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The crystal structures of bicyclo[3.3.1]nonane-2,6-dione and bicyclo[3.3.1]­non­ane-3,7-dione have been solved by direct methods and by direct-space simulated annealing, respectively, from powder synchrotron X-ray diffraction data. Both compounds have a transition to a face-centred-cubic orientationally disordered phase (phase I) near 363 K, as shown by differential scanning calorimetry and powder diffraction measurements. Phase II of bicyclo[3.3.1]nonane-2,6-dione, which occurs below 363 K, is monoclinic, space group C2/c, with a = 7.38042 (4), b = 10.38220 (5), c = 9.75092 (5) Å and β = 95.359 (1)° at 80 K. Phase II of bicyclo[3.3.1]nonane-3,7-dione, which occurs below 365 K, is tetragonal, space group P41212, with a = 6.8558 (1) and c = 16.9375 (1) Å at 100 K. This phase coexists in a biphasic mixture with a minor monoclinic phase II′ [a = 11.450 (6), b = 20.583 (1), c = 6.3779 (3) Å, β = 94.7555 (5)°, at 100 K] detected in the sample, which impeded indexing with standard programs. The crystal structures of phases II were solved by direct methods and by direct-space simulated annealing, employing powder synchrotron X-ray diffraction data of increased instrumental intensity and resolution from the ID31 beamline at the ESRF, and novel indexing algorithms. Ab initio molecular orbital calculations on the two systems are reported. In the solid state, the molecules pack in chair–chair conformation; molecular structures and packing are discussed.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889807028087/he5379sup1.cif
Contains datablocks Structure, refine

pdf

Portable Document Format (PDF) file https://doi.org/10.1107/S0021889807028087/he5379sup2.pdf
Supplementary material

Computing details top

Figures top
[Figure 1]
[Figure 2]
[Figure 3]
[Figure 4]
[Figure 5]
[Figure 6]
[Figure 7]
[Figure 8]
[Figure 9]
[Figure 10]
(Structure) top
Crystal data top
O8C40H48α = 90°
Mr = 656.81β = 90°
?, P41212γ = 90°
Hall symbol: P_4abw_2nwV = ? Å3
a = 6.8558 ÅZ = ?
b = 6.8558 Å? radiation, λ = ? Å
c = 16.9375 Å × × mm
Data collection top
h = ??l = ??
k = ??
Refinement top
Crystal data top
O8C40H48β = 90°
Mr = 656.81γ = 90°
?, P41212V = ? Å3
a = 6.8558 ÅZ = ?
b = 6.8558 Å? radiation, λ = ? Å
c = 16.9375 Å × × mm
α = 90°
Data collection top
Refinement top
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.55050.15700.3279?
C10.46790.30450.3115?
C20.32700.49970.1951?
C30.31690.31190.2450?
C40.49320.49000.3605?
C50.32530.67830.2500?
H10.19940.50290.1578?
H20.17540.30330.2728?
H30.33330.18230.2095?
H40.39570.47660.4103?
H50.63980.49160.3837?
H60.19370.73630.2760?
(refine) top
Crystal data top
O8C34H48α = 90°
Mr = 584.75β = 95.359°
?, C2/cγ = 90°
Hall symbol: -C_2ycV = ? Å3
a = 7.3803 ÅZ = ?
b = 10.3820 Å? radiation, λ = ? Å
c = 9.7508 Å × × mm
Data collection top
h = ??l = ??
k = ??
Refinement top
Crystal data top
O8C34H48β = 95.359°
Mr = 584.75γ = 90°
?, C2/cV = ? Å3
a = 7.3803 ÅZ = ?
b = 10.3820 Å? radiation, λ = ? Å
c = 9.7508 Å × × mm
α = 90°
Data collection top
Refinement top
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
O10.59430.13520.05220.00732*
C10.42950.24040.14270.00732*
C20.57750.15150.07140.00732*
C30.69620.07970.16600.00732*
C40.73550.15820.29680.00732*
C50.50000.32870.25000.00732*0.500
H10.37710.29660.06170.00732*
H20.63290.01140.19310.00732*
H30.82050.05580.10520.00732*
H40.79310.09450.36920.00732*
H50.83630.23120.26900.00732*
H60.38980.38530.29830.00732*

Experimental details

(Structure)(refine)
Crystal data
Chemical formulaO8C40H48O8C34H48
Mr656.81584.75
Crystal system, space group?, P41212?, C2/c
Temperature (K)??
a, b, c (Å)6.8558, 6.8558, 16.93757.3803, 10.3820, 9.7508
α, β, γ (°)90, 90, 9090, 95.359, 90
V3)??
Z??
Radiation type?, λ = ? Å?, λ = ? Å
µ (mm1)??
Crystal size (mm) × × × ×
Data collection
Diffractometer??
Absorption correction??
No. of measured, independent and
observed (?) reflections
?, ?, ? ?, ?, ?
Rint??
Refinement
R[F2 > 2σ(F2)], wR(F2), S ?, ?, ? ?, ?, ?
No. of reflections??
No. of parameters??
No. of restraints??
Δρmax, Δρmin (e Å3)?, ??, ?

 

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