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The interconverting stereoisomers of tri-o-thymotide have been separated by HPLC on chiral stationary phases and the temperature dependence of the dynamic chromatographic patterns has been interpreted in terms of exchange between enantiomeric propeller and helical conformations. Computed low energy structures and CD spectra were used in absolute configuration assignment.

1,7,13-Trimethyl-4,10,16-tris(1-methylethyl)-6H,12H,18H-tribenzo[b,f, j][1,5,9 ]trioxacyclododecin-6,12,18-trione-3-buten-2-ol (2/1), C₃₃H₃₆0₆.½C₄H₈O, Mr = 564.70, trigonal, P3₁21, a = 13.444(3), c = 30.217(9)Å, V = 4730(1)ų, Z = 6, Dx = 1.190 g cm⁻³, λ(Mo Kα) = 0.71069 Å, μ = 0.875 cm⁻¹, F(000) = 1812, T = 153 K, R = 0.068 for 1657 observed reflections at the |Fo| > 3σ(Fo) level. The host structure was refined starting from previously determined coordinates in an isomorphous tri-o-thymotide (TOT) clathrate. A strained conformation of the guest, derived from a calculated two-dimensional energy map, was favourably used as rigid component in the X-ray model. Evidence for low chiral discrimination of the guest was quantitatively demonstrated. Correlation of configuration between TOT in a single crystal and the major included enantiomer was shown to obey previously established structural rules. Lattice- energy calculations corroborate the experimental observations.