(2E,6E)-2,6-Bis(2,6-dichloro­benzyl­idene)­cyclo­hexa­none

Abstract

The title compound, C₂₀H₁₄Cl₄O, was prepared by the reaction of 2,6-dichloro­benzaldehyde and cyclo­hexa­none. In the mol­ecule, the central cyclo­hexa­none ring adopts an envelope conformation, while the terminal benzene rings make a dihedral angle of 57.87 (9)°.

Related literature  

For background and applications of aryl­idene cyclo­alkanones, see: Deli et al. (1984 ▶); Nakano et al. (1987 ▶); Kawamata et al. (1996 ▶); Dimmock et al. (2003 ▶); Raj et al. (2003 ▶); Gangadhara (1995 ▶). For related structures, see: Yu et al. (2000 ▶); Zhou (2007 ▶).

Experimental  

Crystal data  

• C₂₀H₁₄Cl₄O

• M _r = 412.11

• Orthorhombic,

• a = 17.917 (4) Å

• b = 7.3094 (15) Å

• c = 14.093 (3) Å

• V = 1845.7 (7) ų

• Z = 4

• Mo Kα radiation

• μ = 0.65 mm⁻¹

• T = 120 K

• 0.6 × 0.35 × 0.33 mm

Data collection  

• Stoe IPDS 2T diffractometer

• 13510 measured reflections

• 4946 independent reflections

• 4682 reflections with I > 2σ(I)

• R _int = 0.043

Refinement  

• R[F ² > 2σ(F ²)] = 0.031

• wR(F ²) = 0.071

• S = 1.04

• 4946 reflections

• 226 parameters

• 1 restraint

• H-atom parameters constrained

• Δρ_max = 0.25 e Å⁻³

• Δρ_min = −0.20 e Å⁻³

• Absolute structure: Flack (1983 ▶), 2369 Friedel pairs

• Flack parameter: 0.01 (4)

Data collection: X-AREA (Stoe & Cie, 2005 ▶); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2005 ▶); 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

Supplementary material file. DOI: 10.1107/S1600536812006629/xu5466Isup3.cml

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

supplementary crystallographic information

Comment

Cross-aldol condensation of aromatic aldehydes with cyclic ketones is an important protocol for the synthesis of arylidene cycloalkanones, which are very important precursors to potentially bioactive pyrimidine derivates (Deli et al., 1984), intermediates for agrochemical, pharmaceuticals and perfumes (Nakano et al., 1987), new organic material for nonlinear optical applications (Kawamata et al., 1996), cytotoxic analogous (Dimmock et al., 2003), bis-spiropyrrolidines (Raj et al., 2003) and the units of liquid crystalline polymers (Gangadhara, 1995). Usually, this condensation process is catalyzed by strong acid or base.

In the molecule of the title compound, (Fig. 1), the bond lengths and angles are within normal ranges (Yu et al., 2000; Zhou, 2007). A dihedral angle of 57.87 (9) A is found between the mean planes of the two benzene rings.

Experimental

To a 10 ml solution of KOH (0.11 g) in ethanol at 313 K in a round bottom flask, cyclohexanone (5.0 mmol, 0.50 g) and 2,6-dichlorobenzaldehyde (10 mmol, 1.75 g) was added and the mixture was stirred for 2 min. The resulting product was then isolated by simple filtration from the reaction mixture and given washings with water to remove any trace of KOH remaining on the product. Yellow crystals, yield 97%, 1.98 g, m. p. 455–458 K.

Refinement

All H atoms were positioned geometrically with C–H = 0.93–0.97 Å and constrained to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C).

Figures

Fig. 1.

The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

Crystal data

C20H14Cl4O	F(000) = 840
Mr = 412.11	Dx = 1.483 Mg m−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 4949 reflections
a = 17.917 (4) Å	θ = 2.3–29.2°
b = 7.3094 (15) Å	µ = 0.65 mm−1
c = 14.093 (3) Å	T = 120 K
V = 1845.7 (7) Å3	Needle, yellow
Z = 4	0.6 × 0.35 × 0.33 mm

Data collection

Stoe IPDS 2T diffractometer	4682 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.043
Graphite monochromator	θmax = 29.2°, θmin = 2.3°
rotation method scans	h = −24→24
13510 measured reflections	k = −8→10
4946 independent reflections	l = −19→19

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.031	H-atom parameters constrained
wR(F2) = 0.071	w = 1/[σ2(Fo2) + (0.0318P)2 + 0.5994P] where P = (Fo2 + 2Fc2)/3
S = 1.04	(Δ/σ)max = 0.001
4946 reflections	Δρmax = 0.25 e Å−3
226 parameters	Δρmin = −0.20 e Å−3
1 restraint	Absolute structure: Flack (1983), 2369 Friedel pairs
Primary atom site location: structure-invariant direct methods	Flack parameter: 0.01 (4)

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
Cl1	0.23181 (3)	1.40628 (7)	0.99333 (3)	0.03179 (11)
Cl3	−0.14648 (3)	0.88978 (7)	0.82912 (3)	0.03028 (10)
Cl4	0.05216 (3)	0.35099 (7)	0.89917 (4)	0.03460 (11)
Cl2	0.30403 (3)	0.77001 (7)	1.16748 (4)	0.03902 (13)
C12	0.04419 (9)	0.8310 (2)	0.91901 (11)	0.0196 (3)
O1	0.04467 (7)	0.94480 (19)	1.07669 (9)	0.0237 (3)
C6	0.27374 (10)	1.0891 (2)	1.07795 (12)	0.0211 (3)
C13	0.07918 (9)	0.9234 (2)	1.00226 (12)	0.0185 (3)
C7	0.19499 (9)	1.0268 (2)	1.07289 (12)	0.0199 (3)
H7	0.1686	1.0178	1.1295	0.024*
C9	0.19554 (9)	0.9844 (3)	0.89597 (12)	0.0253 (3)
H9A	0.2490	0.9679	0.9032	0.030*
H9B	0.1872	1.1026	0.8666	0.030*
C15	−0.05043 (9)	0.6110 (2)	0.85940 (12)	0.0209 (3)
C5	0.32884 (10)	0.9818 (3)	1.12039 (12)	0.0252 (4)
C18	−0.11451 (11)	0.3989 (3)	0.71361 (15)	0.0317 (4)
H18	−0.1354	0.3295	0.6651	0.038*
C8	0.15938 (9)	0.9827 (2)	0.99274 (12)	0.0186 (3)
C1	0.29745 (11)	1.2584 (3)	1.04280 (12)	0.0253 (4)
C16	−0.02454 (10)	0.4355 (3)	0.83722 (14)	0.0246 (3)
C10	0.16500 (10)	0.8350 (3)	0.83127 (13)	0.0278 (4)
H10A	0.1873	0.8457	0.7688	0.033*
H10B	0.1777	0.7157	0.8568	0.033*
C19	−0.14239 (10)	0.5721 (3)	0.73292 (14)	0.0281 (4)
H19	−0.1820	0.6191	0.6979	0.034*
C11	0.08055 (10)	0.8530 (3)	0.82365 (12)	0.0260 (4)
H11A	0.0681	0.9721	0.7978	0.031*
H11B	0.0615	0.7605	0.7806	0.031*
C3	0.42366 (10)	1.2027 (3)	1.08876 (13)	0.0318 (4)
H3	0.4733	1.2393	1.0916	0.038*
C14	−0.01489 (9)	0.7245 (2)	0.93404 (12)	0.0211 (3)
H14	−0.0350	0.7210	0.9948	0.025*
C20	−0.11038 (10)	0.6741 (3)	0.80531 (12)	0.0222 (3)
C17	−0.05563 (11)	0.3289 (3)	0.76625 (15)	0.0295 (4)
H17	−0.0373	0.2122	0.7541	0.035*
C4	0.40302 (11)	1.0347 (3)	1.12538 (14)	0.0296 (4)
H4	0.4384	0.9584	1.1530	0.036*
C2	0.37123 (11)	1.3166 (3)	1.04810 (13)	0.0298 (4)
H2	0.3850	1.4306	1.0246	0.036*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Cl1	0.0347 (2)	0.0280 (2)	0.0326 (2)	−0.00606 (18)	−0.00506 (19)	0.0103 (2)
Cl3	0.0346 (2)	0.0290 (2)	0.0272 (2)	0.00852 (18)	−0.00735 (18)	−0.00764 (19)
Cl4	0.0329 (2)	0.0303 (2)	0.0406 (3)	0.00904 (18)	−0.0048 (2)	−0.0030 (2)
Cl2	0.0393 (2)	0.0295 (2)	0.0483 (3)	−0.0027 (2)	−0.0170 (2)	0.0103 (2)
C12	0.0205 (7)	0.0212 (8)	0.0172 (7)	0.0006 (6)	−0.0003 (6)	−0.0023 (6)
O1	0.0229 (6)	0.0316 (7)	0.0167 (5)	−0.0022 (5)	0.0025 (4)	−0.0034 (5)
C6	0.0233 (7)	0.0252 (8)	0.0147 (6)	−0.0025 (6)	−0.0014 (6)	−0.0006 (6)
C13	0.0185 (7)	0.0214 (7)	0.0157 (7)	0.0020 (6)	0.0008 (6)	0.0017 (6)
C7	0.0214 (7)	0.0217 (7)	0.0166 (7)	−0.0015 (6)	−0.0011 (6)	0.0020 (6)
C9	0.0218 (8)	0.0344 (10)	0.0197 (7)	−0.0056 (7)	0.0038 (7)	−0.0032 (8)
C15	0.0188 (7)	0.0219 (8)	0.0219 (7)	−0.0041 (6)	0.0023 (6)	−0.0011 (6)
C5	0.0273 (9)	0.0279 (9)	0.0204 (8)	−0.0009 (7)	−0.0027 (7)	−0.0023 (7)
C18	0.0259 (9)	0.0345 (10)	0.0348 (10)	−0.0081 (8)	0.0025 (7)	−0.0151 (9)
C8	0.0196 (7)	0.0193 (7)	0.0169 (6)	−0.0001 (6)	0.0001 (6)	0.0010 (6)
C1	0.0267 (8)	0.0313 (9)	0.0179 (7)	−0.0039 (7)	−0.0008 (6)	0.0017 (7)
C16	0.0228 (7)	0.0228 (8)	0.0283 (9)	−0.0013 (6)	0.0026 (7)	−0.0026 (7)
C10	0.0276 (8)	0.0360 (10)	0.0197 (7)	−0.0038 (7)	0.0050 (7)	−0.0068 (8)
C19	0.0233 (8)	0.0340 (10)	0.0270 (9)	−0.0018 (7)	−0.0015 (7)	−0.0090 (8)
C11	0.0289 (8)	0.0331 (10)	0.0160 (7)	−0.0077 (7)	0.0011 (7)	−0.0018 (7)
C3	0.0220 (8)	0.0518 (12)	0.0216 (8)	−0.0093 (8)	0.0008 (7)	−0.0069 (8)
C14	0.0212 (7)	0.0233 (8)	0.0187 (7)	−0.0006 (7)	−0.0001 (6)	−0.0014 (6)
C20	0.0217 (8)	0.0232 (8)	0.0216 (8)	−0.0014 (7)	0.0017 (6)	−0.0040 (6)
C17	0.0281 (9)	0.0241 (9)	0.0362 (10)	−0.0048 (7)	0.0066 (8)	−0.0085 (8)
C4	0.0232 (8)	0.0412 (11)	0.0243 (8)	0.0021 (8)	−0.0063 (7)	−0.0062 (8)
C2	0.0299 (9)	0.0386 (10)	0.0210 (8)	−0.0137 (8)	0.0032 (7)	0.0017 (8)

Geometric parameters (Å, º)

Cl1—C1	1.743 (2)	C5—C4	1.386 (3)
Cl3—C20	1.7370 (19)	C18—C17	1.388 (3)
Cl4—C16	1.7414 (19)	C18—C19	1.388 (3)
Cl2—C5	1.742 (2)	C18—H18	0.9300
C12—C14	1.331 (2)	C1—C2	1.391 (3)
C12—C13	1.492 (2)	C16—C17	1.385 (3)
C12—C11	1.502 (2)	C10—C11	1.523 (3)
O1—C13	1.228 (2)	C10—H10A	0.9700
C6—C5	1.396 (3)	C10—H10B	0.9700
C6—C1	1.399 (3)	C19—C20	1.388 (2)
C6—C7	1.484 (2)	C19—H19	0.9300
C13—C8	1.507 (2)	C11—H11A	0.9700
C7—C8	1.337 (2)	C11—H11B	0.9700
C7—H7	0.9300	C3—C2	1.380 (3)
C9—C8	1.510 (2)	C3—C4	1.382 (3)
C9—C10	1.524 (3)	C3—H3	0.9300
C9—H9A	0.9700	C14—H14	0.9300
C9—H9B	0.9700	C17—H17	0.9300
C15—C20	1.396 (2)	C4—H4	0.9300
C15—C16	1.399 (3)	C2—H2	0.9300
C15—C14	1.483 (2)
C14—C12—C13	118.29 (15)	C15—C16—Cl4	118.34 (14)
C14—C12—C11	123.35 (15)	C11—C10—C9	109.69 (15)
C13—C12—C11	118.23 (14)	C11—C10—H10A	109.7
C5—C6—C1	115.73 (17)	C9—C10—H10A	109.7
C5—C6—C7	121.37 (17)	C11—C10—H10B	109.7
C1—C6—C7	122.89 (16)	C9—C10—H10B	109.7
O1—C13—C12	121.19 (15)	H10A—C10—H10B	108.2
O1—C13—C8	121.32 (16)	C18—C19—C20	119.04 (18)
C12—C13—C8	117.45 (14)	C18—C19—H19	120.5
C8—C7—C6	124.63 (15)	C20—C19—H19	120.5
C8—C7—H7	117.7	C12—C11—C10	111.02 (15)
C6—C7—H7	117.7	C12—C11—H11A	109.4
C8—C9—C10	112.35 (15)	C10—C11—H11A	109.4
C8—C9—H9A	109.1	C12—C11—H11B	109.4
C10—C9—H9A	109.1	C10—C11—H11B	109.4
C8—C9—H9B	109.1	H11A—C11—H11B	108.0
C10—C9—H9B	109.1	C2—C3—C4	120.58 (18)
H9A—C9—H9B	107.9	C2—C3—H3	119.7
C20—C15—C16	115.85 (16)	C4—C3—H3	119.7
C20—C15—C14	122.20 (16)	C12—C14—C15	123.77 (15)
C16—C15—C14	121.93 (16)	C12—C14—H14	118.1
C4—C5—C6	122.88 (19)	C15—C14—H14	118.1
C4—C5—Cl2	118.28 (15)	C19—C20—C15	122.83 (18)
C6—C5—Cl2	118.83 (14)	C19—C20—Cl3	118.41 (14)
C17—C18—C19	120.36 (18)	C15—C20—Cl3	118.76 (13)
C17—C18—H18	119.8	C16—C17—C18	118.97 (18)
C19—C18—H18	119.8	C16—C17—H17	120.5
C7—C8—C13	116.69 (15)	C18—C17—H17	120.5
C7—C8—C9	123.82 (15)	C3—C4—C5	119.07 (19)
C13—C8—C9	119.47 (14)	C3—C4—H4	120.5
C2—C1—C6	122.69 (18)	C5—C4—H4	120.5
C2—C1—Cl1	118.25 (16)	C3—C2—C1	119.02 (19)
C6—C1—Cl1	119.03 (14)	C3—C2—H2	120.5
C17—C16—C15	122.94 (18)	C1—C2—H2	120.5
C17—C16—Cl4	118.69 (15)
C14—C12—C13—O1	−20.1 (3)	C14—C15—C16—Cl4	−0.5 (2)
C11—C12—C13—O1	163.96 (17)	C8—C9—C10—C11	55.7 (2)
C14—C12—C13—C8	157.57 (16)	C17—C18—C19—C20	0.2 (3)
C11—C12—C13—C8	−18.4 (2)	C14—C12—C11—C10	−132.96 (18)
C5—C6—C7—C8	−112.5 (2)	C13—C12—C11—C10	42.8 (2)
C1—C6—C7—C8	68.8 (3)	C9—C10—C11—C12	−61.2 (2)
C1—C6—C5—C4	−2.0 (3)	C13—C12—C14—C15	−173.89 (16)
C7—C6—C5—C4	179.24 (17)	C11—C12—C14—C15	1.8 (3)
C1—C6—C5—Cl2	179.18 (13)	C20—C15—C14—C12	−92.9 (2)
C7—C6—C5—Cl2	0.4 (2)	C16—C15—C14—C12	85.4 (2)
C6—C7—C8—C13	−179.65 (16)	C18—C19—C20—C15	0.7 (3)
C6—C7—C8—C9	2.1 (3)	C18—C19—C20—Cl3	−179.49 (15)
O1—C13—C8—C7	12.3 (2)	C16—C15—C20—C19	−0.8 (3)
C12—C13—C8—C7	−165.39 (16)	C14—C15—C20—C19	177.55 (17)
O1—C13—C8—C9	−169.41 (17)	C16—C15—C20—Cl3	179.37 (13)
C12—C13—C8—C9	12.9 (2)	C14—C15—C20—Cl3	−2.3 (2)
C10—C9—C8—C7	146.11 (18)	C15—C16—C17—C18	0.8 (3)
C10—C9—C8—C13	−32.1 (2)	Cl4—C16—C17—C18	−176.99 (15)
C5—C6—C1—C2	0.9 (3)	C19—C18—C17—C16	−0.9 (3)
C7—C6—C1—C2	179.69 (17)	C2—C3—C4—C5	0.2 (3)
C5—C6—C1—Cl1	−177.17 (13)	C6—C5—C4—C3	1.4 (3)
C7—C6—C1—Cl1	1.6 (2)	Cl2—C5—C4—C3	−179.70 (14)
C20—C15—C16—C17	0.1 (3)	C4—C3—C2—C1	−1.2 (3)
C14—C15—C16—C17	−178.32 (17)	C6—C1—C2—C3	0.6 (3)
C20—C15—C16—Cl4	177.86 (13)	Cl1—C1—C2—C3	178.73 (14)