TOPOLOGY AND MOLECULAR CHEMISTRY - SYNTHESIS, TOPOGRAPHY AND STABILITY OF A [2]-ROTAXANE DERIVED FROM A LIPOPHILIC CYCLODEXTRIN DERIVATIVE

The Menschutkin reaction of ,7-triphenylheptyloxy)-benzyl]-4,4'-bipyri dinium)- bromide 6, complexed in heptakis (2,6-di-O-butyl-3-O-acetyl)- beta-cyclodextrin 2b, with 4-(7,7,7-triphenylheptyloxy)-benzyl bromide 5 afforded a stable [2]-rotaxane, {[2]-[heptakis trin]-[1,1-bis(4-(7, 7,7-triphenylheptyloxy)-benzyl rotaxane)-4,4'-bipyridinium]-rotaxane} bis(bromide) 3b of up to 50% (36% isolated) yield. The influence of th e solvent polarity and the ring size of the cyclodextrin derivative wa s investigated. The topography of the [2]-rotaxane was studied by circ ular dichroism, H-1, H-1 NOE and C-13 NMR spectroscopy. It was shown t hat the cyclodextrin ring is mainly covering only one half of the inte rnal part of the dumb-bell. The orientations of the rings at the dumb- bells were found to be uniform.