p-(allyloxy)phenyl]per-O-methyl-beta-cyclodextrin, prepared from beta-
cyclodextrin (CD) by a five-step process, has two isomeric forms, Form
A has the two p-(allyloxy)phenyl substituents directed away from the
CD cavity, while form B is a rotoxane with one p-(allyloxy)phenyl grou
p in the CD cavity. CD-hexasiloxane copolymers were prepared by treati
ng each form with 1,1,3,3,5,5,7,7,9,9,11,11-dodecamethylhexasiloxane (
with Si-H functions on each end) using a platinum catalyst. These copo
lymeric stationary phases were coated on fused silica capillary column
s and found to separate enantiomeric solutes in gas chromatography (GC
). The copolymer prepared from form A separated both enantiomeric hydr
ocarbons and polar solutes, Rotoxane copolymer prepared from form B se
parated only polar solutes. Since form B copolymer is a rotoxane with
the benzene part of the copolymer in the cavity, these results show th
at an open CD cavity is necessary for interaction and enantiomeric res
olution of nonpolar hydrocarbons; however, polar solutes interact effe
ctively with the polar CD rim or exterior surface.