4-Eth­oxy­anilinium bromide

The title compound, C₈H₁₂NO⁺·Br⁻, is built up from roughly planar (r.m.s. deviation for the non-H atoms = 0.062 Å) protonated 4-eth­oxy­anilimium cations and Br⁻ anions. In the crystal, the cations and anions are linked by N—H...Br and N—H...(Br,Br) hydrogen bonds, generating (100) sheets. Very weak C—H...π inter­actions may also help to stabilize the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.009 Å
• R factor = 0.061
• wR factor = 0.173
• Data-to-parameter ratio = 22.0

checkCIF/PLATON results

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Alert level C
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       3.66
PLAT341_ALERT_3_C Low Bond Precision on  C-C Bonds (x 1000) Ang ..          9
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          1
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          4

Alert level G
PLAT380_ALERT_4_G Check Incorrectly? Oriented X(sp2)-Methyl Moiety         N1

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   2 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 together with perchlorate is known (Fu, 2009).

The asymmetric unit of the title compound consists of an almost planar protonated 4-ethoxyanilimium cation with the mean deviation of 0.0618 A from the plane formed by its non-hydrogen atoms and a Br^- anion (Fig.1). The N—H···Br hydrogen bonding with the N—Br distance from 3.324 (5)Å to 3.375 (4) Å, make great contribution to the stability of the crystal structure and link the cations and anions into chains along b axis. The C—H···π interactions with the C···Cg1 distances of C7—H7A···Cg1 3.674 (8)Å and C8—H8B···Cg1 3.677 (8) Å, respectively, (Cg1 is the centroid of benzene ring) also help stable crystal structure.

Related literature

For a related structure containing the same cation, see: Fu (2009).

S2. Experimental

Colorless prisms of the title compound were obtained by slow evaporation at room temperature of an ethanol solution of equimolar amounts of 4-ethoxybenzenamine and hydrobromic acid (47% w/w).

S3. Refinement

Positional parameters of all the H atoms for C/N atoms were calculated geometrically and were allowed to ride on the C atoms to which they are bonded, with U_iso(H) = 1.2Ueq(C), U_iso(H) = 1.5Ueq(C) for methyl group and U_iso(H) = 1.5Ueq(N).

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: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level.
	Fig. 2. A view of the packing of the title compound, stacking along the c axis. Dashed lines indicate hydrogen bonds.

4-Ethoxyanilinium bromide

Crystal data

C8H12NO^+·Br^−	F(000) = 440
Mr = 218.09	Dx = 1.510 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3858 reflections
a = 11.842 (2) Å	θ = 3.1–27.7°
b = 6.5263 (13) Å	µ = 4.23 mm^−1
c = 12.488 (3) Å	T = 298 K
β = 96.44 (3)°	Prism, colourless
V = 959.0 (3) Å^3	0.40 × 0.30 × 0.20 mm
Z = 4

Data collection

Rigaku SCXmini diffractometer	2200 independent reflections
Radiation source: fine-focus sealed tube	1579 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.073
Detector resolution: 13.6612 pixels mm^-1	θmax = 27.5°, θmin = 3.3°
ω scans	h = −15→15
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −8→8
Tmin = 0.237, Tmax = 0.429	l = −16→16
9286 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)] = 0.061	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.173	H-atom parameters constrained
S = 1.11	w = 1/[σ^2(Fo^2) + (0.0748P)^2 + 1.0824P] where P = (Fo^2 + 2Fc^2)/3
2200 reflections	(Δ/σ)max < 0.001
100 parameters	Δρmax = 1.55 e Å^−3
0 restraints	Δρmin = −0.42 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
Br1	0.01352 (5)	0.76484 (8)	0.12594 (4)	0.0493 (3)
O1	0.5504 (4)	0.2634 (6)	0.0985 (5)	0.0665 (14)
N1	0.0856 (4)	0.2654 (7)	0.1354 (4)	0.0514 (12)
H1B	0.0671	0.3613	0.1810	0.077*
H1C	0.0632	0.1434	0.1568	0.077*
H1D	0.0516	0.2921	0.0697	0.077*
C6	0.4385 (6)	0.2722 (9)	0.1145 (6)	0.0575 (16)
C4	0.2549 (5)	0.1252 (9)	0.0666 (5)	0.0551 (15)
H4A	0.2087	0.0301	0.0274	0.066*
C3	0.2087 (5)	0.2643 (7)	0.1331 (5)	0.0458 (13)
C5	0.3688 (5)	0.1288 (10)	0.0589 (5)	0.0608 (17)
H5A	0.4001	0.0332	0.0156	0.073*
C1	0.3918 (6)	0.4084 (9)	0.1824 (6)	0.0640 (18)
H1A	0.4380	0.5023	0.2225	0.077*
C8	0.7385 (6)	0.3844 (11)	0.1062 (6)	0.073 (2)
H8A	0.7906	0.4880	0.1355	0.109*
H8B	0.7315	0.3907	0.0289	0.109*
H8C	0.7665	0.2519	0.1296	0.109*
C2	0.2756 (6)	0.4042 (10)	0.1902 (5)	0.0630 (17)
H2A	0.2438	0.4972	0.2346	0.076*
C7	0.6253 (6)	0.4193 (11)	0.1441 (6)	0.075 (2)
H7A	0.6314	0.4131	0.2221	0.089*
H7B	0.5965	0.5534	0.1213	0.089*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0600 (4)	0.0431 (4)	0.0460 (4)	−0.0070 (3)	0.0119 (3)	−0.0002 (2)
O1	0.046 (2)	0.064 (3)	0.090 (4)	−0.0075 (19)	0.010 (2)	−0.017 (2)
N1	0.043 (3)	0.061 (3)	0.050 (3)	−0.007 (2)	0.009 (2)	0.000 (2)
C6	0.050 (4)	0.056 (4)	0.068 (4)	−0.004 (3)	0.012 (3)	−0.002 (3)
C4	0.045 (3)	0.055 (3)	0.067 (4)	−0.011 (3)	0.016 (3)	−0.019 (3)
C3	0.045 (3)	0.044 (3)	0.049 (3)	0.002 (2)	0.010 (2)	−0.002 (2)
C5	0.048 (4)	0.059 (4)	0.077 (5)	−0.007 (3)	0.016 (3)	−0.025 (3)
C1	0.052 (4)	0.064 (4)	0.077 (5)	−0.010 (3)	0.009 (3)	−0.027 (3)
C8	0.053 (4)	0.083 (5)	0.082 (5)	−0.014 (4)	0.006 (4)	0.013 (4)
C2	0.061 (4)	0.061 (4)	0.068 (4)	0.002 (3)	0.011 (3)	−0.021 (3)
C7	0.060 (5)	0.074 (5)	0.088 (6)	−0.021 (4)	−0.001 (4)	0.002 (4)

Geometric parameters (Å, º)

O1—C6	1.363 (9)	C3—C2	1.358 (8)
O1—C7	1.426 (7)	C5—H5A	0.9300
N1—C3	1.461 (8)	C1—C2	1.390 (9)
N1—H1B	0.8900	C1—H1A	0.9300
N1—H1C	0.8900	C8—C7	1.489 (9)
N1—H1D	0.8900	C8—H8A	0.9600
C6—C5	1.382 (9)	C8—H8B	0.9600
C6—C1	1.385 (9)	C8—H8C	0.9600
C4—C5	1.362 (8)	C2—H2A	0.9300
C4—C3	1.384 (7)	C7—H7A	0.9700
C4—H4A	0.9300	C7—H7B	0.9700
C6—O1—C7	118.9 (5)	C6—C1—C2	119.8 (6)
C3—N1—H1B	109.5	C6—C1—H1A	120.1
C3—N1—H1C	109.5	C2—C1—H1A	120.1
H1B—N1—H1C	109.5	C7—C8—H8A	109.5
C3—N1—H1D	109.5	C7—C8—H8B	109.5
H1B—N1—H1D	109.5	H8A—C8—H8B	109.5
H1C—N1—H1D	109.5	C7—C8—H8C	109.5
O1—C6—C5	115.7 (6)	H8A—C8—H8C	109.5
O1—C6—C1	125.3 (6)	H8B—C8—H8C	109.5
C5—C6—C1	119.0 (6)	C3—C2—C1	120.0 (6)
C5—C4—C3	119.5 (5)	C3—C2—H2A	120.0
C5—C4—H4A	120.3	C1—C2—H2A	120.0
C3—C4—H4A	120.3	O1—C7—C8	107.8 (6)
C2—C3—C4	120.6 (6)	O1—C7—H7A	110.1
C2—C3—N1	120.8 (5)	C8—C7—H7A	110.1
C4—C3—N1	118.5 (5)	O1—C7—H7B	110.1
C4—C5—C6	121.1 (6)	C8—C7—H7B	110.1
C4—C5—H5A	119.5	H7A—C7—H7B	108.5
C6—C5—H5A	119.5
C7—O1—C6—C5	173.5 (6)	O1—C6—C1—C2	178.9 (7)
C7—O1—C6—C1	−7.8 (10)	C5—C6—C1—C2	−2.6 (11)
C5—C4—C3—C2	0.3 (10)	C4—C3—C2—C1	−0.1 (10)
C5—C4—C3—N1	176.6 (6)	N1—C3—C2—C1	−176.3 (6)
C3—C4—C5—C6	−1.6 (10)	C6—C1—C2—C3	1.3 (11)
O1—C6—C5—C4	−178.6 (6)	C6—O1—C7—C8	−174.7 (6)
C1—C6—C5—C4	2.7 (11)

Hydrogen-bond geometry (Å, º)

Cg1 is the centroid of the benzene ring.

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···Br1	0.89	2.78	3.368 (4)	125
N1—H1B···Br1^i	0.89	2.76	3.324 (5)	122
N1—H1C···Br1^ii	0.89	2.56	3.375 (4)	153
N1—H1D···Br1^iii	0.89	2.51	3.348 (5)	158
C7—H7A···Cg1^iv	0.97	3.01	3.674 (8)	127
C8—H8B···Cg1^v	0.96	2.96	3.677 (8)	132

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