Molecular and solid state structure of 4,4'-bis(tetrahydrothiopyranyl)

Single crystal X-ray diffraction reveals that 4,4′- bis(tetrahydrothiopyranyl) crystallizes in an equatorial-equatorial geometry with a gauche conformation along the central carbon-carbon bond. B3LYP/6-311G^** and MP2/6-311G^** calculations show that the antiperiplanar conformation is higher in energy than the gauche one because of sulfur induced stretching and widening of the cyclohexane-like rings. Calculations at various levels of theory suggest that in the antiperiplanar region the twisting coordinate of 4,4′- bis(tetrahydrothiopyranyl) exhibits a very shallow double-well potential. The gauche molecular structure of 4,4′-bis(tetrahydrothiopyranyl) thwarts efficient packing of its molecules in the solid state.