Two types of supramolecular stereoisomers formed from a wheel -and - axle shaped host molecular 1,1,6,6-tetraphenylhexa - 2,4- diyne -1,6- diol(1) and isopsoralen (2) or anthole (3) were assembled with the host /guest molar ratio being 1:2 and 2:1 respectively. The single crystal structures of the free host and its two inclusion compounds were determined by X ray diffraction analysis. The results show that in the ctystal with host/guest molar ratio being 1:2, the host bound to isopsoralen (2) by bydrogen bond adopts in antiperipanar conformation, while in the 2:1 crystal, the host is in a gauche conformation due ti the hydrogen bonding within the hosts. The observed of crystallization and molecular conformation of the host (1) were found to be primarily dependent on the nature of the guest environment. An antiperipanar conformation of the host(1) is formed in the gust environment with goodH-bond donors, while a guche conformation is favored in a relatively poor H-bond donor guest. The regularity of thre changes in the dihedral angles of phenyl groups, the angles between the groups attached to C (1) and C(6) as ewll as the energy of the host compound in the three ctystals are also presented.

Key words: STEREOISOMERISM, METHYL PHENYL ETHER, X-RAY DIFFRACTION ANALYSIS