STRUCTURE AND REACTIVITY OF HOST-GUEST INCLUSION COMPOUNDS. Anita Coetzee, Mino R. Caira and Luigi R. Nassimbeni, Department of Chemistry, University of Cape Town, Rondebosch, 7700,South Africa, Edwin Weber and Andreas Wierig, Institut fur Organische Chemie, Technische Universitat Bergakademie Freiberg, Leipziger Strasse 29 D-09596 Freiberg, Germany

The reactivity of a host-guest system can often be related to the crystallographic structure of the host-guest inclusion compound. The rate of guest uptake or release is of interest in the study of inclusion compounds between solid hosts and volatile guest molecules. Guest molecules are most commonly either entrapped in cavities formed by the host compound, or along channels, running through the host network. Molecules which contain the fluorene moiety have proved to be successful hosts, capable of forming inclusion compounds with a wide variety of guests^l. Inclusion compounds of 2,2'-bis (9-hydroxy-9-fluorenyl) biphenyl have been studied extensively². Substituting the fluorene moieties at the 2- and 7-positions with bulky groups such as halogens or p-tert-butyl, also yields successful compounds, which are often stabilised by hydrogen bonding between host and guest. The structures of the inclusion compounds of related host molecules with acetone have been elucidated and the kinetics of desolvation have been studied, using isothermal thermogravimetry.

1. I. Csöregh, E. Weber, L. R. Nassimbeni, O. Gallardo, N. Dörpinghaus, A. Ertan and S. A. Bourne, J. Chem. Soc., Perkin Trans. 2, 1993, 1775.

2. L. J. Barbour, S. A. Bourne, M. R. Caira, L. R. Nassimbeni, E. Weber, K. Skobridis and A. Wierig, Supramolecular Chem, 1993, 1, 331.