2-Amino­pyridinium 4-hydroxy­benzoate

Quah, C.K.; Jebas, S.R.; Fun, H.-K.

doi:10.1107/S1600536808034934

organic compounds

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ISSN: 2056-9890

Volume 64| Part 11| November 2008| Page o2230

doi:10.1107/S1600536808034934

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2-Aminopyridinium 4-hydroxybenzoate

Ching Kheng Quah,^a Samuel Robinson Jebas ^a ‡§ and Hoong-Kun Fun ^a ^*

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
^*Correspondence e-mail: hkfun@usm.my

(Received 24 October 2008; accepted 27 October 2008; online 31 October 2008)

In the title compound, C₅H₇N₂⁺·C₇H₅O₃⁻, the carboxylate mean plane of the 4-hydroxybenzoate anion is twisted by 8.78 (5)° from the attached ring. The cations and anions are linked via O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional network. In addition, π–π interactions involving the benzene and pyridinium rings, with centroid–centroid distances of 3.5500 (6) and 3.6594 (6) Å, are observed.

Related literature

For the applications of 2-aminopyridine, see: Windholz (1976 ). For related structures, see: Chao et al. (1975 ); Heath et al. (1992 ); Jebas & Balasubramanian (2006 ); Joanna & Zaworotko (2005 ); Smith et al. (2000 ).

Experimental

Crystal data

C₅H₇N₂⁺·C₇H₅O₃⁻
M_r = 232.24
Monoclinic, P 2₁ /n
a = 10.0647 (2) Å
b = 10.9369 (2) Å
c = 10.7985 (2) Å
β = 111.036 (1)°
V = 1109.44 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 100.0 (1) K
0.34 × 0.29 × 0.17 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.966, T_max = 0.983
22398 measured reflections
5078 independent reflections
3835 reflections with I > 2σ(I)
R_int = 0.029

Refinement

R[F² > 2σ(F²)] = 0.049
wR(F²) = 0.140
S = 1.02
5078 reflections
158 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.50 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1O1⋯O2ⁱ	0.82	1.86	2.6257 (9)	154
N2—H1N2⋯O2ⁱⁱ	0.86	1.98	2.8224 (11)	167
N2—H2N2⋯O3ⁱⁱⁱ	0.86	1.99	2.8396 (11)	171
N1—H1N1⋯O3ⁱⁱ	0.88 (1)	1.81 (1)	2.6861 (10)	169 (2)
C10—H10A⋯O1	0.93	2.51	3.3482 (14)	149
C11—H11A⋯O2ⁱ	0.93	2.34	3.1899 (12)	152
Symmetry codes: (i) $[-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) x-1, y-1, z; (iii) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 and SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808034934/ci2696sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808034934/ci2696Isup2.hkl

checkCIF report

Comment top

2-Aminopyridine is used in the manufacture of pharmaceuticals, especially antihistaminic drugs (Windholz, 1976). As an extension of our systematic study of hydrogen bonding patterns of 2-aminopyridine with aromatic carboxylic acids, the title compound was synthesized and its crystal structure determined.

The asymmetric unit contains one 2-aminopyridinium cation and 4-hydroxybenzoate anion. The proton transfer from the carboxyl group to atom N1 of 2-aminopyridine resulted in the widening of C8—N1—C12 angle of the pyridinium ring to 122.35°, compared to the corresponding angle of 117.7 (1)° in neutral 2-aminopyridine (Chao et al., 1975). Similar feature is observed in various 2-aminopyridine acid complexes (Joanna & Zaworotko, 2005; Smith et al., 2000). The bond distances and angles in the title compound are comparable to those in various 2-aminopyridine acid complexes and 4-hydroxybenzoic acid (Joanna & Zaworotko, 2005; Heath et al., 1992).

The 2-aminopyridinium cation is essentially planar, with a maximum deviation of 0.016 (1) Å for atom N1. In the 4-hydroxybenzoate anion, the carboxylate group is twisted slightly from the attached ring; the dihedral angle between C1-C6 and O2/O3/C6/C7 planes is 8.78 (5)°.

The crystal packing is consolidated by intermolecular O—H···O, N—H···O and C—H···O hydrogen bonds (Table 1). These hydrogen bonds link the molecules into a three-dimensional network. The packing is further strengthened by π-π interactions involving the benzene (centroid Cg1) and pyridinium (centroid Cg2) rings, with Cg1···Cg2^iv = 3.6594 (6) Å and Cg2···Cg2^v = 3.5500 (6) Å [symmetry code: (iv) 1-x, 1-y, 1-z; (v) -x, 1-y, 1-z].

Related literature top

For the applications of 2-aminopyridine, see: Windholz (1976). For related structures, see: Chao et al. (1975); Heath et al. (1992); Jebas & Balasubramanian (2006); Joanna & Zaworotko (2005); Smith et al. (2000).

Experimental top

2-Aminopyridine and 4-hydroxybenzoic acid were mixed in methanol in a 1:1 molar ratio. The clear colourless solution obtained was allowed to evaporate slowly. Colourless crystals were obtained after a week.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top

	Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom numbering scheme. The dashed line indicates a hydrogen bond.
	Fig. 2. The crystal packing of the title compound, viewed along the c axis. Hydrogen bonds are shown as dashed lines.

2-Aminopyridinium 4-hydroxybenzoate top

Crystal data top

C₅H₇N₂⁺·C₇H₅O₃⁻	F(000) = 488
M_r = 232.24	D_x = 1.390 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 6837 reflections
a = 10.0647 (2) Å	θ = 2.8–35.6°
b = 10.9369 (2) Å	µ = 0.10 mm⁻¹
c = 10.7985 (2) Å	T = 100 K
β = 111.036 (1)°	Block, colourless
V = 1109.44 (4) Å³	0.34 × 0.29 × 0.17 mm
Z = 4

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	5078 independent reflections
Radiation source: fine-focus sealed tube	3835 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.030
ϕ and ω scans	θ_max = 35.6°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −16→11
T_min = 0.966, T_max = 0.983	k = −17→17
22398 measured reflections	l = −16→17

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.140	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ²(F_o²) + (0.0746P)² + 0.2186P] where P = (F_o² + 2F_c²)/3
5078 reflections	(Δ/σ)_max = 0.001
158 parameters	Δρ_max = 0.50 e Å⁻³
1 restraint	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₅H₇N₂⁺·C₇H₅O₃⁻	V = 1109.44 (4) Å³
M_r = 232.24	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 10.0647 (2) Å	µ = 0.10 mm⁻¹
b = 10.9369 (2) Å	T = 100 K
c = 10.7985 (2) Å	0.34 × 0.29 × 0.17 mm
β = 111.036 (1)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	5078 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	3835 reflections with I > 2σ(I)
T_min = 0.966, T_max = 0.983	R_int = 0.030
22398 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.049	1 restraint
wR(F²) = 0.140	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	Δρ_max = 0.50 e Å⁻³
5078 reflections	Δρ_min = −0.21 e Å⁻³
158 parameters

Special details top

Experimental. The data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.

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
O1	0.52173 (8)	0.67777 (7)	0.56764 (7)	0.02345 (16)
H1O1	0.5435	0.6430	0.6395	0.035*
O2	0.97943 (7)	1.10528 (6)	0.70095 (6)	0.01770 (14)
O3	0.88217 (8)	1.12535 (7)	0.48165 (6)	0.02051 (14)
N1	0.06716 (8)	0.30978 (7)	0.51061 (7)	0.01683 (15)
N2	0.18939 (9)	0.28645 (8)	0.73537 (8)	0.02239 (17)
H1N2	0.1354	0.2254	0.7348	0.027*
H2N2	0.2550	0.3085	0.8082	0.027*
C1	0.81342 (9)	0.89872 (8)	0.69825 (8)	0.01647 (16)
H1A	0.8873	0.9180	0.7769	0.020*
C2	0.72397 (10)	0.80096 (9)	0.69536 (8)	0.01740 (16)
H2A	0.7387	0.7548	0.7714	0.021*
C3	0.61195 (10)	0.77231 (9)	0.57782 (9)	0.01771 (16)
C4	0.59084 (11)	0.84236 (10)	0.46429 (9)	0.02258 (19)
H4A	0.5157	0.8243	0.3862	0.027*
C5	0.68141 (10)	0.93876 (9)	0.46745 (9)	0.02087 (18)
H5A	0.6673	0.9842	0.3910	0.025*
C6	0.79383 (9)	0.96844 (8)	0.58454 (8)	0.01518 (15)
C7	0.89111 (9)	1.07305 (8)	0.58888 (8)	0.01503 (15)
C8	0.03894 (10)	0.36798 (9)	0.39292 (9)	0.01886 (17)
H8A	−0.0348	0.3399	0.3183	0.023*
C9	0.11667 (11)	0.46682 (9)	0.38189 (10)	0.02141 (18)
H9A	0.0968	0.5068	0.3012	0.026*
C10	0.22817 (11)	0.50629 (9)	0.49691 (10)	0.02254 (19)
H10A	0.2836	0.5728	0.4919	0.027*
C11	0.25595 (10)	0.44821 (9)	0.61585 (10)	0.02098 (18)
H11A	0.3297	0.4750	0.6911	0.025*
C12	0.17140 (10)	0.34698 (9)	0.62328 (9)	0.01766 (16)
H1N1	0.0145 (17)	0.2453 (12)	0.5101 (19)	0.051 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0264 (4)	0.0269 (4)	0.0164 (3)	−0.0110 (3)	0.0069 (3)	0.0002 (3)
O2	0.0180 (3)	0.0203 (3)	0.0128 (3)	−0.0017 (2)	0.0032 (2)	−0.0020 (2)
O3	0.0219 (3)	0.0218 (3)	0.0143 (3)	−0.0048 (3)	0.0023 (2)	0.0040 (2)
N1	0.0170 (3)	0.0179 (3)	0.0144 (3)	−0.0029 (3)	0.0042 (3)	−0.0020 (3)
N2	0.0227 (4)	0.0254 (4)	0.0147 (3)	−0.0055 (3)	0.0015 (3)	−0.0015 (3)
C1	0.0167 (4)	0.0186 (4)	0.0127 (3)	−0.0001 (3)	0.0036 (3)	0.0001 (3)
C2	0.0189 (4)	0.0194 (4)	0.0136 (3)	−0.0011 (3)	0.0056 (3)	0.0016 (3)
C3	0.0192 (4)	0.0198 (4)	0.0151 (3)	−0.0037 (3)	0.0073 (3)	−0.0011 (3)
C4	0.0230 (4)	0.0288 (5)	0.0126 (3)	−0.0093 (4)	0.0024 (3)	0.0002 (3)
C5	0.0225 (4)	0.0245 (5)	0.0133 (3)	−0.0053 (3)	0.0036 (3)	0.0023 (3)
C6	0.0159 (3)	0.0164 (4)	0.0127 (3)	0.0000 (3)	0.0044 (3)	0.0002 (3)
C7	0.0154 (3)	0.0156 (4)	0.0129 (3)	0.0010 (3)	0.0037 (3)	0.0001 (3)
C8	0.0185 (4)	0.0218 (4)	0.0159 (4)	−0.0018 (3)	0.0057 (3)	−0.0008 (3)
C9	0.0226 (4)	0.0220 (4)	0.0206 (4)	−0.0025 (3)	0.0090 (3)	0.0011 (3)
C10	0.0210 (4)	0.0205 (4)	0.0276 (4)	−0.0052 (3)	0.0105 (4)	−0.0025 (3)
C11	0.0169 (4)	0.0213 (4)	0.0229 (4)	−0.0034 (3)	0.0049 (3)	−0.0046 (3)
C12	0.0162 (4)	0.0190 (4)	0.0163 (4)	−0.0005 (3)	0.0040 (3)	−0.0032 (3)

Geometric parameters (Å, º) top

O1—C3	1.3543 (11)	C3—C4	1.3957 (13)
O1—H1O1	0.8200	C4—C5	1.3861 (13)
O2—C7	1.2675 (10)	C4—H4A	0.93
O3—C7	1.2654 (10)	C5—C6	1.3990 (12)
N1—C12	1.3528 (11)	C5—H5A	0.93
N1—C8	1.3571 (12)	C6—C7	1.4956 (12)
N1—H1N1	0.881 (9)	C8—C9	1.3644 (13)
N2—C12	1.3338 (12)	C8—H8A	0.93
N2—H1N2	0.86	C9—C10	1.4099 (14)
N2—H2N2	0.86	C9—H9A	0.93
C1—C2	1.3908 (13)	C10—C11	1.3687 (14)
C1—C6	1.3980 (12)	C10—H10A	0.93
C1—H1A	0.93	C11—C12	1.4161 (13)
C2—C3	1.3975 (12)	C11—H11A	0.93
C2—H2A	0.93

C3—O1—H1O1	109.5	C1—C6—C5	118.72 (8)
C12—N1—C8	122.35 (8)	C1—C6—C7	120.36 (8)
C12—N1—H1N1	121.1 (13)	C5—C6—C7	120.92 (8)
C8—N1—H1N1	116.5 (13)	O3—C7—O2	122.89 (8)
C12—N2—H1N2	120.0	O3—C7—C6	119.10 (7)
C12—N2—H2N2	120.0	O2—C7—C6	118.00 (7)
H1N2—N2—H2N2	120.0	N1—C8—C9	121.30 (9)
C2—C1—C6	120.90 (8)	N1—C8—H8A	119.3
C2—C1—H1A	119.5	C9—C8—H8A	119.3
C6—C1—H1A	119.5	C8—C9—C10	117.75 (9)
C1—C2—C3	119.83 (8)	C8—C9—H9A	121.1
C1—C2—H2A	120.1	C10—C9—H9A	121.1
C3—C2—H2A	120.1	C11—C10—C9	120.96 (9)
O1—C3—C4	117.49 (8)	C11—C10—H10A	119.5
O1—C3—C2	122.94 (8)	C9—C10—H10A	119.5
C4—C3—C2	119.57 (8)	C10—C11—C12	119.44 (9)
C5—C4—C3	120.30 (8)	C10—C11—H11A	120.3
C5—C4—H4A	119.9	C12—C11—H11A	120.3
C3—C4—H4A	119.9	N2—C12—N1	118.41 (8)
C4—C5—C6	120.67 (8)	N2—C12—C11	123.43 (8)
C4—C5—H5A	119.7	N1—C12—C11	118.17 (8)
C6—C5—H5A	119.7

C6—C1—C2—C3	−0.63 (14)	C5—C6—C7—O3	−8.78 (13)
C1—C2—C3—O1	179.36 (9)	C1—C6—C7—O2	−8.40 (12)
C1—C2—C3—C4	−0.07 (14)	C5—C6—C7—O2	171.26 (9)
O1—C3—C4—C5	−178.61 (9)	C12—N1—C8—C9	1.07 (14)
C2—C3—C4—C5	0.84 (15)	N1—C8—C9—C10	0.35 (14)
C3—C4—C5—C6	−0.92 (16)	C8—C9—C10—C11	−0.87 (15)
C2—C1—C6—C5	0.55 (13)	C9—C10—C11—C12	0.02 (15)
C2—C1—C6—C7	−179.78 (8)	C8—N1—C12—N2	178.22 (9)
C4—C5—C6—C1	0.22 (14)	C8—N1—C12—C11	−1.90 (14)
C4—C5—C6—C7	−179.44 (9)	C10—C11—C12—N2	−178.79 (9)
C1—C6—C7—O3	171.56 (8)	C10—C11—C12—N1	1.33 (14)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O1···O2ⁱ	0.82	1.86	2.6257 (9)	154
N2—H1N2···O2ⁱⁱ	0.86	1.98	2.8224 (11)	167
N2—H2N2···O3ⁱⁱⁱ	0.86	1.99	2.8396 (11)	171
N1—H1N1···O3ⁱⁱ	0.88 (1)	1.81 (1)	2.6861 (10)	169 (2)
C10—H10A···O1	0.93	2.51	3.3482 (14)	149
C11—H11A···O2ⁱ	0.93	2.34	3.1899 (12)	152

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

Experimental details

Crystal data
Chemical formula	C₅H₇N₂⁺·C₇H₅O₃⁻
M_r	232.24
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	100
a, b, c (Å)	10.0647 (2), 10.9369 (2), 10.7985 (2)
β (°)	111.036 (1)
V (Å³)	1109.44 (4)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.34 × 0.29 × 0.17

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.966, 0.983
No. of measured, independent and observed [I > 2σ(I)] reflections	22398, 5078, 3835
R_int	0.030
(sin θ/λ)_max (Å⁻¹)	0.820

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.140, 1.02
No. of reflections	5078
No. of parameters	158
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.50, −0.21

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O1···O2ⁱ	0.82	1.86	2.6257 (9)	154
N2—H1N2···O2ⁱⁱ	0.86	1.98	2.8224 (11)	167
N2—H2N2···O3ⁱⁱⁱ	0.86	1.99	2.8396 (11)	171
N1—H1N1···O3ⁱⁱ	0.88 (1)	1.81 (1)	2.6861 (10)	169 (2)
C10—H10A···O1	0.93	2.51	3.3482 (14)	149
C11—H11A···O2ⁱ	0.93	2.34	3.1899 (12)	152

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

Footnotes

‡Permanent address: Department of Physics, Karunya University, Karunya Nagar, Coimbatore 641 114, India.

§Additional correspondence author, e-mail: robinsunj@yahoo.com.

Acknowledgements

HKF and SRJ thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. SRJ thanks Universiti Sains Malaysia for a post–doctoral research fellowship. CKQ thanks Universiti Sains Malaysia for a student assistanceship.

References

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