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The title compound, C14H14O2, displays approximate twofold symmetry. The six-membered rings shows distortions typical of strained cyclo­phanes, but these effects do not extend to the bridges. The packing is determined by three hydrogen bonds of the type C—H...O.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802015957/bt6190sup1.cif
Contains datablocks 3, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536802015957/bt61903sup2.hkl
Contains datablock 3

CCDC reference: 198334

Key indicators

  • Single-crystal X-ray study
  • T = 173 K
  • Mean [sigma](C-C) = 0.003 Å
  • R factor = 0.038
  • wR factor = 0.088
  • Data-to-parameter ratio = 13.2

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry








Comment top

The title enedione (3) is useful as a starting material in cyclophane chemistry. Having investigated its chemical behaviour and spectroscopic data (Noble et al., 1984a,b), we now describe its crystal structure.

The molecule of (3) (Fig. 1) possesses approximate twofold symmetry, as can be seen from the torsion angles in Table 1. Of the usual features of strained cyclophanes (see e.g. Jones et al., 2002), it shows a flattened boat shape for the six-membered ring (atoms C9 and C12 both lie 0.106 (3) Å out of the plane of C10,C11,C13,C14), with narrow ring angles at C9 and C12. However, bond lengths and angles in the bridges C1—C2 and C7—C8 are normal for sp3 carbons. Contacts involving the bridgehead atoms are C3···C12 2.800 (3) and C6···C9 2.834 (3) Å.

The double bond C4C5 is significantly twisted, with a torsion angle C3—C4—C5—C6 of 167.20 (15)°.

The crystal packing involves three H···O contacts that could be considered as hydrogen bonds (Table 2). These connect the molecules in a three-dimensional network, a section of which is shown in Fig. 2. The hydrogen bond C1—H1···O1 forms rings of graph set R22(10) in the regions z ~0,1, ··· and C8—H8A···O2 rings of the same set in the regions z ~1/2, 3/2, ···; the two hydrogen bonds for which O2 is the acceptor combine to form larger rings R46(18). There are no short contacts of the form C—H···Cg, where Cg is the ring centroid of C10,C11,C13,C14 (Jones et al., 2002); the shortest such contact is H2a···Cg 3.11 Å (C—H normalized to 1.08 Å).

Experimental top

[2](2,5)Furano[2]paracyclophane (1) was treated with bromine in methanol in the presence of potassium acetate to produce the bis-ketal (2), which on hydrolysis with dilute sulfuric acid provided the title compound (3) (Cope & Pawson, 1968; cf. Cram et al., 1966). Single crystals were obtained from ethanol.

Refinement top

Hydrogen atoms were included using a riding model with fixed C—H bond lengths (aromatic 0.95, methylene 0.99 Å); U(H) values were fixed at 1.2 times the U(eq) of the parent atom.

Computing details top

Data collection: P3 (Nicolet, 1987); cell refinement: P3; data reduction: XDISK (Nicolet, 1987); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1994); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The molecule of compound (3) in the crystal. Ellipsoids represent 30% probability levels. H atom radii are arbitrary.
[Figure 2] Fig. 2. Packing of compound (3) in the crystal, viewed parallel to the z axis. Only those H atoms involved in H bonding (dashed bonds) are shown.
(3) top
Crystal data top
C14H14O2F(000) = 456
Mr = 214.25Dx = 1.301 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 11.164 (3) ÅCell parameters from 50 reflections
b = 7.662 (3) Åθ = 10–11.5°
c = 13.063 (4) ŵ = 0.09 mm1
β = 101.84 (3)°T = 173 K
V = 1093.6 (6) Å3Prism, colourless
Z = 40.52 × 0.42 × 0.40 mm
Data collection top
Nicolet R3
diffractometer
Rint = 0.025
Radiation source: fine-focus sealed tubeθmax = 25.0°, θmin = 3.1°
Graphite monochromatorh = 132
ω scansk = 90
2335 measured reflectionsl = 1515
1913 independent reflections3 standard reflections every 147 reflections
1263 reflections with I > 2σ(I) intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.088H-atom parameters constrained
S = 0.89 w = 1/[σ2(Fo2) + (0.0483P)2]
where P = (Fo2 + 2Fc2)/3
1913 reflections(Δ/σ)max < 0.001
145 parametersΔρmax = 0.19 e Å3
0 restraintsΔρmin = 0.15 e Å3
Crystal data top
C14H14O2V = 1093.6 (6) Å3
Mr = 214.25Z = 4
Monoclinic, P21/nMo Kα radiation
a = 11.164 (3) ŵ = 0.09 mm1
b = 7.662 (3) ÅT = 173 K
c = 13.063 (4) Å0.52 × 0.42 × 0.40 mm
β = 101.84 (3)°
Data collection top
Nicolet R3
diffractometer
Rint = 0.025
2335 measured reflections3 standard reflections every 147 reflections
1913 independent reflections intensity decay: none
1263 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.088H-atom parameters constrained
S = 0.89Δρmax = 0.19 e Å3
1913 reflectionsΔρmin = 0.15 e Å3
145 parameters
Special details top

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.

Non-bonded distances:

2.7996 (0.0025) C3 - C12 2.8335 (0.0025) C6 - C9

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

4.8719 (0.0105) x − 5.5652 (0.0046) y + 5.6196 (0.0139) z = 3.8438 (0.0045)

* −0.0021 (0.0009) C10 * 0.0021 (0.0009) C11 * −0.0021 (0.0009) C13 * 0.0021 (0.0009) C14 − 0.1063 (0.0025) C9 − 0.1065 (0.0025) C12

Rms deviation of fitted atoms = 0.0021

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 (Å2) top
xyzUiso*/Ueq
O10.42493 (13)0.27584 (17)0.00371 (10)0.0421 (4)
O20.38876 (13)0.59815 (15)0.33598 (10)0.0400 (4)
C10.68151 (18)0.1319 (2)0.12563 (14)0.0343 (5)
H1A0.65120.03580.07650.041*
H1B0.77210.12760.14200.041*
C20.63780 (18)0.3097 (2)0.07459 (15)0.0336 (5)
H2A0.68580.40530.11440.040*
H2B0.65160.31280.00210.040*
C30.50369 (18)0.3361 (2)0.07330 (14)0.0304 (4)
C40.47128 (17)0.4292 (2)0.16417 (13)0.0281 (4)
H40.52030.52480.19420.034*
C50.37603 (17)0.3825 (2)0.20429 (13)0.0269 (4)
H50.31750.30390.16640.032*
C60.35844 (16)0.4502 (2)0.30735 (14)0.0285 (4)
C70.30701 (17)0.3257 (2)0.37689 (14)0.0325 (5)
H7A0.24730.24700.33290.039*
H7B0.26300.39290.42240.039*
C80.40895 (18)0.2146 (2)0.44610 (14)0.0368 (5)
H8A0.45210.28590.50560.044*
H8B0.37170.11320.47470.044*
C90.49910 (17)0.1518 (2)0.38272 (14)0.0297 (4)
C100.61017 (17)0.2368 (2)0.38916 (14)0.0308 (4)
H100.64080.31000.44730.037*
C110.67682 (17)0.2157 (2)0.31122 (14)0.0319 (5)
H110.75300.27410.31690.038*
C120.63335 (16)0.1098 (2)0.22473 (13)0.0287 (4)
C130.53257 (17)0.0051 (2)0.22694 (14)0.0308 (5)
H130.50870.08120.17450.037*
C140.46627 (17)0.0254 (2)0.30531 (15)0.0326 (5)
H140.39770.04770.30610.039*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0445 (9)0.0480 (8)0.0314 (7)0.0050 (7)0.0020 (7)0.0041 (6)
O20.0546 (10)0.0286 (7)0.0380 (8)0.0011 (7)0.0127 (7)0.0029 (6)
C10.0331 (11)0.0309 (10)0.0396 (11)0.0064 (9)0.0090 (9)0.0015 (8)
C20.0371 (12)0.0323 (10)0.0342 (11)0.0037 (9)0.0137 (9)0.0007 (8)
C30.0382 (12)0.0251 (9)0.0277 (10)0.0031 (9)0.0063 (9)0.0068 (8)
C40.0349 (11)0.0209 (8)0.0273 (10)0.0041 (8)0.0039 (9)0.0035 (7)
C50.0292 (10)0.0246 (8)0.0250 (9)0.0035 (8)0.0013 (8)0.0032 (7)
C60.0257 (10)0.0267 (9)0.0308 (10)0.0064 (8)0.0009 (8)0.0011 (8)
C70.0338 (11)0.0335 (10)0.0310 (10)0.0010 (9)0.0087 (9)0.0018 (8)
C80.0393 (12)0.0401 (10)0.0303 (10)0.0002 (10)0.0060 (9)0.0089 (8)
C90.0320 (11)0.0265 (9)0.0277 (10)0.0024 (8)0.0001 (8)0.0101 (7)
C100.0311 (11)0.0295 (9)0.0278 (10)0.0030 (9)0.0036 (8)0.0024 (8)
C110.0257 (10)0.0279 (9)0.0390 (11)0.0009 (9)0.0003 (9)0.0041 (8)
C120.0273 (11)0.0207 (9)0.0359 (11)0.0067 (8)0.0014 (8)0.0030 (8)
C130.0329 (11)0.0195 (8)0.0369 (11)0.0028 (8)0.0001 (9)0.0002 (7)
C140.0286 (11)0.0234 (9)0.0428 (11)0.0016 (8)0.0008 (9)0.0099 (8)
Geometric parameters (Å, º) top
O1—C31.218 (2)C7—H7A0.9900
O2—C61.219 (2)C7—H7B0.9900
C1—C121.510 (2)C8—C91.507 (2)
C1—C21.551 (2)C8—H8A0.9900
C1—H1A0.9900C8—H8B0.9900
C1—H1B0.9900C9—C101.388 (2)
C2—C31.507 (3)C9—C141.394 (2)
C2—H2A0.9900C10—C111.388 (3)
C2—H2B0.9900C10—H100.9500
C3—C41.492 (2)C11—C121.395 (2)
C4—C51.327 (2)C11—H110.9500
C4—H40.9500C12—C131.387 (2)
C5—C61.493 (2)C13—C141.390 (3)
C5—H50.9500C13—H130.9500
C6—C71.510 (2)C14—H140.9500
C7—C81.554 (3)
C12—C1—C2109.33 (14)C6—C7—H7B109.2
C12—C1—H1A109.8C8—C7—H7B109.2
C2—C1—H1A109.8H7A—C7—H7B107.9
C12—C1—H1B109.8C9—C8—C7110.32 (15)
C2—C1—H1B109.8C9—C8—H8A109.6
H1A—C1—H1B108.3C7—C8—H8A109.6
C3—C2—C1110.29 (15)C9—C8—H8B109.6
C3—C2—H2A109.6C7—C8—H8B109.6
C1—C2—H2A109.6H8A—C8—H8B108.1
C3—C2—H2B109.6C10—C9—C14117.95 (18)
C1—C2—H2B109.6C10—C9—C8120.38 (16)
H2A—C2—H2B108.1C14—C9—C8120.98 (17)
O1—C3—C4121.27 (18)C9—C10—C11120.50 (17)
O1—C3—C2121.37 (17)C9—C10—H10119.7
C4—C3—C2117.25 (17)C11—C10—H10119.7
C5—C4—C3122.02 (17)C10—C11—C12120.80 (17)
C5—C4—H4119.0C10—C11—H11119.6
C3—C4—H4119.0C12—C11—H11119.6
C4—C5—C6121.78 (17)C13—C12—C11117.95 (17)
C4—C5—H5119.1C13—C12—C1121.04 (16)
C6—C5—H5119.1C11—C12—C1120.24 (17)
O2—C6—C5121.33 (16)C12—C13—C14120.48 (17)
O2—C6—C7121.25 (16)C12—C13—H13119.8
C5—C6—C7117.36 (15)C14—C13—H13119.8
C6—C7—C8111.87 (15)C13—C14—C9120.80 (17)
C6—C7—H7A109.2C13—C14—H14119.6
C8—C7—H7A109.2C9—C14—H14119.6
C12—C1—C2—C345.7 (2)C14—C9—C10—C119.7 (3)
C1—C2—C3—O184.5 (2)C8—C9—C10—C11160.82 (16)
C1—C2—C3—C491.75 (18)C9—C10—C11—C120.4 (3)
O1—C3—C4—C534.6 (3)C10—C11—C12—C1310.2 (3)
C2—C3—C4—C5141.63 (17)C10—C11—C12—C1159.87 (16)
C3—C4—C5—C6167.20 (15)C2—C1—C12—C13101.53 (19)
C4—C5—C6—O234.6 (3)C2—C1—C12—C1168.2 (2)
C4—C5—C6—C7142.65 (17)C11—C12—C13—C149.7 (2)
O2—C6—C7—C891.0 (2)C1—C12—C13—C14160.22 (16)
C5—C6—C7—C886.32 (19)C12—C13—C14—C90.4 (3)
C6—C7—C8—C942.9 (2)C10—C9—C14—C1310.1 (2)
C7—C8—C9—C10100.1 (2)C8—C9—C14—C13160.34 (16)
C7—C8—C9—C1470.2 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···O1i0.992.673.633 (3)163
C7—H7A···O2ii0.992.663.613 (3)161
C8—H8A···O2iii0.992.593.553 (3)164
Symmetry codes: (i) x+1, y, z; (ii) x+1/2, y1/2, z+1/2; (iii) x+1, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC14H14O2
Mr214.25
Crystal system, space groupMonoclinic, P21/n
Temperature (K)173
a, b, c (Å)11.164 (3), 7.662 (3), 13.063 (4)
β (°) 101.84 (3)
V3)1093.6 (6)
Z4
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.52 × 0.42 × 0.40
Data collection
DiffractometerNicolet R3
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
2335, 1913, 1263
Rint0.025
(sin θ/λ)max1)0.594
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.088, 0.89
No. of reflections1913
No. of parameters145
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.19, 0.15

Computer programs: P3 (Nicolet, 1987), P3, XDISK (Nicolet, 1987), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), XP (Siemens, 1994), SHELXL97.

Selected geometric parameters (Å, º) top
C1—C21.551 (2)C7—C81.554 (3)
C4—C51.327 (2)
C12—C1—C2109.33 (14)C10—C9—C14117.95 (18)
C9—C8—C7110.32 (15)C13—C12—C11117.95 (17)
C12—C1—C2—C345.7 (2)C5—C6—C7—C886.32 (19)
C1—C2—C3—C491.75 (18)C6—C7—C8—C942.9 (2)
C2—C3—C4—C5141.63 (17)C7—C8—C9—C10100.1 (2)
C3—C4—C5—C6167.20 (15)C2—C1—C12—C13101.53 (19)
C4—C5—C6—C7142.65 (17)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···O1i0.992.673.633 (3)163.1
C7—H7A···O2ii0.992.663.613 (3)160.5
C8—H8A···O2iii0.992.593.553 (3)163.5
Symmetry codes: (i) x+1, y, z; (ii) x+1/2, y1/2, z+1/2; (iii) x+1, y+1, z+1.
 

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