Medium-Ring Compounds 30. cis-1,6-Cyclodecanediol: Molecular Compounds with the trans Isomer and with Itself |
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| Authors: | Otto Ermer Beverly R Vincent Jack D Dunitz |
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| Affiliation: | 1. Organic Chemistry Laboratory, Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092 Zürich, Switzerland;2. Organic Chemistry Laboratory, Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092 Zürich, Switzerland
Holder of an NSERC postdoctoral fellowship (1988). |
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| Abstract: | The crystal structures of cis-1,6-cyclodecanediol ( 1 ) and of the molecular compound formed between cis and trans-1,6-cyclodecanediol in the ratio 2:1 (2) have been established by X-ray diffraction. The two substances are closely isostructural. (Crystal data: both monoclinic, P21/c, Z = 6; ( 1 ) a = 6.665(6), b = 18.074(3), c = 14.351(8) Å, β = 119.77(6)°, V = 1500(2) Å3; (2) a = 6.679(8), b = 18.074(4), c = 14.314(10) Å, β = 119.64(8)°, V = 1502(3) Å3). The asymmetric unit of the molecular compound contains one cis molecule in a general position and one trans molecule at a center of symmetry. In the crystal of the pure cis diol a set of disordered cis molecules mimics the corresponding centrosymmetric trans molecules in the molecular compound. The molecules have the stable BCB cyclodecane ring conformation, except for the disordered cis molecules, which have a conformation about 2 kJ mol−1 higher in energy (molecular mechanics calculations). The intricate three-dimensional hydrogen-bond network found in both crystals is presumably especially favorable from an energetic viewpoint. |
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