2-Amino-5-chloro­pyridinium 6-oxo-1,6-dihydro­pyridine-2-carboxyl­ate 0.85-hydrate

Madhukar Hemamalini; Hoong-Kun Fun

doi:10.1107/S1600536810032307

. 2010 Aug 18;66(Pt 9):o2338. doi: 10.1107/S1600536810032307

2-Amino-5-chloropyridinium 6-oxo-1,6-dihydropyridine-2-carboxylate 0.85-hydrate

Madhukar Hemamalini ^a, Hoong-Kun Fun ^a,^*,^‡

PMCID: PMC3007856 PMID: 21588683

Abstract

In the title salt, C₅H₆ClN₂ ⁺·C₆H₄NO₃ ⁻·0.85H₂O, the pyridinium ring is planar, with a maximum deviation of 0.010 (2) Å. In the crystal structure, the cations, anions and water molecules are linked via N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional network.

Related literature

For applications of intermolecular interactions, see: Braga et al. (2002 ▶); Lam & Mak (2000 ▶). For related structures, see: Hemamalini & Fun (2010a ▶,b ▶,c ▶,d ▶,e ▶,f ▶); Sawada & Ohashi (1998 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₅H₆ClN₂ ⁺·C₆H₄NO₃ ⁻·0.85H₂O
M _r = 282.98
Orthorhombic,
a = 3.8096 (1) Å
b = 15.6046 (3) Å
c = 20.9370 (3) Å
V = 1244.65 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.32 mm⁻¹
T = 296 K
0.52 × 0.22 × 0.11 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.851, T _max = 0.966
15196 measured reflections
3632 independent reflections
3129 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.113
S = 1.10
3632 reflections
215 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.17 e Å⁻³
Absolute structure: Flack (1983 ▶), with 1458 Fridel pairs
Flack parameter: −0.04 (6)

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); 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, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810032307/ci5153sup1.cif

e-66-o2338-sup1.cif^{(17.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810032307/ci5153Isup2.hkl

e-66-o2338-Isup2.hkl^{(174.5KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1W1⋯O3ⁱ	0.85	1.85	2.696 (3)	174
O1W—H2W1⋯O1Wⁱⁱ	0.85	1.99	2.732 (5)	145
N1—H1N1⋯O3ⁱⁱⁱ	0.98 (2)	1.67 (2)	2.637 (2)	170 (2)
N2—H1N2⋯O1^iv	0.87 (2)	1.97 (2)	2.823 (2)	168 (2)
N2—H2N2⋯O2ⁱⁱⁱ	0.84 (3)	2.04 (3)	2.882 (2)	179 (3)
C4—H4⋯O1^v	0.93 (2)	2.39 (2)	3.296 (2)	166 (2)

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

Acknowledgments

The authors thank the Malaysian Government and Universiti Sains Malaysia for Research University Golden Goose grant No. 1001/PFIZIK/811012. MH also thanks Universiti Sains Malaysia for a postdoctoral research fellowship.

supplementary crystallographic information

Comment

Intermolecular interaction analyses in crystalline systems are very important in supramolecular chemistry (Braga et al., 2002). These interactions are responsible for crystal packing, and through an understanding of such interactions we can comprehend collective properties and design new crystals with specific physical and chemical properties (Lam & Mak, 2000). We have been interested in hydrogen-bonded systems formed by 2-amino pyridines and carboxylic acids that generate molecular assemblies (Hemamalini & Fun, 2010a,b,c,d,e,f). In continuation of our studies of pyridinium derivatives, the crystal structure determination of the title compound has been undertaken.

The asymmetric unit, (Fig. 1), contains one 2-amino-5-chloropyridinium cation, one 6-oxo-1,6-dihydropyridine-2-carboxylate anion and one water molecule with a refined site occupany of 0.85. The pyridinium ring is essentially planar, with a maximum deviation of 0.010 (2) Å for atom C5. In the 2-amino-5-chloropyridinium cation, a wider than normal angle [C1—N1—C2 = 122.55 (14)°] is subtended at the protonated N1 atom. The anion exists in the keto–enol tautomerism of the -CONH moiety. Similar tautomerism is also observed in the crystal structure of 2-oxo-1,2-dihydropyridine-6-carboxylic acid (Sawada & Ohashi, 1998).

In the crystal packing (Fig. 2), the protonated N1 atom and the 2-amino group (N2) are hydrogen-bonded to the carboxylate oxygen atoms (O2 and O3) via a pair of intermolecular N1—H1N1···O3 and N2—H2N2···O2 hydrogen bonds, forming an R₂²(8) ring motif (Bernstein et al., 1995). The ion pairs are further connected via O1W—H1W1···O3, O1W—H2W1···O1W, N2—H1N2···O1 and C4—H4···O1 (Table 1) hydrogen bonds, forming a three-dimensional network. The crystal of title compound is isomorphous with that of 2-amino-5-bromopyridinium 6-oxo-1,6-dihydropyridine-2-carboxylate monohydrate (Hemamalini & Fun, 2010f).

Experimental

A hot methanol solution (20 ml) of 2-amino-5-chloropyridine (64 mg, Aldrich) and 6-hydroxypicolinic acid (69 mg, Merck) were mixed and warmed over a heating magnetic stirrer hotplate for a few minutes. The resulting solution was allowed to cool slowly at room temperature and crystals of the title compound appeared after a few days.