CRYSTAL INCLUSION OF OLIGOCYCLIC ANHYDRIDES CONTAINING 9,10-DIHYDRO-9,10-ETHANOANTHRACENE CONSTRUCTIONAL UNITS - CRYSTAL-STRUCTURE OF A BENZENE CLATHRATE

A series of rigid oligocyclic anhydrides comprising a characteristic 9,10-dihydro-9,10-ethanoanthracene framework have been shown to form crystalline inclusion compounds (clathrates) with small organic molecules, in particular of five- and six-membered ring types. Inclusion formation depends on the number of substituents (bromine atoms). The X-ray crystal structure of the clathrate 4 . benzene (2:1) is reported: monoclinic (P2(1)/c), a=8.599(4), b=9.732(5), c=21.023(10) angstrom, beta=92.03(4)-degrees, Z=4. The benzene guest molecules are located in lattice cavities between the bulky host molecules around the crystallographic symmetry centres, and are somewhat disordered. The cocrystal is held together by weak van der Waals forces. The structural model refined to R=0.046 for 1903 reflections with I>3sigma(I).