6(A),6(B)-BETA-CYCLODEXTRIN HEXASILOXANE COPOLYMERS - ENANTIOMERIC SEPARATIONS BY A BETA-CYCLODEXTRIN-CONTAINING ROTOXANE COPOLYMER

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.