2-Amino-4-methyl­pyridinium 4-hy­droxy­benzoate

Sivakumar, P.; Sudhahar, S.; Israel, S.; Chakkaravarthi, G.

doi:10.1107/S2414314616014255

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 1| Part 9| September 2016| x161425

doi:10.1107/S2414314616014255

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2-Amino-4-methylpyridinium 4-hydroxybenzoate

P. Sivakumar,^a,^b S. Sudhahar,^c S. Israel ^d ^* and G. Chakkaravarthi ^b ^*

^aResearch and Development Centre, Bharathiar University, Coimbatore 641 046, India, ^bDepartment of Physics, CPCL Polytechnic College, Chennai 600 068, India, ^cDepartment of Physics, Alagappa University, Karaikkudi 630 003, India, and ^dPost Graduate and Research Department of Physics, The American College, Madurai 625 002, India
^*Correspondence e-mail: israel.samuel@gmail.com, chakkaravarthi_2005@yahoo.com

Edited by M. Bolte, Goethe-Universität Frankfurt Germany (Received 4 September 2016; accepted 7 September 2016; online 13 September 2016)

In the title molecular salt, C₆H₉N₂⁺·C₇H₅O₃⁻, the cation is protonated at the pyridine N atom and the anion is deprotonated. The pyridine ring is inclined at an angle of 24.96 (11)° to the benzene ring. In the crystal, adjacent anions and cations are linked by a pair of N—H⋯O hydrogen bonds, generating an R₂²(8) ring motif; these motifs are further connected by another N—H⋯O and O—H⋯O hydrogen bonds into a three-dimensional network. The crystal structure also features weak C—H⋯O interactions.

Keywords: molecular salt; crystal structure; hydrogen bonding.

CCDC reference: 1503086

Structure description

Pyridine derivatives are known to exhibit anti-inflammatory (Abdel-Alim et al., 2005 ) and anxiolytic (Spanka et al., 2010 ) activities.

We report the synthesis and the crystal structure of the title molecular salt (Fig. 1). The asymmetric unit comprises a 2-amino-4-methylpyridinium cation protonated at the pyridine N (N1) atom and a deprotonated 4-methylbenzoate anion. The benzene ring (C7–C12) makes a dihedral angle of 24.96 (11)° with the pyridine ring (N1/C1–C5). Bond lengths are comparable with those in reported structures (Sivakumar et al., 2016a ,b ).

Figure 1
The molecular structure of the title molecular salt, with atom labelling and 30% probability displacement ellipsoids.

In the crystal, anions and cations are linked by N1—H1⋯O2ⁱ and N2—H2A⋯O1ⁱ hydrogen bonds, generating an R₂²(8) ring motif (Fig. 2) and further connected by N2—H2B⋯O2ⁱⁱ and O—H⋯Oⁱⁱⁱ hydrogen bonds (Table 1) into an infinite three-dimensional network. The crystal structure also features weak interionic C—H⋯O interactions (Table 1, Fig. 3).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O2ⁱ	0.87 (1)	1.81 (1)	2.666 (2)	174 (3)
N2—H2A⋯O1ⁱ	0.86 (1)	1.95 (1)	2.806 (3)	172 (3)
N2—H2B⋯O2ⁱⁱ	0.86 (1)	2.05 (1)	2.887 (3)	167 (2)
O3—H3⋯O1ⁱⁱⁱ	0.83 (1)	1.87 (1)	2.677 (2)	167 (3)
C6—H6C⋯O1^iv	0.96	2.58	3.505 (4)	161
Symmetry codes: (i) -x+1, -y, -z+2; (ii) $[-x+1, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (iii) $[-x, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (iv) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ .

Figure 2
A partial view of the crystal packing showing the R₂²(8) ring motif.

Figure 3
The crystal packing of the title molecular salt viewed along b axis. The hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bonds have been omitted for clarity.

Synthesis and crystallization

The title salt was synthesized using the raw materials 4-hydroxy benzoic acid (0.69 g) and 2-amino 4-methylpyridine (0.54 g) in an equimolar ratio. When these reactants were dissolved in 10 ml of methanol a white precipitate was formed. The precipitate was dissolved in 20 ml of water and kept at room temperature for slow evaporation. After 30 days, crystals suitable for X-ray diffraction were harvested.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The reflection (100) was omitted during refinement because it was obscured by the beamstop.

Table 2
Experimental details

Crystal data
Chemical formula	C₆H₉N₂⁺·C₇H₅O³⁻
M_r	246.26
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	295
a, b, c (Å)	13.069 (1), 9.1387 (6), 11.3367 (9)
β (°)	112.841 (3)
V (Å³)	1247.81 (16)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.10
Crystal size (mm)	0.26 × 0.24 × 0.18

Data collection
Diffractometer	Bruker Kappa APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2004 )
T_min, T_max	0.682, 0.747
No. of measured, independent and observed [I > 2σ(I)] reflections	21655, 4159, 2301
R_int	0.034
(sin θ/λ)_max (Å⁻¹)	0.769

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.069, 0.199, 1.04
No. of reflections	4159
No. of parameters	179
No. of restraints	4
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.23, −0.26
Computer programs: APEX2 and SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008 ), SHELXL2016 (Sheldrick, 2015 ) and PLATON (Spek, 2009 ).

Structural data

CCDC reference: 1503086

Crystal structure: contains datablocks I, global. DOI: 10.1107/S2414314616014255/bt4025sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2414314616014255/bt4025Isup2.hkl

Supporting information file. DOI: 10.1107/S2414314616014255/bt4025Isup3.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2016 (Sheldrick, 2015); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL2016 (Sheldrick, 2015) and PLATON (Spek, 2009).

2-Amino-4-methylpyridinium 4-hydroxybenzoate top

Crystal data top

C₆H₉N₂⁺·C₇H₅O³⁻	F(000) = 520
M_r = 246.26	D_x = 1.311 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 13.069 (1) Å	Cell parameters from 5844 reflections
b = 9.1387 (6) Å	θ = 2.8–32.5°
c = 11.3367 (9) Å	µ = 0.10 mm⁻¹
β = 112.841 (3)°	T = 295 K
V = 1247.81 (16) Å³	Block, colourless
Z = 4	0.26 × 0.24 × 0.18 mm

Data collection top

Bruker Kappa APEXII CCD diffractometer	2301 reflections with I > 2σ(I)
ω and φ scan	R_int = 0.034
Absorption correction: multi-scan (SADABS; Bruker, 2004)	θ_max = 33.1°, θ_min = 2.8°
T_min = 0.682, T_max = 0.747	h = −19→19
21655 measured reflections	k = −13→13
4159 independent reflections	l = −17→16

Refinement top

Refinement on F²	4 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.069	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.199	w = 1/[σ²(F_o²) + (0.0694P)² + 0.7446P] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max < 0.001
4159 reflections	Δρ_max = 0.23 e Å⁻³
179 parameters	Δρ_min = −0.26 e Å⁻³

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1	0.52644 (16)	0.3239 (2)	0.90045 (18)	0.0392 (4)
C2	0.44042 (17)	0.4162 (2)	0.82341 (19)	0.0425 (5)
H2	0.451228	0.474391	0.761933	0.051*
C3	0.34175 (17)	0.4219 (2)	0.8372 (2)	0.0465 (5)
C4	0.32794 (19)	0.3336 (3)	0.9316 (2)	0.0555 (6)
H4	0.260897	0.334077	0.942314	0.067*
C5	0.41194 (19)	0.2487 (3)	1.0062 (2)	0.0531 (6)
H5	0.402979	0.192189	1.069749	0.064*
C6	0.2488 (2)	0.5176 (4)	0.7536 (3)	0.0755 (8)
H6A	0.261945	0.616509	0.784452	0.113*
H6B	0.179993	0.483581	0.755475	0.113*
H6C	0.245072	0.514134	0.667401	0.113*
C7	0.16520 (15)	0.0386 (2)	0.75602 (18)	0.0382 (4)
C8	0.1671 (2)	0.0718 (3)	0.6378 (2)	0.0663 (8)
H8	0.223915	0.034629	0.616305	0.080*
C9	0.0869 (2)	0.1585 (4)	0.5514 (3)	0.0761 (9)
H9	0.088821	0.177112	0.471584	0.091*
C10	0.00385 (18)	0.2180 (3)	0.5823 (2)	0.0504 (5)
C11	−0.00016 (16)	0.1854 (2)	0.6991 (2)	0.0429 (5)
H11	−0.055959	0.224857	0.721143	0.051*
C12	0.07840 (16)	0.0946 (2)	0.78317 (19)	0.0408 (4)
H12	0.073067	0.070264	0.860227	0.049*
C13	0.25253 (16)	−0.0537 (2)	0.84967 (18)	0.0389 (4)
N1	0.50941 (15)	0.2439 (2)	0.99064 (17)	0.0435 (4)
N2	0.62321 (17)	0.3102 (3)	0.8892 (2)	0.0581 (5)
O1	0.23876 (12)	−0.09774 (19)	0.94694 (14)	0.0525 (4)
O2	0.33935 (12)	−0.08189 (18)	0.83009 (14)	0.0511 (4)
O3	−0.07119 (16)	0.3049 (2)	0.49415 (18)	0.0724 (6)
H1	0.560 (2)	0.189 (3)	1.045 (2)	0.090 (10)*
H2A	0.6699 (18)	0.247 (2)	0.936 (2)	0.067 (8)*
H2B	0.6333 (19)	0.356 (2)	0.8288 (17)	0.051 (7)*
H3	−0.115 (2)	0.339 (3)	0.523 (3)	0.076*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0423 (10)	0.0429 (10)	0.0366 (9)	−0.0021 (8)	0.0198 (8)	−0.0028 (8)
C2	0.0474 (11)	0.0466 (11)	0.0378 (10)	0.0020 (9)	0.0211 (8)	0.0040 (8)
C3	0.0436 (11)	0.0502 (12)	0.0463 (11)	0.0040 (9)	0.0182 (9)	−0.0043 (9)
C4	0.0417 (11)	0.0720 (16)	0.0605 (13)	−0.0011 (11)	0.0285 (10)	−0.0005 (12)
C5	0.0514 (12)	0.0656 (15)	0.0517 (12)	−0.0034 (11)	0.0302 (10)	0.0096 (11)
C6	0.0573 (15)	0.088 (2)	0.0773 (19)	0.0229 (14)	0.0215 (13)	0.0161 (16)
C7	0.0378 (9)	0.0423 (10)	0.0407 (10)	0.0032 (8)	0.0220 (8)	0.0025 (8)
C8	0.0663 (15)	0.0905 (19)	0.0618 (14)	0.0410 (14)	0.0465 (13)	0.0314 (14)
C9	0.0796 (18)	0.109 (2)	0.0623 (15)	0.0500 (17)	0.0522 (14)	0.0408 (16)
C10	0.0479 (11)	0.0562 (13)	0.0535 (12)	0.0161 (10)	0.0267 (10)	0.0137 (10)
C11	0.0389 (9)	0.0489 (12)	0.0483 (11)	0.0036 (8)	0.0250 (8)	−0.0006 (9)
C12	0.0419 (10)	0.0496 (11)	0.0382 (9)	0.0018 (8)	0.0234 (8)	0.0014 (8)
C13	0.0388 (9)	0.0429 (10)	0.0385 (10)	0.0016 (8)	0.0190 (8)	0.0002 (8)
N1	0.0435 (9)	0.0499 (10)	0.0422 (9)	0.0014 (8)	0.0221 (7)	0.0053 (8)
N2	0.0508 (11)	0.0753 (15)	0.0609 (12)	0.0146 (10)	0.0354 (10)	0.0203 (11)
O1	0.0433 (8)	0.0731 (11)	0.0479 (8)	0.0088 (7)	0.0252 (7)	0.0157 (8)
O2	0.0471 (8)	0.0666 (10)	0.0483 (8)	0.0169 (7)	0.0279 (7)	0.0115 (7)
O3	0.0717 (12)	0.0929 (14)	0.0660 (11)	0.0431 (11)	0.0412 (9)	0.0318 (10)

Geometric parameters (Å, º) top

C1—N2	1.326 (3)	C7—C13	1.483 (3)
C1—N1	1.344 (3)	C8—C9	1.375 (3)
C1—C2	1.406 (3)	C8—H8	0.9300
C2—C3	1.359 (3)	C9—C10	1.376 (3)
C2—H2	0.9300	C9—H9	0.9300
C3—C4	1.407 (3)	C10—O3	1.353 (3)
C3—C6	1.498 (3)	C10—C11	1.379 (3)
C4—C5	1.342 (3)	C11—C12	1.375 (3)
C4—H4	0.9300	C11—H11	0.9300
C5—N1	1.353 (3)	C12—H12	0.9300
C5—H5	0.9300	C13—O1	1.251 (2)
C6—H6A	0.9600	C13—O2	1.264 (2)
C6—H6B	0.9600	N1—H1	0.865 (10)
C6—H6C	0.9600	N2—H2A	0.859 (10)
C7—C12	1.384 (3)	N2—H2B	0.855 (10)
C7—C8	1.384 (3)	O3—H3	0.827 (10)

N2—C1—N1	117.89 (19)	C9—C8—H8	119.3
N2—C1—C2	124.03 (19)	C7—C8—H8	119.3
N1—C1—C2	118.07 (18)	C8—C9—C10	120.4 (2)
C3—C2—C1	121.14 (19)	C8—C9—H9	119.8
C3—C2—H2	119.4	C10—C9—H9	119.8
C1—C2—H2	119.4	O3—C10—C9	117.5 (2)
C2—C3—C4	118.3 (2)	O3—C10—C11	123.33 (19)
C2—C3—C6	121.5 (2)	C9—C10—C11	119.2 (2)
C4—C3—C6	120.3 (2)	C12—C11—C10	119.96 (18)
C5—C4—C3	119.7 (2)	C12—C11—H11	120.0
C5—C4—H4	120.1	C10—C11—H11	120.0
C3—C4—H4	120.1	C11—C12—C7	121.69 (18)
C4—C5—N1	121.2 (2)	C11—C12—H12	119.2
C4—C5—H5	119.4	C7—C12—H12	119.2
N1—C5—H5	119.4	O1—C13—O2	122.34 (18)
C3—C6—H6A	109.5	O1—C13—C7	118.69 (17)
C3—C6—H6B	109.5	O2—C13—C7	118.95 (17)
H6A—C6—H6B	109.5	C1—N1—C5	121.58 (19)
C3—C6—H6C	109.5	C1—N1—H1	123 (2)
H6A—C6—H6C	109.5	C5—N1—H1	115 (2)
H6B—C6—H6C	109.5	C1—N2—H2A	118.8 (19)
C12—C7—C8	117.33 (18)	C1—N2—H2B	118.6 (16)
C12—C7—C13	121.37 (17)	H2A—N2—H2B	122 (2)
C8—C7—C13	121.29 (17)	C10—O3—H3	110 (2)
C9—C8—C7	121.4 (2)

N2—C1—C2—C3	177.9 (2)	O3—C10—C11—C12	179.2 (2)
N1—C1—C2—C3	−1.7 (3)	C9—C10—C11—C12	0.1 (4)
C1—C2—C3—C4	0.5 (3)	C10—C11—C12—C7	2.6 (3)
C1—C2—C3—C6	−178.7 (2)	C8—C7—C12—C11	−3.0 (3)
C2—C3—C4—C5	1.0 (3)	C13—C7—C12—C11	177.11 (19)
C6—C3—C4—C5	−179.8 (2)	C12—C7—C13—O1	10.0 (3)
C3—C4—C5—N1	−1.4 (4)	C8—C7—C13—O1	−169.9 (2)
C12—C7—C8—C9	0.8 (4)	C12—C7—C13—O2	−168.28 (19)
C13—C7—C8—C9	−179.3 (3)	C8—C7—C13—O2	11.9 (3)
C7—C8—C9—C10	1.8 (5)	N2—C1—N1—C5	−178.3 (2)
C8—C9—C10—O3	178.6 (3)	C2—C1—N1—C5	1.3 (3)
C8—C9—C10—C11	−2.2 (5)	C4—C5—N1—C1	0.2 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2ⁱ	0.87 (1)	1.81 (1)	2.666 (2)	174 (3)
N2—H2A···O1ⁱ	0.86 (1)	1.95 (1)	2.806 (3)	172 (3)
N2—H2B···O2ⁱⁱ	0.86 (1)	2.05 (1)	2.887 (3)	167 (2)
O3—H3···O1ⁱⁱⁱ	0.83 (1)	1.87 (1)	2.677 (2)	167 (3)
C6—H6C···O1^iv	0.96	2.58	3.505 (4)	161

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

Acknowledgements

The authors acknowledge the SAIF, IIT, Madras for the data collection.

References

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