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Acta Crystallogr Sect E Struct Rep Online. 2008 November 1; 64(Pt 11): o2236.
Published online 2008 October 31. doi:  10.1107/S1600536808034843
PMCID: PMC2959663

A redetermination at low temperature of the structure of triethyl­ammonium bromide

Abstract

The structure of the title compound, C6H16N+·Br, was determined at low temperature and the cell dimensions were comparable to those reported for room-temperature studies [James, Cameron, Knop, Newman & Falp, (1985). Can. J. Chem. 63, 1750–1758]. Initial analysis of the data led to the assignment of P31 c as the space group rather than P63 mc as reported for the room-temperature structure. Careful examination of the appropriate |F o| values in the low-temperature data showed that the equalities |F(An external file that holds a picture, illustration, etc.
Object name is e-64-o2236-efi1.jpg kl)| = |F(h An external file that holds a picture, illustration, etc.
Object name is e-64-o2236-efi2.jpg l)| and |F(hkl)| = |F(hk An external file that holds a picture, illustration, etc.
Object name is e-64-o2236-efi3.jpg)| did not hold at low temperature, confirming P31c as the appropriate choice of space group. As a consequence of this choice, the N atom sat on a threefold axis and the ethyl arms were not disordered as observed at room temperature. The crystal studied was an inversion twin with a 0.68 (3):0.32 (3) domain ratio.

Related literature

For related structures, see: James et al. (1985 [triangle]). For the preparation, see: Lecolley et al. (2004 [triangle]).

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Object name is e-64-o2236-scheme1.jpg

Experimental

Crystal data

  • C6H16N+·Br
  • M r = 182.10
  • Trigonal, An external file that holds a picture, illustration, etc.
Object name is e-64-o2236-efi4.jpg
  • a = 8.3589 (2) Å
  • c = 7.3125 (2) Å
  • V = 442.48 (1) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 4.56 mm−1
  • T = 90 (2) K
  • 0.27 × 0.11 × 0.10 mm

Data collection

  • Bruker APEXII CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2004 [triangle]) T min = 0.450, T max = 0.632
  • 8583 measured reflections
  • 555 independent reflections
  • 550 reflections with I > 2σ(I)
  • R int = 0.026

Refinement

  • R[F 2 > 2σ(F 2)] = 0.020
  • wR(F 2) = 0.058
  • S = 1.24
  • 555 reflections
  • 23 parameters
  • 1 restraint
  • H-atom parameters constrained
  • Δρmax = 0.39 e Å−3
  • Δρmin = −0.39 e Å−3
  • Absolute structure: Flack (1983 [triangle]), 273 Friedel pairs
  • Flack parameter: 0.32 (3)

Data collection: APEX2 (Bruker, 2006 [triangle]); cell refinement: APEX2 and SAINT (Bruker, 2006 [triangle]); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1993 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808034843/pv2113sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808034843/pv2113Isup2.hkl

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

Acknowledgments

We acknowledge the award of a John Edmond Postgraduate Scholarship in Chemistry (NHM) and thank the University of Otago Research Committee and the New Economic Research Fund (grant No UOO-X0404 from the New Zealand Foundation of Research Science and Technology) for financial support.

supplementary crystallographic information

Comment

The title compound, (I), was isolated as a by-product in a reaction to form (2,5-oxo-1-pyrrolidyl)oxy-2-bromo-2-methylpropionate (Lecolley et al., 2004). A view of the structure of (I) is presented in Fig. 1. The crystal structures of (I) and the other halide analogues at ambient temperature have previously been described by James et al. (1985). Unlike previous work, analysis of our low-temperature data showed that (I) crystallized in the space group P31c with the ethyl chains in fixed locations. The e.s.d.'s of the positional parameters and the R factors were significantly lower than those reported for the room temperature structure. The packing of (I) (Fig. 2) at low temperature is very similar to that of the room temperature disordered structure. James et al. (1985) also analysed the IR spectra of these compounds in some detail.

Experimental

The title compound, (I), was prepared as a by-product in a reaction to form (2,5-oxo-1-pyrrolidyl)oxy-2-bromo-2-methylpropionate by the method of Lecolley et al. (2004). X-Ray quality crystals were grown by the slow evaporation of an acetonitrile solution.

Refinement

All H-atoms bound to carbon were refined using a riding model with d(C—H) = 0.96 Å, Uiso=1.5Ueq (C) for the methyl CH H atoms and d(C—H) = 0.97 Å, Uiso=1.2Ueq (C) for the methylene CH H atoms. The H-atom bound to nitrogen was refined using a riding model with d(N—H) = 0.87 Å, Uiso=1.2Ueq (N).

Figures

Fig. 1.
A view of the molecule of (I) showing the atom numbering with displacement ellipsoids drawn at the 50% probability level. Symmetry codes: (i) -x+y, -x+1, z; (ii) -y+1, x-y+1, z.
Fig. 2.
Packing diagram of (I) in the ab plane.

Crystal data

C6H16N+·BrDx = 1.367 Mg m3
Mr = 182.10Mo Kα radiation, λ = 0.71073 Å
Trigonal, P31cCell parameters from 7729 reflections
Hall symbol: P 3 -2cθ = 2.8–27.5°
a = 8.3589 (2) ŵ = 4.56 mm1
c = 7.3125 (2) ÅT = 90 K
V = 442.48 (1) Å3Rod, colourless
Z = 20.27 × 0.11 × 0.10 mm
F(000) = 188

Data collection

Bruker APEXII CCD area-detector diffractometer555 independent reflections
Radiation source: fine-focus sealed tube550 reflections with I > 2σ(I)
graphiteRint = 0.026
[var phi] and ω scansθmax = 25.5°, θmin = 4.0°
Absorption correction: multi-scan (SADABS; Bruker, 2004)h = −10→10
Tmin = 0.450, Tmax = 0.633k = −10→10
8583 measured reflectionsl = −8→8

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.020H-atom parameters constrained
wR(F2) = 0.058w = 1/[σ2(Fo2) + (0.0371P)2 + 0.4873P] where P = (Fo2 + 2Fc2)/3
S = 1.24(Δ/σ)max < 0.001
555 reflectionsΔρmax = 0.39 e Å3
23 parametersΔρmin = −0.39 e Å3
1 restraintAbsolute structure: Flack (1983), 273 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: 0.32 (3)

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. The crystal studied was an inversion twin with a 0.68 (3);0.32 (3) domain ratio.

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

xyzUiso*/Ueq
C10.1624 (6)0.8395 (6)0.4111 (5)0.0323 (9)
H1A0.15360.81810.28150.048*
H1B0.26900.95710.43730.048*
H1C0.05330.83890.45340.048*
N10.33330.66670.4505 (6)0.0168 (12)
H10.33330.66670.32600.020*
C20.1789 (5)0.6982 (5)0.5011 (5)0.0232 (7)
H2A0.06440.58300.48200.028*
H2B0.18840.72400.63120.028*
Br10.66670.33330.50170.01786 (16)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.034 (2)0.038 (2)0.035 (2)0.026 (2)−0.0004 (16)−0.0026 (17)
N10.0162 (14)0.0162 (14)0.018 (3)0.0081 (7)0.0000.000
C20.0168 (15)0.0228 (14)0.0293 (17)0.0095 (12)0.0004 (14)0.0001 (16)
Br10.01867 (19)0.01867 (19)0.0162 (2)0.00933 (9)0.0000.000

Geometric parameters (Å, °)

C1—C21.418 (5)N1—C2i1.488 (4)
C1—H1A0.9600N1—C2ii1.488 (4)
C1—H1B0.9600N1—H10.9100
C1—H1C0.9600C2—H2A0.9700
N1—C21.488 (4)C2—H2B0.9700
C2—C1—H1A109.5C2—N1—H1104.4
C2—C1—H1B109.5C2i—N1—H1104.4
H1A—C1—H1B109.5C2ii—N1—H1104.4
C2—C1—H1C109.5C1—C2—N1119.1 (3)
H1A—C1—H1C109.5C1—C2—H2A107.5
H1B—C1—H1C109.5N1—C2—H2A107.5
C2—N1—C2i114.03 (18)C1—C2—H2B107.5
C2—N1—C2ii114.03 (18)N1—C2—H2B107.5
C2i—N1—C2ii114.03 (18)H2A—C2—H2B107.0

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: PV2113).

References

  • Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst.26, 343–350.
  • Bruker (2004). SADABS Bruker AXS Inc., Madison, Wisconsin, USA..
  • Bruker (2006). APEX2 and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Flack, H. D. (1983). Acta Cryst. A39, 876–881.
  • James, M. A., Cameron, S. T., Knop, O., Neuman, M. & Falk, M. (1985). Can. J. Chem.63, 1750–1758.
  • Lecolley, F., Tao, L., Mantovani, G., Durkin, I., Lautru, S. & Haddleton, D. M. (2004). Chem. Commun. pp. 2026–2027. [PubMed]
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography