New host architecture of hydroquinone with enclathrated C70

Abstract

The room-temperature crystal structure of a molecular 1:4.5:1 complex of C[sub 70], hydroquinone (HQ), and benzene (bz), C[sub 70](HQ)[sub 4.5]bz, is reported. The solid-state architecture of the donor-acceptor complex has trigonal symmetry and consists of a novel H-bonded superoctahedral HQ host network with three different types of cavities enclathrating the C[sub 70] and bz guest molecules. Giant HQ twin cages shaped according to the shell of a peanut house a pair of C[sub 70] molecules, large single cages accommodate one C[sub 70] guest, and smaller HQ cages of tetrahedral shape embrace a sandwich pair of bz molecules. The long axes of the C[sub 70] guest molecules are orthogonal to the trigonal crystal and cage axes. Their HQ host cages may be viewed as expanded supercubes and related to the simple supercube cavities of the sister complex C[sub 60](HQ)[sub 3] reported previously. A topological analogy exists between the tetrahedral HQ cages and the supertetrahedral building blocks of the pyrochlore network. The HQ host network of C[sub 70](HQ)[sub 4.5]bz is essentially ordered, and the C[sub 70] and bz guest species are orientationally disordered. The adopted benzene guest model is provisional only and requires further backing. 8 refs., 4 figs., 1 tab.