Alteration of cage geometry by systematic structural modification of a clathrate host molecule

Abstract

A study of compounds structurally related to the versatile host compound, 4-p-hydroxyphenyl-2,2,4-trimethyl-thiachroman (I) is described. The compounds (II)–(IV) which possess an additional methyl group at the 6-, 7-, or 8-position of (I) have been synthesised and found to exhibit an interesting spectrum of behaviour. The previously described 7-methyl analogue (III) forms spontaneously-resolved unsolvated crystals while (II) and (IV) are new hosts. A single-crystal X-ray investigation of the trigonal crystals of the cyclo-octane clathrate of the 8-methyl analogue (IV), space group R, a= 33.629(9), c= 8.239(3), and Z= 18 (host), has established the formation of a fundamentally new cage-shape. Compound (V) has also been synthesised in the present study, as have analogues (VII) and (VIII) of the host Dianin's compound (VI), but in these three cases no inclusion behaviour has been found.