Tetra-n-butyl-ammonium bromide: a redetermination at 150 K addressing the merohedral twinning.

The redetermined, low temperature (150 K), structure of tetra-n-butyl-ammonium bromide, (C(4)H(9))(4)N(+)·Br(-), has been found to be merohedrally twinned via twin law -1 0 0, 0 - 1 0, 1 0 1. The structure was previously determined, with low precision, no inclusion of H atoms and only the bromide ion refined with anisotropic displacement parameters, by Wang et al. (1995 ▶). Mol. Cryst. Liq. Cryst. Sci. Tech. A, 264, 115-129. The redetermined structure has considerably improved precision in all geometrical parameters, has all non-H atoms refined anisotropically, H atoms included, and is isomorphous with the iodide analogue. The structure is otherwise routine, with the shortest cation to anion contacts being between the bromide anion and the CH atoms close to the ammonium nitro-gen centre at a distance of ca. 2.98-3.11 Å. Each anion makes eight such contacts to four different anions. The n-butyl chains are fully extended, adopting an all-anti conformation with approximate S(4) point symmetry.

Related literature

The structure was previously determined by Wang et al. (1995 ▶). For the uses of tetra-n-alkyl­ammonium salts and the isomorphous structure of tetra-n-butyl ammonium iodide, see: Prukała et al. (2007 ▶). For a related stucture, see: McMullan & Jeffrey (1959 ▶). For the conformation of n-butyl chains, see: Alder et al. (1990 ▶). For details of the Cambridge Structural Database, see: Fletcher et al. (1996 ▶); Allen (2002 ▶).

Experimental

Crystal data

C16H36N+·Br−

M = 322.37

Monoclinic,

a = 13.9773 (9) Å

b = 13.8623 (9) Å

c = 20.0450 (14) Å

β = 110.383 (10)°

V = 3640.7 (4) Å3

Z = 8

Mo Kα radiation

μ = 2.25 mm−1

T = 150 K

0.41 × 0.31 × 0.16 mm

Data collection

Bruker APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 2008a ▶) T min = 0.459, T max = 0.715

21135 measured reflections

5485 independent reflections

4415 reflections with I > 2σ(I)

R int = 0.029

Refinement

R[F 2 > 2σ(F 2)] = 0.028

wR(F 2) = 0.073

S = 1.04

5485 reflections

168 parameters

H-atom parameters constrained

Δρmax = 0.62 e Å−3

Δρmin = −0.24 e Å−3

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b ▶) and PLATON (Spek, 2009 ▶); molecular graphics: SHELXTL (Sheldrick, 2008b ▶); software used to prepare material for publication: SHELXTL and local programs.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811032612/rn2089sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811032612/rn2089Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811032612/rn2089Isup3.cml

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

C16H36N+·Br−	F(000) = 1392
Mr = 322.37	Dx = 1.176 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 7468 reflections
a = 13.9773 (9) Å	θ = 2.6–30.1°
b = 13.8623 (9) Å	µ = 2.25 mm−1
c = 20.0450 (14) Å	T = 150 K
β = 110.383 (10)°	Block, colourless
V = 3640.7 (4) Å3	0.41 × 0.31 × 0.16 mm
Z = 8

Bruker APEXII CCD diffractometer	5485 independent reflections
Radiation source: fine-focus sealed tube	4415 reflections with I > 2σ(I)
graphite	Rint = 0.029
ω rotation with narrow frames scans	θmax = 30.5°, θmin = 1.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 2008a)	h = −19→19
Tmin = 0.459, Tmax = 0.715	k = −18→19
21135 measured reflections	l = −28→28

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)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.073	H-atom parameters constrained
S = 1.04	w = 1/[σ2(Fo2) + (0.0379P)2 + 0.7322P] where P = (Fo2 + 2Fc2)/3
5485 reflections	(Δ/σ)max = 0.001
168 parameters	Δρmax = 0.62 e Å−3
0 restraints	Δρmin = −0.24 e Å−3

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.

	x	y	z	Uiso*/Ueq
Br1	0.737682 (14)	0.00074 (2)	0.475441 (8)	0.03037 (6)
N1	0.49621 (18)	0.25167 (8)	0.49516 (13)	0.0172 (2)
C1	0.44659 (14)	0.30519 (13)	0.54096 (10)	0.0195 (4)
H1A	0.4927	0.3579	0.5664	0.023*
H1B	0.3826	0.3352	0.5093	0.023*
C2	0.4221 (2)	0.24346 (12)	0.59514 (15)	0.0252 (6)
H2A	0.4848	0.2105	0.6258	0.030*
H2B	0.3718	0.1934	0.5702	0.030*
C3	0.37887 (16)	0.30443 (14)	0.64107 (11)	0.0253 (4)
H3A	0.3187	0.3406	0.6101	0.030*
H3B	0.4309	0.3519	0.6682	0.030*
C4	0.3476 (3)	0.24244 (16)	0.69282 (16)	0.0302 (6)
H4A	0.2984	0.1936	0.6663	0.045*
H4B	0.3163	0.2833	0.7194	0.045*
H4C	0.4081	0.2106	0.7261	0.045*
C5	0.42140 (14)	0.17734 (13)	0.45040 (10)	0.0191 (4)
H5A	0.4085	0.1292	0.4827	0.023*
H5B	0.3559	0.2101	0.4249	0.023*
C6	0.45519 (19)	0.12433 (12)	0.39615 (10)	0.0230 (4)
H6A	0.5208	0.0911	0.4206	0.028*
H6B	0.4659	0.1712	0.3621	0.028*
C7	0.37484 (16)	0.05075 (14)	0.35601 (11)	0.0259 (4)
H7A	0.3613	0.0065	0.3905	0.031*
H7B	0.3104	0.0847	0.3296	0.031*
C8	0.4089 (3)	−0.00752 (19)	0.30414 (11)	0.0347 (5)
H8A	0.4195	0.0358	0.2687	0.052*
H8B	0.3563	−0.0551	0.2801	0.052*
H8C	0.4729	−0.0409	0.3301	0.052*
C9	0.59273 (14)	0.19965 (13)	0.54137 (10)	0.0202 (4)
H9A	0.5729	0.1462	0.5666	0.024*
H9B	0.6262	0.1708	0.5099	0.024*
C10	0.6700 (2)	0.26295 (15)	0.59616 (14)	0.0253 (5)
H10A	0.6917	0.3163	0.5718	0.030*
H10B	0.6382	0.2914	0.6287	0.030*
C11	0.76246 (15)	0.20341 (15)	0.63871 (12)	0.0291 (4)
H11A	0.7914	0.1715	0.6058	0.035*
H11B	0.7412	0.1526	0.6653	0.035*
C12	0.8439 (3)	0.26686 (18)	0.69083 (16)	0.0365 (6)
H12A	0.8637	0.3181	0.6646	0.055*
H12B	0.9037	0.2275	0.7163	0.055*
H12C	0.8165	0.2957	0.7251	0.055*
C13	0.52549 (14)	0.32450 (13)	0.44859 (10)	0.0200 (4)
H13A	0.5701	0.3741	0.4798	0.024*
H13B	0.5659	0.2908	0.4238	0.024*
C14	0.43636 (18)	0.37509 (13)	0.39317 (10)	0.0241 (4)
H14A	0.3960	0.4108	0.4171	0.029*
H14B	0.3912	0.3267	0.3611	0.029*
C15	0.47602 (16)	0.44495 (14)	0.35002 (11)	0.0263 (4)
H15A	0.5139	0.4086	0.3247	0.032*
H15B	0.5238	0.4912	0.3826	0.032*
C16	0.3885 (3)	0.5001 (2)	0.29610 (10)	0.0343 (5)
H16A	0.3445	0.4549	0.2613	0.051*
H16B	0.4162	0.5477	0.2716	0.051*
H16C	0.3486	0.5332	0.3209	0.051*

	U11	U22	U33	U12	U13	U23
Br1	0.02772 (9)	0.02330 (8)	0.04278 (10)	0.00074 (10)	0.01565 (8)	0.0010 (2)
N1	0.0158 (9)	0.0157 (5)	0.0192 (6)	−0.0003 (5)	0.0048 (12)	0.0008 (7)
C1	0.0217 (9)	0.0173 (8)	0.0213 (9)	0.0011 (7)	0.0099 (8)	−0.0019 (7)
C2	0.0345 (15)	0.0197 (10)	0.0255 (12)	−0.0008 (7)	0.0157 (11)	0.0002 (7)
C3	0.0274 (10)	0.0261 (9)	0.0271 (10)	0.0023 (8)	0.0154 (8)	0.0008 (8)
C4	0.0316 (15)	0.0361 (12)	0.0308 (12)	0.0011 (9)	0.0208 (14)	0.0059 (10)
C5	0.0177 (9)	0.0181 (8)	0.0221 (10)	−0.0031 (6)	0.0076 (7)	−0.0022 (7)
C6	0.0215 (10)	0.0229 (8)	0.0251 (9)	−0.0023 (8)	0.0088 (9)	−0.0047 (6)
C7	0.0289 (10)	0.0219 (9)	0.0284 (10)	−0.0029 (8)	0.0117 (8)	−0.0061 (8)
C8	0.0435 (15)	0.0270 (10)	0.0368 (9)	−0.0008 (11)	0.0182 (12)	−0.0112 (11)
C9	0.0189 (9)	0.0189 (8)	0.0223 (9)	0.0029 (7)	0.0067 (7)	0.0004 (7)
C10	0.0218 (12)	0.0236 (9)	0.0254 (12)	−0.0009 (8)	0.0017 (10)	0.0011 (8)
C11	0.0193 (9)	0.0299 (10)	0.0341 (11)	0.0015 (8)	0.0042 (8)	−0.0038 (9)
C12	0.0218 (13)	0.0513 (16)	0.0310 (12)	−0.0006 (13)	0.0026 (11)	−0.0076 (12)
C13	0.0227 (10)	0.0169 (8)	0.0227 (10)	−0.0026 (7)	0.0108 (8)	0.0013 (7)
C14	0.0247 (11)	0.0243 (8)	0.0252 (9)	0.0029 (8)	0.0109 (9)	0.0057 (7)
C15	0.0291 (10)	0.0222 (9)	0.0276 (11)	−0.0012 (8)	0.0100 (8)	0.0037 (8)
C16	0.0371 (15)	0.0302 (8)	0.0319 (8)	0.0019 (11)	0.0073 (9)	0.0101 (14)

N1—C5	1.519 (3)	C8—H8B	0.9800
N1—C1	1.522 (3)	C8—H8C	0.9800
N1—C13	1.524 (3)	C9—C10	1.522 (3)
N1—C9	1.526 (3)	C9—H9A	0.9900
C1—C2	1.513 (3)	C9—H9B	0.9900
C1—H1A	0.9900	C10—C11	1.520 (3)
C1—H1B	0.9900	C10—H10A	0.9900
C2—C3	1.521 (3)	C10—H10B	0.9900
C2—H2A	0.9900	C11—C12	1.527 (4)
C2—H2B	0.9900	C11—H11A	0.9900
C3—C4	1.523 (4)	C11—H11B	0.9900
C3—H3A	0.9900	C12—H12A	0.9800
C3—H3B	0.9900	C12—H12B	0.9800
C4—H4A	0.9800	C12—H12C	0.9800
C4—H4B	0.9800	C13—C14	1.521 (3)
C4—H4C	0.9800	C13—H13A	0.9900
C5—C6	1.518 (3)	C13—H13B	0.9900
C5—H5A	0.9900	C14—C15	1.526 (3)
C5—H5B	0.9900	C14—H14A	0.9900
C6—C7	1.523 (3)	C14—H14B	0.9900
C6—H6A	0.9900	C15—C16	1.526 (3)
C6—H6B	0.9900	C15—H15A	0.9900
C7—C8	1.518 (3)	C15—H15B	0.9900
C7—H7A	0.9900	C16—H16A	0.9800
C7—H7B	0.9900	C16—H16B	0.9800
C8—H8A	0.9800	C16—H16C	0.9800
C5—N1—C1	108.81 (17)	C7—C8—H8C	109.5
C5—N1—C13	111.35 (18)	H8A—C8—H8C	109.5
C1—N1—C13	108.81 (12)	H8B—C8—H8C	109.5
C5—N1—C9	108.62 (12)	C10—C9—N1	114.89 (16)
C1—N1—C9	110.88 (17)	C10—C9—H9A	108.5
C13—N1—C9	108.39 (18)	N1—C9—H9A	108.5
C2—C1—N1	114.96 (15)	C10—C9—H9B	108.5
C2—C1—H1A	108.5	N1—C9—H9B	108.5
N1—C1—H1A	108.5	H9A—C9—H9B	107.5
C2—C1—H1B	108.5	C11—C10—C9	110.05 (17)
N1—C1—H1B	108.5	C11—C10—H10A	109.7
H1A—C1—H1B	107.5	C9—C10—H10A	109.7
C1—C2—C3	110.93 (15)	C11—C10—H10B	109.7
C1—C2—H2A	109.5	C9—C10—H10B	109.7
C3—C2—H2A	109.5	H10A—C10—H10B	108.2
C1—C2—H2B	109.5	C10—C11—C12	110.9 (2)
C3—C2—H2B	109.5	C10—C11—H11A	109.5
H2A—C2—H2B	108.0	C12—C11—H11A	109.5
C2—C3—C4	111.53 (18)	C10—C11—H11B	109.5
C2—C3—H3A	109.3	C12—C11—H11B	109.5
C4—C3—H3A	109.3	H11A—C11—H11B	108.1
C2—C3—H3B	109.3	C11—C12—H12A	109.5
C4—C3—H3B	109.3	C11—C12—H12B	109.5
H3A—C3—H3B	108.0	H12A—C12—H12B	109.5
C3—C4—H4A	109.5	C11—C12—H12C	109.5
C3—C4—H4B	109.5	H12A—C12—H12C	109.5
H4A—C4—H4B	109.5	H12B—C12—H12C	109.5
C3—C4—H4C	109.5	C14—C13—N1	115.22 (17)
H4A—C4—H4C	109.5	C14—C13—H13A	108.5
H4B—C4—H4C	109.5	N1—C13—H13A	108.5
C6—C5—N1	115.45 (17)	C14—C13—H13B	108.5
C6—C5—H5A	108.4	N1—C13—H13B	108.5
N1—C5—H5A	108.4	H13A—C13—H13B	107.5
C6—C5—H5B	108.4	C13—C14—C15	109.86 (18)
N1—C5—H5B	108.4	C13—C14—H14A	109.7
H5A—C5—H5B	107.5	C15—C14—H14A	109.7
C5—C6—C7	110.28 (19)	C13—C14—H14B	109.7
C5—C6—H6A	109.6	C15—C14—H14B	109.7
C7—C6—H6A	109.6	H14A—C14—H14B	108.2
C5—C6—H6B	109.6	C14—C15—C16	111.1 (2)
C7—C6—H6B	109.6	C14—C15—H15A	109.4
H6A—C6—H6B	108.1	C16—C15—H15A	109.4
C8—C7—C6	111.6 (2)	C14—C15—H15B	109.4
C8—C7—H7A	109.3	C16—C15—H15B	109.4
C6—C7—H7A	109.3	H15A—C15—H15B	108.0
C8—C7—H7B	109.3	C15—C16—H16A	109.5
C6—C7—H7B	109.3	C15—C16—H16B	109.5
H7A—C7—H7B	108.0	H16A—C16—H16B	109.5
C7—C8—H8A	109.5	C15—C16—H16C	109.5
C7—C8—H8B	109.5	H16A—C16—H16C	109.5
H8A—C8—H8B	109.5	H16B—C16—H16C	109.5
C5—N1—C1—C2	63.9 (2)	C5—N1—C9—C10	−172.7 (2)
C13—N1—C1—C2	−174.6 (2)	C1—N1—C9—C10	−53.2 (2)
C9—N1—C1—C2	−55.5 (2)	C13—N1—C9—C10	66.2 (2)
N1—C1—C2—C3	176.5 (2)	N1—C9—C10—C11	−179.95 (19)
C1—C2—C3—C4	176.5 (2)	C9—C10—C11—C12	176.4 (2)
C1—N1—C5—C6	174.16 (17)	C5—N1—C13—C14	54.1 (2)
C13—N1—C5—C6	54.2 (2)	C1—N1—C13—C14	−65.8 (2)
C9—N1—C5—C6	−65.0 (2)	C9—N1—C13—C14	173.53 (16)
N1—C5—C6—C7	178.84 (17)	N1—C13—C14—C15	−179.49 (17)
C5—C6—C7—C8	−176.82 (18)	C13—C14—C15—C16	−177.50 (18)