hydrogen oxalate hemi(oxalic acid)

Waly Diallo,^a Ndongo Gueye,^a Aurélien Crochet,^b Laurent Plasseraud ^c and Hélène Cattey ^c ^*

^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.

Keywords: crystal structure; organic salt; hydrogen bonding; hydrogenoxalate; dialkyammonium; oxalic acid..

CCDC reference: 1055825

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 ] and dimethylammonium dichloridotriphenylstannate(IV) [Sow et al., 2012 ]. 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.

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 ; Thomas & Pramatus, 1975 ; Thomas, 1977 ; Gündisch et al., 2001 ; Warden et al., 2005 ). 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 ).

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). All three entities are linked by intermolecular interactions (Table 1 and Fig. 2). 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). 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	D⋯A	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
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
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

). 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 and Fig. 3), 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 and Figs. 2 and 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

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) and then completed in 1977 (Thomas, 1977), 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 and Figs. 2 and 3).

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. 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 U_iso(H) = 1.5U_eq(C,O) and 1.2U_eq(N).

Table 2
Experimental details

Crystal data
Chemical formula	C₂H₈N⁺·C₂HO₄⁻·0.5C₂H₂O₄
M_r	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)
V (Å³)	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 )
T_min, T_max	0.693, 0.746
No. of measured, independent and observed [I ≥ 2σ(I)] reflections	10413, 1840, 1655
R_int	0.023
(sin θ/λ)_max (Å⁻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
Δρ_max, Δρ_min (e Å⁻³)	0.38, −0.26
Computer programs: APEX2 and SAINT (Bruker, 2014), SUPERFLIP (Palatinus & Chapuis, 2007 ), SHELXL2014 (Sheldrick, 2015 ), OLEX2 (Dolomanov et al., 2009 ) and Mercury (Macrae et al., 2008 .

Supporting information

CCDC reference: 1055825

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2056989015005964/su5097sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989015005964/su5097Isup2.hkl

checkCIF report

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⁻·0.5C₂H₂O₄	Z = 2
M_r = 180.14	F(000) = 190.1598
Triclinic, P1	D_x = 1.497 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.6519 (3) Å	Cell parameters from 7049 reflections
b = 7.5809 (4) Å	θ = 3.0–27.6°
c = 10.3100 (6) Å	µ = 0.14 mm⁻¹
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-90C	1655 reflections with I ≥ 2σ(I)
TRIUMPH curved crystal monochromator	R_int = 0.023
φ and ω scans	θ_max = 27.6°, θ_min = 3.0°
Absorption correction: multi-scan (SADABS; Bruker, 2014)	h = −7→7
T_min = 0.693, T_max = 0.746	k = −9→9
10413 measured reflections	l = −13→13

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.028	H-atom parameters not refined
wR(F²) = 0.075	w = 1/[σ²(F_o²) + (0.0375P)² + 0.1325P] where P = (F_o² + 2F_c²)/3
S = 1.07	(Δ/σ)_max = 0.001
1840 reflections	Δρ_max = 0.38 e Å⁻³
113 parameters	Δρ_min = −0.26 e Å⁻³

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

	x	y	z	U_iso*/U_eq
O1	0.75407 (12)	0.32103 (10)	0.47166 (7)	0.01407 (16)
O2	0.57685 (12)	0.40754 (10)	0.26360 (7)	0.01329 (16)
O3	0.14369 (12)	0.38767 (11)	0.36954 (7)	0.01625 (17)
H3	0.0215	0.3632	0.4083	0.024*
O4	0.36051 (14)	0.20987 (11)	0.56626 (7)	0.02010 (17)
O5	0.29036 (13)	0.37192 (10)	0.09144 (7)	0.01471 (16)
H5	0.3683	0.3944	0.1497	0.022*
O6	0.01961 (13)	0.67729 (10)	0.07499 (7)	0.01568 (16)
C1	0.57857 (16)	0.34999 (13)	0.38821 (9)	0.01061 (18)
C2	0.34558 (17)	0.30728 (13)	0.45205 (9)	0.01216 (19)
C3	0.08336 (17)	0.52128 (13)	0.04793 (9)	0.01171 (19)
N1	0.22327 (15)	0.83866 (11)	0.24521 (8)	0.01223 (17)
H1A	0.3034	0.7852	0.3284	0.015*
H1B	0.1697	0.7490	0.2236	0.015*
C4	0.40571 (19)	0.88277 (15)	0.14735 (10)	0.0182 (2)
H4A	0.3224	0.9359	0.0569	0.027*
H4B	0.5500	0.7630	0.1500	0.027*
H4C	0.4653	0.9785	0.1705	0.027*
C5	−0.00007 (19)	1.01362 (14)	0.24892 (11)	0.0177 (2)
H5A	−0.0886	1.0711	0.1598	0.027*
H5B	0.0557	1.1091	0.2751	0.027*
H5C	−0.1149	0.9761	0.3143	0.027*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0100 (3)	0.0212 (4)	0.0119 (3)	−0.0072 (3)	−0.0008 (2)	−0.0031 (3)
O2	0.0113 (3)	0.0178 (3)	0.0107 (3)	−0.0060 (3)	−0.0004 (2)	−0.0024 (3)
O3	0.0089 (3)	0.0274 (4)	0.0131 (3)	−0.0087 (3)	0.0002 (3)	−0.0030 (3)
O4	0.0162 (4)	0.0286 (4)	0.0148 (3)	−0.0123 (3)	−0.0008 (3)	0.0022 (3)
O5	0.0134 (3)	0.0149 (3)	0.0150 (3)	−0.0021 (3)	−0.0044 (3)	−0.0059 (3)
O6	0.0178 (3)	0.0130 (3)	0.0166 (3)	−0.0046 (3)	−0.0040 (3)	−0.0051 (3)
C1	0.0087 (4)	0.0105 (4)	0.0127 (4)	−0.0028 (3)	0.0003 (3)	−0.0039 (3)
C2	0.0103 (4)	0.0154 (4)	0.0126 (4)	−0.0057 (3)	0.0004 (3)	−0.0050 (3)
C3	0.0127 (4)	0.0138 (4)	0.0091 (4)	−0.0059 (3)	−0.0003 (3)	−0.0018 (3)
N1	0.0145 (4)	0.0118 (4)	0.0107 (4)	−0.0050 (3)	−0.0005 (3)	−0.0028 (3)
C4	0.0166 (5)	0.0202 (5)	0.0186 (5)	−0.0074 (4)	0.0050 (4)	−0.0055 (4)
C5	0.0152 (5)	0.0148 (4)	0.0211 (5)	−0.0037 (4)	0.0033 (4)	−0.0034 (4)

Geometric parameters (Å, º) top

O1—C1	1.2573 (11)	N1—H1A	0.9100
O2—C1	1.2480 (11)	N1—H1B	0.9100
O3—H3	0.8400	N1—C4	1.4822 (12)
O3—C2	1.3089 (11)	N1—C5	1.4842 (12)
O4—C2	1.2105 (12)	C4—H4A	0.9800
O5—H5	0.8400	C4—H4B	0.9800
O5—C3	1.3051 (11)	C4—H4C	0.9800
O6—C3	1.2111 (12)	C5—H5A	0.9800
C1—C2	1.5515 (13)	C5—H5B	0.9800
C3—C3ⁱ	1.5501 (17)	C5—H5C	0.9800

C2—O3—H3	109.5	C5—N1—H1A	109.0
C3—O5—H5	109.5	C5—N1—H1B	109.0
O1—C1—C2	114.27 (8)	N1—C4—H4A	109.5
O2—C1—O1	126.60 (8)	N1—C4—H4B	109.5
O2—C1—C2	119.13 (8)	N1—C4—H4C	109.5
O3—C2—C1	112.45 (8)	H4A—C4—H4B	109.5
O4—C2—O3	126.54 (9)	H4A—C4—H4C	109.5
O4—C2—C1	121.01 (8)	H4B—C4—H4C	109.5
O5—C3—C3ⁱ	111.64 (10)	N1—C5—H5A	109.5
O6—C3—O5	126.87 (8)	N1—C5—H5B	109.5
O6—C3—C3ⁱ	121.48 (10)	N1—C5—H5C	109.5
H1A—N1—H1B	107.8	H5A—C5—H5B	109.5
C4—N1—H1A	109.0	H5A—C5—H5C	109.5
C4—N1—H1B	109.0	H5B—C5—H5C	109.5
C4—N1—C5	112.87 (8)

O1—C1—C2—O3	162.31 (8)	O2—C1—C2—O3	−17.79 (12)
O1—C1—C2—O4	−17.45 (13)	O2—C1—C2—O4	162.45 (9)

Symmetry code: (i) −x, −y+1, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O1ⁱⁱ	0.84	1.73	2.564 (1)	174
O5—H5···O2	0.84	1.73	2.565 (1)	170
N1—H1A···O1ⁱⁱⁱ	0.91	2.08	2.854 (1)	143
N1—H1A···O4ⁱⁱⁱ	0.91	2.23	2.964 (1)	137
N1—H1B···O6	0.91	2.05	2.846 (1)	146
C5—H5C···O4^iv	0.98	2.41	3.346 (1)	159

Symmetry codes: (ii) x−1, 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).

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