NMR study of molecular motions in some clathrate hydrates.

An N.M.R. study of the clathrate hydrates of SF₆, C₃H₆ and (CH₃)₂CO has been carried out to examine the type of motion a guest molecule undergoes in the clathrated cavity. ¹⁹F nuclear magnetic resonance spectra of Sulphur Hexafluoride Hydrate and Deuterate show isotropic rotation or reorientation about an axis at random of the SF₆molecule. ¹H magnetic resonance spectra of Cyclopropane Deuterate show highly restricted rotation up to 240°K, and then free rotation about C₃-axis at high temperatures. ¹H magnetic resonance spectra of Acetone Deuterate show that the CH₃-group is rotating even at 77°K, and self diffusion occurs at 172°K. The barrier hindering diffusion of the (CH₃)₂CO has been calculated and is 3.9 kcal/mole.Science, Faculty ofChemistry, Department ofGraduat