trans-1,4-Dimethyl­cyclo­hexane

Bream, R.; Watkin, D.J.

doi:10.1107/S1600536805042273

organic compounds

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ISSN: 2056-9890

Volume 62| Part 2| February 2006| Pages o414-o415

https://doi.org/10.1107/S1600536805042273

trans-1,4-Dimethylcyclohexane

Richard Bream ^a ^* and David J. Watkin ^a

^aChemical Crystallography, Central Chemistry Laboratory, University of Oxford, Oxford OX1 3TA, England
^*Correspondence e-mail: Richard.Bream@pmb.ox.ac.uk

(Received 9 December 2005; accepted 16 December 2005; online 7 January 2006)

trans-1,4-Dimethylcyclohexane, C₈H₁₆, was studied as part of a project to develop a computer-controlled low-temperature crystal-growing device. The liquid crystallizes with the molecule lying on a centre of symmetry, leading to Z′ = $[{1 \over 2}]$ .

Comment

trans-1,4-Dimethylcyclohexane, (I) (Fig. 1), was one of eight alkylcyclohexanes whose thermodynamic properties were published in 1949 (Huffman et al., 1949 ). That work reported a melting point of 236.217 K and showed no evidence for phase changes in the range down to liquid-nitrogen temperatures.

The sample used for the present study was one of several sealed in 0.2 mm Lindeman tubes for preliminary work carried out in 1979. Data had been collected at that time on a Stoe Weissenberg diffractometer and the structure solved, but it was not of a publishable quality (Courseille et al., 1979 ).

The sample solidified spontaneously to a polycrystalline mass on flash cooling to 150 K. The temperature was then raised to 230 K and the sample zone-refined into a single-crystal using tandem computer-controlled heating elements. The temperature was then slowly reduced to 150 K for data collection.

The structure of (I) consists of molecules lying on centres of symmetry. This leads to the packing consisting of columns of molecules lying along the b axis (Fig. 2), with the mean plane of the molecule inclined at 145° to that axis (Fig. 3).

Figure 1
The structure of (I)

, with displacement ellipsoids drawn at the 50% probability level and H atoms shown as spheres of arbitary radii. Unlabelled atoms are related to labelled atoms by a centre of symmetry.

Figure 2
A projection of (I)

along the b axis. The low specific gravity (0.98 Mg m⁻³) is explained by the open texture of the structure.

Figure 3
A projection of (I)

along the c axis, showing the molecular stacks parallel to the b axis.

Experimental

The material was used as supplied by Aldrich Chemical Company Inc. in 1979.

Crystal data

C₈H₁₆
M_r = 112.22
Monoclinic, P 2₁ /c
a = 6.0843 (2) Å
b = 5.4818 (2) Å
c = 11.7629 (5) Å
β = 103.8918 (18)°
V = 380.85 (2) Å³
Z = 2
D_x = 0.978 Mg m⁻³
Mo Kα radiation
Cell parameters from 882 reflections
θ = 1–27°
μ = 0.05 mm⁻¹
T = 150 K
Cylinder, colourless
1.00 (length) × 0.20 mm (diameter)

Data collection

Nonius KappaCCD area-detector diffractometer
ω scans
Absorption correction: multi-scan(DENZO/SCALEPACK; Otwinowski & Minor, 1997 )T_min = 0.758, T_max = 1.000
4141 measured reflections
862 independent reflections
861 reflections with I > 3σ(I)
R_int = 0.027
θ_max = 27.6°
h = −7 → 7
k = −7 → 6
l = −15 → 15

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.044
wR(F²) = 0.091
S = 0.99
861 reflections
13 parameters
H-atom parameters constrained
w = 1/[σ²(F²) + ( 0.03P)² + 0.07P] where P = (max(F_o²,0) + 2F_c²)/3
(Δ/σ)_max < 0.001
Δρ_max = 0.19 e Å⁻³
Δρ_min = −0.17 e Å⁻³

The H atoms were all located in a difference map and then repositioned geometrically. The H atoms were initially refined with soft restraints on the bond lengths and angles to regularize their geometry, with C—H distances in the range 0.93–0.98 Å, and on the displacement parameters, with U_iso(H) = 1.2–1.5 times U_eq of the parent atom, after which their positions were refined with riding constraints.

Data collection: COLLECT (Nonius, 2001 ).; cell refinement: DENZO/SCALEPACK; data reduction: DENZO/SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994 ); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003 ); molecular graphics: CAMERON (Watkin et al., 1996 ); software used to prepare material for publication: CRYSTALS.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536805042273/fl6205sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536805042273/fl6205Isup2.hkl

Computing details top

Data collection: COLLECT (Nonius, 2001).; cell refinement: DENZO/SCALEPACK; data reduction: DENZO/SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: CAMERON (Watkin et al., 1996); software used to prepare material for publication: CRYSTALS.

Trans-1,4 dimethyl cyclohexane top

Crystal data top

C₈H₁₆	D_x = 0.978 Mg m⁻³
M_r = 112.22	Melting point: 236.217 K
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 6.0843 (2) Å	Cell parameters from 882 reflections
b = 5.4818 (2) Å	θ = 1–27°
c = 11.7629 (5) Å	µ = 0.05 mm⁻¹
β = 103.8918 (18)°	T = 150 K
V = 380.85 (2) Å³	Cylinder, colourless
Z = 2	1.00 × 0.20 (radius) mm
F(000) = 128

Data collection top

Nonius KappaCCD area-detector diffractometer	861 reflections with I > 3σ(I)
Graphite monochromator	R_int = 0.027
ω scans	θ_max = 27.6°, θ_min = 3.5°
Absorption correction: multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1997)	h = −7→7
T_min = 0.758, T_max = 1.000	k = −7→6
4141 measured reflections	l = −15→15
862 independent reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.044	H-atom parameters constrained
wR(F²) = 0.091	w = 1/[σ²(F²) + ( 0.03P)² + 0.07P] where P = (max(F_o²,0) + 2F_c²)/3
S = 0.99	(Δ/σ)_max = 0.000356
861 reflections	Δρ_max = 0.19 e Å⁻³
13 parameters	Δρ_min = −0.17 e Å⁻³
0 restraints

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

	x	y	z	U_iso*/U_eq
C1	0.22877 (14)	0.08561 (16)	0.56580 (7)	0.0289
C2	0.13233 (14)	0.14820 (17)	0.43681 (7)	0.0323
C3	0.03582 (15)	0.04284 (17)	0.62583 (8)	0.0331
C4	0.39112 (15)	0.28192 (18)	0.62800 (9)	0.0389
H11	0.3132	−0.0696	0.5701	0.0332*
H21	0.0554	0.3079	0.4325	0.0369*
H22	0.2582	0.1675	0.3975	0.0380*
H31	−0.0450	0.2001	0.6270	0.0402*
H32	0.0987	−0.0087	0.7079	0.0404*
H41	0.4578	0.2351	0.7116	0.0558*
H42	0.3105	0.4379	0.6274	0.0552*
H43	0.5149	0.3077	0.5892	0.0549*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0289	0.0268	0.0303	0.0042	0.0054	0.0008
C2	0.0333	0.0345	0.0302	0.0002	0.0098	0.0043
C3	0.0370	0.0383	0.0243	0.0006	0.0078	−0.0002
C4	0.0356	0.0360	0.0418	−0.0014	0.0028	−0.0019

Geometric parameters (Å, º) top

C1—C2	1.5286 (12)	C2—H22	0.991
C1—C3	1.5264 (12)	C3—H31	0.994
C1—C4	1.5238 (12)	C3—H32	0.990
C1—H11	0.989	C4—H41	1.003
C2—C3ⁱ	1.5246 (12)	C4—H42	0.985
C2—H21	0.988	C4—H43	0.980

C2—C1—C3	109.82 (7)	C1—C3—C2ⁱ	112.54 (7)
C2—C1—C4	111.60 (7)	C1—C3—H31	108.1
C3—C1—C4	111.61 (7)	C2ⁱ—C3—H31	109.0
C2—C1—H11	108.4	C1—C3—H32	109.5
C3—C1—H11	107.0	C2ⁱ—C3—H32	109.4
C4—C1—H11	108.3	H31—C3—H32	108.1
C1—C2—C3ⁱ	112.25 (7)	C1—C4—H41	110.7
C1—C2—H21	108.3	C1—C4—H42	110.2
C3ⁱ—C2—H21	109.2	H41—C4—H42	108.2
C1—C2—H22	109.4	C1—C4—H43	111.1
C3ⁱ—C2—H22	110.6	H41—C4—H43	108.6
H21—C2—H22	106.9	H42—C4—H43	108.0

Symmetry code: (i) −x, −y, −z+1.

References

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