1,1′-(p-Phenyl­enedimethyl­ene)dipyridinium bis­(hexa­fluoridophosphate)

Abstract

The title salt, C₁₈H₁₈N₂ ²⁺·2PF₆ ⁻, exists as non-inter­acting cations and anions. In the cation, the pyridine and phenyl­ene rings are aligned at 62.9 (1)°; the pyridine ring lies on a special position of m site symmetry and the phenyl­ene ring on a special position of 2/m site symmetry. The angle at the methyl­ene C atom is 112.8 (1)°. The anion lies on a special position of m site symmetry; four F atoms lie on this mirror plane.

Related literature

For the tetra­phenyl­borate salt, see: Wu et al. (2007 ▶) and for the tetra­cyano­quinodimethanide salt, see: Ashwell et al. (1975 ▶); Hudson & Robson (2009 ▶).

Experimental

Crystal data

• C₁₈H₁₈N₂ ²⁺·2PF₆ ⁻

• M _r = 552.28

• Orthorhombic,

• a = 11.1013 (11) Å

• b = 12.6742 (12) Å

• c = 7.3483 (7) Å

• V = 1033.91 (17) ų

• Z = 2

• Mo Kα radiation

• μ = 0.33 mm⁻¹

• T = 100 K

• 0.30 × 0.20 × 0.10 mm

Data collection

• Bruker SMART APEX diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.908, T _max = 0.968

• 6200 measured reflections

• 1280 independent reflections

• 1121 reflections with I > 2σ(I)

• R _int = 0.028

Refinement

• R[F ² > 2σ(F ²)] = 0.029

• wR(F ²) = 0.088

• S = 1.05

• 1280 reflections

• 91 parameters

• H-atom parameters constrained

• Δρ_max = 0.33 e Å⁻³

• Δρ_min = −0.44 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: X-SEED (Barbour, 2001 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Comment

The structure of the 1,1'-(4-dimethylphenylene)dipyridinium cation has been reported in a number of examples (Ashwell et al., 1975; Hudson & Robson, 2009; Wu et al.,2007). We ourselves have reported other examples. The title hexafluorophosphate (Scheme I, Fig. 1) exists as non-interacting cations and anions. In the cation, the pyridyl and phenylene rings are aligned at 62.9 (1) °. The angle at the methylene C atom is 112.8 (1) °. The anion lies on a mirror plane such that four F atoms lie within the mirror plane.

Experimental

α,α'-Dibromo-p-xylene (5.28 g, 20 mmol) was dissolved in acetonitrile (30 ml) and to the solution was added pyridine (2.96 g, 40 mmol). The solution was heated for 2 h. The solid product was recrystallized from a methanol/ethanol mixture to afford 1,1'-(4-dimethylphenylene)dipyridinium bromide. The bromide ion was exchanged by the hexafluorophosphate ion by reaction of the salt (1 mmol) with ammonium hexafluorophosphate (2 mmol) in water. The reactants were mixed in water for 2 h to give a solid material. This was collected and recrystallized from acetonitrile.

Refinement

Carbon-bound H-atoms were placed in calculated positions (C—H 0.95 to 0.99 Å) and were included in the refinement in the riding model approximation, with U(H) set to 1.2U(C).

Figures

Fig. 1.

Thermal ellipsoid plot (Barbour, 2001) of C18H18N22+ 2PF6- at the 70% probability level; hydrogen atoms are drawn as spheres of arbitrary radius.

Crystal data

C18H18N22+·2PF6−	F(000) = 556
Mr = 552.28	Dx = 1.774 Mg m−3
Orthorhombic, Pbam	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2 2ab	Cell parameters from 2836 reflections
a = 11.1013 (11) Å	θ = 2.8–28.2°
b = 12.6742 (12) Å	µ = 0.33 mm−1
c = 7.3483 (7) Å	T = 100 K
V = 1033.91 (17) Å3	Block, colorless
Z = 2	0.30 × 0.20 × 0.10 mm

Data collection

Bruker SMART APEX diffractometer	1280 independent reflections
Radiation source: fine-focus sealed tube	1121 reflections with I > 2σ(I)
graphite	Rint = 0.028
ω scans	θmax = 27.5°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −14→14
Tmin = 0.908, Tmax = 0.968	k = −12→16
6200 measured reflections	l = −9→8

Refinement

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)] = 0.029	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.088	H-atom parameters constrained
S = 1.05	w = 1/[σ2(Fo2) + (0.0505P)2 + 0.3897P] where P = (Fo2 + 2Fc2)/3
1280 reflections	(Δ/σ)max < 0.001
91 parameters	Δρmax = 0.33 e Å−3
0 restraints	Δρmin = −0.44 e Å−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
P1	0.25173 (4)	0.14923 (4)	0.0000	0.01624 (16)
F1	0.25218 (7)	0.14917 (6)	0.21872 (11)	0.0238 (2)
F2	0.31281 (13)	0.26387 (9)	0.0000	0.0351 (3)
F3	0.12080 (10)	0.20151 (10)	0.0000	0.0281 (3)
F4	0.19348 (10)	0.03444 (8)	0.0000	0.0238 (3)
F5	0.38395 (10)	0.09687 (10)	0.0000	0.0282 (3)
N1	0.00180 (13)	0.29642 (11)	0.5000	0.0151 (3)
C1	0.17001 (16)	0.45395 (14)	0.5000	0.0227 (4)
H1	0.2269	0.5100	0.5000	0.027*
C2	0.12837 (12)	0.41294 (11)	0.3374 (2)	0.0231 (3)
H2	0.1579	0.4391	0.2247	0.028*
C3	0.04351 (11)	0.33362 (10)	0.34067 (18)	0.0192 (3)
H3	0.0143	0.3050	0.2296	0.023*
C4	−0.09367 (16)	0.21325 (14)	0.5000	0.0203 (4)
H4A	−0.1451	0.2225	0.3911	0.024*	0.50
H4B	−0.1451	0.2225	0.6089	0.024*	0.50
C5	−0.04278 (15)	0.10309 (13)	0.5000	0.0153 (4)
C6	−0.02152 (11)	0.05152 (10)	0.66385 (17)	0.0181 (3)
H6	−0.0364	0.0867	0.7758	0.022*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
P1	0.0184 (3)	0.0162 (3)	0.0141 (3)	−0.00093 (16)	0.000	0.000
F1	0.0274 (4)	0.0300 (5)	0.0140 (4)	−0.0014 (3)	−0.0013 (3)	−0.0022 (3)
F2	0.0502 (8)	0.0217 (6)	0.0333 (7)	−0.0156 (6)	0.000	0.000
F3	0.0272 (6)	0.0346 (7)	0.0224 (6)	0.0125 (5)	0.000	0.000
F4	0.0309 (6)	0.0196 (5)	0.0210 (6)	−0.0068 (5)	0.000	0.000
F5	0.0189 (6)	0.0400 (7)	0.0255 (6)	0.0042 (5)	0.000	0.000
N1	0.0150 (6)	0.0115 (6)	0.0187 (7)	0.0018 (5)	0.000	0.000
C1	0.0148 (8)	0.0134 (8)	0.0398 (11)	0.0014 (6)	0.000	0.000
C2	0.0222 (6)	0.0212 (6)	0.0260 (7)	0.0022 (5)	0.0048 (5)	0.0064 (5)
C3	0.0220 (6)	0.0197 (6)	0.0161 (6)	0.0030 (5)	−0.0002 (5)	0.0003 (5)
C4	0.0148 (8)	0.0136 (8)	0.0323 (10)	−0.0005 (6)	0.000	0.000
C5	0.0129 (7)	0.0130 (8)	0.0201 (9)	−0.0020 (6)	0.000	0.000
C6	0.0215 (6)	0.0167 (6)	0.0159 (6)	−0.0027 (5)	0.0021 (5)	−0.0021 (5)

Geometric parameters (Å, °)

P1—F4	1.5921 (11)	C1—H1	0.9500
P1—F3	1.5975 (12)	C2—C3	1.3779 (18)
P1—F2	1.6034 (12)	C2—H2	0.9500
P1—F1i	1.6072 (8)	C3—H3	0.9500
P1—F1	1.6072 (8)	C4—C5	1.506 (2)
P1—F5	1.6107 (12)	C4—H4A	0.9900
N1—C3ii	1.3444 (15)	C4—H4B	0.9900
N1—C3	1.3444 (15)	C5—C6	1.3902 (15)
N1—C4	1.495 (2)	C5—C6ii	1.3902 (15)
C1—C2	1.3828 (18)	C6—C6iii	1.391 (2)
C1—C2ii	1.3828 (18)	C6—H6	0.9500
F4—P1—F3	90.54 (7)	C2ii—C1—H1	120.2
F4—P1—F2	178.95 (7)	C3—C2—C1	119.18 (14)
F3—P1—F2	90.51 (7)	C3—C2—H2	120.4
F4—P1—F1i	90.05 (3)	C1—C2—H2	120.4
F3—P1—F1i	90.17 (3)	N1—C3—C2	120.45 (13)
F2—P1—F1i	89.95 (3)	N1—C3—H3	119.8
F4—P1—F1	90.05 (3)	C2—C3—H3	119.8
F3—P1—F1	90.17 (3)	N1—C4—C5	112.81 (14)
F2—P1—F1	89.95 (3)	N1—C4—H4A	109.0
F1i—P1—F1	179.64 (7)	C5—C4—H4A	109.0
F4—P1—F5	89.64 (7)	N1—C4—H4B	109.0
F3—P1—F5	179.82 (7)	C5—C4—H4B	109.0
F2—P1—F5	89.31 (7)	H4A—C4—H4B	107.8
F1i—P1—F5	89.83 (3)	C6—C5—C6ii	120.02 (16)
F1—P1—F5	89.83 (3)	C6—C5—C4	119.97 (8)
C3ii—N1—C3	121.11 (16)	C6ii—C5—C4	119.97 (8)
C3ii—N1—C4	119.44 (8)	C5—C6—C6iii	119.99 (8)
C3—N1—C4	119.44 (8)	C5—C6—H6	120.0
C2—C1—C2ii	119.60 (17)	C6iii—C6—H6	120.0
C2—C1—H1	120.2
C2ii—C1—C2—C3	1.7 (3)	C3—N1—C4—C5	90.39 (12)
C3ii—N1—C3—C2	−1.6 (2)	N1—C4—C5—C6	91.26 (13)
C4—N1—C3—C2	177.67 (13)	N1—C4—C5—C6ii	−91.26 (13)
C1—C2—C3—N1	−0.1 (2)	C6ii—C5—C6—C6iii	0.3 (3)
C3ii—N1—C4—C5	−90.39 (12)	C4—C5—C6—C6iii	177.77 (16)

Symmetry codes: (i) x, y, −z; (ii) x, y, −z+1; (iii) −x, −y, z.