3,3′-Di-n-butyl-1,1′-(p-phenyl­ene­dimethyl­ene)diimidazolium bis­(hexa­fluoro­phosphate)

Haque, R.A.; Washeel, A.; Nasri, S.F.; Yeap, C.S.; Fun, H.-K.

doi:10.1107/S1600536810008536

Volume 66
Part 4
Pages o824-o825
April 2010

Received 25 February 2010
Accepted 5 March 2010
Online 13 March 2010

Key indicators
Single-crystal X-ray study
T = 100 K
Mean (C-C) = 0.002 Å
R = 0.036
wR = 0.121
Data-to-parameter ratio = 29.2
Details

3,3'-Di-n-butyl-1,1'-(p-phenylenedimethylene)diimidazolium bis(hexafluorophosphate)

Rosenani A. Haque,^a Abbas Washeel,^a S. Fatimah Nasri,^a Chin Sing Yeap ^b ⁺ and Hoong-Kun Fun ^b ^*⁺⁺

^aSchool of Chemical Science, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and ^bX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
Correspondence e-mail: hkfun@usm.my

The asymmetric unit of the title N-heterocyclic carbene compound, C₂₂H₃₂N₄²⁺·2PF₆^-, consists of one half of the N-heterocyclic carbene dication and one hexafluorophosphate anion. The dication lies across a crystallographic inversion center. The imidazole ring is twisted away from the central benzene ring, making a dihedral angle of 76.23 (6)°. The hexafluorophosphate anions link the cations into a three-dimensional network via intermolecular C-HF hydrogen bonds. A weak C-H [pi] interaction further stabilizes the crystal structure.

Related literature

For background to N-heterocyclic carbenes, see: Arduengo et al. (1991); Papini et al. (2008). For applications of N-heterocyclic carbene derivatives, see: Meyer et al. (2009); Barnard et al. (2004); Lin & Vasam (2007). For a related structure, see: Washeel et al. (2010). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986).

Experimental

Crystal data

C₂₂H₃₂N₄²⁺·2PF₆^-
M_r = 642.46
Monoclinic, P 2₁ /c
a = 8.9802 (5) Å
b = 17.8421 (10) Å
c = 9.3637 (5) Å
= 113.233 (1)°
V = 1378.64 (13) Å³
Z = 2
Mo K radiation
= 0.26 mm^-1
T = 100 K
0.37 × 0.25 × 0.20 mm

Data collection

Bruker APEX Duo CCD area detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009) T_min = 0.910, T_max = 0.950
21938 measured reflections
5550 independent reflections
4750 reflections with I > 2(I)
R_int = 0.027

Refinement

R[F² > 2(F²)] = 0.036
wR(F²) = 0.121
S = 1.10
5550 reflections
190 parameters
H atoms treated by a mixture of independent and constrained refinement
_max = 0.52 e Å^-3
_min = -0.35 e Å^-3

Table 1
Hydrogen-bond geometry (Å, °)

Table 1. Hydrogen bond geometry (Å, °). Cg1 is the centroid of the C1-C3,C1A-C3A benzene ring.

D-HA	D-H	HA	DA	D-HA
C1-H1AF3ⁱ	1.004 (17)	2.532 (18)	3.3945 (14)	143.8 (15)
C4-H4AF4ⁱ	0.97	2.52	3.3516 (14)	144
C4-H4BF2ⁱⁱ	0.97	2.45	3.3497 (14)	153
C7-H7AF1ⁱⁱⁱ	0.93	2.36	2.8798 (13)	115
C8-H8BF6^iv	0.97	2.49	3.3537 (13)	148
C8-H8ACg1^v	0.97	2.84	3.7376 (12)	154
C8-H8ACg1^vi	0.97	2.84	3.7376 (12)	154
Symmetry codes: (i) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ii) x, y-1, z; (iii) $[-x, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iv) $[x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (v) x-1, y, z; (vi) -x, -y, -z+1.

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009).

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SJ2739 ).

Acknowledgements

RAH, AW and SFN thank Universiti Sains Malaysia (USM) for the FRGS fund (203/PKIMIA/671115). HKF and CSY thank USM for the Research University Golden Goose grant (1001/PFIZIK/811012). CSY also thanks USM for the award of a USM Fellowship.

References

Arduengo, A. J., Harlow, R. L. & Kline, M. (1991). J. Am. Chem. Soc. 113, 361-363.
Barnard, P. J., Baker, M. V., Berners-Price, S. J. & Day, D. A. J. (2004). Inorg. Biochem. 98, 1642-1647.
Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105-107.
Lin, I. J. B. & Vasam, C. S. (2007). Coord. Chem. Rev. 251, 642-670.
Meyer, D., Taige, M. A., Zeller, A., Hohlfeld, K., Ahrens, S. & Strassner, T. (2009). Organometallics, 28, 2142-2149.
Papini, G., Bandoli, G., Dolmella, A., Lobbia, G. G., Pellei, M. & Santini, C. (2008). Inorg. Chem. Commun. 11, 1103-1106.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Spek, A. L. (2009). Acta Cryst. D65, 148-155.
Washeel, A., Haque, R. A., Teoh, S. G., Yeap, C. S. & Fun, H.-K. (2010). Acta Cryst. E66, o556.

organic compounds