Design of inclusion compounds: systematic structural modification of the hexa-host molecule hexakis(benzylthiomethyl)benzene

Abstract

A study of the inclusion behaviour of the title compound (I) and eleven structurally related compounds (II)–(XII) is described. Substitution of each of the six outer aromatic rings of (I) with a single methyl group gives new hosts, the most general of which is the meta-analogue (III). A parallel situation is found for the hexachloro-compounds (X)–(XII) where inclusion is again favoured by meta-substitution. The versatile host (VII) favours inclusion of o-xylene from an equimolar mixture of o- and p-xylene, in contrast to host (III) which selectively includes the para-isomer. A detailed X-ray study of the 1,4-dioxan adduct of the parent (I) has been carried out. The crystals are monoclinic, space group P2₁/c, with a= 10.542, b= 20.863, c= 12.496 Å, β= 95.48°, and 2 host and 2 guest molecules in the unit cell. A true clathrate structure is found, the chair-shaped dioxan guest molecules being accommodated in effectively closed cages.