Guanidinium quinoline-2-carboxyl­ate

Graham Smith; Urs D Wermuth

doi:10.1107/S1600536809049733

. 2009 Nov 25;65(Pt 12):o3220. doi: 10.1107/S1600536809049733

Guanidinium quinoline-2-carboxylate

Graham Smith ^a,^*, Urs D Wermuth ^a

PMCID: PMC2972072 PMID: 21578928

Abstract

In the structure of the guanidinium salt of quinaldic acid, CH₆N₃ ⁺·C₁₀H₆NO₂ ⁻, the asymmetric unit contains two independent cations and anions having similar inter-species hydrogen-bonding environments, which include cyclic R ₂ ²(8), R ₂ ¹(6) and R ₁ ²(5) associations. These and additional weak aromatic ring π–π interactions [minimum ring-centroid separation = 3.662 (2) Å] give a two-dimensional layered structure.

Related literature

For guanidinium salts of aromatic acids, see: Parthasarathi et al. (1982 ▶); Schürmann et al. (1998 ▶); Najafpour et al. (2007 ▶); Pereira Silva et al. (2007 ▶). For quinaldic acid structures, see: Dobrzyńska & Jerzykiewicz (2004 ▶); Smith et al. (2004 ▶, 2007 ▶, 2008a ▶,b ▶). graphic file with name e-65-o3220-scheme1.jpg

Experimental

Crystal data

CH₆N₃ ⁺·C₁₀H₆NO₂ ⁻
M _r = 232.25
Monoclinic,
a = 7.4318 (3) Å
b = 42.2105 (18) Å
c = 7.3035 (4) Å
β = 94.045 (4)°
V = 2285.40 (18) Å³
Z = 8
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 297 K
0.35 × 0.20 × 0.18 mm

Data collection

Oxford Diffraction Gemini-S Ultra CCD-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.740, T _max = 0.870
10626 measured reflections
3981 independent reflections
2931 reflections with I > 2σ(I)
R _int = 0.035

Refinement

R[F ² > 2σ(F ²)] = 0.069
wR(F ²) = 0.162
S = 1.04
3981 reflections
355 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.15 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction, 2008 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2008 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SIR92 (Altomare et al., 1994 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶) within WinGX (Farrugia, 1999 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: PLATON.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809049733/wn2367sup1.cif

e-65-o3220-sup1.cif^{(28.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809049733/wn2367Isup2.hkl

e-65-o3220-Isup2.hkl^{(191.2KB, 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
N1C—H11C⋯O21B	0.82 (4)	2.12 (4)	2.937 (5)	176 (3)
N1C—H12C⋯O21A ⁱ	0.92 (4)	2.03 (4)	2.852 (5)	149 (3)
N1D—H11D⋯O22A	0.87 (4)	2.04 (4)	2.902 (4)	177 (4)
N1D—H12D⋯O21B ⁱⁱ	0.85 (5)	2.47 (5)	3.312 (5)	173 (4)
N2C—H21C⋯O22A	0.94 (4)	1.87 (4)	2.784 (4)	166 (4)
N2C—H22C⋯O21A ⁱ	0.91 (4)	2.57 (4)	3.163 (5)	124 (4)
N2C—H22C⋯N1A ⁱ	0.91 (4)	2.08 (5)	2.964 (4)	165 (4)
N2D—H21D⋯O21B ⁱⁱⁱ	0.84 (4)	2.11 (4)	2.899 (5)	155 (3)
N2D—H22D⋯O21A	0.89 (4)	2.01 (5)	2.890 (4)	173 (4)
N3C—H31C⋯O22B	0.93 (5)	1.96 (5)	2.891 (4)	173 (4)
N3C—H32C⋯O22A	0.84 (4)	2.57 (5)	3.216 (5)	135 (4)
N3D—H31D⋯O21B ⁱⁱⁱ	0.93 (4)	2.60 (4)	3.268 (5)	130 (3)
N3D—H31D⋯N1B ⁱⁱⁱ	0.93 (4)	2.12 (4)	3.000 (4)	159 (3)
N3D—H32D⋯O22B ⁱⁱ	0.93 (4)	1.95 (4)	2.826 (4)	157 (4)

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

Acknowledgments

The authors acknowledge financial support from the Australian Research Council and the School of Physical and Chemical Sciences, Queensland University of Technology,

supplementary crystallographic information

Comment

The guanidinium salts of aromatic and heteroaromatic carboxylic acids have proved to be a particularly useful means of generating stable hydrogen-bonded supramolecular framework structures. Three-dimensional structures are most common, largely the result of the interactive efficiency of the symmetrical guanidinium cation in commonly forming cyclic R₂²(8) hydrogen-bonding associations with carboxylate-O acceptors. Among the known structures are the guanidinium salts with the aromatic monocarboxylic acids, 4-chloro-3-nitrobenzoic acid (a monohydrate) (Najafpour et al., 2007), and the anhydrous salts with benzoic acid (Pereira Silva et al., 2007), 4-nitrobenzoic acid (Schürmann et al., 1998), 3,5-dinitrobenzoic acid (Smith et al., 2007) and 4-amino-3,5,6-trichloropicolinic acid (Parthasarathi et al., 1982).

Our 1:1 stoichiometric reaction of quinoline-2-carboxylic acid (quinaldic acid) in 50% 2-propanol-water gave large chemically stable crystals of the title compound, anhydrous guanidinium quinoline-2-carboxylate, CH₆N₃⁺ C₁₀H₆NO₂^- and the structure is reported here. Quinaldic acid in the solid state exists as a zwitterionic hydrogen-bonded dimer (Dobrzyńska & Jerzykiewicz, 2004) and is commonly found in that form as an adduct species in some proton-transfer compounds where it acts as a Lewis base rather than an acid. Examples are the 1/1/1 quinolinium salt adducts with 5-sulfosalicylic acid (Smith et al., 2004), picrylsulfonic acid (Smith et al., 2008a) and 4,5-dichlorophthalic acid (Smith et al., 2008b).

In the structure of the title compound the asymmetric unit contains two guanidinium cations (C and D) and two quinoline-2-carboxylate anions (A and B) (Fig. 1). The H atom donors of the two cations form similar cyclic hydrogen-bonding interactions with carboxylate O and quinoline N acceptors (Table 1) (Fig. 2), both pairs having two guanidinium-N–H, N'–H'···O associations [graph set R₂¹(6)] and one N–H, N'–H'···O,O' association [R₂²(8)]. In addition, each has an R₁²(5) guanidinium N–H···N,O_{quinoline-carboxyl} association. A two-dimensional layered structure is generated (Fig. 3), in which some aromatic ring overlap down the c cell direction gives weak π–π interactions [minimum ring centroid separation,for the six-membered ring N1B–C5B, 3.662 (2) Å]. The quinoline-2-carboxylate cations are conformationally similar with only minor differences in the N1–C2–C21–O22 torsion angles [170.3 (3)° (A), 163.6 (3)° (B)].

Experimental

The title compound was synthesized by heating together under reflux for 10 minutes, 1 mmol quantities of quinoline-2-carboxylic acid and guanidine carbonate in 50 ml of 50% aqueous propan-2-ol. After concentration to ca 30 ml, partial room temperature evaporation of the hot-filtered solution gave colourless prisms [m.p. 543–544 K].