Pseudosymmetry in tetra­decyl­tri­methyl­ammonium bromide

In the title compound, C₁₇H₃₈N⁺·Br^-, the tetra­decyl chain is extended in a zigzag form. The mol­ecules are packed in layers with the tetra­decyl chains parallel within a layer and antiparallel in alternate layers. There is pseudosymmmetry which emulates a c-halved unit cell in P2₁/m, but it is not supported by the diffraction pattern, which is consistent with the reported space group and unit cell.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.033
• wR factor = 0.101
• Data-to-parameter ratio = 21.3

checkCIF results

No syntax errors found


 Alert Level A:



PLAT_113  Alert A ADDSYM Suggests Possible Pseudo/New Spacegroup .      P21/m

Author Response: This spacegroup requires the halving of the unit cell c parameter. Yet, we could clearly measure c odd reflections (although weaker than the c even). The intensities of these reflections, calculated from the refined model, match the observed intensities.

 Alert Level B:



PLAT_110  Alert B ADDSYM Detects Potential Lattice Centering or Halving .   ?


 1 Alert Level A = Potentially serious problem

 1 Alert Level B = Potential problem

 0 Alert Level C = Please check

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Computing details

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: HELENA (Spek, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

Tetradecyltrimethylammmonium bromide

Crystal data

C17H38N^+·Br^−	F(000) = 728
Mr = 336.39	Dx = 1.156 Mg m^−3
Monoclinic, P21/c	Cu Kα radiation, λ = 1.5418 Å
a = 5.6323 (13) Å	Cell parameters from 25 reflections
b = 7.240 (2) Å	θ = 23.0–28.3°
c = 47.3900 (15) Å	µ = 2.80 mm^−1
β = 91.170 (11)°	T = 293 K
V = 1932.1 (7) Å^3	Plate, colourless
Z = 4	0.34 × 0.27 × 0.12 mm

Data collection

Enraf–Nonius CAD-4 diffractometer	2481 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.034
Graphite monochromator	θmax = 72.6°, θmin = 3.7°
ω–2θ scans	h = −6→6
Absorption correction: ψ scan (North et al., 1968)	k = 0→8
Tmin = 0.471, Tmax = 0.711	l = −58→35
6399 measured reflections	3 standard reflections every 180 min
3750 independent reflections	intensity decay: 10%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.101	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0395P)^2 + 0.767P] where P = (Fo^2 + 2Fc^2)/3
3750 reflections	(Δ/σ)max < 0.001
176 parameters	Δρmax = 0.97 e Å^−3
0 restraints	Δρmin = −0.51 e Å^−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.

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

	x	y	z	Uiso*/Ueq
N1	0.4927 (3)	0.7501 (3)	0.54338 (3)	0.0379 (4)
C1	0.2998 (3)	0.7528 (3)	0.56497 (4)	0.0422 (5)
H1A	0.1857	0.6571	0.5601	0.051*
H1B	0.2178	0.8703	0.5635	0.051*
C1N	0.6390 (4)	0.5784 (3)	0.54550 (5)	0.0489 (6)
H1N1	0.7478	0.5746	0.5302	0.073*
H1N2	0.5368	0.4724	0.5446	0.073*
H1N3	0.7263	0.5780	0.5631	0.073*
C2	0.3766 (4)	0.7254 (3)	0.59536 (4)	0.0515 (6)
H2A	0.4216	0.5975	0.5985	0.062*
H2B	0.5134	0.8024	0.5997	0.062*
C2N	0.6509 (4)	0.9152 (3)	0.54615 (5)	0.0505 (6)
H2N1	0.7343	0.9112	0.5640	0.076*
H2N2	0.5568	1.0256	0.5450	0.076*
H2N3	0.7632	0.9147	0.5312	0.076*
C3	0.1750 (4)	0.7758 (4)	0.61436 (5)	0.0573 (7)
H3A	0.0323	0.7145	0.6074	0.069*
H3B	0.1481	0.9078	0.6129	0.069*
C3N	0.3697 (4)	0.7551 (4)	0.51505 (4)	0.0527 (6)
H3N1	0.4860	0.7555	0.5005	0.079*
H3N2	0.2745	0.8648	0.5136	0.079*
H3N3	0.2700	0.6483	0.5129	0.079*
C4	0.2116 (4)	0.7268 (4)	0.64525 (4)	0.0553 (7)
H4A	0.2197	0.5935	0.6471	0.066*
H4B	0.3627	0.7769	0.6518	0.066*
C5	0.0178 (5)	0.7986 (4)	0.66387 (5)	0.0547 (7)
H5A	−0.1345	0.7626	0.6557	0.066*
H5B	0.0242	0.9325	0.6639	0.066*
C6	0.0312 (5)	0.7313 (4)	0.69410 (4)	0.0546 (6)
H6A	0.0217	0.5975	0.6941	0.066*
H6B	0.1845	0.7654	0.7022	0.066*
C7	−0.1609 (5)	0.8068 (4)	0.71254 (5)	0.0551 (7)
H7A	−0.3140	0.7796	0.7038	0.066*
H7B	−0.1450	0.9401	0.7135	0.066*
C8	−0.1575 (4)	0.7304 (4)	0.74246 (5)	0.0533 (6)
H8A	−0.1766	0.5973	0.7416	0.064*
H8B	−0.0035	0.7556	0.7512	0.064*
C9	−0.3481 (5)	0.8094 (4)	0.76097 (5)	0.0545 (6)
H9A	−0.5020	0.7859	0.7521	0.065*
H9B	−0.3274	0.9422	0.7621	0.065*
C10	−0.3468 (5)	0.7308 (4)	0.79062 (5)	0.0551 (6)
H10A	−0.3688	0.5981	0.7894	0.066*
H10B	−0.1923	0.7531	0.7994	0.066*
C11	−0.5350 (5)	0.8100 (4)	0.80937 (5)	0.0571 (7)
H11A	−0.6897	0.7882	0.8006	0.068*
H11B	−0.5126	0.9426	0.8107	0.068*
C12	−0.5327 (5)	0.7293 (4)	0.83902 (5)	0.0582 (7)
H12A	−0.5570	0.5969	0.8377	0.070*
H12B	−0.3773	0.7497	0.8477	0.070*
C13	−0.7195 (6)	0.8103 (4)	0.85805 (5)	0.0695 (8)
H13A	−0.6939	0.9423	0.8597	0.083*
H13B	−0.8751	0.7914	0.8494	0.083*
C14	−0.7163 (8)	0.7261 (5)	0.88719 (6)	0.0968 (13)
H14A	−0.7473	0.5960	0.8858	0.145*
H14B	−0.8363	0.7834	0.8983	0.145*
H14C	−0.5633	0.7454	0.8960	0.145*
Br	0.11566 (4)	0.25148 (4)	0.539455 (6)	0.05787 (12)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0351 (8)	0.0420 (10)	0.0367 (7)	−0.0001 (9)	0.0044 (6)	−0.0015 (9)
C1	0.0342 (9)	0.0552 (13)	0.0374 (9)	0.0033 (11)	0.0061 (7)	−0.0003 (12)
C1N	0.0449 (14)	0.0446 (14)	0.0576 (14)	0.0068 (10)	0.0072 (11)	−0.0033 (11)
C2	0.0514 (13)	0.0638 (17)	0.0395 (10)	0.0078 (13)	0.0052 (9)	0.0054 (12)
C2N	0.0461 (14)	0.0479 (14)	0.0577 (14)	−0.0082 (11)	0.0066 (12)	0.0011 (11)
C3	0.0567 (14)	0.077 (2)	0.0385 (10)	0.0115 (14)	0.0089 (10)	0.0018 (12)
C3N	0.0520 (12)	0.0717 (16)	0.0345 (9)	0.0019 (13)	0.0003 (8)	−0.0029 (12)
C4	0.0544 (13)	0.0714 (19)	0.0403 (10)	0.0049 (13)	0.0096 (9)	0.0038 (12)
C5	0.0585 (14)	0.0676 (18)	0.0385 (10)	0.0060 (13)	0.0097 (10)	0.0016 (11)
C6	0.0572 (14)	0.0652 (18)	0.0418 (10)	0.0047 (13)	0.0098 (10)	0.0021 (12)
C7	0.0598 (14)	0.0652 (18)	0.0408 (11)	0.0020 (13)	0.0088 (10)	−0.0001 (11)
C8	0.0561 (13)	0.0624 (17)	0.0419 (10)	0.0002 (13)	0.0100 (10)	0.0002 (12)
C9	0.0596 (15)	0.0604 (16)	0.0438 (11)	0.0018 (13)	0.0098 (10)	−0.0011 (11)
C10	0.0583 (14)	0.0626 (18)	0.0448 (11)	0.0009 (13)	0.0114 (10)	0.0017 (12)
C11	0.0611 (16)	0.0637 (16)	0.0468 (12)	0.0007 (13)	0.0101 (11)	−0.0020 (11)
C12	0.0689 (16)	0.0603 (18)	0.0458 (11)	−0.0030 (14)	0.0132 (11)	0.0017 (12)
C13	0.081 (2)	0.075 (2)	0.0529 (14)	−0.0059 (16)	0.0223 (14)	−0.0063 (14)
C14	0.137 (3)	0.101 (3)	0.0544 (15)	−0.023 (2)	0.0374 (18)	−0.0028 (18)
Br	0.04412 (17)	0.04799 (18)	0.08176 (19)	0.00047 (13)	0.00778 (12)	0.00093 (16)

Geometric parameters (Å, º)

N1—C1N	1.493 (3)	C6—C7	1.507 (3)
N1—C2N	1.495 (3)	C6—H6A	0.9700
N1—C3N	1.499 (2)	C6—H6B	0.9700
N1—C1	1.508 (2)	C7—C8	1.522 (3)
C1—C2	1.508 (3)	C7—H7A	0.9700
C1—H1A	0.9700	C7—H7B	0.9700
C1—H1B	0.9700	C8—C9	1.513 (3)
C1N—H1N1	0.9600	C8—H8A	0.9700
C1N—H1N2	0.9600	C8—H8B	0.9700
C1N—H1N3	0.9600	C9—C10	1.516 (3)
C2—C3	1.508 (3)	C9—H9A	0.9700
C2—H2A	0.9700	C9—H9B	0.9700
C2—H2B	0.9700	C10—C11	1.510 (3)
C2N—H2N1	0.9600	C10—H10A	0.9700
C2N—H2N2	0.9600	C10—H10B	0.9700
C2N—H2N3	0.9600	C11—C12	1.522 (3)
C3—C4	1.516 (3)	C11—H11A	0.9700
C3—H3A	0.9700	C11—H11B	0.9700
C3—H3B	0.9700	C12—C13	1.518 (4)
C3N—H3N1	0.9600	C12—H12A	0.9700
C3N—H3N2	0.9600	C12—H12B	0.9700
C3N—H3N3	0.9600	C13—C14	1.509 (4)
C4—C5	1.510 (3)	C13—H13A	0.9700
C4—H4A	0.9700	C13—H13B	0.9700
C4—H4B	0.9700	C14—H14A	0.9600
C5—C6	1.513 (3)	C14—H14B	0.9600
C5—H5A	0.9700	C14—H14C	0.9600
C5—H5B	0.9700
C1N—N1—C2N	109.41 (17)	C7—C6—C5	114.2 (2)
C1N—N1—C3N	108.94 (17)	C7—C6—H6A	108.7
C2N—N1—C3N	108.83 (17)	C5—C6—H6A	108.7
C1N—N1—C1	111.68 (17)	C7—C6—H6B	108.7
C2N—N1—C1	111.53 (17)	C5—C6—H6B	108.7
C3N—N1—C1	106.35 (15)	H6A—C6—H6B	107.6
N1—C1—C2	116.71 (17)	C6—C7—C8	114.4 (2)
N1—C1—H1A	108.1	C6—C7—H7A	108.7
C2—C1—H1A	108.1	C8—C7—H7A	108.7
N1—C1—H1B	108.1	C6—C7—H7B	108.7
C2—C1—H1B	108.1	C8—C7—H7B	108.7
H1A—C1—H1B	107.3	H7A—C7—H7B	107.6
N1—C1N—H1N1	109.5	C9—C8—C7	114.0 (2)
N1—C1N—H1N2	109.5	C9—C8—H8A	108.7
H1N1—C1N—H1N2	109.5	C7—C8—H8A	108.7
N1—C1N—H1N3	109.5	C9—C8—H8B	108.7
H1N1—C1N—H1N3	109.5	C7—C8—H8B	108.7
H1N2—C1N—H1N3	109.5	H8A—C8—H8B	107.6
C3—C2—C1	109.47 (19)	C8—C9—C10	113.9 (2)
C3—C2—H2A	109.8	C8—C9—H9A	108.8
C1—C2—H2A	109.8	C10—C9—H9A	108.8
C3—C2—H2B	109.8	C8—C9—H9B	108.8
C1—C2—H2B	109.8	C10—C9—H9B	108.8
H2A—C2—H2B	108.2	H9A—C9—H9B	107.7
N1—C2N—H2N1	109.5	C11—C10—C9	114.4 (2)
N1—C2N—H2N2	109.5	C11—C10—H10A	108.7
H2N1—C2N—H2N2	109.5	C9—C10—H10A	108.7
N1—C2N—H2N3	109.5	C11—C10—H10B	108.7
H2N1—C2N—H2N3	109.5	C9—C10—H10B	108.7
H2N2—C2N—H2N3	109.5	H10A—C10—H10B	107.6
C2—C3—C4	115.5 (2)	C10—C11—C12	113.9 (2)
C2—C3—H3A	108.4	C10—C11—H11A	108.8
C4—C3—H3A	108.4	C12—C11—H11A	108.8
C2—C3—H3B	108.4	C10—C11—H11B	108.8
C4—C3—H3B	108.4	C12—C11—H11B	108.8
H3A—C3—H3B	107.5	H11A—C11—H11B	107.7
N1—C3N—H3N1	109.5	C13—C12—C11	114.0 (2)
N1—C3N—H3N2	109.5	C13—C12—H12A	108.7
H3N1—C3N—H3N2	109.5	C11—C12—H12A	108.7
N1—C3N—H3N3	109.5	C13—C12—H12B	108.7
H3N1—C3N—H3N3	109.5	C11—C12—H12B	108.7
H3N2—C3N—H3N3	109.5	H12A—C12—H12B	107.6
C5—C4—C3	113.5 (2)	C14—C13—C12	113.1 (3)
C5—C4—H4A	108.9	C14—C13—H13A	109.0
C3—C4—H4A	108.9	C12—C13—H13A	109.0
C5—C4—H4B	108.9	C14—C13—H13B	109.0
C3—C4—H4B	108.9	C12—C13—H13B	109.0
H4A—C4—H4B	107.7	H13A—C13—H13B	107.8
C4—C5—C6	114.8 (2)	C13—C14—H14A	109.5
C4—C5—H5A	108.6	C13—C14—H14B	109.5
C6—C5—H5A	108.6	H14A—C14—H14B	109.5
C4—C5—H5B	108.6	C13—C14—H14C	109.5
C6—C5—H5B	108.6	H14A—C14—H14C	109.5
H5A—C5—H5B	107.5	H14B—C14—H14C	109.5
C1N—N1—C1—C2	54.1 (3)	C5—C6—C7—C8	176.4 (2)
C2N—N1—C1—C2	−68.7 (2)	C6—C7—C8—C9	179.0 (2)
C3N—N1—C1—C2	172.8 (2)	C7—C8—C9—C10	179.1 (2)
N1—C1—C2—C3	166.8 (2)	C8—C9—C10—C11	179.5 (2)
C1—C2—C3—C4	170.7 (2)	C9—C10—C11—C12	179.7 (2)
C2—C3—C4—C5	173.6 (2)	C10—C11—C12—C13	179.3 (3)
C3—C4—C5—C6	172.3 (2)	C11—C12—C13—C14	179.1 (3)
C4—C5—C6—C7	179.0 (2)