8-(2,2,2-Trifluoro­ethoxy)quinolinium perchlorate–8-(2,2,2-trifluoro­ethoxy)quinoline (1/1)

Jun Wu; Lu-Sheng Chen; Qi-Kui Liu; Dian-Shun Guo

doi:10.1107/S1600536811013250

. 2011 Apr 13;67(Pt 5):o1131–o1132. doi: 10.1107/S1600536811013250

8-(2,2,2-Trifluoroethoxy)quinolinium perchlorate–8-(2,2,2-trifluoroethoxy)quinoline (1/1)

Jun Wu ^a, Lu-Sheng Chen ^a, Qi-Kui Liu ^a, Dian-Shun Guo ^a,^*

PMCID: PMC3089229 PMID: 21754442

Abstract

The title compound, C₁₁H₉F₃NO⁺·ClO₄ ⁻·C₁₁H₈F₃NO or [(C₁₁H₈F₃NO)H(C₁₁H₈F₃NO)]ClO₄, contains two 8-(2,2,2-trifluoroethoxy)quinoline molecules, one of which combines a proton from perchloric acid to form the corresponding quinolinium cation. The quinolinium and quinoline rings form a cationic unit via an intermolecular N—H⋯N hydrogen bond. The heterocyclic units are almost perpendicular to each other [interplanar angle 86.97 (6)°]. In the crystal, each perchlorate anion bridges two adjacent cationic units and creates a chain by a combination of C—H⋯O hydrogen bonds. Two inversion-related chains associate into a molecular column by π–π stacking interactions between the quinolinium rings. The perpendicular and centroid–centroid distances between adjacent quinolinium rings are 3.501 (3) and 3.634 (9) Å, respectively. The molecular column is linked to its neighbors, creating a two-dimensional network via the weak π–π stacking between the quinoline rings [perpendicular and centroid–centroid separations 3.340 (4) and 4.408 (4) Å, respectively]. Finally, a three-dimensional framework is formed by a combination of intermolecular C—F⋯π contacts. One –CF₃ group is disordered over two positions of equal occupancy.

Related literature

For background to quinoline derivatives, see: Moret et al. (2006 ▶); Kalita et al. (2009 ▶). For related structures, see: Ouyang & Khoo et al. (1998 ▶); Karmakar et al. (2009 ▶); Al-Mandhary & Steel (2003 ▶); Zhang et al. (2006 ▶); Zheng et al. (2006 ▶). For π–π stacking, see: Kalita & Baruah (2010 ▶); Chen et al. (2005 ▶); Liang et al. (2002 ▶). For C—F⋯π contacts, see: Prasanna & Row (2000 ▶); Saraogi et al. (2003 ▶); Choudhury & Row (2004 ▶).

Experimental

Crystal data

C₁₁H₉F₃NO⁺·ClO₄ ⁻·C₁₁H₈F₃NO
M _r = 554.83
Triclinic,
a = 9.462 (2) Å
b = 11.229 (3) Å
c = 11.832 (3) Å
α = 82.910 (3)°
β = 77.048 (3)°
γ = 74.536 (3)°
V = 1178.0 (5) Å³
Z = 2
Mo Kα radiation
μ = 0.25 mm⁻¹
T = 293 K
0.50 × 0.32 × 0.25 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1999 ▶) T _min = 0.884, T _max = 0.940
6301 measured reflections
4364 independent reflections
3400 reflections with I > 2σ(I)
R _int = 0.021

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.137
S = 1.02
4364 reflections
361 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: SMART (Bruker, 1999 ▶); cell refinement: SAINT (Bruker, 1999 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811013250/im2278sup1.cif

e-67-o1131-sup1.cif^{(23.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811013250/im2278Isup2.hkl

e-67-o1131-Isup2.hkl^{(213.8KB, hkl)}

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

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

Cg1, Cg2 and Cg3 are the midpoints of the N1–C5, C5–C9 and C17–C18 bonds, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯N2	0.86	1.87	2.684 (3)	158
C22—F5⋯Cg1	1.33	3.10	3.796 (3)	111
C22—F6⋯Cg2	1.33	3.17	3.804 (4)	109
C13—H13⋯O3ⁱ	0.93	2.60	3.393 (6)	144
C21—H21B⋯O4ⁱⁱ	0.97	2.48	3.437 (7)	169
C22—F5⋯Cg3ⁱⁱⁱ	1.33	3.24	3.860 (8)	108

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

Acknowledgments

Financial support from the National Natural Science Foundation of China (grant No. 20572064) and the Natural Science Foundation of Shandong Province (grant No. ZR2010BM022) is gratefully acknowledged.

supplementary crystallographic information

Comment

Molecules containing quinoline moieties have attracted much interest due to their significant bioactivities (Moret et al., 2006) and potential applications for constructing supramolecular systems by various hydrogen bonds and π–π interactions (Kalita et al., 2009). Numerous crystal structures of 8-substituented quinolines, most of which are 8-alkyloxyquinoline derivatives have been reported (Karmakar et al., 2009; Al-Mandhary et al., 2003; Zhang et al., 2006; Zheng et al., 2006), while the crystal structures of such compounds exhibiting fluorinated alkyl groups have rarely been described. We synthesized a new trifluoroethoxyquinoline derivative and attempted to prepare its Ni(II)-complex. Surprisingly, a complex without the Ni(II) ion, namely 8-(2,2,2-trifluoroethoxy)-quinolinium-[8-(2,2,2-trifluoroethoxy)-quinoline] perchlorate, was obtained. Here, we report its crystal structure.

In the crystal structure of the title complex the asymmetric unit contains one perchlorate anion and one organic cation consisting of two 8-(2,2,2-trifluoroethoxy)-quinolines and a proton (Fig. 1). In the cationic unit, one quinoline ring is protonated forming a quinolinium and is connected to the other one via a N—H···N hydrogen bond (N–H···N angle 155.33 (5)°, N1···N2 2.684 (3) Å, Fig. 2, Table 1). This distance is shorter than 2.729 Å reported for a similar quinoline derivative (Ouyang et al., 1998). Such a short distance may be ascribed to the presence of two weak C—F···π contacts (Prasanna & Row, 2000; Saraogi et al., 2003; Choudhury & Row, 2004) between the non-disordered trifluoromethyl group and the quinoline ring. Separations of F5···Cg1 and F6···Cg2 (Cg1 and Cg2 are the centroids of N1–C5 and C5–C9 bonds, respectively) are 3.099 (3) and 3.166 (3) Å, respectively. The quinolinium and quinoline rings are almost perpendicular to each other, with a dihedral angle of 86.97 (6)°. The other trifluoromethyl group is disordered over two orientations, with refined site-occupancy factors of 0.5.

In the packing of the title complex, there exist intermolecular C—H···O hydrogen bonds, C—F···π contacts (Table 1) and π–π stackings (Kalita & Baruah, 2010; Chen et al., 2005; Liang et al., 2002). The cationic units are alternately bridged by perchlorate anions with intermolecular C—H···O hydrogen bonds and form an infinite one-dimensional chain along the c axis (Fig. 3). Hydrogen bonds arise from atoms C13—H13 and C21—H21B in the molecule at (x, y, z) acting as hydrogen bond donors towards atoms O3 at (-x + 1, -y + 1, -z + 1) and O4 (-x + 1, -y + 1, -z + 2), respectively. Two adjacent chains running along the alternate orientation are further combined to a molecular column by π–π stacking interactions between the quinolinium rings, with perpendicular and centroid-centroid distances of 3.501 (3) and 3.634 (9) Å, respectively, between neighboring phenyl rings of the quinolinium units. Finally, a complicated three-dimensional framework is formed by a combination of C—F···π contacts, with a F5···Cg3 (Cg3 is the centroid of C17–C18 bond) distance of 3.240 (7) Å (Table 1), and weak π–π stackings between adjacent phenyl rings of the quinoline moieties, with perpendicular and centroid-centroid separations of 3.340 (4) and 4.408 (4) Å, respectively.

Experimental

A suspension of 8-hydroxyquinoline (0.200 g, 1.378 mmol), anhydrous KOH (0.093 g, 1.657 mmol) and 2,2,2-trifluoroethyl-4-methylbenzenesulfonate (0.385 g, 1.514 mmol) in dry NMP (5 ml) was stirred for 5 h at 393 K and then cooled to room temperature. The resulting mixture was neutralized with 5% aqueous HCl and extracted with CH₂Cl₂. The organic layer was separated and washed with saturated sodium hydrogen carbonate and brine, and dried over anhydrous MgSO₄. Removal of the solvent under reduced pressure gave 8-(2,2,2-trifluoroethoxy)-quinoline as a yellow solid (yield 73%), which was purified by flash column chromatography (EtOAc/petroleum ether = 1:3, R_F = 1/2).

Single crystals of the title complex suitable for X-ray analysis were obtained from a solution of Ni(ClO₄)₂ (0.013 g, 0.050 mmol) in MeOH (1 ml) which was layered onto a solution of 8-(2,2,2-trifluoroethoxy)-quinoline (0.012 g, 0.053 mmol) in CH₂Cl₂ (1 ml) at 298 K.