4-(Dimethyl­amino)pyridinium tribromide: whole mol­ecule disorder of cation and anion

Ng, S.W.

doi:10.1107/S1600536809017048

organic compounds

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doi:10.1107/S1600536809017048

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4-(Dimethylamino)pyridinium tribromide: whole molecule disorder of cation and anion

Seik Weng Ng ^a ^*

^aDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
^*Correspondence e-mail: seikweng@um.edu.my

(Received 5 May 2009; accepted 6 May 2009; online 14 May 2009)

In the title salt, C₇H₁₁N₂⁺·Br₃⁻, the cation and the near-linear anion [Br—Br—Br = 179.41 (8)°] both show whole-molecule disorder about crystallographic twofold rotation axes. The cation is weakly hydrogen-bonded to the anion by an N—H⋯Br interaction. The crystal studied was found to be a racemic twin, with a twin component of nearly 50%.

Related literature

The compound is known commercially as 4-(dimethylamino)pyridine hydrobromide perbromide, [C₇H₁₀N₂]·[HBr]·[Br₂]. The 4-dimethylaminopyridinium cation furnishes a number of salts with organic and inorganic acids. For 4-dimethylaminopyridinium bromide, see: Mayr-Stein & Bolte (2000 ). For dimethylaminopyridinium chloride and its dihydrate, see: Bryant & King (1992 ); Chao et al. (1977 ).

Experimental

Crystal data

C₇H₁₁N₂⁺·Br₃⁻
M_r = 362.91
Orthorhombic, P 222₁
a = 4.1688 (1) Å
b = 8.8349 (2) Å
c = 14.7255 (4) Å
V = 542.35 (2) Å³
Z = 2
Mo Kα radiation
μ = 11.11 mm⁻¹
T = 100 K
0.20 × 0.15 × 0.10 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.656, T_max = 1.000 (expected range = 0.216–0.329)
5156 measured reflections
1256 independent reflections
1114 reflections with I > 2σ(I)
R_int = 0.025

Refinement

R[F² > 2σ(F²)] = 0.021
wR(F²) = 0.051
S = 0.98
1256 reflections
100 parameters
60 restraints
H-atom parameters constrained
Δρ_max = 0.42 e Å⁻³
Δρ_min = −0.34 e Å⁻³
Absolute structure: Flack (1983 ), 480 Friedel pairs
Flack parameter: 0.47 (4)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯Br2	0.88	2.42	3.286 (2)	167

Data collection: APEX2 (Bruker, 2008 ); cell refinement: SAINT (Bruker, 2008); 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, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809017048/hb2966sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809017048/hb2966Isup2.hkl

checkCIF report

Related literature top

The compound is known commercially as 4-(dimethylamino)pyridine hydrobromide perbromide, [C₇H₁₀N₂]^.[HBr]^.[Br₂]. The 4-dimethylaminopyridinium cation furnishes a number of salts with organic and inorganic acids. For 4-dimethylaminopyridinium bromide, see: Mayr-Stein & Bolte (2000). For dimethylaminopyridinium chloride and its dihydrate, see: Bryant & King (1992); Chao et al. (1977).

Experimental top

Commercially-available 4-dimethylaminopyridine hydrobromide perbromide was recrystallized from ethanol to give colourless blocks of (I).

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); 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: pubCIF (Westrip, 2009).

Figures top

Fig. 1. Thermal ellipsoid plot (Barbour, 2001) of [C₇H₁₁N₂][Br₃] at the 70% probability level. Hydrogen atoms are drawn as spheres of arbitrary radius.

4-(Dimethylamino)pyridinium tribromide top

Crystal data top

C₇H₁₁N₂⁺·Br₃⁻	F(000) = 344
M_r = 362.91	D_x = 2.222 Mg m⁻³
Orthorhombic, P222₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c 2	Cell parameters from 2094 reflections
a = 4.1688 (1) Å	θ = 2.7–28.3°
b = 8.8349 (2) Å	µ = 11.11 mm⁻¹
c = 14.7255 (4) Å	T = 100 K
V = 542.35 (2) Å³	Block, colorless
Z = 2	0.20 × 0.15 × 0.10 mm

Data collection top

Bruker SMART APEX CCD diffractometer	1256 independent reflections
Radiation source: fine-focus sealed tube	1114 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.025
ω scans	θ_max = 27.5°, θ_min = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −5→5
T_min = 0.656, T_max = 1.000	k = −11→11
5156 measured reflections	l = −19→19

Refinement top

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)] = 0.021	H-atom parameters constrained
wR(F²) = 0.051	w = 1/[σ²(F_o²) + (0.0322P)²] where P = (F_o² + 2F_c²)/3
S = 0.98	(Δ/σ)_max = 0.001
1256 reflections	Δρ_max = 0.42 e Å⁻³
100 parameters	Δρ_min = −0.34 e Å⁻³
60 restraints	Absolute structure: Flack (1983), 480 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.47 (4)

Crystal data top

C₇H₁₁N₂⁺·Br₃⁻	V = 542.35 (2) Å³
M_r = 362.91	Z = 2
Orthorhombic, P222₁	Mo Kα radiation
a = 4.1688 (1) Å	µ = 11.11 mm⁻¹
b = 8.8349 (2) Å	T = 100 K
c = 14.7255 (4) Å	0.20 × 0.15 × 0.10 mm

Data collection top

Bruker SMART APEX CCD diffractometer	1256 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1114 reflections with I > 2σ(I)
T_min = 0.656, T_max = 1.000	R_int = 0.025
5156 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.021	H-atom parameters constrained
wR(F²) = 0.051	Δρ_max = 0.42 e Å⁻³
S = 0.98	Δρ_min = −0.34 e Å⁻³
1256 reflections	Absolute structure: Flack (1983), 480 Friedel pairs
100 parameters	Absolute structure parameter: 0.47 (4)
60 restraints

Special details top

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.

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
Br1	0.5290 (6)	0.25953 (5)	0.23869 (12)	0.0155 (3)	0.50
Br2	0.2738 (3)	0.27497 (11)	0.07779 (5)	0.0196 (2)	0.50
Br3	0.7682 (3)	0.24565 (11)	0.39355 (5)	0.01777 (18)	0.50
N2	1.1882 (7)	0.2417 (5)	−0.3550 (3)	0.0144 (9)	0.50
N1	0.7232 (7)	0.2399 (4)	−0.10428 (15)	0.0209 (11)	0.50
H1	0.6250	0.2392	−0.0514	0.025*	0.50
C1	0.7724 (9)	0.1050 (3)	−0.1509 (2)	0.0190 (11)	0.50
H1A	0.7000	0.0122	−0.1257	0.023*	0.50
C2	0.9276 (8)	0.1061 (3)	−0.23446 (19)	0.0196 (13)	0.50
H2	0.9612	0.0140	−0.2663	0.024*	0.50
C3	1.0335 (5)	0.2420 (3)	−0.27138 (13)	0.0147 (11)	0.50
C4	0.9844 (9)	0.3768 (3)	−0.2248 (2)	0.0195 (12)	0.50
H4	1.0568	0.4697	−0.2500	0.023*	0.50
C5	0.8292 (9)	0.3757 (3)	−0.1412 (2)	0.0208 (14)	0.50
H5	0.7956	0.4679	−0.1093	0.025*	0.50
C6	1.2376 (13)	0.1015 (6)	−0.4024 (3)	0.0226 (13)	0.50
H6A	1.0314	0.0498	−0.4102	0.034*	0.50
H6B	1.3829	0.0370	−0.3672	0.034*	0.50
H6C	1.3321	0.1220	−0.4620	0.034*	0.50
C7	1.2983 (11)	0.3839 (6)	−0.3936 (4)	0.0223 (14)	0.50
H7A	1.1130	0.4479	−0.4077	0.033*	0.50
H7B	1.4196	0.3638	−0.4493	0.033*	0.50
H7C	1.4366	0.4359	−0.3497	0.033*	0.50

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0195 (8)	0.01421 (16)	0.0128 (8)	−0.0005 (3)	0.0021 (5)	−0.0007 (2)
Br2	0.0201 (4)	0.0274 (5)	0.0112 (4)	0.0019 (3)	0.0015 (3)	−0.0010 (3)
Br3	0.0210 (4)	0.0207 (4)	0.0116 (4)	−0.0011 (3)	0.0007 (3)	0.0001 (3)
N2	0.021 (2)	0.0110 (19)	0.011 (2)	−0.001 (2)	−0.0034 (17)	0.005 (2)
N1	0.023 (3)	0.032 (3)	0.008 (2)	0.007 (3)	0.0025 (19)	−0.001 (2)
C1	0.019 (3)	0.021 (3)	0.017 (3)	−0.001 (2)	−0.003 (3)	0.002 (2)
C2	0.012 (3)	0.0175 (19)	0.029 (4)	−0.0005 (16)	0.004 (3)	0.003 (2)
C3	0.019 (2)	0.0179 (18)	0.008 (3)	−0.001 (3)	−0.002 (2)	0.0001 (17)
C4	0.020 (2)	0.022 (2)	0.016 (3)	−0.004 (3)	−0.005 (4)	0.0004 (16)
C5	0.019 (3)	0.023 (3)	0.020 (3)	0.001 (2)	−0.001 (3)	0.001 (3)
C6	0.032 (3)	0.019 (2)	0.017 (3)	0.000 (3)	−0.001 (4)	0.004 (2)
C7	0.023 (4)	0.023 (3)	0.020 (3)	0.005 (2)	0.008 (3)	−0.005 (2)

Geometric parameters (Å, º) top

Br1—Br3	2.492 (3)	C2—H2	0.9500
Br1—Br2	2.601 (3)	C3—C4	1.3900
N2—C3	1.390 (5)	C4—C5	1.3900
N2—C6	1.436 (7)	C4—H4	0.9500
N2—C7	1.454 (7)	C5—H5	0.9500
N1—C1	1.3900	C6—H6A	0.9800
N1—C5	1.3900	C6—H6B	0.9800
N1—H1	0.8800	C6—H6C	0.9800
C1—C2	1.3900	C7—H7A	0.9800
C1—H1A	0.9500	C7—H7B	0.9800
C2—C3	1.3900	C7—H7C	0.9800

Br3—Br1—Br2	179.41 (8)	C5—C4—H4	120.0
C3—N2—C6	119.9 (4)	C3—C4—H4	120.0
C3—N2—C7	119.4 (4)	C4—C5—N1	120.0
C6—N2—C7	120.7 (4)	C4—C5—H5	120.0
C1—N1—C5	120.0	N1—C5—H5	120.0
C1—N1—H1	120.0	N2—C6—H6A	109.5
C5—N1—H1	120.0	N2—C6—H6B	109.5
N1—C1—C2	120.0	H6A—C6—H6B	109.5
N1—C1—H1A	120.0	N2—C6—H6C	109.5
C2—C1—H1A	120.0	H6A—C6—H6C	109.5
C1—C2—C3	120.0	H6B—C6—H6C	109.5
C1—C2—H2	120.0	N2—C7—H7A	109.5
C3—C2—H2	120.0	N2—C7—H7B	109.5
N2—C3—C4	120.5 (3)	H7A—C7—H7B	109.5
N2—C3—C2	119.5 (3)	N2—C7—H7C	109.5
C4—C3—C2	120.0	H7A—C7—H7C	109.5
C5—C4—C3	120.0	H7B—C7—H7C	109.5

C5—N1—C1—C2	0.0	C1—C2—C3—N2	−179.96 (9)
N1—C1—C2—C3	0.0	C1—C2—C3—C4	0.0
C6—N2—C3—C4	179.95 (9)	N2—C3—C4—C5	179.96 (9)
C7—N2—C3—C4	−0.07 (11)	C2—C3—C4—C5	0.0
C6—N2—C3—C2	−0.08 (13)	C3—C4—C5—N1	0.0
C7—N2—C3—C2	179.90 (9)	C1—N1—C5—C4	0.0

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Br2	0.88	2.42	3.286 (2)	167

Experimental details

Crystal data
Chemical formula	C₇H₁₁N₂⁺·Br₃⁻
M_r	362.91
Crystal system, space group	Orthorhombic, P222₁
Temperature (K)	100
a, b, c (Å)	4.1688 (1), 8.8349 (2), 14.7255 (4)
V (Å³)	542.35 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	11.11
Crystal size (mm)	0.20 × 0.15 × 0.10

Data collection
Diffractometer	Bruker SMART APEX CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.656, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	5156, 1256, 1114
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.021, 0.051, 0.98
No. of reflections	1256
No. of parameters	100
No. of restraints	60
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.42, −0.34
Absolute structure	Flack (1983), 480 Friedel pairs
Absolute structure parameter	0.47 (4)

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001), pubCIF (Westrip, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Br2	0.88	2.42	3.286 (2)	167

Acknowledgements

I thank the University of Malaya for supporting this study.

References

Barbour, L. J. (2001). J. Supramol. Chem. 1, 189–191. CrossRef CAS Google Scholar
Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bryant, G. L. & King, J. A. (1992). Acta Cryst. C48, 2036–2039. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Chao, M., Schempp, E. & Rosenstein, D. (1977). Acta Cryst. B33, 1820–1823. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Mayr-Stein, R. & Bolte, M. (2000). Acta Cryst. C56, e19–e20. CSD CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2009). publCIF. In preparation. Google Scholar

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CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 65| Part 6| June 2009| Page o1276

doi:10.1107/S1600536809017048

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4-(Di­methyl­amino)pyridinium tribromide: whole mol­ecule disorder of cation and anion

Related literature

Experimental

Crystal data

Data collection

Refinement

Supporting information

Acknowledgements

References

organic compounds

4-(Dimethylamino)pyridinium tribromide: whole molecule disorder of cation and anion