Polymorphism of Crystalline Inclusion Complexes and Unsolvated Hosts. Part 8. ? Endocyclic Modification of the Cyclotriveratrylene Host-Guest Complex with Acetone

Crystallization of cyclotriveratrylene (CTV) from solutions in acetone at 40 Cg ave a new 4 : 1 host-guest complex instead of the conventional 2 : 1 clathrate (-phase) whose X-ray crystal structure was determined. Data for 2(C27H30O6) 0.5(CO(CH3)2): monoclinic, P21/c, a = 18.942(4),b = 24.697(5),c = 10.508(2) A, = 91.10(2), V = 4915(2) A 3 ,Z=8 , Dx = 1.257 g/cm 3 , T = 293 K, R = 0.077 (for 2694 reflections). One of the two crystallographically independent CTV molecules (molecule A) is stacked into columns characteristic of the CTV -o r-phase complexes. Molecules B face each other enclathrating inside around the inversion center disordered acetone molecules giving rise to the molecular capsule. The acetone molecule is H-bonded simultaneously to both host molecules by C(H2)-H O type bonds forming centrosymmetric dimers. Dimers are incorporated together with two A molecules into centrosymmetric units also by C(H2)-H O type H-bonds. Packing of these units gives rise to the crystal structure of the clathrate.