N,N,2,4,6-Penta­methyl­anilinium hexa­fluoro­phosphate–1,4,7,10,13,16-hexa­oxa­cyclo­octa­decane (2/1)

Yi Qi Chang; Yuan Zhang; Huo Lin Lian

doi:10.1107/S1600536813033734

. 2013 Dec 18;70(Pt 1):o72. doi: 10.1107/S1600536813033734

N,N,2,4,6-Pentamethylanilinium hexafluorophosphate–1,4,7,10,13,16-hexaoxacyclooctadecane (2/1)

Yi Qi Chang ^a, Yuan Zhang ^a,^*, Huo Lin Lian ^a

PMCID: PMC3914100 PMID: 24527005

Abstract

In the title compound, 2C₁₁H₁₈N⁺·2PF₆ ⁻·C₁₂H₂₄O₆, the 18-crown-6 molecule has crystallographically imposed inversion symmetry. In the crystal, it interacts with the cation through weak C—H⋯O hydrogen bonds. The cations and anions are further linked via N—H⋯F and C—H⋯F hydrogen bonds, leading to a sandwich structure .

Related literature

For background to the development of ferroelectric pure organic or inorganic compounds, see: Haertling (1999 ▶); Homes et al. (2001 ▶). For the structure of a related compound, see: Zhang (2013 ▶). graphic file with name e-70-00o72-scheme1.jpg

Experimental

Crystal data

2C₁₁H₁₈N⁺·2PF₆ ⁻·C₁₂H₂₄O₆
M _r = 882.78
Monoclinic,
a = 8.9122 (18) Å
b = 16.775 (3) Å
c = 15.136 (3) Å
β = 103.71 (3)°
V = 2198.4 (8) Å³
Z = 2
Mo Kα radiation
μ = 0.19 mm⁻¹
T = 293 K
0.40 × 0.30 × 0.20 mm

Data collection

Rigaku Mercury2 (2x2 bin mode) diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ▶) T _min = 0.832, T _max = 1.000
18170 measured reflections
3858 independent reflections
2524 reflections with I > 2σ(I)
R _int = 0.053

Refinement

R[F ² > 2σ(F ²)] = 0.083
wR(F ²) = 0.195
S = 1.20
3858 reflections
253 parameters
H-atom parameters constrained
Δρ_max = 0.49 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Data collection: CrystalClear (Rigaku, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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 datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S1600536813033734/rz5098sup1.cif

e-70-00o72-sup1.cif^{(20.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813033734/rz5098Isup2.hkl

e-70-00o72-Isup2.hkl^{(189.1KB, hkl)}

Click here for additional data file.^{(16.3KB, cml)}

Supporting information file. DOI: 10.1107/S1600536813033734/rz5098Isup3.cml

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1C⋯F4	0.91	2.38	3.077 (5)	134
C16—H16A⋯O3ⁱ	0.96	2.52	3.334 (5)	143
C16—H16B⋯O2ⁱⁱ	0.96	2.51	3.443 (5)	164
C16—H16C⋯O1ⁱ	0.96	2.57	3.381 (5)	143
C17—H17B⋯F4	0.96	2.54	3.122 (6)	119

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

supplementary crystallographic information

1. Comment

As a continuation of our studies on the development of novel ferroelectric pure organic or inorganic compounds (Haertling et al., 1999; Homes et al., 2001), we investigated the physical properties of the title compound. Recently the crystal structure of the strictly related compound N,N,2,4,6-pentamethylanilinium hexafluorophosphate was reported by our group (Zhang, 2013). The dielectric constant of the title compound as a function of the temperature indicates that the permittivity is basically temperature-independent (dielectric constant equaling to 4.1 to 6.1), suggesting that this compound should be not a real ferroelectrics or there may be no distinct phase transition occurring within the measured temperature range. Similarly, below the melting point (180°C) of the compound, the dielectric constant as a function of temperature also goes smoothly, and there is no dielectric anomaly observed (dielectric constant equaling to 4.1 to 6.1). Herein, we report the synthesis and crystal structure of the title compound.

The asymmetric unit of the title compound (Fig. 1) consists of one N,N,2,4,6-pentamethylanilinium cation, one hexafluorophosphate anion and one half of a 1,4,7,10,13,16-hexaoxacyclooctadecane molecule. Bond distances and bond angles are not unusual. In the crystal structure (Fig. 2), the 18-crown-6 molecule interacts with the cation through weak C—H···O hydrogen bonds (Table 1). Cation and anion are further linked via N—H···F and C—H···F hydrogen bonds. Dipole–dipole and van der Waals interactions are effective in stabilizing the molecular packing.

2. Experimental

A mixture of N,N,2,4,6-pentamethylbenzenamine (1.36 g, 10 mmol), hexafluorophosphoric acid(1.90 g, 10 mmol) and 1,4,7,10,13,16-hexaoxacyclooctadecane (2.64, 10 mmol) in methanol(30 ml) was stirred until clear. After several days, the title compound was formed and recrystallized from a methanol solution to afford colourless prismatic crystals suitable for X-ray analysis.