1,1′-(Hexane-1,6-di­yl)dipyridinium bis­(hexa­fluoro­phosphate)

Jin-hua Liang; Dong Jin; Xiao-feng Gao; Jin-tang Wang

doi:10.1107/S1600536808039639

. 2008 Nov 29;64(Pt 12):o2495. doi: 10.1107/S1600536808039639

1,1′-(Hexane-1,6-diyl)dipyridinium bis(hexafluorophosphate)

Jin-hua Liang ^a, Dong Jin ^b, Xiao-feng Gao ^a, Jin-tang Wang ^a,^*

PMCID: PMC2959814 PMID: 21581456

Abstract

The asymmetric unit of the title compound, C₁₆H₂₂N₂ ²⁺·2PF₆ ⁻, contains one half-molecule and a hexafluorophosphate anion. In the crystal structure, intermolecular C—H⋯F hydrogen bonds link the molecules. The F atoms in the hexafluorophosphate anion are disordered over two positions and were refined with occupancies of 0.43 (2) and 0.57 (2).

Related literature

For general background, see: Jared et al. (2005 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₆H₂₂N₂ ²⁺·2PF₆ ⁻
M _r = 532.30 (3)
Triclinic,
a = 7.9140 (16) Å
b = 9.2930 (18) Å
c = 9.4870 (19) Å
α = 65.13 (3)°
β = 65.46 (3)°
γ = 74.37 (3)°
V = 572.0 (3) Å³
Z = 1
Mo Kα radiation
μ = 0.29 mm⁻¹
T = 298 (2) K
0.30 × 0.30 × 0.20 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.917, T _max = 0.944
2172 measured reflections
2014 independent reflections
1499 reflections with I > 2σ(I)
R _int = 0.047
3 standard reflections frequency: 120 min intensity decay: none

Refinement

R[F ² > 2σ(F ²)] = 0.065
wR(F ²) = 0.166
S = 1.00
2014 reflections
200 parameters
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.38 e Å⁻³

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ▶); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); 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, x1. DOI: 10.1107/S1600536808039639/hk2581sup1.cif

e-64-o2495-sup1.cif^{(17.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808039639/hk2581Isup2.hkl

e-64-o2495-Isup2.hkl^{(99KB, 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
C1—H1A⋯F4′ⁱ	0.93	2.48	3.333 (17)	153
C2—H2A⋯F2′ⁱⁱ	0.93	2.53	3.267 (18)	137
C3—H3A⋯F3′ⁱⁱ	0.93	2.47	3.257 (15)	142
C4—H4A⋯F1′ⁱⁱⁱ	0.93	2.52	3.287 (14)	140

Open in a new tab

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

Acknowledgments

The authors thank Professor Hua-qin Wang of the Analysis Centre, Nanjing University, for carrying out the X-ray crystallographic analysis.

supplementary crystallographic information

Comment

The title compound is a dicationic ionic liquid, which has high thermal stability. Applications of the dicationic ionic liquid are found in biochemistry as well as many areas of chemistry (Jared et al., 2005). We report herein the crystal structure of the title compound.

The asymmetric unit of the title compound (Fig. 1) contains one-half molecule and a hexafluorophosphate molecule, where the bond lengths (Allen et al., 1987) and angles are within normal ranges.

In the crystal structure, intermolecular C-H···F hydrogen bonds (Table 1) link the molecules (Fig. 2), in which they may be effective in the stabilization of the structure.

Experimental

For the preparation of the title compound, 1,6-dibromide hexane (12.2 g, 0.05 mol) was added to acetonitrile solution (50 ml) of dehydrate pyridine (7.91 g, 0.10 mol) at 353 K. After stirring for 24 h, the mixture was cooled to room temperature and filtered. The solid was washed with ethyl acetate and dried. Then, the solid (2.01 g, 5 mmol) was dissolved in distilled water (50 ml) and potassium hexafluorophosphate (1.84 g, 10 mmol) was added. After stirring at room temperature for 3 h, the colorless solid formed was collected by filtration, washed with distilled water (50 ml) and dried. The product was purified by repeated crystallization. Crystals suitable for X-ray analysis were obtained by slow evaporation of acetone (yield; 3.08 g, 80%, m.p. 513 K).