POLYMORPHISM OF INCLUSION COMPLEXES AND UNSOLVATED HOSTS .1. TRIMORPHISM OF THE HOST-GUEST COMPLEX OF GOSSYPOL WITH DICHLOROMETHANE - THE STRUCTURE OF THE BETA-PHASE

The formation of host-guest complexes of gossypol at different tempera tures has been investigated for the same pressure and concentration. G ossypol forms three different clathrates with dichloromethane within t he temperature interval of 22-36 degrees C. Single crystals of these t hree modifications (phases) were obtained and their crystallographic p arameters measured. The structure of the alpha-phase has been determin ed previously and the gamma-phase is isostructural to the inclusion co mplex of gossypol with benzene, while the structure of the beta-phase has been solved during the present research. Crystals of C30H30O8 . CH 2Cl2 are triclinic, space group P (1) over bar, a = 8.604(1), b = 11.8 58(2), c = 14.405(2) (Angstrom), alpha = 84.60(1), beta = 89.14(1), ga mma = 89.73(1)degrees, V = 1463(1) Angstrom(3), Z = 2, R = 0.089 for 2 419 observed reflections. Under ambient conditions gossypol forms unst able tubulates of the alpha-phase; the gamma-phase is a stable cage-ty pe clathrate (cryptate) and the host-guest complex of the beta-phase i s a clathrate of intermediate tubulato-cryptate type.