Journal of Polymer Science Part A: Polymer Chemistry, Vol.40, No.22, 4038-4044, 2002
Synthesis of optically active alicyclic polyimides from a chiral, nonracemic dianhydride
Optically active alicyclic polyimides were prepared for the first time from (-)-[1S*,5R*,6S*]-3-oxabicyclo[3.2.1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione) [(-)-DAn] via polycondensation with diamines and subsequent chemical or thermal imidization. The dianhydride (-)-DAn was synthesized by an asymmetric Diels-Alder reaction of a chiral itaconic acid derivative as a key step. Colorless or slightly yellow flexible films were obtained for the (-)-DAn-derived polyimides {PI[(-)DAn]s}. PI[(-)-DAn]s showed good solubility toward dipolar aprotic solvents and pyridine. For 1,4-dioxane and chloroform, the optically active polyimides showed slightly better solubility than the corresponding polyimides prepared from rac-DAn [PI(racDAn)s]. PI[(-)-DAn]s showed glass-transition temperatures of 267-268 degreesC and 10% weight-loss temperatures of 416-424 degreesC in nitrogen. These values were almost identical to those of PI(rac-DAn)s. The circular dichroism spectra of PI[(-)-DAn]s showed exciton coupling patterns indicating that to some extent these polyimides had a higher order structure in solution.