2-Hy­droxy­benzenaminium acetate

In the crystal, the mol­ecules are linked by O—H⋯O and N—H⋯O hydrogen bonds into a three-dimensional network.

Abstract

In the title molecular salt, C₆H₈NO⁺·C₂H₃O₂ ⁻, the cations and anions are linked by O—H⋯O and N—H⋯O hydrogen bonds, generating a three-dimensional network.

Structure description

In recent years, substituted anilines and their derivatives have been studied extensively for applications as anti­bacterials and in non-linear optical systems (Vivek & Murugakoothan, 2014 ▸). Amino­phenols containing equal stoichiometries of –OH, and –NH₂ groups have been widely studied to understand the supra­molecular synthons existing in their assemblies (Allen et al., 1997 ▸; Dey et al., 2004 ▸).

In spite of this inter­est, there has been very little structural characterization of ortho-hy­droxy­anilinium salts. The structures reported include 2-hy­droxy­anilinium squarate (Yeşilel, 2007 ▸), 2-hy­droxy­anilinium hydrogen phthalate (Jagan & Sivakumar, 2009 ▸), 2-hy­droxy­anilinium 3,5-di­nitro­salicylate (Smith et al., 2011 ▸), 2-hy­droxy­anilinium 3,5-di­nitro­benzoate (Zhao, 2012 ▸), and 2-hy­droxy­anilinium 2-hy­droxy-5-nitro­benzoate and 2-hy­droxy­anilinium 3,5-di­nitro­benzoate (Jin & Wang, 2013 ▸).

Here, we report the structure of 2-hy­droxy­benzenaminium acetate, C₆H₈NO⁺·C₂H₃O₂ ⁻, 1, obtained from the reaction of 2-hy­droxy­aniline and acetic acid. The mol­ecular structure of the title compound is shown in Fig.1. The asymmetric unit contains one 2-hy­droxy­benzenaminium cation and one acetate anion. The cation is protonated at the amine N atom (N1) and linked to the anion by an N—H⋯O hydrogen bond (Fig. 1 ▸ and Table 1 ▸).

Figure 1.

Diagram showing the C₆H₈NO⁺ cation and C₂H₃O₂ ⁻ anion linked by an N—H⋯O inter­action (shown as a dashed line). Displacement ellipsoids are drawn at the 50% probability level.

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯O3i	0.894 (14)	1.709 (14)	2.6025 (9)	177.8 (16)
N1—H1A⋯O2	0.930 (13)	1.807 (13)	2.7251 (9)	168.7 (12)
N1—H1B⋯O2ii	0.923 (12)	1.891 (12)	2.8019 (9)	168.8 (11)
N1—H1C⋯O3iii	0.935 (12)	1.834 (12)	2.7531 (8)	167.2 (12)
C6—H6⋯O3iii	0.95	2.55	3.2493 (11)	131

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

The best planes through the 2-hy­droxy­benzenaminium cation and acetate anion are almost perpendicular to each other, subtending a dihedral angle of 79.23 (4)°. The C—OH bond length (C2—O1) of 1.3520 (9) Å is similar to that observed for structures containing 2-hy­droxy­benzenaminium as a cation [1.350 (3) Å; Jin & Wang, 2013 ▸]. All bond lengths and angles in the 2-hy­droxy­benzenaminium cation are within normal ranges (Zhao, 2012 ▸).

The presence of hydroxyl groups leads to the formation of inter­molecular O1—H1⋯O3 hydrogen bonds. The O1—H1⋯O3 and N1—H1C⋯O3 cation–anion hydrogen bonds generate a succession of infinite chains [graph set (7)] that propagate in a zigzag manner along the c-axis direction (Fig. 2 ▸ and Table 1 ▸). The N1—H1A⋯O2 hydrogen bonds (Table 1 ▸) link the chains into corrugated layers parallel to the bc plane, which are formed by a succession of (22) rings (Fig. 2 ▸). N1—H1B⋯O2 hydrogen bonds lead to the formation of a three-dimensional network (Fig. 3 ▸). No significant π–π stacking inter­actions were observed, despite the presence of an aromatic ring in the cation.

Figure 2.

A portion of one corrugated layer viewed along the b-axis direction. O—H\⋯O and N—H⋯O hydrogen bonds are shown as dashed lines.

Figure 3.

View of two layers viewed along the b- and c-axis directions.

Synthesis and crystallization

The title compound was prepared by heating of a mixture of 2-amino­phenol (Alfa Aesar, purity 98%) and acetic acid. This mixture was obtained by dissolution and agitation under reflux for 3 h of 0.5 g of the 2-amino­phenol and 0.27 g of acetic acid in a 1:1 stoichiometric ratio in a hot ethano­lic solution (20 ml). After warming for a few minutes using a water bath, the solution was cooled and kept at room temperature. Within a few days, yellow needle-like crystals suitable for the X-ray analysis were obtained (yield 60%) by evaporation of the solution.

Refinement

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

Table 2. Experimental details.

Crystal data
Chemical formula	C6H8NO+·C2H3O2 −
M r	169.18
Crystal system, space group	Monoclinic, P21/c
Temperature (K)	100
a, b, c (Å)	9.9150 (2), 7.2523 (2), 11.9573 (3)
β (°)	98.558 (2)
V (Å3)	850.23 (4)
Z	4
Radiation type	Mo Kα
μ (mm−1)	0.10
Crystal size (mm)	0.10 × 0.10 × 0.08
Data collection
Diffractometer	Oxford Diffraction Xcalibur Sapphire2 CCD
Absorption correction	Integration (ABSORB; DeTitta, 1985 ▸)
T min, T max	0.966, 0.991
No. of measured, independent and observed [I > 2σ(I)] reflections	52913, 3105, 2736
R int	0.038
(sin θ/λ)max (Å−1)	0.766
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.038, 0.109, 1.05
No. of reflections	3105
No. of parameters	122
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)	0.49, −0.27

Computer programs: CrysAlis PRO (Rigaku OD, 2018 ▸), SHELXS (Sheldrick, 2008 ▸), SHELXL2018/3 (Sheldrick, 2015 ▸) and OLEX2 (Dolomanov et al., 2009 ▸).

Supplementary Material

CCDC reference: 2149479

Additional supporting information: crystallographic information; 3D view; checkCIF report

full crystallographic data

Crystal data

C6H8NO+·C2H3O2−	F(000) = 360
Mr = 169.18	Dx = 1.322 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.9150 (2) Å	Cell parameters from 52927 reflections
b = 7.2523 (2) Å	θ = 3.3–33.0°
c = 11.9573 (3) Å	µ = 0.10 mm−1
β = 98.558 (2)°	T = 100 K
V = 850.23 (4) Å3	Prism, yellow
Z = 4	0.1 × 0.1 × 0.08 mm

Data collection

Oxford Diffraction Xcalibur Sapphire2 CCD diffractometer	2736 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.038
Absorption correction: integration (ABSORB; DeTitta, 1985)	θmax = 33.0°, θmin = 3.3°
Tmin = 0.966, Tmax = 0.991	h = −15→15
52913 measured reflections	k = −11→11
3105 independent reflections	l = −17→18

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.038	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.109	w = 1/[σ2(Fo2) + (0.0542P)2 + 0.320P] where P = (Fo2 + 2Fc2)/3
S = 1.05	(Δ/σ)max = 0.001
3105 reflections	Δρmax = 0.49 e Å−3
122 parameters	Δρmin = −0.27 e Å−3
0 restraints

Special details

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. The hydrogen atoms of the NH3 and hydroxyl groups were localized in the difference-Fourier map and refined with Uiso(H) set to 1.5Ueq(O) or 1.2Ueq(N). All the other hydrogen atoms were placed in calculated positions with C—H = 0.95 Å for aromatic CH and C—H = 0.96 Å for CH3 and refined using a riding model with fixed isotropic displacement parameters [Uiso(H) = 1.2Ueq(C-aromatic) and Uiso(H) = 1.5Ueq(C-methyl)].

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.12872 (6)	0.83288 (9)	0.65994 (5)	0.01629 (13)
H1	0.1381 (14)	0.928 (2)	0.6142 (12)	0.024*
O2	0.09592 (7)	0.29888 (8)	0.65411 (5)	0.01686 (13)
O3	0.15033 (7)	0.10731 (8)	0.52349 (5)	0.01664 (13)
N1	0.12133 (7)	0.56570 (9)	0.81635 (5)	0.01242 (13)
H1A	0.1133 (12)	0.4870 (19)	0.7543 (10)	0.015*
H1B	0.0461 (12)	0.6407 (18)	0.8160 (10)	0.015*
H1C	0.1280 (12)	0.4909 (18)	0.8806 (10)	0.015*
C3	0.35594 (9)	0.93249 (12)	0.74235 (7)	0.01774 (16)
H3	0.358215	1.025256	0.686567	0.021*
C5	0.46510 (9)	0.77468 (13)	0.90970 (8)	0.01994 (17)
H5	0.540747	0.760726	0.967953	0.024*
C4	0.46648 (9)	0.91021 (13)	0.82754 (8)	0.02042 (17)
H4	0.543738	0.988327	0.829677	0.025*
C2	0.24139 (8)	0.81883 (11)	0.73847 (6)	0.01328 (14)
C6	0.35205 (8)	0.65957 (12)	0.90596 (7)	0.01606 (15)
H6	0.350402	0.566114	0.961414	0.019*
C1	0.24197 (8)	0.68208 (10)	0.82091 (6)	0.01217 (14)
C8	0.13683 (8)	0.26870 (11)	0.56096 (6)	0.01288 (14)
C7	0.16938 (9)	0.42886 (12)	0.48900 (8)	0.01940 (16)
H7A	0.096016	0.443787	0.425025	0.029*
H7B	0.255531	0.405118	0.460661	0.029*
H7C	0.177717	0.541719	0.534587	0.029*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0172 (3)	0.0157 (3)	0.0153 (3)	−0.0014 (2)	0.0001 (2)	0.0046 (2)
O2	0.0220 (3)	0.0142 (3)	0.0157 (3)	−0.0024 (2)	0.0073 (2)	−0.0030 (2)
O3	0.0255 (3)	0.0124 (3)	0.0124 (2)	0.0019 (2)	0.0041 (2)	−0.00051 (19)
N1	0.0147 (3)	0.0109 (3)	0.0120 (3)	−0.0006 (2)	0.0030 (2)	0.0005 (2)
C3	0.0180 (3)	0.0161 (3)	0.0198 (4)	−0.0030 (3)	0.0053 (3)	0.0024 (3)
C5	0.0150 (3)	0.0222 (4)	0.0217 (4)	−0.0007 (3)	−0.0003 (3)	0.0001 (3)
C4	0.0154 (3)	0.0212 (4)	0.0248 (4)	−0.0040 (3)	0.0036 (3)	0.0000 (3)
C2	0.0149 (3)	0.0121 (3)	0.0131 (3)	0.0002 (2)	0.0032 (2)	0.0005 (2)
C6	0.0162 (3)	0.0160 (3)	0.0157 (3)	0.0013 (3)	0.0015 (3)	0.0011 (3)
C1	0.0133 (3)	0.0110 (3)	0.0126 (3)	−0.0001 (2)	0.0033 (2)	0.0000 (2)
C8	0.0128 (3)	0.0123 (3)	0.0135 (3)	0.0001 (2)	0.0019 (2)	0.0007 (2)
C7	0.0213 (4)	0.0154 (3)	0.0229 (4)	0.0008 (3)	0.0078 (3)	0.0063 (3)

Geometric parameters (Å, º)

O1—H1	0.892 (14)	C5—H5	0.9500
O1—C2	1.3520 (9)	C5—C4	1.3912 (13)
O2—C8	1.2600 (9)	C5—C6	1.3930 (12)
O3—C8	1.2675 (9)	C4—H4	0.9500
N1—H1A	0.930 (13)	C2—C1	1.3978 (11)
N1—H1B	0.922 (13)	C6—H6	0.9500
N1—H1C	0.935 (12)	C6—C1	1.3863 (11)
N1—C1	1.4583 (10)	C8—C7	1.5087 (11)
C3—H3	0.9500	C7—H7A	0.9800
C3—C4	1.3903 (12)	C7—H7B	0.9800
C3—C2	1.3985 (11)	C7—H7C	0.9800
C2—O1—H1	109.4 (9)	O1—C2—C1	117.36 (7)
H1A—N1—H1B	112.7 (11)	C1—C2—C3	118.48 (7)
H1A—N1—H1C	106.7 (11)	C5—C6—H6	120.2
H1B—N1—H1C	107.7 (10)	C1—C6—C5	119.66 (8)
C1—N1—H1A	110.9 (8)	C1—C6—H6	120.2
C1—N1—H1B	108.5 (8)	C2—C1—N1	117.84 (7)
C1—N1—H1C	110.3 (7)	C6—C1—N1	120.74 (7)
C4—C3—H3	119.9	C6—C1—C2	121.40 (7)
C4—C3—C2	120.24 (8)	O2—C8—O3	122.53 (7)
C2—C3—H3	119.9	O2—C8—C7	119.65 (7)
C4—C5—H5	120.2	O3—C8—C7	117.81 (7)
C4—C5—C6	119.55 (8)	C8—C7—H7A	109.5
C6—C5—H5	120.2	C8—C7—H7B	109.5
C3—C4—C5	120.66 (8)	C8—C7—H7C	109.5
C3—C4—H4	119.7	H7A—C7—H7B	109.5
C5—C4—H4	119.7	H7A—C7—H7C	109.5
O1—C2—C3	124.17 (7)	H7B—C7—H7C	109.5
O1—C2—C1—N1	−0.22 (10)	C4—C3—C2—O1	178.84 (8)
O1—C2—C1—C6	−178.85 (7)	C4—C3—C2—C1	−0.83 (12)
C3—C2—C1—N1	179.48 (7)	C4—C5—C6—C1	−0.39 (13)
C3—C2—C1—C6	0.85 (12)	C2—C3—C4—C5	0.22 (13)
C5—C6—C1—N1	−178.83 (7)	C6—C5—C4—C3	0.40 (14)
C5—C6—C1—C2	−0.24 (12)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O3i	0.894 (14)	1.709 (14)	2.6025 (9)	177.8 (16)
N1—H1A···O2	0.930 (13)	1.807 (13)	2.7251 (9)	168.7 (12)
N1—H1B···O2ii	0.923 (12)	1.891 (12)	2.8019 (9)	168.8 (11)
N1—H1C···O3iii	0.935 (12)	1.834 (12)	2.7531 (8)	167.2 (12)
C6—H6···O3iii	0.95	2.55	3.2493 (11)	131

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