2-Ethyl-imidazolium terephthalate.

The asymmetric unit of the title compound, C(5)H(9)N(2) (+)·C(8)H(5)O(4) (-), consists of one protonated 2-ethyl-imidazolium cation and two half terephthalate anions. The anions and cations are linked through N-H⋯O hydrogen bonds while the anions are associated via O-H⋯O inter-actions, resulting in a layered structure. The ethyl group of the cation is disordered over twosites of occupancies 0.812 (14) and 0.188 (14). The hydroxy H atoms of the anions are equally disordered over two symmetry-related sites.

Related literature

The title compound was synthesized as part of our search for ferroelectric materials. For general background to ferroelectric organic frameworks, see: Fu et al. (2009 ▶); Ye et al. (2006 ▶); Zhang et al. (2008 ▶, 2010 ▶). For related structures, see: Tian (2007 ▶); Qu (2007 ▶).

Experimental

Crystal data

C5H9N2 +·C8H5O4 −

M = 262.26

Triclinic,

a = 6.4587 (13) Å

b = 7.0719 (14) Å

c = 14.688 (3) Å

α = 78.60 (3)°

β = 78.77 (3)°

γ = 89.50 (3)°

V = 644.7 (2) Å3

Z = 2

Mo Kα radiation

μ = 0.10 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 = 0.970, T max = 0.980

6568 measured reflections

2933 independent reflections

2197 reflections with I > 2σ(I)

R int = 0.034

Refinement

R[F 2 > 2σ(F 2)] = 0.060

wR(F 2) = 0.171

S = 1.07

2933 reflections

194 parameters

H-atom parameters constrained

Δρmax = 0.29 e Å−3

Δρmin = −0.24 e Å−3

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: DIAMOND (Brandenburg & Putz, 2005 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811038578/vm2120sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811038578/vm2120Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811038578/vm2120Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C5H9N2+·C8H5O4−	Z = 2
Mr = 262.26	F(000) = 276
Triclinic, P1	Dx = 1.348 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.4587 (13) Å	Cell parameters from 2933 reflections
b = 7.0719 (14) Å	θ = 2.2–27.5°
c = 14.688 (3) Å	µ = 0.10 mm−1
α = 78.60 (3)°	T = 293 K
β = 78.77 (3)°	Block, colourless
γ = 89.50 (3)°	0.30 × 0.25 × 0.20 mm
V = 644.7 (2) Å3

Rigaku SCXmini diffractometer	2933 independent reflections
Radiation source: fine-focus sealed tube	2197 reflections with I > 2σ(I)
graphite	Rint = 0.034
CCD Profile fitting scans	θmax = 27.5°, θmin = 3.0°
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	h = −8→8
Tmin = 0.970, Tmax = 0.980	k = −9→9
6568 measured reflections	l = −18→19

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)] = 0.060	H-atom parameters constrained
wR(F2) = 0.171	w = 1/[σ2(Fo2) + (0.0708P)2 + 0.3515P] where P = (Fo2 + 2Fc2)/3
S = 1.07	(Δ/σ)max < 0.001
2933 reflections	Δρmax = 0.29 e Å−3
194 parameters	Δρmin = −0.24 e Å−3
0 restraints	Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.084 (10)

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.

	x	y	z	Uiso*/Ueq	Occ. (<1)
C1	0.7347 (7)	0.9795 (9)	0.2520 (3)	0.0599 (13)	0.808 (14)
H1A	0.6126	1.0576	0.2508	0.090*	0.808 (14)
H1B	0.8455	1.0340	0.1999	0.090*	0.808 (14)
H1C	0.7815	0.9756	0.3105	0.090*	0.808 (14)
C2	0.6784 (7)	0.7753 (6)	0.2440 (3)	0.0508 (13)	0.808 (14)
H2A	0.5645	0.7218	0.2961	0.061*	0.808 (14)
H2B	0.6286	0.7802	0.1854	0.061*	0.808 (14)
C1'	0.544 (5)	0.812 (5)	0.2476 (14)	0.113 (11)	0.192 (14)
H1'A	0.4549	0.9202	0.2539	0.170*	0.192 (14)
H1'B	0.4893	0.7036	0.2965	0.170*	0.192 (14)
H1'C	0.5486	0.7805	0.1867	0.170*	0.192 (14)
C2'	0.759 (4)	0.863 (4)	0.2564 (12)	0.068 (7)	0.192 (14)
H2'A	0.7635	0.8948	0.3174	0.082*	0.192 (14)
H2'B	0.8256	0.9671	0.2057	0.082*	0.192 (14)
C3	0.8617 (4)	0.6470 (4)	0.24548 (17)	0.0477 (6)
C4	1.1731 (4)	0.5205 (4)	0.21494 (18)	0.0477 (6)
H4	1.3152	0.5068	0.1905	0.057*
C5	1.0399 (4)	0.3850 (4)	0.27270 (18)	0.0511 (6)
H5	1.0717	0.2583	0.2960	0.061*
C6	0.3529 (3)	0.2725 (3)	0.46010 (16)	0.0378 (5)
C7	0.1695 (3)	0.1309 (3)	0.48246 (14)	0.0327 (5)
C8	0.1917 (3)	−0.0380 (3)	0.44744 (16)	0.0392 (5)
H8	0.3206	−0.0636	0.4118	0.047*
C9	0.0230 (4)	−0.1691 (3)	0.46529 (16)	0.0398 (5)
H9	0.0394	−0.2826	0.4421	0.048*
C10	0.2463 (3)	0.1473 (3)	1.03616 (15)	0.0356 (5)
C11	0.3795 (3)	0.3302 (3)	1.01537 (14)	0.0303 (5)
C12	0.3127 (3)	0.5022 (3)	0.96744 (15)	0.0336 (5)
H12	0.1871	0.5039	0.9453	0.040*
C13	0.4326 (3)	0.6717 (3)	0.95247 (15)	0.0336 (5)
H13	0.3867	0.7866	0.9208	0.040*
N1	0.8498 (3)	0.4672 (3)	0.29095 (14)	0.0505 (6)
H1D	0.7379	0.4096	0.3271	0.061*
N2	1.0596 (3)	0.6826 (3)	0.19901 (14)	0.0472 (5)
H2C	1.1087	0.7915	0.1642	0.057*
O1	0.2779 (3)	0.0121 (2)	1.09758 (13)	0.0556 (5)
O2	0.1042 (3)	0.1504 (2)	0.98639 (14)	0.0573 (5)
H2	0.0476	0.0429	0.9968	0.086*	0.50
O3	0.4954 (3)	0.2675 (3)	0.39276 (13)	0.0595 (6)
O4	0.3451 (3)	0.3907 (3)	0.51614 (14)	0.0648 (6)
H4A	0.4374	0.4752	0.4941	0.097*	0.50

	U11	U22	U33	U12	U13	U23
C1	0.082 (3)	0.044 (3)	0.053 (2)	0.011 (2)	−0.0086 (18)	−0.0121 (18)
C2	0.043 (3)	0.055 (2)	0.050 (2)	−0.0016 (17)	0.0018 (16)	−0.0096 (16)
C1'	0.09 (2)	0.21 (3)	0.051 (11)	0.055 (18)	−0.021 (11)	−0.040 (14)
C2'	0.088 (14)	0.072 (19)	0.044 (8)	−0.025 (13)	−0.010 (8)	−0.012 (9)
C3	0.0503 (14)	0.0481 (13)	0.0376 (12)	−0.0027 (11)	0.0033 (10)	−0.0032 (10)
C4	0.0409 (13)	0.0482 (14)	0.0496 (14)	−0.0041 (10)	−0.0002 (11)	−0.0078 (11)
C5	0.0583 (16)	0.0408 (13)	0.0500 (14)	−0.0033 (11)	−0.0084 (12)	−0.0010 (11)
C6	0.0347 (11)	0.0369 (11)	0.0402 (12)	−0.0150 (9)	−0.0043 (9)	−0.0063 (9)
C7	0.0297 (10)	0.0330 (10)	0.0338 (10)	−0.0121 (8)	−0.0050 (8)	−0.0037 (8)
C8	0.0307 (11)	0.0415 (12)	0.0442 (12)	−0.0085 (9)	0.0012 (9)	−0.0138 (9)
C9	0.0386 (12)	0.0334 (11)	0.0471 (13)	−0.0105 (9)	−0.0011 (10)	−0.0143 (9)
C10	0.0339 (11)	0.0308 (10)	0.0400 (11)	−0.0143 (8)	−0.0007 (9)	−0.0073 (9)
C11	0.0296 (10)	0.0272 (9)	0.0319 (10)	−0.0110 (8)	−0.0002 (8)	−0.0062 (8)
C12	0.0284 (10)	0.0341 (10)	0.0394 (11)	−0.0086 (8)	−0.0093 (8)	−0.0069 (8)
C13	0.0337 (11)	0.0264 (9)	0.0392 (11)	−0.0069 (8)	−0.0082 (9)	−0.0016 (8)
N1	0.0473 (12)	0.0518 (12)	0.0420 (11)	−0.0162 (9)	0.0033 (9)	0.0040 (9)
N2	0.0486 (12)	0.0369 (10)	0.0459 (11)	−0.0128 (9)	0.0060 (9)	0.0019 (8)
O1	0.0599 (11)	0.0355 (9)	0.0645 (12)	−0.0245 (8)	−0.0137 (9)	0.0091 (8)
O2	0.0574 (11)	0.0468 (10)	0.0699 (12)	−0.0323 (9)	−0.0257 (10)	−0.0024 (9)
O3	0.0464 (10)	0.0627 (12)	0.0623 (12)	−0.0298 (9)	0.0151 (9)	−0.0197 (9)
O4	0.0571 (12)	0.0692 (13)	0.0679 (13)	−0.0384 (10)	0.0113 (9)	−0.0345 (10)

C1—C2	1.525 (7)	C6—O4	1.278 (3)
C1—H1A	0.9600	C6—C7	1.501 (3)
C1—H1B	0.9600	C7—C9i	1.383 (3)
C1—H1C	0.9600	C7—C8	1.387 (3)
C2—C3	1.486 (5)	C8—C9	1.388 (3)
C2—H2A	0.9700	C8—H8	0.9300
C2—H2B	0.9700	C9—C7i	1.383 (3)
C1'—C2'	1.47 (4)	C9—H9	0.9300
C1'—H1'A	0.9600	C10—O1	1.224 (3)
C1'—H1'B	0.9600	C10—O2	1.277 (3)
C1'—H1'C	0.9600	C10—C11	1.506 (3)
C2'—C3	1.69 (3)	C11—C13ii	1.384 (3)
C2'—H2'A	0.9700	C11—C12	1.390 (3)
C2'—H2'B	0.9700	C12—C13	1.389 (3)
C3—N1	1.310 (3)	C12—H12	0.9300
C3—N2	1.327 (3)	C13—C11ii	1.384 (3)
C4—C5	1.337 (3)	C13—H13	0.9300
C4—N2	1.361 (3)	N1—H1D	0.8600
C4—H4	0.9300	N2—H2C	0.8600
C5—N1	1.356 (4)	O2—H2	0.8200
C5—H5	0.9300	O4—H4A	0.8200
C6—O3	1.219 (3)
C2—C1—H1A	109.5	C4—C5—H5	126.5
C2—C1—H1B	109.5	N1—C5—H5	126.5
H1A—C1—H1B	109.5	O3—C6—O4	125.1 (2)
C2—C1—H1C	109.5	O3—C6—C7	119.7 (2)
H1A—C1—H1C	109.5	O4—C6—C7	115.20 (19)
H1B—C1—H1C	109.5	C9i—C7—C8	119.54 (18)
C3—C2—C1	112.1 (4)	C9i—C7—C6	121.07 (19)
C3—C2—H2A	109.2	C8—C7—C6	119.35 (19)
C1—C2—H2A	109.2	C7—C8—C9	120.4 (2)
C3—C2—H2B	109.2	C7—C8—H8	119.8
C1—C2—H2B	109.2	C9—C8—H8	119.8
H2A—C2—H2B	107.9	C7i—C9—C8	120.0 (2)
C2'—C1'—H1'A	109.5	C7i—C9—H9	120.0
C2'—C1'—H1'B	109.5	C8—C9—H9	120.0
H1'A—C1'—H1'B	109.5	O1—C10—O2	125.55 (19)
C2'—C1'—H1'C	109.5	O1—C10—C11	119.7 (2)
H1'A—C1'—H1'C	109.5	O2—C10—C11	114.72 (19)
H1'B—C1'—H1'C	109.5	C13ii—C11—C12	119.61 (18)
C1'—C2'—C3	96 (2)	C13ii—C11—C10	119.44 (18)
C1'—C2'—H2'A	112.6	C12—C11—C10	120.91 (18)
C3—C2'—H2'A	112.6	C13—C12—C11	120.29 (19)
C1'—C2'—H2'B	112.6	C13—C12—H12	119.9
C3—C2'—H2'B	112.6	C11—C12—H12	119.9
H2'A—C2'—H2'B	110.1	C11ii—C13—C12	120.10 (19)
N1—C3—N2	107.0 (2)	C11ii—C13—H13	120.0
N1—C3—C2	124.2 (3)	C12—C13—H13	120.0
N2—C3—C2	128.7 (2)	C3—N1—C5	110.0 (2)
N1—C3—C2'	140.7 (6)	C3—N1—H1D	125.0
N2—C3—C2'	106.2 (7)	C5—N1—H1D	125.0
C2—C3—C2'	31.6 (7)	C3—N2—C4	109.5 (2)
C5—C4—N2	106.4 (2)	C3—N2—H2C	125.2
C5—C4—H4	126.8	C4—N2—H2C	125.2
N2—C4—H4	126.8	C10—O2—H2	109.5
C4—C5—N1	107.0 (2)	C6—O4—H4A	109.5

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4A···O4iii	0.82	1.67	2.452 (3)	160.
O2—H2···O2iv	0.82	1.64	2.450 (3)	170.
N2—H2C···O1v	0.86	1.90	2.739 (3)	166.
N1—H1D···O3	0.86	1.86	2.713 (3)	173.

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H4A⋯O4i	0.82	1.67	2.452 (3)	160
O2—H2⋯O2ii	0.82	1.64	2.450 (3)	170
N2—H2C⋯O1iii	0.86	1.90	2.739 (3)	166
N1—H1D⋯O3	0.86	1.86	2.713 (3)	173

Symmetry codes: (i) ; (ii) ; (iii) .