Structure of an Inclusion Compound of 28,28,35,35-tetramethyl-11-oxo-1,4,18,21-tetraoxa[4,1,4,1,1]paracyclophane with para-xylene

The structure of the 2:3 complex between cyclophane 1 and para-xylene has b een determined by a single crystal X-ray diffraction study at 143 K. One pa ra-xylene molecule is enclosed within the cavity formed by two molecules of the host cyclophane; this ensemble displays crystallographic inversion sym metry. The other independent para-xylene molecule is located on a general p osition in the intermolecular cavities of the crystal lattice. The complex crystallizes in the triclinic space group P(-1) with a = 10.473(4), b = 13. 589(4), c = 16.322(4) Angstrom, alpha = 67.01(3), beta = 89.51(3), gamma = 87.26(2)degrees, and Z = 1. Refinement based on 7539 unique reflections led to a final R(F) value of 0.0609.