3,3′-Dimethyl-1,1′-[2,2′-bipyridine-5,5′-diylbis(methyl­ene)]diimidazol-3-ium bis­(hexa­fluoro­phosphate)

Sunhong Park; Suk-Hee Moon; Tae Ho Kim; Ki-Min Park

doi:10.1107/S160053681103340X

. 2011 Aug 27;67(Pt 9):o2392. doi: 10.1107/S160053681103340X

3,3′-Dimethyl-1,1′-[2,2′-bipyridine-5,5′-diylbis(methylene)]diimidazol-3-ium bis(hexafluorophosphate)

Sunhong Park ^a, Suk-Hee Moon ^b, Tae Ho Kim ^a,^*, Ki-Min Park ^a,^*

PMCID: PMC3200939 PMID: 22058989

Abstract

The title compound, C₂₀H₂₂N₆ ²⁺·2PF₆ ⁻, was prepared by the reaction of 5,5′-bis(bromomethyl)-2,2′-bipyridine with 1-methylimidazole. The main molecule lies on an inversion center located at the mid-point of the C—C bond joining the two pyridine rings. The asymmetric unit therefore contains one half-molecule and one hexafluorophosphate anion. The dihedral angle between the pyridine and imidazole rings is 76.93 (7)°. In the crystal, weak intermolecular C—H⋯F hydrogen bonds contribute to the stabilization of the packing.

Related literature

For related syntheses, see: Sambrook et al. (2006 ▶); Zang et al. (2010 ▶). For related structures, see: Moon et al. (2011 ▶); Zang et al. (2010 ▶). For reference bond lengths, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₂₀H₂₂N₆ ²⁺·2PF₆ ⁻
M _r = 636.38
Monoclinic,
a = 7.5323 (4) Å
b = 10.7169 (6) Å
c = 15.4602 (9) Å
β = 93.922 (1)°
V = 1245.07 (12) Å³
Z = 2
Mo Kα radiation
μ = 0.29 mm⁻¹
T = 173 K
0.40 × 0.40 × 0.10 mm

Data collection

Bruker APEXII CCD diffractometer
7489 measured reflections
2717 independent reflections
1788 reflections with I > 2σ(I)
R _int = 0.049

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.117
S = 1.02
2717 reflections
181 parameters
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and DIAMOND (Brandenburg, 1998 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S160053681103340X/lx2201sup1.cif

e-67-o2392-sup1.cif^{(22.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681103340X/lx2201Isup2.hkl

e-67-o2392-Isup2.hkl^{(133.4KB, hkl)}

Supplementary material file. DOI: 10.1107/S160053681103340X/lx2201Isup3.cml

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
C7—H7⋯F1	0.95	2.23	3.111 (3)	154
C7—H7⋯F4	0.95	2.39	3.230 (3)	147
C8—H8⋯F1ⁱ	0.95	2.50	3.163 (3)	127
C8—H8⋯F2ⁱ	0.95	2.50	3.446 (3)	176
C9—H9⋯F2ⁱⁱ	0.95	2.52	3.240 (3)	133

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

Acknowledgments

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011–0006413).

supplementary crystallographic information

Comment

The title compound was prepared for use as a N-heterocyclic carbene ligand in the formation of coordination polymers in line with similar previously reported compounds (Sambrook et al., 2006; Zang et al., 2010).

In the title compound (Scheme 1, Fig. 1), two pyridine rings are coplanar because the title compound lies on a crystallographic inversion center. The geomeries of the title compound are very similar with those of the previously reported compound (Moon et al., 2011) The dihedral angle between the pyridine and imidazole rings is 76.93 (7)°. All the bond lengths are within normal values (Allen et al., 1987).

The crystal packing (Fig. 2) is stabilized by weak intermolecular C—H···F hydrogen bonds (see, Table 1)

Experimental

A mixture of 1-methylimidazole (0.150 g, 1.83 mmol) and 5,5'-bis(bromomethyl)-2,2'-bipyridine (0.30 g, 0.88 mmol) in 1,4-dioxane (15 ml) was stirred for 10 min and then heated at reflux for 6 h. After cooling to room temperature, Et₂O (15 ml) was added and 5,5'-bis((N-methylimidazolium-1-yl)methyl)-2,2'-bipyridine bis(chloride) obtained as a white precipitate was separated by filtration and washed with Et₂O. For the anion exchange, an excess of KPF₆ was added to the aqueous solution of the chloride salts. After stirring for 1 hr, the title compound as a white precipitate was obtained. X–ray quality single crystals were obtained by slow evaporation of a solution of the title compound in acetonitrile at room temperature.