Free-Radical Polymerization and Ring-Expansion of a Cubane Acrylate: a Unique Low-Shrink Polymer

Abstract

A pendant cubane substituent has been incorporated into an acrylate polymer side chain to give poly[methyl 4-(acryloyloxymethyl)cubane carboxylate]. Treating this polymer with a rhodium(i) salt triggers a catalytic, ring-opening rearrangement of the cubane substructure to cyclooctatetraene, with a concomitant expansion in molecular volume. This system offers a unique opportunity to reverse the shrinkage associated with polymerization.