1,1′-Dimethyl-4,4′-bipyridinium bis­(tetra­fluorido­borate)

Abstract

In the title compound, C₁₂H₁₄N₂ ²⁺·2BF₄ ⁻, the cation has a centre of symmetry at the mid-point of the central C—C bond. π–π inter­actions, with a shortest atom-to-atom distance of 3.757 (4) Å, extend the crystal structure into a one-dimensional supra­molecular chain.

Related literature

For related literature, see: Dou et al. (2007 ▶).

Experimental

Crystal data

• C₁₂H₁₄N₂ ²⁺·2BF₄ ⁻

• M _r = 359.87

• Monoclinic,

• a = 5.824 (2) Å

• b = 8.849 (3) Å

• c = 14.855 (6) Å

• β = 94.825 (5)°

• V = 762.9 (5) ų

• Z = 2

• Mo Kα radiation

• μ = 0.16 mm⁻¹

• T = 293 (2) K

• 0.26 × 0.12 × 0.07 mm

Data collection

• Bruker APEX CCD area-detector diffractometer

• Absorption correction: multi-scan (SAINT-Plus; Bruker, 2003 ▶) T _min = 0.960, T _max = 0.988

• 3923 measured reflections

• 1508 independent reflections

• 843 reflections with I > 2σ(I)

• R _int = 0.029

Refinement

• R[F ² > 2σ(F ²)] = 0.082

• wR(F ²) = 0.249

• S = 1.02

• 1508 reflections

• 110 parameters

• H-atom parameters constrained

• Δρ_max = 0.35 e Å⁻³

• Δρ_min = −0.23 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SAINT-Plus (Bruker, 2003 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997 ▶); molecular graphics: SHELXTL (Bruker, 1998 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

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

supplementary crystallographic information

Comment

Dou et al. have reported a structure, synthesized by in situ reaction under hydrothermal conditions, in which pyridine nitrogen atoms are covalently bonded to methyl groups and the counterion are ClO₄^- anions (Dou et al., 2007). Here we report the structure of the title compound, which is essentially isomorphous with the perchlorate compound.

The title compound, shown in Fig. 1, consists of 1,1'-dimethyl-4,4'-bipyridinium cations and tetrafluoroborate anions. There is a centre of symmetry at the mid-point of the C—C bond linking the two pyridine rings. The two pyridine rings are exactly parallel by symmetry, and essentially coplanar.

In the crystal structure, there are π···π interactions between pyridine rings at (x, y, z) and (1 - x,1 - y, -z), with the shortest atom-to-atom distance of 3.757 (4) Å, which leads to a one-dimensional supramolecular chain running in the c-direction. (Fig. 2).

Experimental

Compound (I) was solvothermally prepared from a reaction mixture of Cu(BF₄)₂ (0.2 mmol), 4,4'-bipyridine (0.1 mmol), methanol (3 ml) and distilled water (8 ml) in a molar ratio of 2:1:740:4444; the pH value was adjusted to 4.6 with trimethylamine and acetic acid. The mixture was stirred for 20 min at room temperature and then sealed in a Teflon-lined stainless steel autoclave with a 23 ml capacity at 423 K for 72 h. After cooling to room temperature, colourless block-shaped crystals were obtained; these were washed with deionized water, filtered, and dried in air (yield 54% based on Cu).

Refinement

H atoms were placed geometrically and included in the refinement with fixed individual displacement parameters [U_iso(H) = 1.2U_eq(C,N)], using a riding model, with C—H distances of 0.93 Å for sp² C and 0.96 Å for methyl C.

Figures

Fig. 1.

A view of the title compound, showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. [Symmetry code: (A) -x, 1 - y, -z].

Fig. 2.

Perspective view along the c axis of the packing of the title compound. For the sake of clarity, H atoms have been omitted. Dashed lines indicated π···π interactions.

Crystal data

C12H14N22+·2BF4–	F000 = 364
Mr = 359.87	Dx = 1.567 Mg m−3
Monoclinic, P21/c	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 852 reflections
a = 5.824 (2) Å	θ = 2.7–21.8º
b = 8.849 (3) Å	µ = 0.16 mm−1
c = 14.855 (6) Å	T = 293 (2) K
β = 94.825 (5)º	Block, white
V = 762.9 (5) Å3	0.26 × 0.12 × 0.07 mm
Z = 2

Data collection

Bruker APEX CCD area-detector diffractometer	1508 independent reflections
Radiation source: fine-focus sealed tube	843 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.029
T = 293(2) K	θmax = 26.1º
φ and ω scans	θmin = 2.7º
Absorption correction: multi-scan(SAINT-Plus; Bruker, 2003)	h = −7→7
Tmin = 0.960, Tmax = 0.988	k = −7→10
3923 measured reflections	l = −18→18

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.082	H-atom parameters constrained
wR(F2) = 0.249	w = 1/[σ2(Fo2) + (0.1212P)2 + 0.6686P] where P = (Fo2 + 2Fc2)/3
S = 1.02	(Δ/σ)max = 0.027
1508 reflections	Δρmax = 0.35 e Å−3
110 parameters	Δρmin = −0.23 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

Special details

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

	x	y	z	Uiso*/Ueq
N1	0.4587 (6)	0.7384 (4)	0.0761 (2)	0.0562 (10)
C1	0.3344 (8)	0.6666 (6)	0.1356 (3)	0.0630 (13)
H1	0.3694	0.6820	0.1972	0.076*
C2	0.1604 (8)	0.5727 (6)	0.1078 (3)	0.0595 (12)
H2	0.0809	0.5225	0.1505	0.071*
C3	0.0967 (7)	0.5493 (4)	0.0157 (2)	0.0467 (10)
C4	0.2275 (9)	0.6266 (5)	−0.0436 (3)	0.0638 (13)
H4	0.1937	0.6151	−0.1056	0.077*
C5	0.4030 (9)	0.7182 (6)	−0.0129 (3)	0.0667 (13)
H5	0.4872	0.7684	−0.0542	0.080*
C6	0.6523 (9)	0.8417 (6)	0.1092 (4)	0.0796 (15)
H6A	0.5918	0.9252	0.1411	0.119*
H6B	0.7278	0.8789	0.0587	0.119*
H6C	0.7609	0.7871	0.1491	0.119*
B	0.8454 (9)	0.5924 (6)	0.3254 (3)	0.0587 (14)
F1	0.7199 (7)	0.7234 (4)	0.3254 (3)	0.1178 (14)
F2	0.7561 (6)	0.5028 (4)	0.2566 (2)	0.0984 (12)
F3	1.0703 (5)	0.6258 (4)	0.3118 (2)	0.0984 (12)
F4	0.8324 (6)	0.5244 (5)	0.4071 (2)	0.1099 (14)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
N1	0.059 (2)	0.059 (2)	0.052 (2)	0.0147 (18)	0.0171 (17)	0.0058 (17)
C1	0.064 (3)	0.085 (3)	0.042 (2)	0.005 (3)	0.017 (2)	0.002 (2)
C2	0.067 (3)	0.077 (3)	0.037 (2)	0.003 (2)	0.022 (2)	0.012 (2)
C3	0.060 (2)	0.048 (2)	0.034 (2)	0.0214 (18)	0.0180 (17)	0.0048 (16)
C4	0.087 (3)	0.073 (3)	0.034 (2)	0.003 (3)	0.017 (2)	0.007 (2)
C5	0.090 (3)	0.070 (3)	0.044 (2)	0.005 (3)	0.026 (2)	0.010 (2)
C6	0.072 (3)	0.088 (4)	0.080 (4)	0.001 (3)	0.012 (3)	−0.002 (3)
B	0.063 (3)	0.068 (3)	0.048 (3)	−0.008 (3)	0.020 (2)	−0.007 (3)
F1	0.145 (3)	0.103 (3)	0.110 (3)	0.041 (2)	0.038 (2)	−0.007 (2)
F2	0.106 (2)	0.116 (3)	0.075 (2)	−0.028 (2)	0.0209 (17)	−0.0357 (18)
F3	0.076 (2)	0.145 (3)	0.078 (2)	−0.030 (2)	0.0309 (16)	−0.0211 (19)
F4	0.122 (3)	0.153 (3)	0.0570 (18)	−0.022 (2)	0.0204 (17)	0.0248 (19)

Geometric parameters (Å, °)

N1—C5	1.347 (6)	C4—H4	0.9300
N1—C1	1.348 (5)	C5—H5	0.9300
N1—C6	1.502 (6)	C6—H6A	0.9600
C1—C2	1.348 (7)	C6—H6B	0.9600
C1—H1	0.9300	C6—H6C	0.9600
C2—C3	1.402 (5)	B—F4	1.361 (6)
C2—H2	0.9300	B—F2	1.362 (6)
C3—C4	1.392 (6)	B—F1	1.371 (6)
C3—C3i	1.470 (9)	B—F3	1.374 (6)
C4—C5	1.353 (7)
C5—N1—C1	118.9 (4)	N1—C5—C4	121.5 (4)
C5—N1—C6	121.0 (4)	N1—C5—H5	119.2
C1—N1—C6	120.2 (4)	C4—C5—H5	119.2
C2—C1—N1	121.4 (4)	N1—C6—H6A	109.5
C2—C1—H1	119.3	N1—C6—H6B	109.5
N1—C1—H1	119.3	H6A—C6—H6B	109.5
C1—C2—C3	121.4 (4)	N1—C6—H6C	109.5
C1—C2—H2	119.3	H6A—C6—H6C	109.5
C3—C2—H2	119.3	H6B—C6—H6C	109.5
C4—C3—C2	115.5 (4)	F4—B—F2	111.4 (4)
C4—C3—C3i	122.5 (4)	F4—B—F1	107.7 (4)
C2—C3—C3i	122.0 (4)	F2—B—F1	108.8 (4)
C5—C4—C3	121.3 (4)	F4—B—F3	110.6 (4)
C5—C4—H4	119.4	F2—B—F3	108.9 (4)
C3—C4—H4	119.4	F1—B—F3	109.4 (5)

Symmetry codes: (i) −x, −y+1, −z.