Crystal structure of 2-amino­pyridinium 6-chloro­nicotinate

N Jeeva Jasmine; A Rajam; P Thomas Muthiah; N Stanley; I Abdul Razak; M Mustaqim Rosli

doi:10.1107/S2056989015014796

. 2015 Aug 12;71(Pt 9):o655–o656. doi: 10.1107/S2056989015014796

Crystal structure of 2-aminopyridinium 6-chloronicotinate

N Jeeva Jasmine ^a, A Rajam ^a, P Thomas Muthiah ^a,^*, N Stanley ^a, I Abdul Razak ^b, M Mustaqim Rosli ^b

PMCID: PMC4555436 PMID: 26396888

Abstract

In the title salt, C₅H₇N⁺·C₆H₃ClNO⁻, the 2-aminopyridinium cation interacts with the carboxylate group of the 6-chloronicotinate anion through a pair of independent N—H⋯O hydrogen bonds, forming an R ₂ ²(8) ring motif. In the crystal, these dimeric units are connected further via N—H⋯O hydrogen bonds, forming chains along [001]. In addition, weak C—H⋯N and C—H⋯O hydrogen bonds, together with weak π–π interactions, with centroid–centroid distances of 3.6560 (5) and 3.6295 (5) Å, connect the chains, forming a two-dimensional network parallel to (100).

Keywords: crystal structure, 2-aminopyridinium, 6-chloronicotinate, 6-chloropyridine-3-carboxylate, noncovalent interactions, π–π stacking interactions

Related literature

For a background to noncovalent interactions, see: García-Raso et al. (2009 ▸). For the applications of pyridine compounds, see: Schwid et al. (1997 ▸); Rajkumar et al. (2015 ▸). For related structures, see: Xie (2007 ▸); Jennifer & Muthiah (2014 ▸); Chao et al. (1975 ▸); Bis & Zaworotko (2005 ▸); Jebas & Balasubramanian (2006 ▸). For information on π–π stacking interactions, see: Hunter (1994 ▸). For hydrogen-bond graph-set motifs, see: Bernstein et al. (1995 ▸);

Experimental

Crystal data

C₅H₇N₂ ⁺·C₆H₃ClNO₂ ⁻
M _r = 251.67
Monoclinic,
a = 8.6844 (4) Å
b = 10.8112 (5) Å
c = 11.9235 (6) Å
β = 95.2046 (9)°
V = 1114.87 (9) Å³
Z = 4
Mo Kα radiation
μ = 0.34 mm⁻¹
T = 100 K
0.51 × 0.40 × 0.17 mm

Data collection

Bruker SMART APEXII DUO CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▸) T _min = 0.993, T _max = 0.994
15546 measured reflections
4073 independent reflections
3771 reflections with I > 2σ(I)
R _int = 0.019

Refinement

R[F ² > 2σ(F ²)] = 0.031
wR(F ²) = 0.092
S = 1.07
4073 reflections
166 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.50 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▸); cell refinement: SAINT (Bruker, 2009 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▸); molecular graphics: PLATON (Spek, 2009 ▸) and Mercury (Macrae et al., 2008 ▸); software used to prepare material for publication: PLATON.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989015014796/lh5778sup1.cif

e-71-0o655-sup1.cif^{(19.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015014796/lh5778Isup2.hkl

e-71-0o655-Isup2.hkl^{(195.6KB, hkl)}

Click here for additional data file.^{(4.4KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015014796/lh5778Isup3.cml

Click here for additional data file.^{(1.1MB, tif)}

. DOI: 10.1107/S2056989015014796/lh5778fig1.tif

The asymmetric unit of the title compound, showing 30% probability displacement ellipsoids.

Click here for additional data file.^{(1.5MB, tif)}

. DOI: 10.1107/S2056989015014796/lh5778fig2.tif

Part of the crystal structure with hydrogen bonds shown as dashed lines. Hydrogen atoms not involved hydrogen bonding have been removed for clarity.

CCDC reference: 1417413

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

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
N2H1N2O2ⁱ	0.923(17)	1.781(17)	2.7000(9)	173.5(15)
N3H2N3O1ⁱ	0.844(16)	1.942(17)	2.7830(10)	174.1(15)
N3H1N3O2ⁱⁱ	0.890(15)	1.962(15)	2.8490(9)	174.0(13)
C7H7AN1ⁱⁱⁱ	0.95	2.44	3.2808(11)	147
C10H10AO1^iv	0.95	2.25	3.1574(10)	160

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

NJJ thanks the UGC–SAP, India, for the award of an RFSMS. PTM is thankful to the UGC, New Delhi, for a UGC–BSR one-time grant to Faculty. IAR and MMR thank the Malaysian Government and Universiti Sains Malaysia (USM) for the research facilities to conduct this work.

supplementary crystallographic information

S1. Comment

Noncovalent interactions such as hydrogen bonding, anion-π, cation-π, and π-π interactions, and other weak forces play a central role in many areas. They are very important in deciding the conformation of molecules, chemical reactions, molecular recognition, regulating biochemical processes and governing the organization of multicomponent supramolecular assemblies (García-Raso et al., 2009). 2-Aminopyridines are used in the manufacture of pharmaceutical drugs, especially for the treatment of neurological ailments (Schwid et al., 1997). Pyridine heterocycles and their derivatives have large applications in the field of photo-chemical, electrochemical and catalytic process. Some pyridine derivatives possess non-linear optical (NLO) properties (Rajkumar et al., 2015). The crystal structure of 2-aminopyridinium isonicotinate 2-aminopyridine has already been reported (Xie, 2007). The salts of aminopyridine-thiophenecarboxylic acid (Jennifer & Muthiah, 2014) have been recently reported from our laboratory. We report herein the crystal structure of the title molecular salt, obtained by the reaction of 2-aminopyridine with 6-chloronicotinic acid.

The asymmetric unit of the title salt, (I), contains one 2-aminopyridinium cation and a 6-chloronicotinate anion (Fig. 1). Protonation of the cation occurs at N2, providing a C7—N2—C11 angle of 122.45 (7)° compared with 117.7 (1)° in the unprotonated 2-aminopyridine (Chao et al., 1975). A similar type of protonation is observed in various 2-aminopyridine acid complexes (Bis & Zaworotko, 2005). The bond lengths and angles in complex (I) are within normal ranges and comparable to those in other 2-aminopyridinium complexes (Jebas & Balasubramanian, 2006). The carboxylate group of the 6-chloronicotinate anion interacts with the protonated atom N2 and the amino group of the pyridine moiety through a pair of N—H···O hydrogen bonds, forming an eight membered R₂²(8) ring motif (Bernstein et al., 1995). Furthermore, these motifs are connected via N3—H1···O2ⁱⁱ, C7—H7A···N1ⁱⁱⁱ and C10—H10A···O1^iv hydrogen bonds (see Table 1 for symmetry codes), forming a two-dimensional network parallel to (100) (Fig 2). The crystal structure is further stabilized by two distinct π–π stacking interactions involving the 6-chloronicotinate and pyridinium ions. A Cg1-Cg2 distance of 3.6560 (5) Å and Cg2—Cg2 distance of 3.6295 (5) Å is observed (where Cg1 is the centroid of the N1/C1-C5 ring and Cg2 is the centroid of the N2/C7-C11 ring). The perpendicular distances of 3.2545 (3) and 3.5411 (3)Å together with the slip angles of 22.3 & 12.7°, respectively are typical for aromatic stacking values (Hunter, 1994).

S2. Experimental

A hot ethanolic solution of 2-aminopyridine (23 mg, Aldrich) and 6-chloronicotinic acid (39 mg, Alfa Aesar) was warmed for half an hour over a water bath. The mixture was cooled slowly and kept at room temperature. After a few days colourless plate like crystals were obtained.