CYCLIC POLYESTERS .2. TOPOLOGICAL TRAPPING EXPERIMENTS AND THEORETICAL-STUDIES

A topological trapping method was employed to confirm the cyclic natur e of the polyester, which was prepared in part 1 using a polymer-suppo rted reagent. It was found that approximately equal amounts of cyclic polyesters and cyclic poly(dimethylsiloxane)s (PDMS) (with comparable molar masses) could be entrapped in PDMS networks. By contrast, under similar conditions, far smaller quantities of a linear polyester were entrapped. The 'sizes' and 'shapes' of cyclic polyesters were compared with those of cyclic PDMS using a rotational isomeric state model (RI SM). Molecular modelling using Quanta and CHARMm programs showed that cyclic polyesters adopted approximately circular conformations when th ey were subject to energy minimization.