CH···O and CH···F Links Form the Cage Structure of Dioxane-Trifluoromethane

The molecular beam Fourier transform microwave spectrum of 1,4-dioxane-trifluoromethane has been assigned and measured. The two subunits form a cage stabilized by one C-H···O and two C-H···F weak hydrogen bonds. The C-H···O link involves the axial lone pair of one of the two equivalent ring oxygens, while the two C-H···F bridges connect trifluoromethane to the two axial hydrogens in positions 3 and 5. The dissociation energy has been estimated from the DJ centrifugal distortion parameter to be 6.8 kJ/mol.