2,6-Bis(2,4-dimethyl­benzyl­idene)cyclo­hexa­none

Katarzyna A Solanko; Andrew D Bond

doi:10.1107/S1600536810018684

. 2010 May 22;66(Pt 6):o1435. doi: 10.1107/S1600536810018684

2,6-Bis(2,4-dimethylbenzylidene)cyclohexanone

Katarzyna A Solanko ^a, Andrew D Bond ^a,^*

PMCID: PMC2979581 PMID: 21579510

Abstract

In the crystal structure of the title compound, C₂₄H₆O, the molecule exhibits point symmetry m but the mirror plane is not utilized as part of the space-group symmetry. The structure contains face-to-face interactions between the 2,4-dimethylbenzylidene substituents in which the methyl groups lie directly above the centroids of adjacent benzene rings.

Related literature

For related structures, see: Guo et al. (2008 ▶); Jia et al. (1989 ▶); Liu (2009 ▶); Ompraba et al. (2003 ▶); Shi et al. (2008 ▶); Zhang et al. (2005 ▶); Zhou (2007 ▶). For quantification of the molecular point symmetry, see: Pilati & Forni (1998 ▶, 2000 ▶).

Experimental

Crystal data

C₂₄H₂₆O
M _r = 330.45
Monoclinic,
a = 6.9784 (4) Å
b = 19.2540 (12) Å
c = 14.2829 (10) Å
β = 102.179 (3)°
V = 1875.9 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 120 K
0.60 × 0.20 × 0.20 mm

Data collection

Bruker–Nonius X8 APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2003 ▶) T _min = 0.895, T _max = 0.986
32106 measured reflections
3565 independent reflections
2399 reflections with I > 2σ(I)
R _int = 0.042

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.113
S = 1.08
3565 reflections
230 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2003 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810018684/jh2159sup1.cif

e-66-o1435-sup1.cif^{(27.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810018684/jh2159Isup2.hkl

e-66-o1435-Isup2.hkl^{(174.8KB, hkl)}

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

Table 1. C—H⋯π interactions (Å, °).

Cg1 and Cg2 are the centroids of the C21–C26 and C11–C16 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C17—H17B⋯Cg1ⁱ	0.98	3.00	3.532 (1)	154
C17—H17C⋯Cg1ⁱⁱ	0.98	2.62	3.469 (1)	111
C27—H27B⋯Cg2ⁱⁱⁱ	0.98	2.64	3.486 (1)	145
C27—H27C⋯Cg2^iv	0.98	2.80	3.510 (1)	130

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

We are grateful to the Danish Natural Sciences Research Council for funding (grant No. 272-08-0237).

supplementary crystallographic information

Comment

We were interested in the crystal structure of 2,6-bis(2,4-dichlorobenzylidene)cyclohexanone (Guo et al., 2008) because we have found that it exhibits a relatively large change in structure on cooling from room temperature to 100 K (Solanko & Bond, unpublished results). We synthesised the analogous tetra-methyl-substituted compound to examine whether it might form a similar structure and display similar behaviour. It does not.

We note that in the publication of Guo et al. (2008), the chloro compound is stated to be synthesised by reaction of 2,4-dichlorobenzophenone with cyclohexanone. It seems likely that this should be 2,4-dichlorobenzaldehyde with cyclohexanone, as described here in the Experimental section.

The molecular point symmetry m referred to in the Abstract was quantified using the program SYMMOL (Pilati & Forni, 1998, 2000): the rms deviation of the molecule from its m symmetrised counterpart is 0.055 Å.

Experimental

2,4-Dimethylbenzaldehyde (2.8 ml, 0.02 mol), cyclohexanone (1.0 ml, 0.01 mol) and 30% NaOH(aq) (1 ml) were stirred in ethanol (3 ml) at room temperature for 6 h. The yellow product was filtered and washed using EtOH (3 × 2 ml). Crystals were obtained by slow evaporation from acetone under ambient conditions.