4-Eth­oxy­anilinium chloride

The title compound, C₈H₁₂NO⁺·Cl⁻, consists of an almost planar protonated 4-eth­oxy­anilinium cation with the N atom showing the biggest deviation from the plane formed by all non-H atoms of the cation [0.066 (1) Å]. In the crystal, N—H...Cl hydrogen bonds link cations and anions into chains along the a axis. Additional C—H...π and π–π inter­actions [centroid–centroid distance = 4.873 (2) Å] stabilize the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.045
• wR factor = 0.106
• Data-to-parameter ratio = 18.9

checkCIF/PLATON results

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Alert level C
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          2
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          2

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The crystal structure of 4-ethoxyanilinium perchlorate as well as those of 2- and 4-methoxyanilinium chloride are known (Fu, 2009; Zhao, 2009; Jiang et al., 1996). In this article, the crystal structure of (I) is presented.

The asymmetric unit of the title compound is built by an almost planar protonated 4-ethoxyanilinium cation and a Cl^- anion (Fig. 1). C—H···π interactions with a C4—H4A···Cg1 distance of 3.654 (2) Å and a C7—H7B···Cg1 distance of 3.710 (2) Å, respectively, as well as π-π packing interactions of adjacent benzene rings with a Cg1—Cg1 distance of 4.873 (2) Å, make a great contribution to the observed crystal structure (Cg1 is the centroid of benzene ring). Additional N—H···Cl hydrogen bonding with N—Cl distances of 3.104 (2) Å to 3.114 (2) Å (Table.1) link the cations and anions into chains along a axis (Fig.2).

Related literature

For background to phase-transition materials, see: Li et al. (2008); Ye et al. (2009); Zhang et al. (2009). For similar structures, see: Fu (2009); Jiang et al. (1996); Zhao (2009).

S2. Experimental

Single crystals suitable for X-ray diffraction were obtained by slow evaporation at room temperature of an ethanolic solution of equimolar amounts of 4-ethoxyaniline and 6M hydrochloric acid.

Dielectric studies (capacitance and dielectric loss measurements) were performed using an automatic impedance TongHui2828 Analyzer on powder samples that were pressed into tablets on the surfaces of which a conducting carbon glue was deposited. Dielectric permittivity of the compound was tested to systematically to investigate the possibility of ferroelectric phase transitions (Li et al., 2008, Ye et al., 2009; Zhang et al., 2009). Unfortunately, the temperature dependence of the relative permittivity at 1 MHz varied smoothly from 4.0 to 4.3 and there was no distinct anomaly observed from 93 K to 350 K (sublimation higher than 378 K) in the title compound, suggesting that this compound should not be a real ferroelectric or that no distinct phase transition occurred within the measured temperature range.

S3. Refinement

Positional parameters of all the H atoms for C atoms were calculated geometrically and were allowed to ride on the C atoms to which they are bonded, with U_iso(H) = 1.2U_eq(C). H atoms bonded to nitrogen atom were found in the difference maps and refined freely.

Computing details

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

	Fig. 1. Molecular structure of the title compound, with the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. A view of the packing of the title compound, stacking along the b axis. Dashed lines indicate hydrogen bonds.

4-Ethoxyanilinium chloride

Crystal data

C8H12NO^+·Cl^−	F(000) = 736
Mr = 173.64	Dx = 1.245 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 7266 reflections
a = 11.422 (2) Å	θ = 3.0–27.7°
b = 7.0890 (14) Å	µ = 0.36 mm^−1
c = 22.887 (5) Å	T = 298 K
V = 1853.2 (6) Å^3	Prism, colourless
Z = 8	0.40 × 0.30 × 0.20 mm

Data collection

Rigaku SCXmini diffractometer	2116 independent reflections
Radiation source: fine-focus sealed tube	1655 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.044
Detector resolution: 13.6612 pixels mm^-1	θmax = 27.5°, θmin = 3.5°
ω scans	h = −14→14
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −9→9
Tmin = 0.879, Tmax = 0.931	l = −29→29
17046 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.106	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0383P)^2 + 0.7382P] where P = (Fo^2 + 2Fc^2)/3
2116 reflections	(Δ/σ)max < 0.001
112 parameters	Δρmax = 0.27 e Å^−3
0 restraints	Δρmin = −0.23 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Cl1	0.36897 (4)	0.14153 (8)	0.73645 (2)	0.0565 (2)
C3	0.39597 (14)	0.6120 (3)	0.64180 (8)	0.0382 (4)
O1	0.39659 (12)	0.76724 (19)	0.46863 (5)	0.0495 (4)
C6	0.39549 (15)	0.7056 (3)	0.52510 (8)	0.0384 (4)
N1	0.39087 (15)	0.5668 (3)	0.70418 (7)	0.0456 (4)
H1D	0.323 (2)	0.619 (3)	0.7215 (10)	0.072 (7)*
H1C	0.451 (2)	0.614 (4)	0.7224 (11)	0.081 (8)*
H1B	0.387 (2)	0.442 (5)	0.7096 (12)	0.084 (9)*
C7	0.34271 (19)	0.6523 (3)	0.42485 (8)	0.0509 (5)
H7A	0.2601	0.6365	0.4333	0.061*
H7B	0.3791	0.5287	0.4240	0.061*
C5	0.34210 (18)	0.5419 (3)	0.54364 (9)	0.0511 (5)
H5A	0.3060	0.4626	0.5168	0.061*
C4	0.34242 (17)	0.4958 (3)	0.60251 (9)	0.0507 (5)
H4A	0.3061	0.3858	0.6152	0.061*
C1	0.45119 (17)	0.8200 (3)	0.56533 (8)	0.0468 (5)
H1A	0.4890	0.9289	0.5528	0.056*
C8	0.3583 (2)	0.7490 (4)	0.36708 (9)	0.0651 (6)
H8A	0.3226	0.6748	0.3369	0.098*
H8B	0.4403	0.7631	0.3590	0.098*
H8C	0.3220	0.8711	0.3684	0.098*
C2	0.45113 (17)	0.7739 (3)	0.62369 (8)	0.0456 (5)
H2A	0.4882	0.8517	0.6507	0.055*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0385 (3)	0.0715 (4)	0.0596 (3)	−0.0036 (2)	−0.0107 (2)	0.0117 (3)
C3	0.0278 (8)	0.0501 (11)	0.0366 (9)	0.0017 (7)	−0.0005 (7)	0.0041 (8)
O1	0.0676 (9)	0.0474 (8)	0.0334 (7)	−0.0125 (7)	−0.0020 (6)	0.0020 (6)
C6	0.0387 (9)	0.0406 (10)	0.0359 (9)	−0.0017 (8)	0.0015 (7)	0.0015 (8)
N1	0.0329 (9)	0.0653 (13)	0.0387 (9)	0.0010 (8)	−0.0008 (7)	0.0082 (9)
C7	0.0576 (12)	0.0565 (12)	0.0387 (10)	−0.0041 (10)	−0.0017 (8)	−0.0069 (9)
C5	0.0571 (12)	0.0524 (12)	0.0438 (11)	−0.0209 (10)	−0.0067 (9)	0.0004 (9)
C4	0.0510 (11)	0.0532 (12)	0.0477 (11)	−0.0204 (9)	−0.0022 (8)	0.0079 (10)
C1	0.0583 (12)	0.0393 (10)	0.0428 (10)	−0.0122 (9)	0.0003 (9)	0.0029 (8)
C8	0.0884 (17)	0.0686 (15)	0.0382 (11)	0.0068 (13)	−0.0028 (10)	−0.0032 (11)
C2	0.0511 (11)	0.0438 (11)	0.0418 (10)	−0.0087 (9)	−0.0053 (8)	−0.0045 (8)

Geometric parameters (Å, º)

C3—C4	1.364 (3)	C7—H7A	0.9700
C3—C2	1.373 (3)	C7—H7B	0.9700
C3—N1	1.464 (2)	C5—C4	1.386 (3)
O1—C6	1.364 (2)	C5—H5A	0.9300
O1—C7	1.431 (2)	C4—H4A	0.9300
C6—C5	1.378 (3)	C1—C2	1.375 (3)
C6—C1	1.382 (3)	C1—H1A	0.9300
N1—H1D	0.94 (2)	C8—H8A	0.9600
N1—H1C	0.87 (3)	C8—H8B	0.9600
N1—H1B	0.90 (3)	C8—H8C	0.9600
C7—C8	1.500 (3)	C2—H2A	0.9300
C4—C3—C2	120.75 (17)	C6—C5—C4	119.76 (18)
C4—C3—N1	119.51 (18)	C6—C5—H5A	120.1
C2—C3—N1	119.70 (17)	C4—C5—H5A	120.1
C6—O1—C7	118.49 (15)	C3—C4—C5	119.98 (18)
O1—C6—C5	124.45 (17)	C3—C4—H4A	120.0
O1—C6—C1	116.03 (16)	C5—C4—H4A	120.0
C5—C6—C1	119.51 (17)	C2—C1—C6	120.50 (17)
C3—N1—H1D	110.9 (14)	C2—C1—H1A	119.7
C3—N1—H1C	110.6 (17)	C6—C1—H1A	119.7
H1D—N1—H1C	107 (2)	C7—C8—H8A	109.5
C3—N1—H1B	110.7 (18)	C7—C8—H8B	109.5
H1D—N1—H1B	107 (2)	H8A—C8—H8B	109.5
H1C—N1—H1B	111 (2)	C7—C8—H8C	109.5
O1—C7—C8	107.79 (18)	H8A—C8—H8C	109.5
O1—C7—H7A	110.1	H8B—C8—H8C	109.5
C8—C7—H7A	110.1	C3—C2—C1	119.47 (17)
O1—C7—H7B	110.1	C3—C2—H2A	120.3
C8—C7—H7B	110.1	C1—C2—H2A	120.3
H7A—C7—H7B	108.5
C7—O1—C6—C5	−2.4 (3)	C6—C5—C4—C3	−0.3 (3)
C7—O1—C6—C1	178.51 (17)	O1—C6—C1—C2	177.53 (18)
C6—O1—C7—C8	−178.74 (17)	C5—C6—C1—C2	−1.6 (3)
O1—C6—C5—C4	−177.57 (19)	C4—C3—C2—C1	0.7 (3)
C1—C6—C5—C4	1.5 (3)	N1—C3—C2—C1	−177.14 (18)
C2—C3—C4—C5	−0.8 (3)	C6—C1—C2—C3	0.5 (3)
N1—C3—C4—C5	177.04 (18)

Hydrogen-bond geometry (Å, º)

Cg1 is the centroid of the C1–C6 ring.

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1D···Cl1^i	0.94 (2)	2.23 (3)	3.104 (2)	154 (2)
N1—H1C···Cl1^ii	0.87 (3)	2.27 (3)	3.107 (2)	161 (2)
N1—H1B···Cl1	0.90 (3)	2.23 (3)	3.114 (2)	172 (2)
C4—H4A···Cg1^iii	0.93	2.91	3.654 (2)	138
C7—H7B···Cg1^iv	0.97	2.89	3.710 (2)	143

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