Acta Cryst. (2009). E65, o729 [ doi:10.1107/S1600536809005844 ]
The title compound, C10H8O2, is a precursor to an unusual bis-homoaromatic dication and to heterodiamantanes and other oxa-cage compounds. Two independent molecules, each of which is situated on a center of symmetry, comprise the unit cell. Both molecules are in nearly identical chair conformations.
The synthesis of the title compound, 4, is described in our previous structure report (Harris et al., 2008). Crystals for data collection were obtained from a chloroform solution.
H atoms were constrained using a riding model. The olefinic C—H bond lengths were fixed at 0.93 Å and the methine C—H bond lengths at 0.98 Å, with Uiso(H) = 1.2 Ueq. (C).
Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
![[Figure 1]](./fl2229fig1thm.gif)
| Fig. 1. View of the two independent molecules of the title compound, 4, with 50% probability displacement ellipsoids. [Symmetry codes: (i) -x, -y + 1, -z + 2; (ii) -x + 1, -y + 2, -z + 1] |
![[Figure 2]](./fl2229fig2thm.gif)
| Fig. 2. The formation of the title compound. |
| C10H8O2 | Z = 2 |
| Mr = 160.16 | F(000) = 168 |
| Triclinic, P1 | Dx = 1.434 Mg m−3 |
| Hall symbol: -P 1 | Cu Kα radiation, λ = 1.54178 Å |
| a = 6.4458 (7) Å | Cell parameters from 24 reflections |
| b = 6.6120 (6) Å | θ = 10.1–44.8° |
| c = 8.9758 (6) Å | µ = 0.82 mm−1 |
| α = 81.671 (8)° | T = 295 K |
| β = 79.176 (10)° | Prism, yellow |
| γ = 84.745 (8)° | 0.3 × 0.2 × 0.2 mm |
| V = 370.96 (6) Å3 |
| Enraf–Nonius CAD-4 diffractometer | θmax = 67.4°, θmin = 5.1° |
| Non–profiled ω/2θ scans | h = −7→7 |
| 2624 measured reflections | k = −7→7 |
| 1329 independent reflections | l = −10→10 |
| 1179 reflections with I > 2σ(I) | 3 standard reflections every 82 reflections |
| Rint = 0.045 | intensity decay: 1% |
| Refinement on F2 | H-atom parameters constrained |
| Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0242P)2 + 0.0776P] where P = (Fo2 + 2Fc2)/3 |
| R[F2 > 2σ(F2)] = 0.037 | (Δ/σ)max < 0.001 |
| wR(F2) = 0.092 | Δρmax = 0.2 e Å−3 |
| S = 1.12 | Δρmin = −0.15 e Å−3 |
| 1329 reflections | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| 110 parameters | Extinction coefficient: 0.115 (5) |
| 0 restraints |
| C10H8O2 | γ = 84.745 (8)° |
| Mr = 160.16 | V = 370.96 (6) Å3 |
| Triclinic, P1 | Z = 2 |
| a = 6.4458 (7) Å | Cu Kα radiation |
| b = 6.6120 (6) Å | µ = 0.82 mm−1 |
| c = 8.9758 (6) Å | T = 295 K |
| α = 81.671 (8)° | 0.3 × 0.2 × 0.2 mm |
| β = 79.176 (10)° |
| Enraf–Nonius CAD-4 diffractometer | Rint = 0.045 |
| 2624 measured reflections | θmax = 67.4° |
| 1329 independent reflections | 3 standard reflections every 82 reflections |
| 1179 reflections with I > 2σ(I) | intensity decay: 1% |
| R[F2 > 2σ(F2)] = 0.037 | H-atom parameters constrained |
| wR(F2) = 0.092 | Δρmax = 0.2 e Å−3 |
| S = 1.12 | Δρmin = −0.15 e Å−3 |
| 1329 reflections | Absolute structure: ? |
| 110 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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. |
| x | y | z | Uiso*/Ueq | ||
| O1 | 0.30420 (16) | 0.67650 (15) | 0.48107 (14) | 0.0495 (3) | |
| O2 | −0.21014 (18) | 0.85668 (16) | 0.94715 (16) | 0.0593 (4) | |
| C5 | 0.5818 (2) | 0.8181 (2) | 0.58171 (17) | 0.0369 (4) | |
| H5 | 0.5912 | 0.6967 | 0.6575 | 0.044* | |
| C10 | −0.2032 (2) | 0.5136 (2) | 1.09484 (17) | 0.0392 (4) | |
| H10 | −0.3204 | 0.556 | 1.173 | 0.047* | |
| C8 | 0.1509 (2) | 0.6126 (2) | 1.13965 (18) | 0.0438 (4) | |
| H8 | 0.1613 | 0.6898 | 1.2164 | 0.053* | |
| C7 | 0.0067 (2) | 0.4394 (2) | 1.15786 (17) | 0.0409 (4) | |
| H7 | −0.0169 | 0.3633 | 1.2611 | 0.049* | |
| C3 | 0.2728 (2) | 1.0665 (2) | 0.67086 (18) | 0.0423 (4) | |
| H3 | 0.1766 | 1.0349 | 0.7606 | 0.051* | |
| C2 | 0.5100 (2) | 1.0222 (2) | 0.65388 (17) | 0.0381 (4) | |
| H2 | 0.566 | 1.0299 | 0.747 | 0.046* | |
| C9 | −0.2602 (2) | 0.3614 (2) | 1.00162 (19) | 0.0427 (4) | |
| H9 | −0.3583 | 0.2631 | 1.0381 | 0.051* | |
| C1 | 0.4297 (2) | 0.8034 (2) | 0.47378 (17) | 0.0362 (4) | |
| C6 | −0.1443 (2) | 0.6803 (2) | 0.96120 (18) | 0.0395 (4) | |
| C4 | 0.7783 (2) | 0.8433 (2) | 0.46039 (19) | 0.0420 (4) | |
| H4 | 0.9153 | 0.8016 | 0.4756 | 0.05* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| O1 | 0.0444 (6) | 0.0450 (6) | 0.0619 (8) | −0.0112 (5) | −0.0102 (5) | −0.0107 (5) |
| O2 | 0.0608 (7) | 0.0390 (6) | 0.0810 (9) | 0.0080 (5) | −0.0283 (6) | −0.0043 (6) |
| C5 | 0.0368 (7) | 0.0364 (7) | 0.0373 (8) | 0.0005 (5) | −0.0110 (6) | −0.0003 (6) |
| C10 | 0.0323 (6) | 0.0466 (8) | 0.0378 (8) | −0.0031 (6) | −0.0034 (5) | −0.0066 (6) |
| C8 | 0.0398 (7) | 0.0495 (8) | 0.0480 (9) | 0.0004 (6) | −0.0172 (7) | −0.0161 (7) |
| C7 | 0.0418 (7) | 0.0494 (8) | 0.0317 (7) | −0.0050 (6) | −0.0099 (6) | 0.0005 (6) |
| C3 | 0.0413 (7) | 0.0427 (8) | 0.0405 (8) | −0.0024 (6) | 0.0024 (6) | −0.0102 (6) |
| C2 | 0.0421 (7) | 0.0429 (8) | 0.0312 (7) | −0.0024 (6) | −0.0106 (6) | −0.0060 (6) |
| C9 | 0.0335 (7) | 0.0417 (8) | 0.0554 (10) | −0.0060 (6) | −0.0128 (6) | −0.0057 (7) |
| C1 | 0.0331 (6) | 0.0369 (7) | 0.0395 (8) | 0.0010 (5) | −0.0063 (6) | −0.0102 (6) |
| C6 | 0.0351 (7) | 0.0397 (8) | 0.0468 (9) | −0.0015 (6) | −0.0169 (6) | −0.0041 (6) |
| C4 | 0.0317 (7) | 0.0420 (8) | 0.0523 (9) | 0.0026 (6) | −0.0083 (6) | −0.0086 (7) |
| O1—C1 | 1.2049 (16) | C8—H8 | 0.93 |
| O2—C6 | 1.2012 (17) | C7—C6i | 1.522 (2) |
| C5—C4 | 1.5116 (19) | C7—H7 | 0.98 |
| C5—C1 | 1.5202 (19) | C3—C4ii | 1.326 (2) |
| C5—C2 | 1.575 (2) | C3—C2 | 1.5129 (19) |
| C5—H5 | 0.98 | C3—H3 | 0.93 |
| C10—C9 | 1.509 (2) | C2—H2 | 0.98 |
| C10—C6 | 1.5232 (19) | C9—H9 | 0.93 |
| C10—C7 | 1.5741 (19) | C1—C2ii | 1.5248 (18) |
| C10—H10 | 0.98 | C6—C7i | 1.522 (2) |
| C8—C9i | 1.326 (2) | C4—H4 | 0.93 |
| C8—C7 | 1.512 (2) | ||
| C4—C5—C1 | 96.67 (11) | C4ii—C3—C2 | 110.37 (12) |
| C4—C5—C2 | 111.33 (11) | C4ii—C3—H3 | 124.8 |
| C1—C5—C2 | 105.88 (10) | C2—C3—H3 | 124.8 |
| C4—C5—H5 | 113.8 | C3—C2—C1ii | 96.61 (10) |
| C1—C5—H5 | 113.8 | C3—C2—C5 | 111.11 (11) |
| C2—C5—H5 | 113.8 | C1ii—C2—C5 | 106.04 (11) |
| C9—C10—C6 | 96.32 (12) | C3—C2—H2 | 113.9 |
| C9—C10—C7 | 111.22 (12) | C1ii—C2—H2 | 113.9 |
| C6—C10—C7 | 106.35 (11) | C5—C2—H2 | 113.9 |
| C9—C10—H10 | 113.8 | C8i—C9—C10 | 110.46 (13) |
| C6—C10—H10 | 113.8 | C8i—C9—H9 | 124.8 |
| C7—C10—H10 | 113.8 | C10—C9—H9 | 124.8 |
| C9i—C8—C7 | 110.14 (14) | O1—C1—C5 | 128.74 (13) |
| C9i—C8—H8 | 124.9 | O1—C1—C2ii | 128.48 (14) |
| C7—C8—H8 | 124.9 | C5—C1—C2ii | 102.57 (11) |
| C8—C7—C6i | 96.36 (11) | O2—C6—C7i | 128.63 (14) |
| C8—C7—C10 | 111.33 (11) | O2—C6—C10 | 128.41 (15) |
| C6i—C7—C10 | 106.49 (12) | C7i—C6—C10 | 102.44 (11) |
| C8—C7—H7 | 113.7 | C3ii—C4—C5 | 110.25 (12) |
| C6i—C7—H7 | 113.7 | C3ii—C4—H4 | 124.9 |
| C10—C7—H7 | 113.7 | C5—C4—H4 | 124.9 |
| Symmetry codes: (i) −x, −y+1, −z+2; (ii) −x+1, −y+2, −z+1. |
Acknowledgement is made to the Donors of the American Chemical Society Petroleum Research Fund for partial support of this research. This work was supported in part by funds provided by The University of North Carolina at Charlotte.
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The polycyclic title compound, dione 4, is formally a dimer of the elusive cyclopentadienone 1. The latter compound has only a fleeting existence and could be trapped in the form of its Diels-Alder adduct 3 (Hafner & Goliasch, 1961) or stabilized as an iron pentacarbonyl complex (Weiss et al., 1960), although derivatives with bulky substituents have been prepared as stable monomers (Dilthey & Quint, 1930; Garbisch & Sprecher, 1966; Saito & Ito, 2008). The title compound 4 is accessible through photoisomerization of Diels-Alder adduct 3, a transformation that has been thoroughly studied (Baggiolini et al., 1967; Klinsmann et al., 1972) since dione 4 – via diol 5 (Amman et al., 1980; Amman & Ganter, 1977; Amman & Ganter, 1981) - is a valuable precursor to an unusual bishomoaromatic dication (Prakash et al., 1987) and to heterodiamantanes and other oxa-cage compounds (Amman et al., 1980; Amman & Ganter, 1977; Amman & Ganter, 1981). We have recently reported the structure of diol derivative 5 (Harris et al., 2008) and herein report the structure of the parent dione 4.
Two independent molecules, each of which is situated on a center of symmetry, comprise the unit cell. Both molecules are in nearly identical "chair" conformations, with a maximum deviation between corresponding bond lengths of 0.01 Å. The molecular packing exhibits several short intermolecular contacts, with the shortest being 0.15 Å less than the sum of the van der Waals radii.
Two related structures have been reported. The first (Eaton et al., 2002) has a chlorine atom in place of each hydrogen atom of the title compound, while the second (Masters et al., 1994) lacks the double bonds of the title compound and has methyl groups on each of the four bridgehead carbon atoms.