MOLECULAR DYNAMICS IN SUBSTITUTED CUBANES- A JOINT CRYSTALLOGRAPHIC AND SOLID STATE NMR STUDY Alison J. Edwards, Michaele J. Hardie and Frances Separovic School of Chemistry University of Melbourne, Parkville, Vic., Australia; John Tsanaktsidis CSIRO Division of Chemicals and Polymers, Clayton, Vic., Australia

As part of a systematic search for n-fold reorientational dynamics in molecular crystals, a range of halogen substituted cubane compounds I - V (X = Cl, Br or I) are being examined by joint application of solid state Nuclear Magnetic Resonance spectroscopy and X-ray Crystallographic techniques. These compounds were chosen for the wide range of possible symmetry elements about which dynamic behaviour might be observed and for their relative ease of synthesis. Studies of the molecules of type I are furthest advanced and results to date for these dimethyl compounds will form the basis of this presentation.