Poly(2-oxazoline)s with pendant cubane groups

The effect of cubane side chains on polymer properties is rarely explored. Here, the synthesis of a 2-oxazoline monomer having a cubane moiety in the 2-position is reported. Cationic ring-opening polymerization gives the corresponding poly(2-oxazoline). However, homopolymerization only yields oligomeric species that were found to be insoluble in a wide range of solvents. Soluble polymers are obtained by copolymerization of the cubane containing monomer with 2-ethyl-2-oxazoline. The resulting copolymers show thermoresponsive behaviour in aqueous solution with a cloud point temperature that varies with copolymer composition. The methyl ester functionality of the cubane containing monomer can be used for side-chain modifications via a direct amidation post-polymerization modification reaction