Download citation
Download citation
link to html
The title compound, C10H4Cl8O2, is a poly­chloro-substituted tricyclic diene, comprised of a norbornene section with a cis-endo cyclo­pentene fused to it. This strained ring system has been described before, but not with the two hydroxyl substituents found here. It was synthesized as a possible precursor to homocubane or cubane cage systems, but conditions for a cage closure reaction have not yet been found.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802006992/cf6170sup1.cif
Contains datablocks global, 2

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536802006992/cf61702sup2.hkl
Contains datablock 2

CCDC reference: 185800

Key indicators

  • Single-crystal X-ray study
  • T = 98 K
  • Mean [sigma](C-C) = 0.002 Å
  • Disorder in main residue
  • R factor = 0.026
  • wR factor = 0.064
  • Data-to-parameter ratio = 18.6

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Amber Alert Alert Level B:
CELLV_02 Alert B The supplied cell volume s.u. differs from that calculated from the cell parameter s.u.'s by > 4 Calculated cell volume su = 7.01 Cell volume su given = 13.00 General Notes
FORMU_01 There is a discrepancy between the atom counts in the _chemical_formula_sum and the formula from the _atom_site* data. Atom count from _chemical_formula_sum:C10 H4 Cl8 O2 Atom count from the _atom_site data: C10.115 H4.345 Cl7.885 O2.115 CELLZ_01 From the CIF: _cell_formula_units_Z 4 From the CIF: _chemical_formula_sum C10 H4 Cl8 O2 TEST: Compare cell contents of formula and atom_site data atom Z*formula cif sites diff C 40.00 40.46 -0.46 H 16.00 17.38 -1.38 Cl 32.00 31.54 0.46 O 8.00 8.46 -0.46 Difference between formula and atom_site contents detected. ALERT: Large difference may be due to a symmetry error - see SYMMG tests
0 Alert Level A = Potentially serious problem
1 Alert Level B = Potential problem
0 Alert Level C = Please check

Comment top

The three-dimensional structure of a polycyclic organic compound is often difficult to prove, even qualitatively, with only NMR evidence. If the compound is a perhalo derivative, or nearly so, the task is made even more difficult because there are few or no 1H NMR signals. Several misassignments of this type of structure were recently corrected by crystallographic analyses (Eaton et al., 2001, 2002). The title compound, (2), is one of several new polyhalo compounds discovered in a study by Tang (2002) of the reactions of halogenated cyclopentadiene dimers and cages.

The title compound is made by reducing a dione, (1), with LiAlH4 in anhydrous ether at room temperature. The molecular structure of the title compound, (2), is presented in Fig. 1. A compound with exactly the same ring system, stereochemistry, and chloro-substitution pattern (but different oxygen functionalities) has been reported (Galesic et al., 1985), and the internal structural details reported for it are a close match to those seen here for (2). The following indications of strain are present in both molecules. The C—C bonds between sp3 C atoms are elongated (average distance 1.571 Å), ranging from 1.540 (2) to 1.595 (2) Å. Bond angles as small as 92.9, 97.5, and 98.1° are seen at sp3 C atoms in the vicinity of the bridge atom C10, and intra-ring bond angles of 107.2 and 108.0° are seen at the sp2 atoms C8 and C9, where the unstrained expected value would be 120°. All of these anomalies are primarily attributable to the strain encountered in closing unsaturated five-membered rings. There are also short non-bonded intramolecular cross-cavity distances: C5···C8 = 2.81, C3···C9 = 3.01, and O3···C9 = 2.88 Å. Each of these is less than the corresponding van der Waals distances (C···C 3.40 Å and C···O 3.22 Å; Rowland & Taylor, 1996) by more than 0.3 Å.

A probable impurity was indicated by two anomalous difference map peaks. The title compound refined to give an R of 0.032 for 3014 Fo > 4σ(Fo), a good final value, but two peaks in the difference map were about twice as large as other random features. Their sizes were 1.1 and 1.25 e Å-3, values less than usually seen for carbon atoms, but greater than seen for the H atoms. These two peaks were incompatible with Cl5, as they bracketed Cl5 closely. One difference peak was about 1 Å from C5 and the other about 1.7 Å from the first one. This did not strongly suggest any group, but it was deemed likely that the massive chlorine presence might be distorting their locations.

The two peaks were assigned carbon identities and refined with partial occupancies equal to one minus the occupancy of Cl5. After refinement, the two bond distances in the impurity group were each about 1.35 Å, the occupancy was about 10%, and the isotropic displacement parameter now favored the identification of the inner peak as an O atom. This geometry was still unusual for a methoxy group, but somewhat improved. A search of the Cambridge Structural Database (CSD; Version 5.22 of October 2001, using Conquest 1.3; Allen et al., 1987; Allen & Kennard, 1993) for 1-chloro-2-methoxycyclopentenes revealed five hits. The bond-distance averages from this search indicated expected values of 1.355 Å for the ring–oxygen distance, 1.411 Å for the oxygen–methyl distance, and 2.382 Å for the non-bonded distance from the ring to the methyl C atom. Using these values as targets, the methoxy group was restrained to fit them to within 0.005 Å. This refinement reduced R to 0.026 and indicated an impurity occupation of 12%. Fig. 2 compares the locations of the methoxy impurity and Cl5, by showing them simultaneously on the same C atom.

The precursor sample, (1), was made several decades ago at the University of Chicago, probably from a dimethoxyperhalocyclopentadiene. In the course of the Diels–Alder dimerization to form (1), a methoxy migration is mechanistically possible, leading to the possibility that a methoxy-tainted precursor was used to make the title compound. Recrystallization often removes such impurities, so a small sample of (2) was recystallized from 2-butanone/n-octane, and the X-ray analysis was repeated. There was no significant difference in the appearance of the difference map, or in the refined impurity occupancy. There is enough room for an occasional methoxy in the crystal lattice with little intermolecular crowding. However, the methoxy group is close to a center of symmetry, and serious collisions would preclude the simultaneous presence of its centrosymmetrically related equivalent. At the occupancy level seen, this would not be a problem.

Fig. 3 illustrates the packing of (2). The crystal contains strong O—H···O hydrogen bonds and somewhat longer O—H···Cl hydrogen bonds, which link the molecules together in two-dimensional layers perpendicular to the b axis. These layers are corrugated, not flat, with just a few Cl···Cl close approaches. The shortest of these, Cl4···Cl9, at 3.26 Å, is significantly less than the Cl···Cl van der Waals distance (3.5 Å; Rowland & Taylor, 1996).

Experimental top

A solution of dione (1) (718 mg, 1.71 mmol) in anhydrous ether (15 ml) was added dropwise to a solution of LiAlH4 (163 mg, 4.29 mmol) in anhydrous ether (10 ml) at room temperature. The solution was stirred for 1 h and than slowly poured into ice water. The phases were separated and the aqueous layer was extracted with ether (2 × 20 ml). The combined organic layers were dried over MgSO4 and filtered. Removal of solvent in vacuo and column chromatography (CH2Cl2–hexanes, 3:1) afforded the title compound (2) (645 mg, 89%) as a white crystalline solid. A crystal sample (fine colorless plates) for X-ray analysis was obtained by crystallization from hot n-pentane.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SMART; data reduction: SHELXTL (Sheldrick, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXTL (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. View of the title compound with 50% probability ellipsoids.
[Figure 2] Fig. 2. A view of the title compound showing the location of the impurity (12% occupancy) methoxyl group on C5 that was indicated by two significant difference map peaks and subsequent refinement.
[Figure 3] Fig. 3. A view of the packing of the title compound, seen down the b axis. For clarity, only half the unit-cell contents (0 < y < 1/2) are shown. An identical, but inverted, layer occurs in the other half of the cell. All of the hydrogen bonds occurring in this crystal structure are used to link together layers such as the one shown here.
1,2,4,5,6,7,8,9-octachlorotricyclo[5.2.1.02,6]deca-4,8-diene-3,10-diol top
Crystal data top
C10H4Cl8O2Dx = 1.987 Mg m3
Mr = 439.73Melting point: >240C K
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 8.323 (2) ÅCell parameters from 7940 reflections
b = 16.967 (5) Åθ = 2.3–28.3°
c = 10.411 (3) ŵ = 1.53 mm1
β = 91.31 (2)°T = 98 K
V = 1469.7 (13) Å3Irregular chunk, colorless
Z = 40.44 × 0.29 × 0.09 mm
F(000) = 864
Data collection top
Bruker CCD area-detector
diffractometer
3575 independent reflections
Radiation source: fine-focus sealed tube3014 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.040
ϕ and ω scansθmax = 28.3°, θmin = 2.3°
Absorption correction: integration
(Wuensch & Prewitt, 1965)
h = 1110
Tmin = 0.617, Tmax = 0.825k = 2221
11732 measured reflectionsl = 1313
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: structure-invariant direct methods
R[F2 > 2σ(F2)] = 0.026Hydrogen site location: difference Fourier map
wR(F2) = 0.064H-atom parameters constrained
S = 1.01 w = 1/[σ2(Fo2) + (0.0328P)2 + 0.0735P]
where P = (Fo2 + 2Fc2)/3
3575 reflections(Δ/σ)max < 0.001
192 parametersΔρmax = 0.48 e Å3
3 restraintsΔρmin = 0.32 e Å3
Crystal data top
C10H4Cl8O2V = 1469.7 (13) Å3
Mr = 439.73Z = 4
Monoclinic, P21/nMo Kα radiation
a = 8.323 (2) ŵ = 1.53 mm1
b = 16.967 (5) ÅT = 98 K
c = 10.411 (3) Å0.44 × 0.29 × 0.09 mm
β = 91.31 (2)°
Data collection top
Bruker CCD area-detector
diffractometer
3575 independent reflections
Absorption correction: integration
(Wuensch & Prewitt, 1965)
3014 reflections with I > 2σ(I)
Tmin = 0.617, Tmax = 0.825Rint = 0.040
11732 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0263 restraints
wR(F2) = 0.064H-atom parameters constrained
S = 1.01Δρmax = 0.48 e Å3
3575 reflectionsΔρmin = 0.32 e Å3
192 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.

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 > 2σ(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*/UeqOcc. (<1)
C10.5158 (2)0.16437 (10)0.38102 (16)0.0140 (3)
Cl10.70779 (5)0.20011 (3)0.42141 (4)0.01986 (11)
C20.4239 (2)0.21053 (10)0.27008 (17)0.0144 (3)
Cl20.45082 (5)0.31380 (3)0.29058 (4)0.02063 (11)
C30.4687 (2)0.18841 (11)0.12999 (17)0.0167 (4)
H30.47030.23740.07660.020*
O30.61744 (15)0.14998 (8)0.12129 (12)0.0204 (3)
H3A0.68350.18000.08620.031*
C40.3304 (2)0.13737 (10)0.08535 (17)0.0172 (4)
Cl40.33981 (6)0.08962 (3)0.05841 (4)0.02607 (12)
C50.2077 (2)0.13717 (10)0.16470 (17)0.0162 (4)
Cl50.02625 (7)0.09073 (4)0.13879 (6)0.0207 (2)0.885 (3)
O5M0.0517 (8)0.1154 (9)0.1582 (15)0.030 (5)*0.115 (3)
C5M0.0081 (19)0.0531 (10)0.0745 (18)0.040 (5)*0.115 (3)
H5A0.10760.04320.07960.060*0.115 (3)
H5B0.06740.00540.09950.060*0.115 (3)
H5C0.03420.06750.01380.060*0.115 (3)
C60.2440 (2)0.18066 (10)0.28725 (16)0.0140 (3)
Cl60.09911 (5)0.25682 (3)0.30924 (4)0.01856 (11)
C70.2607 (2)0.12493 (11)0.40896 (16)0.0141 (3)
Cl70.08070 (5)0.10266 (3)0.48585 (4)0.01924 (11)
C80.3574 (2)0.05353 (10)0.36683 (16)0.0141 (3)
Cl80.27801 (5)0.03716 (3)0.33544 (4)0.01949 (11)
C90.5089 (2)0.07636 (10)0.35249 (16)0.0138 (3)
Cl90.66962 (5)0.01975 (3)0.31588 (4)0.01750 (10)
C100.3924 (2)0.16515 (10)0.49216 (17)0.0150 (4)
H100.42890.12980.56400.018*
O100.34762 (15)0.23895 (7)0.53908 (12)0.0192 (3)
H10A0.41610.25430.59410.029*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0121 (8)0.0135 (9)0.0162 (9)0.0004 (7)0.0023 (6)0.0005 (6)
Cl10.0140 (2)0.0192 (2)0.0261 (2)0.00254 (17)0.00400 (17)0.00151 (17)
C20.0145 (8)0.0120 (8)0.0166 (9)0.0005 (7)0.0004 (7)0.0010 (6)
Cl20.0231 (2)0.0127 (2)0.0260 (2)0.00090 (17)0.00203 (18)0.00153 (17)
C30.0161 (9)0.0164 (9)0.0176 (9)0.0019 (7)0.0009 (7)0.0025 (7)
O30.0150 (6)0.0227 (7)0.0238 (7)0.0017 (5)0.0053 (5)0.0037 (5)
C40.0225 (10)0.0155 (9)0.0135 (9)0.0019 (7)0.0018 (7)0.0005 (7)
Cl40.0305 (3)0.0305 (3)0.0173 (2)0.0013 (2)0.00119 (19)0.00738 (18)
C50.0172 (9)0.0143 (9)0.0169 (9)0.0003 (7)0.0046 (7)0.0012 (7)
Cl50.0164 (3)0.0228 (4)0.0226 (3)0.0043 (2)0.0050 (2)0.0002 (2)
C60.0129 (8)0.0145 (9)0.0146 (8)0.0026 (7)0.0005 (6)0.0014 (6)
Cl60.0171 (2)0.0195 (2)0.0190 (2)0.00605 (17)0.00047 (16)0.00090 (16)
C70.0123 (8)0.0165 (9)0.0135 (8)0.0006 (7)0.0007 (6)0.0013 (6)
Cl70.0145 (2)0.0234 (2)0.0200 (2)0.00035 (17)0.00379 (16)0.00355 (17)
C80.0175 (9)0.0114 (8)0.0134 (8)0.0007 (7)0.0017 (7)0.0009 (6)
Cl80.0208 (2)0.0145 (2)0.0231 (2)0.00349 (17)0.00181 (17)0.00075 (17)
C90.0156 (8)0.0143 (9)0.0115 (8)0.0041 (7)0.0010 (6)0.0007 (6)
Cl90.0169 (2)0.0170 (2)0.0187 (2)0.00429 (17)0.00210 (16)0.00023 (16)
C100.0159 (9)0.0140 (9)0.0151 (9)0.0032 (7)0.0004 (7)0.0005 (6)
O100.0198 (7)0.0185 (7)0.0191 (7)0.0029 (5)0.0043 (5)0.0075 (5)
Geometric parameters (Å, º) top
C1—C91.523 (2)O5M—C5M1.412 (5)
C1—C101.565 (2)C5M—H5A0.980
C1—C21.579 (2)C5M—H5B0.980
C1—Cl11.7511 (17)C5M—H5C0.980
C2—C31.559 (2)C6—C71.585 (2)
C2—C61.595 (2)C6—Cl61.7855 (17)
C2—Cl21.7787 (18)C7—C81.524 (2)
C3—O31.404 (2)C7—C101.540 (2)
C3—C41.505 (3)C7—Cl71.7560 (17)
C3—H31.000C8—C91.331 (2)
O3—H3A0.840C8—Cl81.7032 (17)
C4—C51.328 (2)C9—Cl91.6971 (17)
C4—Cl41.7052 (18)C10—O101.398 (2)
C5—O5M1.350 (5)C10—H101.000
C5—C61.499 (2)O10—H10A0.840
C5—Cl51.7192 (19)
C9—C1—C1097.47 (13)O5M—C5M—H5B109.5
C9—C1—C2109.16 (14)H5A—C5M—H5B109.5
C10—C1—C2102.78 (13)O5M—C5M—H5C109.5
C9—C1—Cl1114.61 (12)H5A—C5M—H5C109.5
C10—C1—Cl1115.49 (12)H5B—C5M—H5C109.5
C2—C1—Cl1115.35 (12)C5—C6—C7113.54 (14)
C3—C2—C1116.26 (14)C5—C6—C2103.43 (13)
C3—C2—C6105.88 (14)C7—C6—C2102.33 (13)
C1—C2—C6101.59 (13)C5—C6—Cl6110.01 (12)
C3—C2—Cl2108.49 (12)C7—C6—Cl6112.13 (11)
C1—C2—Cl2110.07 (12)C2—C6—Cl6115.01 (12)
C6—C2—Cl2114.57 (12)C8—C7—C1098.09 (13)
O3—C3—C4112.46 (14)C8—C7—C6106.36 (13)
O3—C3—C2113.71 (14)C10—C7—C6103.52 (14)
C4—C3—C2103.28 (13)C8—C7—Cl7114.93 (12)
O3—C3—H3109.1C10—C7—Cl7116.26 (12)
C4—C3—H3109.1C6—C7—Cl7115.62 (12)
C2—C3—H3109.1C9—C8—C7107.97 (15)
C3—O3—H3A109.5C9—C8—Cl8127.28 (14)
C5—C4—C3113.75 (16)C7—C8—Cl8124.64 (13)
C5—C4—Cl4126.59 (15)C8—C9—C1107.16 (14)
C3—C4—Cl4119.61 (13)C8—C9—Cl9127.89 (14)
C4—C5—O5M136.2 (6)C1—C9—Cl9124.90 (13)
C4—C5—C6112.68 (16)O10—C10—C7113.67 (14)
O5M—C5—C6110.6 (6)O10—C10—C1116.79 (14)
C4—C5—Cl5126.07 (15)C7—C10—C192.93 (13)
O5M—C5—Cl513.2 (5)O10—C10—H10110.8
C6—C5—Cl5121.22 (13)C7—C10—H10110.8
C5—O5M—C5M118.0 (8)C1—C10—H10110.8
O5M—C5M—H5A109.5C10—O10—H10A109.5
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3A···O10i0.842.012.8334 (17)168
O10—H10A···Cl6ii0.842.693.4680 (14)156
Symmetry codes: (i) x+1/2, y+1/2, z1/2; (ii) x+1/2, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC10H4Cl8O2
Mr439.73
Crystal system, space groupMonoclinic, P21/n
Temperature (K)98
a, b, c (Å)8.323 (2), 16.967 (5), 10.411 (3)
β (°) 91.31 (2)
V3)1469.7 (13)
Z4
Radiation typeMo Kα
µ (mm1)1.53
Crystal size (mm)0.44 × 0.29 × 0.09
Data collection
DiffractometerBruker CCD area-detector
diffractometer
Absorption correctionIntegration
(Wuensch & Prewitt, 1965)
Tmin, Tmax0.617, 0.825
No. of measured, independent and
observed [I > 2σ(I)] reflections
11732, 3575, 3014
Rint0.040
(sin θ/λ)max1)0.667
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.026, 0.064, 1.01
No. of reflections3575
No. of parameters192
No. of restraints3
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.48, 0.32

Computer programs: SMART (Bruker, 2001), SMART, SHELXTL (Sheldrick, 1997), SHELXS97 (Sheldrick, 1990), SHELXTL.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3A···O10i0.842.012.8334 (17)168
O10—H10A···Cl6ii0.842.693.4680 (14)156
Symmetry codes: (i) x+1/2, y+1/2, z1/2; (ii) x+1/2, y+1/2, z+1/2.
 

Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds