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

organic compounds

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ISSN: 2056-9890

Volume 66| Part 4| April 2010| Pages o824-o825

doi:10.1107/S1600536810008536

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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

(Received 25 February 2010; accepted 5 March 2010; online 13 March 2010)

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—H⋯F hydrogen bonds. A weak C—H⋯π 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
β = 113.233 (1)°
V = 1378.64 (13) Å³
Z = 2
Mo Kα radiation
μ = 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 > 2σ(I)
R_int = 0.027

Refinement

R[F² > 2σ(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
Δρ_max = 0.52 e Å⁻³
Δρ_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—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1A⋯F3ⁱ	1.004 (17)	2.532 (18)	3.3945 (14)	143.8 (15)
C4—H4A⋯F4ⁱ	0.97	2.52	3.3516 (14)	144
C4—H4B⋯F2ⁱⁱ	0.97	2.45	3.3497 (14)	153
C7—H7A⋯F1ⁱⁱⁱ	0.93	2.36	2.8798 (13)	115
C8—H8B⋯F6^iv	0.97	2.49	3.3537 (13)	148
C8—H8A⋯Cg1^v	0.97	2.84	3.7376 (12)	154
C8—H8A⋯Cg1^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 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810008536/sj2739sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810008536/sj2739Isup2.hkl

checkCIF report

Comment top

N-heterocyclic carbene (NHC) ligands have enjoyed wide applicability as ligands for transition and main group metals since the first crystalline free carbene were isolated in 1991 by Arduengo and co-workers (Arduengo et al., 1991). They display rich coordination chemistry and are able to form stable complexes with a large number of transition metals in both high and low oxidation states (Papini et al., 2008). The complexes are widely used in catalysis and are useful in medicinal science applications (Meyer et al., 2009; Barnard et al., 2004; Lin & Vasam, 2007). These compounds show unusually high thermal stability and nucleophilic behavior, in part due to the analogy of N-heterocyclic carbenes with strong Lewis-basic phosphines. NHCs are also cheap, non-toxic and easily prepared as an azolium salt precursor (Papini et al., 2008).

The asymmetric unit of the title compound consists of half of the N-heterocyclic carbene dication and one hexafluorophosphate anion (Fig. 1). The dication lies across a crystallograpic inversion center. The geometrical parameters are comparable to its related structure (Washeel et al., 2010). The imidazole ring (N1–C5–N2–C7–C6) is planar with a maximum deviation of 0.003 (1) Å for atom C6 and is twisted away from the central benzene ring making a dihedral angle of 76.23 (6)°. The hexafluorophosphate anions linked the molecules into a three-dimensional network via intermolecular C—H···F hydrogen bonds (Fig. 2, Table 1). Short intermolecular F1···C5 and F1···C7 of 2.8636 (12) and 2.8798 (13) Å contacts are observed. A weak C–H···π interaction further stabilizes the crystal structure (Table 1).

Related literature top

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 top

To a solution of p-xylylene dichloride (1 g, 5.75 mmol) in 30 ml of 1,4-dioxane, 1-butylimidazole (1.42 g, 11.5 mmol) was added. The mixture was refluxed at 373 K for 24 h. The slurry product was isolated by decantation then washed with diethyl ether (2x3 ml). KPF₆ (2.1 g, 11.5 mmol) in 20 ml of distilled water was then added with stirring for 1 h and the suspension was left standing overnight. The white precipitate was filtered, washed with distilled water several times and recrystallized from acetonitrile. The yield was found to be 2.30 g (62.7 %), m.p.: 411-413 K. Crystals suitable for X-ray was obtained by slow evaporation of the salt solution in acetonitrile at 281 K.

Computing details top

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

Figures top

	Fig. 1. The molecular structure of the title compound with 50% probability ellipsoids for non-H atoms. Atoms with suffix A are generated by the symmetry operation (1-x, -y, 1-z).
	Fig. 2. Crystal packing of the title compound, viewed down the c axis, showing the molecules linked into a 3-D network. Intermolecular hydrogen bonds are shown as dashed lines.

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

Crystal data top

C₂₂H₃₂N₄²⁺·2PF₆⁻	F(000) = 660
M_r = 642.46	D_x = 1.548 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 8699 reflections
a = 8.9802 (5) Å	θ = 3.3–35.1°
b = 17.8421 (10) Å	µ = 0.26 mm⁻¹
c = 9.3637 (5) Å	T = 100 K
β = 113.233 (1)°	Block, colourless
V = 1378.64 (13) Å³	0.37 × 0.25 × 0.20 mm
Z = 2

Data collection top

Bruker APEX Duo CCD area detector diffractometer	5550 independent reflections
Radiation source: fine-focus sealed tube	4750 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.027
ϕ and ω scans	θ_max = 34.0°, θ_min = 3.3°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −12→14
T_min = 0.910, T_max = 0.950	k = −25→28
21938 measured reflections	l = −14→14

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.121	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	w = 1/[σ²(F_o²) + (0.0669P)² + 0.3404P] where P = (F_o² + 2F_c²)/3
5550 reflections	(Δ/σ)_max < 0.001
190 parameters	Δρ_max = 0.52 e Å⁻³
0 restraints	Δρ_min = −0.35 e Å⁻³

Crystal data top

C₂₂H₃₂N₄²⁺·2PF₆⁻	V = 1378.64 (13) Å³
M_r = 642.46	Z = 2
Monoclinic, P2₁/c	Mo Kα radiation
a = 8.9802 (5) Å	µ = 0.26 mm⁻¹
b = 17.8421 (10) Å	T = 100 K
c = 9.3637 (5) Å	0.37 × 0.25 × 0.20 mm
β = 113.233 (1)°

Data collection top

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

Refinement top

R[F² > 2σ(F²)] = 0.036	0 restraints
wR(F²) = 0.121	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	Δρ_max = 0.52 e Å⁻³
5550 reflections	Δρ_min = −0.35 e Å⁻³
190 parameters

Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
P1	0.24993 (3)	0.644667 (14)	0.41525 (3)	0.01504 (7)
F1	0.17538 (13)	0.58756 (4)	0.27368 (9)	0.0377 (2)
F2	0.32152 (11)	0.70282 (5)	0.55641 (8)	0.03461 (19)
F3	0.40070 (10)	0.59059 (5)	0.49878 (11)	0.0363 (2)
F4	0.15300 (10)	0.60287 (5)	0.50374 (10)	0.03387 (18)
F5	0.34534 (10)	0.68616 (5)	0.32536 (10)	0.03212 (18)
F6	0.09980 (9)	0.70032 (5)	0.33174 (9)	0.02912 (16)
N1	−0.09308 (9)	−0.12292 (5)	0.43634 (9)	0.01428 (14)
N2	0.12122 (9)	−0.11365 (5)	0.38494 (10)	0.01434 (14)
C1	0.42820 (12)	−0.01546 (6)	0.34135 (11)	0.01608 (16)
C2	0.39498 (11)	−0.06136 (5)	0.44620 (11)	0.01435 (15)
C3	0.46724 (12)	−0.04565 (6)	0.60501 (11)	0.01585 (16)
C4	0.28430 (11)	−0.12854 (6)	0.38858 (12)	0.01716 (17)
H4A	0.2753	−0.1415	0.2849	0.021*
H4B	0.3314	−0.1710	0.4560	0.021*
C5	0.05423 (11)	−0.15095 (5)	0.46797 (11)	0.01380 (15)
H5A	0.1022	−0.1900	0.5365	0.017*
C6	0.01313 (13)	−0.05969 (6)	0.29775 (13)	0.01997 (18)
H6A	0.0295	−0.0256	0.2301	0.024*
C7	−0.12157 (12)	−0.06587 (6)	0.32955 (13)	0.01986 (18)
H7A	−0.2152	−0.0371	0.2873	0.024*
C8	−0.20778 (12)	−0.14960 (6)	0.50215 (12)	0.01732 (17)
H8A	−0.2538	−0.1069	0.5344	0.021*
H8B	−0.1501	−0.1799	0.5934	0.021*
C9	−0.34402 (11)	−0.19587 (6)	0.38501 (12)	0.01788 (17)
H9A	−0.4209	−0.2086	0.4304	0.021*
H9B	−0.4004	−0.1652	0.2940	0.021*
C10	−0.28848 (13)	−0.26785 (6)	0.33359 (13)	0.02143 (19)
H10A	−0.3792	−0.2892	0.2475	0.026*
H10B	−0.2049	−0.2557	0.2961	0.026*
C11	−0.22253 (16)	−0.32643 (7)	0.46144 (18)	0.0314 (3)
H11B	−0.1973	−0.3714	0.4194	0.047*
H11C	−0.3025	−0.3372	0.5028	0.047*
H11D	−0.1262	−0.3076	0.5428	0.047*
H1A	0.372 (2)	−0.0256 (10)	0.227 (2)	0.026 (4)*
H3A	0.447 (2)	−0.0786 (10)	0.671 (2)	0.025 (4)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
P1	0.01633 (12)	0.01343 (12)	0.01512 (11)	0.00062 (7)	0.00596 (9)	0.00052 (7)
F1	0.0666 (6)	0.0170 (3)	0.0251 (4)	−0.0065 (3)	0.0134 (4)	−0.0070 (3)
F2	0.0451 (5)	0.0276 (4)	0.0184 (3)	−0.0044 (3)	−0.0011 (3)	−0.0044 (3)
F3	0.0324 (4)	0.0346 (4)	0.0439 (5)	0.0182 (3)	0.0173 (3)	0.0191 (4)
F4	0.0300 (4)	0.0430 (5)	0.0339 (4)	−0.0048 (3)	0.0182 (3)	0.0085 (3)
F5	0.0322 (4)	0.0337 (4)	0.0369 (4)	−0.0006 (3)	0.0204 (3)	0.0123 (3)
F6	0.0231 (3)	0.0298 (4)	0.0278 (3)	0.0112 (3)	0.0029 (3)	0.0008 (3)
N1	0.0115 (3)	0.0145 (3)	0.0169 (3)	0.0003 (2)	0.0056 (3)	0.0004 (3)
N2	0.0127 (3)	0.0128 (3)	0.0185 (3)	−0.0015 (2)	0.0071 (3)	−0.0015 (3)
C1	0.0163 (4)	0.0168 (4)	0.0167 (4)	−0.0029 (3)	0.0081 (3)	−0.0029 (3)
C2	0.0125 (3)	0.0133 (4)	0.0192 (4)	−0.0020 (3)	0.0083 (3)	−0.0030 (3)
C3	0.0168 (4)	0.0158 (4)	0.0178 (4)	−0.0029 (3)	0.0099 (3)	−0.0010 (3)
C4	0.0147 (4)	0.0144 (4)	0.0258 (4)	−0.0035 (3)	0.0116 (3)	−0.0058 (3)
C5	0.0118 (3)	0.0133 (4)	0.0164 (4)	−0.0002 (3)	0.0056 (3)	−0.0003 (3)
C6	0.0180 (4)	0.0168 (4)	0.0248 (4)	−0.0006 (3)	0.0082 (3)	0.0057 (3)
C7	0.0156 (4)	0.0163 (4)	0.0265 (5)	0.0023 (3)	0.0070 (3)	0.0057 (3)
C8	0.0142 (4)	0.0214 (4)	0.0186 (4)	−0.0014 (3)	0.0089 (3)	−0.0021 (3)
C9	0.0124 (4)	0.0197 (4)	0.0218 (4)	−0.0007 (3)	0.0071 (3)	−0.0008 (3)
C10	0.0196 (4)	0.0212 (5)	0.0263 (5)	−0.0028 (3)	0.0121 (4)	−0.0044 (4)
C11	0.0290 (6)	0.0223 (5)	0.0447 (7)	0.0055 (4)	0.0166 (5)	0.0043 (5)

Geometric parameters (Å, º) top

P1—F3	1.5939 (8)	C4—H4A	0.9700
P1—F1	1.5948 (8)	C4—H4B	0.9700
P1—F5	1.5999 (8)	C5—H5A	0.9300
P1—F2	1.6020 (8)	C6—C7	1.3595 (15)
P1—F4	1.6029 (8)	C6—H6A	0.9300
P1—F6	1.6073 (7)	C7—H7A	0.9300
N1—C5	1.3337 (12)	C8—C9	1.5241 (14)
N1—C7	1.3782 (13)	C8—H8A	0.9700
N1—C8	1.4725 (12)	C8—H8B	0.9700
N2—C5	1.3335 (12)	C9—C10	1.5229 (15)
N2—C6	1.3822 (13)	C9—H9A	0.9700
N2—C4	1.4755 (12)	C9—H9B	0.9700
C1—C3ⁱ	1.3966 (13)	C10—C11	1.5222 (17)
C1—C2	1.3981 (13)	C10—H10A	0.9700
C1—H1A	1.005 (17)	C10—H10B	0.9700
C2—C3	1.3964 (13)	C11—H11B	0.9600
C2—C4	1.5141 (13)	C11—H11C	0.9600
C3—C1ⁱ	1.3966 (13)	C11—H11D	0.9600
C3—H3A	0.925 (17)

F3—P1—F1	91.03 (5)	H4A—C4—H4B	107.9
F3—P1—F5	90.61 (5)	N2—C5—N1	108.63 (8)
F1—P1—F5	89.70 (5)	N2—C5—H5A	125.7
F3—P1—F2	90.02 (5)	N1—C5—H5A	125.7
F1—P1—F2	178.91 (5)	C7—C6—N2	107.00 (9)
F5—P1—F2	90.60 (5)	C7—C6—H6A	126.5
F3—P1—F4	89.66 (5)	N2—C6—H6A	126.5
F1—P1—F4	89.82 (5)	C6—C7—N1	106.99 (9)
F5—P1—F4	179.45 (5)	C6—C7—H7A	126.5
F2—P1—F4	89.87 (5)	N1—C7—H7A	126.5
F3—P1—F6	179.09 (5)	N1—C8—C9	111.68 (8)
F1—P1—F6	89.64 (5)	N1—C8—H8A	109.3
F5—P1—F6	88.78 (4)	C9—C8—H8A	109.3
F2—P1—F6	89.31 (4)	N1—C8—H8B	109.3
F4—P1—F6	90.95 (5)	C9—C8—H8B	109.3
C5—N1—C7	108.79 (8)	H8A—C8—H8B	107.9
C5—N1—C8	125.60 (8)	C10—C9—C8	114.48 (8)
C7—N1—C8	125.60 (8)	C10—C9—H9A	108.6
C5—N2—C6	108.59 (8)	C8—C9—H9A	108.6
C5—N2—C4	124.66 (8)	C10—C9—H9B	108.6
C6—N2—C4	126.75 (8)	C8—C9—H9B	108.6
C3ⁱ—C1—C2	120.28 (9)	H9A—C9—H9B	107.6
C3ⁱ—C1—H1A	120.5 (10)	C11—C10—C9	113.87 (9)
C2—C1—H1A	119.2 (10)	C11—C10—H10A	108.8
C3—C2—C1	119.47 (8)	C9—C10—H10A	108.8
C3—C2—C4	120.16 (9)	C11—C10—H10B	108.8
C1—C2—C4	120.36 (8)	C9—C10—H10B	108.8
C2—C3—C1ⁱ	120.25 (9)	H10A—C10—H10B	107.7
C2—C3—H3A	117.1 (11)	C10—C11—H11B	109.5
C1ⁱ—C3—H3A	122.5 (11)	C10—C11—H11C	109.5
N2—C4—C2	111.82 (8)	H11B—C11—H11C	109.5
N2—C4—H4A	109.3	C10—C11—H11D	109.5
C2—C4—H4A	109.3	H11B—C11—H11D	109.5
N2—C4—H4B	109.3	H11C—C11—H11D	109.5
C2—C4—H4B	109.3

C3ⁱ—C1—C2—C3	−0.02 (16)	C8—N1—C5—N2	178.85 (8)
C3ⁱ—C1—C2—C4	−178.77 (9)	C5—N2—C6—C7	−0.48 (12)
C1—C2—C3—C1ⁱ	0.02 (16)	C4—N2—C6—C7	179.81 (9)
C4—C2—C3—C1ⁱ	178.77 (9)	N2—C6—C7—N1	0.50 (12)
C5—N2—C4—C2	−118.10 (10)	C5—N1—C7—C6	−0.35 (12)
C6—N2—C4—C2	61.57 (13)	C8—N1—C7—C6	−179.15 (9)
C3—C2—C4—N2	78.63 (11)	C5—N1—C8—C9	−104.24 (11)
C1—C2—C4—N2	−102.63 (10)	C7—N1—C8—C9	74.36 (12)
C6—N2—C5—N1	0.26 (11)	N1—C8—C9—C10	63.05 (11)
C4—N2—C5—N1	179.98 (8)	C8—C9—C10—C11	67.80 (12)
C7—N1—C5—N2	0.05 (11)

Symmetry code: (i) −x+1, −y, −z+1.

Hydrogen-bond geometry (Å, º) top

Table 1. Hydrogen bond geometry (Å, °). Cg1 is centroids of benzene ring C1-C2-C3-C1A-C2A-C3A.

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···F3ⁱⁱ	1.004 (17)	2.532 (18)	3.3945 (14)	143.8 (15)
C4—H4A···F4ⁱⁱ	0.97	2.52	3.3516 (14)	144
C4—H4B···F2ⁱⁱⁱ	0.97	2.45	3.3497 (14)	153
C7—H7A···F1^iv	0.93	2.36	2.8798 (13)	115
C8—H8B···F6^v	0.97	2.49	3.3537 (13)	148
C8—H8A···Cg1^vi	0.97	2.84	3.7376 (12)	154
C8—H8A···Cg1^vii	0.97	2.84	3.7376 (12)	154

Symmetry codes: (ii) x, −y+1/2, z−1/2; (iii) x, y−1, z; (iv) −x, y−1/2, −z+1/2; (v) x, −y+1/2, z+1/2; (vi) x−1, y, z; (vii) −x, −y, −z+1.

Experimental details

Crystal data
Chemical formula	C₂₂H₃₂N₄²⁺·2PF₆⁻
M_r	642.46
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	8.9802 (5), 17.8421 (10), 9.3637 (5)
β (°)	113.233 (1)
V (Å³)	1378.64 (13)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.26
Crystal size (mm)	0.37 × 0.25 × 0.20

Data collection
Diffractometer	Bruker APEX Duo CCD area detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2009)
T_min, T_max	0.910, 0.950
No. of measured, independent and observed [I > 2σ(I)] reflections	21938, 5550, 4750
R_int	0.027
(sin θ/λ)_max (Å⁻¹)	0.787

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.121, 1.10
No. of reflections	5550
No. of parameters	190
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.52, −0.35

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

Table 1. Hydrogen bond geometry (Å, °). Cg1 is centroids of benzene ring C1-C2-C3-C1A-C2A-C3A.

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···F3ⁱ	1.004 (17)	2.532 (18)	3.3945 (14)	143.8 (15)
C4—H4A···F4ⁱ	0.9700	2.5200	3.3516 (14)	144.00
C4—H4B···F2ⁱⁱ	0.9700	2.4500	3.3497 (14)	153.00
C7—H7A···F1ⁱⁱⁱ	0.9300	2.3600	2.8798 (13)	115.00
C8—H8B···F6^iv	0.9700	2.4900	3.3537 (13)	148.00
C8—H8A···Cg1^v	0.97	2.84	3.7376 (12)	154
C8—H8A···Cg1^vi	0.97	2.84	3.7376 (12)	154

Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) x, y−1, z; (iii) −x, y−1/2, −z+1/2; (iv) x, −y+1/2, z+1/2; (v) x−1, y, z; (vi) −x, −y, −z+1.

Footnotes

‡Thomson Reuters ResearcherID: A-5523-2009.

§Thomson Reuters ResearcherID: A-3561-2009.

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.

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