2-Ethyl-1H-imidazol-3-ium hemioxalate oxalic acid monohydrate

Zhu, R.-Q.

doi:10.1107/S1600536811020733

organic compounds

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Volume 67| Part 7| July 2011| Page o1627

doi:10.1107/S1600536811020733

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2-Ethyl-1H-imidazol-3-ium hemioxalate oxalic acid monohydrate

Run-Qiang Zhu ^a ^*

^aOrdered Matter Science Research Center, College of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, People's Republic of China
^*Correspondence e-mail: zhurunqiang@163.com

(Received 25 April 2011; accepted 30 May 2011; online 11 June 2011)

In the title compound, C₅H₉N₂⁺·0.5C₂O₄²⁻·C₂H₂O₄·H₂O, the anions, cations and water moleculars are linked by N—H⋯O and O—H⋯O hydrogen bonds which define a tightly bound three-dimensional structure. The title compound is a layered structure as viewed along the a or c axis; one layer contains water and oxalic acid molecules, the other the imidazolium cation. The C atoms of the ethyl group of the 2-ethylimidazolium cation are disordered over two positions of equal occupancy.

Related literature

For general background to ferroelectric organic frameworks, see: Fu et al. (2009 ); Ye et al. (2006 ); Zhang et al. (2008 , 2010 ).

Experimental

Crystal data

C₅H₉N₂⁺·0.5C₂O₄²⁻·C₂H₂O₄·H₂O
M_r = 249.20
Monoclinic, P 2₁ /c
a = 6.971 (3) Å
b = 15.716 (7) Å
c = 10.484 (4) Å
β = 93.736 (8)°
V = 1146.1 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.13 mm⁻¹
T = 293 K
0.30 × 0.25 × 0.20 mm

Data collection

Rigaku SCXmini diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ) T_min = 0.962, T_max = 0.975
12371 measured reflections
2614 independent reflections
2192 reflections with I > 2σ(I)
R_int = 0.039

Refinement

R[F² > 2σ(F²)] = 0.046
wR(F²) = 0.115
S = 1.08
2614 reflections
183 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.44 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1B⋯O3ⁱ	0.86	2.01	2.855 (2)	166
N1—H1B⋯O1ⁱ	0.86	2.53	3.026 (2)	118
N2—H2A⋯O7ⁱⁱ	0.86	2.17	2.949 (2)	151
N2—H2A⋯O3	0.86	2.47	3.060 (2)	126
O1—H1A⋯O6ⁱⁱ	0.82	1.70	2.4800 (16)	159
O4—H4⋯O7ⁱⁱ	0.82	1.71	2.5283 (17)	174
O7—H7A⋯O5ⁱⁱ	0.84 (3)	1.87 (3)	2.7006 (18)	166 (2)
O7—H7B⋯O5ⁱⁱⁱ	0.88 (3)	1.82 (3)	2.6856 (19)	169 (2)
O7—H7B⋯O6^iv	0.88 (3)	2.47 (3)	2.923 (2)	113 (2)
Symmetry codes: (i) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ii) -x+1, -y+1, -z+1; (iii) x, y, z+1; (iv) -x+2, -y+1, -z+1.

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

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811020733/qm2009sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811020733/qm2009Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536811020733/qm2009Isup3.cml

checkCIF report

Comment top

The basic method to find potential ferroelectric phase change material is Dielectric constant measurement of compounds with temperature (Fu et al., 2009; Ye et al., 2006; Zhang et al., 2008; Zhang et al., 2010). Unfortunately, the title compound's dielectric dose not appear strange from 80 K to 298 K (m.p.219–229).

By X-ray diffraction analysis in 123 K, we can define the structure of title compound as Fig.1. Title compound, of the formula [C₅H₉N₂] ₂⁺ [C₂O₄]^2-.C₂H₂O₄.2H₂O, was obtained by 2 - ethyl imidazole, oxalic acid in water in basic aqueous solution and was isolated as colourless crystals. The whole molecules are organized in a three-dimensional structure involving hydrogen bonds, both intercationic and between cations and water molecules. The O···O distances of the hydrogen bonding are observed to be in the range of 2.476 (3)–2.924 (3) Å and the N···O distances of the hydrogen bonding are in the range of 2.054 (2) - 3.059 (2) Å for table1.

Related literature top

For general background on ferroelectric organic frameworks, see: Fu et al. (2009); Ye et al. (2006); Zhang et al. (2008, 2010).

Experimental top

A mixture of 2 - ethyl imidazole (2.4 g, 25 mmol), oxalic acid (3.15 g, 25 mmol) in water was stirred for several days at ambient temperature, Colourless sheet crystals were obtained.

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 (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. A partial packing diagram of the title compound, with the displacement ellipsoids were drawn at the 30% probability level.
	Fig. 2. Packing diagram of the title compound, hydrogen bonds are shown as dashed lines.

2-Ethyl-1H-imidazol-3-ium hemioxalate oxalic acid monohydrate top

Crystal data top

C₅H₉N₂⁺·0.5C₂O₄²⁻·C₂H₂O₄·H₂O	Z = 4
M_r = 249.20	F(000) = 524.0
Monoclinic, P2₁/c	D_x = 1.444 Mg m⁻³
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 6.971 (3) Å	θ = 2.3–27.5°
b = 15.716 (7) Å	µ = 0.13 mm⁻¹
c = 10.484 (4) Å	T = 293 K
β = 93.736 (8)°	Prism, colourless
V = 1146.1 (8) Å³	0.30 × 0.25 × 0.20 mm

Data collection top

Rigaku SCXmini diffractometer	2614 independent reflections
Radiation source: fine-focus sealed tube	2192 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.039
CCD_Profile_fitting scans	θ_max = 27.5°, θ_min = 2.9°
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	h = −9→9
T_min = 0.962, T_max = 0.975	k = −20→20
12371 measured reflections	l = −13→13

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.046	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.115	w = 1/[σ²(F_o²) + (0.0549P)² + 0.3631P] where P = (F_o² + 2F_c²)/3
S = 1.08	(Δ/σ)_max < 0.001
2614 reflections	Δρ_max = 0.35 e Å⁻³
183 parameters	Δρ_min = −0.44 e Å⁻³
3 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008)
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0

Crystal data top

C₅H₉N₂⁺·0.5C₂O₄²⁻·C₂H₂O₄·H₂O	V = 1146.1 (8) Å³
M_r = 249.20	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 6.971 (3) Å	µ = 0.13 mm⁻¹
b = 15.716 (7) Å	T = 293 K
c = 10.484 (4) Å	0.30 × 0.25 × 0.20 mm
β = 93.736 (8)°

Data collection top

Rigaku SCXmini diffractometer	2614 independent reflections
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	2192 reflections with I > 2σ(I)
T_min = 0.962, T_max = 0.975	R_int = 0.039
12371 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.046	3 restraints
wR(F²) = 0.115	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	Δρ_max = 0.35 e Å⁻³
2614 reflections	Δρ_min = −0.44 e Å⁻³
183 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

	x	y	z	U_iso*/U_eq	Occ. (<1)
C1	0.1308 (3)	0.28168 (12)	0.2483 (2)	0.0343 (4)
H1	0.0466	0.3066	0.3025	0.041*
C2	0.1140 (3)	0.20420 (12)	0.1945 (2)	0.0364 (5)
H2	0.0158	0.1652	0.2044	0.044*
C3	0.3798 (4)	0.26258 (12)	0.1326 (2)	0.0475 (6)
C6	0.2852 (2)	0.51305 (9)	0.44765 (14)	0.0159 (3)
C7	0.1981 (2)	0.55010 (10)	0.56719 (14)	0.0181 (3)
C8	0.9398 (2)	0.49850 (10)	0.06011 (14)	0.0169 (3)
N1	0.2691 (3)	0.19373 (9)	0.12234 (15)	0.0358 (4)
H1B	0.2914	0.1495	0.0774	0.043*
N2	0.2952 (2)	0.31678 (9)	0.20807 (16)	0.0349 (4)
H2A	0.3378	0.3666	0.2286	0.042*
O1	0.14141 (16)	0.48966 (7)	0.64012 (10)	0.0203 (3)
H1A	0.0967	0.5104	0.7036	0.031*
O2	0.1875 (2)	0.62570 (8)	0.58419 (13)	0.0393 (4)
O3	0.31598 (17)	0.43711 (7)	0.43807 (10)	0.0212 (3)
O4	0.32172 (16)	0.57027 (7)	0.36275 (10)	0.0201 (3)
H4	0.3622	0.5469	0.2999	0.030*
O5	0.76442 (16)	0.51317 (9)	0.04421 (11)	0.0278 (3)
O6	1.03061 (15)	0.48204 (8)	0.16451 (10)	0.0218 (3)
O7	0.54960 (17)	0.51036 (7)	0.82209 (11)	0.0202 (3)
H7A	0.442 (4)	0.5011 (14)	0.852 (2)	0.042 (6)*
H7B	0.631 (4)	0.5075 (15)	0.890 (3)	0.054 (7)*
C4	0.5878 (6)	0.2787 (2)	0.0900 (3)	0.0317 (8)	0.655 (6)
H4A	0.6477	0.3251	0.1390	0.038*	0.655 (6)
H4B	0.6659	0.2281	0.1040	0.038*	0.655 (6)
C5	0.5713 (5)	0.3010 (2)	−0.0500 (3)	0.0474 (11)	0.655 (6)
H5A	0.6971	0.3114	−0.0788	0.071*	0.655 (6)
H5B	0.4938	0.3511	−0.0627	0.071*	0.655 (6)
H5C	0.5126	0.2546	−0.0976	0.071*	0.655 (6)
C5'	0.6915 (11)	0.2936 (4)	0.0908 (7)	0.0416 (18)	0.345 (6)
H5'A	0.7855	0.3046	0.0299	0.062*	0.345 (6)
H5'B	0.7294	0.2445	0.1408	0.062*	0.345 (6)
H5'C	0.6822	0.3419	0.1459	0.062*	0.345 (6)
C4'	0.4958 (9)	0.2770 (3)	0.0199 (6)	0.0285 (17)	0.345 (6)
H4'A	0.4507	0.3258	−0.0301	0.034*	0.345 (6)
H4'B	0.4980	0.2272	−0.0347	0.034*	0.345 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0365 (10)	0.0252 (9)	0.0430 (11)	0.0018 (7)	0.0161 (9)	−0.0093 (8)
C2	0.0340 (10)	0.0249 (9)	0.0510 (12)	0.0005 (8)	0.0089 (9)	−0.0090 (9)
C3	0.0680 (14)	0.0176 (8)	0.0619 (14)	0.0043 (8)	0.0436 (12)	−0.0004 (9)
C6	0.0147 (7)	0.0181 (7)	0.0152 (7)	−0.0011 (5)	0.0025 (5)	0.0011 (6)
C7	0.0186 (7)	0.0197 (8)	0.0167 (7)	0.0002 (6)	0.0054 (6)	−0.0007 (6)
C8	0.0158 (7)	0.0207 (7)	0.0148 (7)	0.0004 (6)	0.0047 (6)	−0.0005 (6)
N1	0.0606 (11)	0.0176 (7)	0.0312 (8)	0.0073 (6)	0.0169 (8)	−0.0054 (6)
N2	0.0422 (9)	0.0179 (7)	0.0466 (10)	0.0011 (6)	0.0166 (8)	−0.0085 (7)
O1	0.0273 (6)	0.0199 (6)	0.0149 (5)	0.0002 (4)	0.0096 (4)	0.0004 (4)
O2	0.0628 (9)	0.0165 (6)	0.0427 (8)	0.0004 (6)	0.0359 (7)	−0.0034 (5)
O3	0.0300 (6)	0.0157 (5)	0.0188 (6)	0.0006 (4)	0.0085 (5)	0.0001 (4)
O4	0.0275 (6)	0.0173 (5)	0.0166 (5)	0.0009 (4)	0.0089 (4)	0.0024 (4)
O5	0.0141 (6)	0.0540 (8)	0.0158 (6)	0.0034 (5)	0.0051 (4)	0.0023 (5)
O6	0.0172 (6)	0.0350 (7)	0.0134 (5)	0.0028 (5)	0.0037 (4)	0.0025 (5)
O7	0.0159 (6)	0.0284 (6)	0.0168 (6)	0.0005 (5)	0.0046 (5)	−0.0002 (5)
C4	0.0362 (17)	0.0220 (15)	0.0368 (16)	0.0076 (14)	0.0020 (19)	−0.0043 (12)
C5	0.051 (2)	0.048 (2)	0.0449 (17)	0.0109 (16)	0.0211 (17)	0.0148 (16)
C5'	0.028 (4)	0.037 (4)	0.059 (4)	−0.001 (3)	−0.001 (3)	−0.014 (3)
C4'	0.036 (3)	0.023 (3)	0.028 (4)	0.002 (2)	0.010 (3)	−0.002 (2)

Geometric parameters (Å, º) top

C1—C2	1.344 (3)	N2—H2A	0.8600
C1—N2	1.363 (3)	O1—H1A	0.8200
C1—H1	0.9300	O4—H4	0.8200
C2—N1	1.369 (2)	O7—H7A	0.84 (3)
C2—H2	0.9300	O7—H7B	0.88 (3)
C3—N1	1.329 (3)	C4—C5	1.505 (5)
C3—N2	1.327 (2)	C4—H4A	0.9700
C3—C4'	1.491 (6)	C4—H4B	0.9700
C3—C4	1.565 (5)	C5—H5A	0.9600
C6—O3	1.2179 (19)	C5—H5B	0.9600
C6—O4	1.3022 (18)	C5—H5C	0.9600
C6—C7	1.542 (2)	C5'—C4'	1.532 (10)
C7—O2	1.204 (2)	C5'—H5'A	0.9600
C7—O1	1.2970 (19)	C5'—H5'B	0.9600
C8—O5	1.2449 (19)	C5'—H5'C	0.9600
C8—O6	1.2550 (19)	C4'—H4'A	0.9700
C8—C8ⁱ	1.559 (3)	C4'—H4'B	0.9700
N1—H1B	0.8600

C2—C1—N2	106.81 (16)	C7—O1—H1A	109.5
C2—C1—H1	126.6	C6—O4—H4	109.5
N2—C1—H1	126.6	H7A—O7—H7B	104 (2)
C1—C2—N1	106.87 (17)	C5—C4—C3	107.6 (3)
C1—C2—H2	126.6	C5—C4—H4A	110.2
N1—C2—H2	126.6	C3—C4—H4A	110.2
N1—C3—N2	106.99 (18)	C5—C4—H4B	110.2
N1—C3—C4'	113.7 (3)	C3—C4—H4B	110.2
N2—C3—C4'	131.3 (3)	H4A—C4—H4B	108.5
N1—C3—C4	130.74 (19)	C4—C5—H5A	109.5
N2—C3—C4	121.5 (2)	C4—C5—H5B	109.5
C4'—C3—C4	35.9 (3)	H5A—C5—H5B	109.5
O3—C6—O4	125.24 (14)	C4—C5—H5C	109.5
O3—C6—C7	121.20 (13)	H5A—C5—H5C	109.5
O4—C6—C7	113.55 (13)	H5B—C5—H5C	109.5
O2—C7—O1	127.68 (14)	C4'—C5'—H5'A	109.5
O2—C7—C6	121.60 (14)	C4'—C5'—H5'B	109.5
O1—C7—C6	110.71 (13)	H5'A—C5'—H5'B	109.5
O5—C8—O6	126.16 (14)	C4'—C5'—H5'C	109.5
O5—C8—C8ⁱ	117.49 (17)	H5'A—C5'—H5'C	109.5
O6—C8—C8ⁱ	116.35 (16)	H5'B—C5'—H5'C	109.5
C3—N1—C2	109.44 (15)	C3—C4'—C5'	98.8 (5)
C3—N1—H1B	125.3	C3—C4'—H4'A	112.0
C2—N1—H1B	125.3	C5'—C4'—H4'A	112.0
C3—N2—C1	109.87 (16)	C3—C4'—H4'B	112.0
C3—N2—H2A	125.1	C5'—C4'—H4'B	112.0
C1—N2—H2A	125.1	H4'A—C4'—H4'B	109.7

Symmetry code: (i) −x+2, −y+1, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O3ⁱⁱ	0.86	2.01	2.855 (2)	166
N1—H1B···O1ⁱⁱ	0.86	2.53	3.026 (2)	118
N2—H2A···O7ⁱⁱⁱ	0.86	2.17	2.949 (2)	151
N2—H2A···O3	0.86	2.47	3.060 (2)	126
O1—H1A···O6ⁱⁱⁱ	0.82	1.70	2.4800 (16)	159
O4—H4···O7ⁱⁱⁱ	0.82	1.71	2.5283 (17)	174
O7—H7A···O5ⁱⁱⁱ	0.84 (3)	1.87 (3)	2.7006 (18)	166 (2)
O7—H7B···O5^iv	0.88 (3)	1.82 (3)	2.6856 (19)	169 (2)
O7—H7B···O6^v	0.88 (3)	2.47 (3)	2.923 (2)	113 (2)

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

Experimental details

Crystal data
Chemical formula	C₅H₉N₂⁺·0.5C₂O₄²⁻·C₂H₂O₄·H₂O
M_r	249.20
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	6.971 (3), 15.716 (7), 10.484 (4)
β (°)	93.736 (8)
V (Å³)	1146.1 (8)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.13
Crystal size (mm)	0.30 × 0.25 × 0.20

Data collection
Diffractometer	Rigaku SCXmini diffractometer
Absorption correction	Multi-scan (CrystalClear; Rigaku, 2005)
T_min, T_max	0.962, 0.975
No. of measured, independent and observed [I > 2σ(I)] reflections	12371, 2614, 2192
R_int	0.039
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.046, 0.115, 1.08
No. of reflections	2614
No. of parameters	183
No. of restraints	3
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.35, −0.44

Computer programs: CrystalClear (Rigaku, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O3ⁱ	0.86	2.01	2.855 (2)	166.4
N1—H1B···O1ⁱ	0.86	2.53	3.026 (2)	117.7
N2—H2A···O7ⁱⁱ	0.86	2.17	2.949 (2)	151.2
N2—H2A···O3	0.86	2.47	3.060 (2)	126.2
O1—H1A···O6ⁱⁱ	0.82	1.70	2.4800 (16)	159.4
O4—H4···O7ⁱⁱ	0.82	1.71	2.5283 (17)	174.4
O7—H7A···O5ⁱⁱ	0.84 (3)	1.87 (3)	2.7006 (18)	166 (2)
O7—H7B···O5ⁱⁱⁱ	0.88 (3)	1.82 (3)	2.6856 (19)	169 (2)
O7—H7B···O6^iv	0.88 (3)	2.47 (3)	2.923 (2)	113 (2)

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

Acknowledgements

This work was supported by Southeast University.

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