Ethyl­ammonium hydrogen oxalate–oxalic acid (2/1)

Toure, A.; Diop, C.A.K.; Diop, L.; Plasseraud, L.; Cattey, H.

doi:10.1107/S2414314619006357

organic compounds

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ISSN: 2414-3146

Volume 4| Part 5| May 2019| x190635

https://doi.org/10.1107/S2414314619006357

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Ethylammonium hydrogen oxalate–oxalic acid (2/1)

Assane Toure,^a Cheikh Abdoul Khadir Diop,^a Libasse Diop,^a ^* Laurent Plasseraud ^b and Hélène Cattey ^b

^aLaboratoire de Chimie Minérale et Analytique (LACHIMIA), Département de Chimie, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal, and ^bICMUB UMR 6302, Université de Bourgogne, Faculté des Sciences, 9 avenue Alain Savary, 21000 DIJON, France
^*Correspondence e-mail: dlibasse@gmail.com

Edited by R. J. Butcher, Howard University, USA (Received 30 March 2019; accepted 4 May 2019; online 14 May 2019)

The reaction between ethylamine and oxalic acid in water in a 1:1 molar ratio afforded the title salt, C₂H₈N⁺·C₂HO₄⁻·0.5C₂H₂O₄. The hydrogen oxalate anions interact through hydrogen bonding and are organized into a chains propagating along the c-axis direction. The chains are connected to the neighbouring cations and oxalic acid molecules by N—H⋯O and O—H⋯O hydrogen bonds and N⋯O dipole–dipole contacts, leading to a supramolecular three-dimensional network.

Keywords: crystal structure; ammonium carboxylate salt; hydrogen bonding; hydrogen oxalate; oxalic acid.

CCDC reference: 1914197

Structure description

Ammonium carboxylate networks obtained by mixing dicarboxylic acids with amines is of interest in the field of crystal engineering (Ballabh et al. 2002 ; Haynes & Pietersen, 2008 ; Dziuk et al. 2014a ). These compounds exhibit a variety of structures that can lead, through non-covalent interactions (hydrogen bonding, π–π stacking, van der Waals and C—H⋯π contacts), to a large diversity of architectures and topologies. Dicarboxylic acids can act as polydirectional synthons, and amines, via the formation of ammonium, greatly increase the possible of linkages and interactions (Ivasenko & Perepichka, 2011 ; Yuge et al., 2008 ; Lemmerer, 2011 ). To date, many examples of such crystalline networks from oxalic acid and hydrogen oxalate have been described, see for example: Dziuk et al. (2014b ,c ); Braga et al. (2013 ); Ejsmont (2006 , 2007 ); Ejsmont & Zaleski (2006a ,b ); MacDonald et al. (2001 ). Our group has also contributed to this area by reporting recently two new structures of such compounds (Diallo et al., 2015 ; Diop et al., 2016 ). In a continuation of this work, we describe herein the synthesis and structure of the title salt I, isolated from an equimolar mixture of oxalic acid and ethylamine.

Compound I crystallizes in the monoclinic C2/c space group with the asymmetric unit comprising of one ethylammonium cation (C₂H₈N⁺), one hydrogen oxalate anion (C₂HO₄⁻) and a half-molecule of oxalic acid (C₂H₂O₄). The three components are linked together by several intermolecular interactions (Table 1 and Fig. 1). The interatomic distances and angles of the ethylammonium cation are in the range of those previously measured for comparable salts (Ejsmont & Zaleski, 2006a; Ejsmont, 2006). Each C₂H₈N⁺ cation is involved in N—H⋯O hydrogen bonding with two distinct C₂HO₄⁻ anions [N—HA⋯O4 = 2.8472 (11) and N—HB⋯O1 = 2.9409 (11) Å] and also with one neutral C₂H₂O₄ molecule [N—HC⋯O6 = 3.0400 (10) Å]. These interactions are reinforced by van der Waals contacts involving C₂H₈N⁺, and C₂HO₄⁻ and C₂H₂O₄, respectively [N⋯O3 = 2.8960 (11) and N⋯O5 = 2.9423 (11) Å]. The hydrogen oxalate anion is twisted with an O3—C2—C1—O2 torsion angle of 168.94 (8)°. The C—C and C—O bond distances [C1—C2 = 1.5570 (13), C1—O1 = 1.2141 (12), C1—O2 = 1.3090 (11), C2—O3 = 1.2415 (11), C2—O4 = 1.2565 (12) Å] are similar to those observed in the literature for other organic salts containing this anion (Barnes, 2003 ; Essid et al., 2013 ).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O3ⁱ	0.84	1.74	2.5717 (9)	173
N—HA⋯O4	0.91	1.94	2.8472 (11)	177
N—HB⋯O1ⁱⁱ	0.91	2.04	2.9409 (11)	172
N—HC⋯O6ⁱⁱⁱ	0.91	2.16	3.0400 (10)	163
O5—H5⋯O4	0.84	1.68	2.5139 (10)	173
Symmetry codes: (i) $[x, -y, z+{\script{1\over 2}}]$ ; (ii) $[-x+{\script{3\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iii) $[-x+1, y, -z+{\script{1\over 2}}]$ .

Figure 1
View of the title salt showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bonds are shown as dotted lines [symmetry codes: (i) x, −y, $[{1\over 2}]$ + z; (ii) 1 − x, −y, 1 − z; (iii) 1 − x, y, $[{1\over 2}]$ − z; (iv): $[{3\over 2}]$ − x, − $[{1\over 2}]$ + y, $[{1\over 2}]$ − z].

The hydrogen oxalate anions in I are linked into chains running parallel to the c axis by O2—H2⋯O3 hydrogen bonds [2.5717 (9) Å]. Adjacent chains are bridged by neutral oxalic acid molecules whose two OH groups participate in hydrogen-bonding interactions with two distinct hydrogen oxalate anions [O5—H5⋯O4 = 2.5139 (10) Å], resulting in the formation of sheets. These sheets are stacked along the b axis with the ethylammonium cations intercalated between the sheets, generating a three-dimensional network (Fig. 2).

Figure 2
The packing, viewed along the c axis, showing the intermolecular hydrogen-bonding scheme (dashed lines) [colour code: C dark grey, H white, O red, N blue].

A search on the online portal of the Cambridge Structural Database (WebCSD; Thomas et al., 2010 ) yielded 188 hits for ethylammonium salts and 25 hits for the hydrogen oxalate–oxalic acid combination.

Synthesis and crystallization

All the chemicals were purchased from Aldrich (Germany) and used without further purification. The title compound was obtained by reacting equimolar amounts of oxalic acid (1.26 g, 0.02 mol) and ethylamine (50% in water, 2.6 ml, 0.02 mol), in 25 ml of water at 298 K. The resulting solution was allowed to evaporate at 338 K, leading after few days to colourless prismatic suitable for X-ray analysis.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₂H₈N⁺·C₂HO₄⁻·0.5C₂H₂O₄
M_r	360.28
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	100
a, b, c (Å)	21.1667 (8), 6.6243 (3), 11.3247 (4)
β (°)	91.509 (2)
V (Å³)	1587.34 (11)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.14
Crystal size (mm)	0.47 × 0.3 × 0.17

Data collection
Diffractometer	Bruker D8 Venture triumph Mo
Absorption correction	Multi-scan (SADABS; Bruker, 2014 )
T_min, T_max	0.712, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	14201, 1829, 1624
R_int	0.027
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.028, 0.075, 1.03
No. of reflections	1829
No. of parameters	113
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.50, −0.20
Computer programs: APEX3 and SAINT (Bruker, 2014), SHELXT (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 1914197

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2414314619006357/bv4024sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314619006357/bv4024Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX3 (Bruker, 2014); cell refinement: SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Ethylammonium hydrogen oxalate–oxalic acid (2/1) top

Crystal data top

C₂H₈N⁺·C₂HO₄⁻·0.5C₂H₂O₄	F(000) = 760
M_r = 360.28	D_x = 1.508 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 21.1667 (8) Å	Cell parameters from 7758 reflections
b = 6.6243 (3) Å	θ = 3.2–27.5°
c = 11.3247 (4) Å	µ = 0.14 mm⁻¹
β = 91.509 (2)°	T = 100 K
V = 1587.34 (11) Å³	Prism, colourless
Z = 4	0.47 × 0.3 × 0.17 mm

Data collection top

Bruker D8 Venture triumph Mo diffractometer	1829 independent reflections
Radiation source: X-ray tube, Siemens KFF Mo 2K-90C	1624 reflections with I > 2σ(I)
TRIUMPH curved crystal monochromator	R_int = 0.027
Detector resolution: 1024 x 1024 pixels mm^-1	θ_max = 27.5°, θ_min = 3.2°
φ and ω scans'	h = −27→27
Absorption correction: multi-scan (SADABS; Bruker, 2014)	k = −8→8
T_min = 0.712, T_max = 0.746	l = −14→13
14201 measured reflections

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 constrained
wR(F²) = 0.075	w = 1/[σ²(F_o²) + (0.0383P)² + 1.1891P] where P = (F_o² + 2F_c²)/3
S = 1.03	(Δ/σ)_max = 0.001
1829 reflections	Δρ_max = 0.50 e Å⁻³
113 parameters	Δρ_min = −0.20 e Å⁻³

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. H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C—H = 0.99 Å (ethyl group) with U_iso(H) = 1.2U_eq(C) or O—H = 0.84 Å (hydroxyl), N—H = 0.91 Å (ammonium) and C—H = 0.98 Å (methyl group) with U_iso(H) = 1.5U_eq(O or N or C).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1	0.75227 (4)	−0.01386 (14)	0.48767 (8)	0.01041 (19)
O1	0.80530 (3)	−0.07888 (11)	0.50554 (6)	0.01374 (16)
C2	0.72301 (4)	−0.00320 (14)	0.36024 (8)	0.01042 (19)
O2	0.71415 (3)	0.05216 (11)	0.56824 (6)	0.01410 (17)
H2	0.731311	0.037617	0.635430	0.021*
O3	0.76073 (3)	−0.03334 (11)	0.28000 (6)	0.01506 (17)
O4	0.66506 (3)	0.03493 (11)	0.34790 (6)	0.01416 (17)
N	0.61063 (4)	0.32342 (12)	0.18905 (7)	0.01222 (18)
HA	0.626827	0.230748	0.240865	0.018*
HB	0.639850	0.352637	0.134066	0.018*
HC	0.575304	0.272353	0.152545	0.018*
C4	0.59405 (5)	0.51142 (15)	0.25420 (9)	0.0146 (2)
H4A	0.630646	0.555335	0.304026	0.018*
H4B	0.558307	0.484025	0.306532	0.018*
C5	0.57599 (5)	0.67710 (16)	0.16787 (10)	0.0199 (2)
H5A	0.612135	0.708562	0.118768	0.030*
H5B	0.563719	0.798067	0.211491	0.030*
H5C	0.540406	0.632035	0.117391	0.030*
C3	0.52681 (4)	0.03067 (14)	0.45853 (8)	0.0111 (2)
O5	0.57859 (3)	−0.06835 (11)	0.48337 (6)	0.01553 (17)
H5	0.607761	−0.025239	0.441275	0.023*
O6	0.51865 (3)	0.15638 (11)	0.38186 (6)	0.01596 (17)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0115 (4)	0.0107 (4)	0.0091 (4)	−0.0012 (3)	0.0008 (3)	0.0006 (3)
O1	0.0110 (3)	0.0190 (4)	0.0111 (3)	0.0022 (3)	−0.0007 (2)	0.0001 (3)
C2	0.0111 (4)	0.0109 (4)	0.0092 (4)	0.0000 (3)	−0.0002 (3)	0.0009 (3)
O2	0.0135 (3)	0.0212 (4)	0.0076 (3)	0.0033 (3)	0.0003 (3)	−0.0010 (3)
O3	0.0112 (3)	0.0251 (4)	0.0090 (3)	0.0026 (3)	0.0014 (2)	−0.0004 (3)
O4	0.0094 (3)	0.0218 (4)	0.0113 (3)	0.0026 (3)	0.0007 (2)	0.0037 (3)
N	0.0109 (4)	0.0143 (4)	0.0114 (4)	−0.0009 (3)	−0.0008 (3)	0.0014 (3)
C4	0.0131 (5)	0.0162 (5)	0.0145 (5)	0.0005 (4)	0.0012 (4)	−0.0009 (4)
C5	0.0187 (5)	0.0164 (5)	0.0247 (5)	0.0010 (4)	0.0022 (4)	0.0048 (4)
C3	0.0102 (4)	0.0130 (4)	0.0100 (4)	−0.0011 (3)	0.0003 (3)	−0.0016 (3)
O5	0.0095 (3)	0.0216 (4)	0.0157 (4)	0.0027 (3)	0.0040 (3)	0.0060 (3)
O6	0.0126 (3)	0.0202 (4)	0.0152 (4)	0.0001 (3)	0.0012 (3)	0.0064 (3)

Geometric parameters (Å, º) top

C1—O1	1.2141 (12)	C4—H4A	0.9900
C1—C2	1.5570 (13)	C4—H4B	0.9900
C1—O2	1.3090 (11)	C4—C5	1.5122 (14)
C2—O3	1.2415 (11)	C5—H5A	0.9800
C2—O4	1.2565 (12)	C5—H5B	0.9800
O2—H2	0.8400	C5—H5C	0.9800
N—HA	0.9100	C3—C3ⁱ	1.5467 (18)
N—HB	0.9100	C3—O5	1.3016 (12)
N—HC	0.9100	C3—O6	1.2121 (12)
N—C4	1.4940 (12)	O5—H5	0.8400

O1—C1—C2	120.93 (8)	N—C4—C5	110.14 (8)
O1—C1—O2	125.90 (9)	H4A—C4—H4B	108.1
O2—C1—C2	113.17 (8)	C5—C4—H4A	109.6
O3—C2—C1	115.04 (8)	C5—C4—H4B	109.6
O3—C2—O4	126.56 (9)	C4—C5—H5A	109.5
O4—C2—C1	118.40 (8)	C4—C5—H5B	109.5
C1—O2—H2	109.5	C4—C5—H5C	109.5
HA—N—HB	109.5	H5A—C5—H5B	109.5
HA—N—HC	109.5	H5A—C5—H5C	109.5
HB—N—HC	109.5	H5B—C5—H5C	109.5
C4—N—HA	109.5	O5—C3—C3ⁱ	111.32 (10)
C4—N—HB	109.5	O6—C3—C3ⁱ	121.50 (11)
C4—N—HC	109.5	O6—C3—O5	127.18 (9)
N—C4—H4A	109.6	C3—O5—H5	109.5
N—C4—H4B	109.6

O1—C1—C2—O3	−11.28 (13)	O2—C1—C2—O3	168.94 (8)
O1—C1—C2—O4	169.03 (9)	O2—C1—C2—O4	−10.75 (12)

Symmetry code: (i) −x+1, −y, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O3ⁱⁱ	0.84	1.74	2.5717 (9)	173
N—HA···O4	0.91	1.94	2.8472 (11)	177
N—HB···O1ⁱⁱⁱ	0.91	2.04	2.9409 (11)	172
N—HC···O6^iv	0.91	2.16	3.0400 (10)	163
O5—H5···O4	0.84	1.68	2.5139 (10)	173

Symmetry codes: (ii) x, −y, z+1/2; (iii) −x+3/2, y+1/2, −z+1/2; (iv) −x+1, y, −z+1/2.

Acknowledgements

The authors gratefully acknowledge the Cheikh Anta Diop University of Dakar (Senegal), the Centre National de la Recherche Scientifique (CNRS, France) and the University of Bourgogne Franche-Comté (Dijon, France) for support.

References

Ballabh, A., Trivedi, D. D., Dastidar, P. & Suresh, E. (2002). CrystEngComm, 4, 135–142. Web of Science CSD CrossRef CAS Google Scholar
Barnes, J. C. (2003). Acta Cryst. E59, o931–o933. Web of Science CSD CrossRef IUCr Journals Google Scholar
Braga, D., Chelazzi, L., Ciabatti, I. & Grepionoi, F. (2013). New J. Chem. 37, 97–104. Web of Science CSD CrossRef CAS Google Scholar
Bruker (2014). APEX3, SADABS and SAINT. Bruker AXS Inc, Madison, Wisconsin, USA. Google Scholar
Diallo, W., Gueye, N., Crochet, A., Plasseraud, L. & Cattey, H. (2015). Acta Cryst. E71, 473–475. Web of Science CSD CrossRef IUCr Journals Google Scholar
Diop, M. B., Diop, L., Plasseraud, L. & Cattey, H. (2016). Acta Cryst. E72, 1113–1115. Web of Science CSD CrossRef IUCr Journals Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Dziuk, B., Ejsmont, K. & Zaleski, J. (2014a). CHEMIK, 68, 391–395. CAS Google Scholar
Dziuk, B., Zarychta, B. & Ejsmont, K. (2014b). Acta Cryst. E70, o852. CSD CrossRef IUCr Journals Google Scholar
Dziuk, B., Zarychta, B. & Ejsmont, K. (2014c). Acta Cryst. E70, o917–o918. CSD CrossRef IUCr Journals Google Scholar
Ejsmont, K. (2006). Acta Cryst. E62, o5852–o5854. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Ejsmont, K. (2007). Acta Cryst. E63, o107–o109. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Ejsmont, K. & Zaleski, J. (2006a). Acta Cryst. E62, o3879–o3880. Web of Science CSD CrossRef IUCr Journals Google Scholar
Ejsmont, K. & Zaleski, J. (2006b). Acta Cryst. E62, o2512–o2513. Web of Science CSD CrossRef IUCr Journals Google Scholar
Essid, M., Marouani, H., Al-Deyab, S. S. & Rzaigui, M. (2013). Acta Cryst. E69, o1279. CSD CrossRef IUCr Journals Google Scholar
Haynes, D. A. & Pietersen, L. K. (2008). CrystEngComm, 10, 518–524. Web of Science CSD CrossRef CAS Google Scholar
Ivasenko, O. & Perepichka, D. F. (2011). Chem. Soc. Rev. 40, 191–206. Web of Science CrossRef CAS PubMed Google Scholar
Lemmerer, A. (2011). Cryst. Growth Des. 11, 583–593. Web of Science CSD CrossRef CAS Google Scholar
MacDonald, J. C., Dorrestein, P. C. & Pilley, M. M. (2001). Cryst. Growth Des. 1, 29–38. Web of Science CSD CrossRef CAS Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Thomas, I. R., Bruno, I. J., Cole, J. C., Macrae, C. F., Pidcock, E. & Wood, P. A. (2010). J. Appl. Cryst. 43, 362–366. Web of Science CrossRef CAS IUCr Journals Google Scholar
Yuge, T., Sakai, T., Kai, N., Hisaki, I., Miyata, M. & Tohnai, N. (2008). Chem. Eur. J. 14, 2984–2993. Web of Science CSD CrossRef PubMed CAS Google Scholar

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