Catalytic living ring-opening metathesis polymerization with Grubbs' second- and third-generation catalysts.

In a conventional living ring-opening metathesis polymerization (ROMP), an equal number of ruthenium complexes to the number of polymer chains synthesized are required. This can lead to high loadings of ruthenium complexes when aiming for shorter polymers. Here, a reversible chain-transfer agent was used to produce living ROMP polymers from norbornene derivatives using catalytic amounts of Grubbs' ruthenium complexes.

Towards Polymers with Molecular Auxeticity.

For many decades, it has been challenging to synthesize auxetic materials at the molecular level. Auxetic materials exhibit counterintuitive behavior; they expand perpendicularly to the direction in which they are stretched. An aromatic macrocycle containing a sequence of -substituted and -unsubstituted amides was designed to resemble the re-entrant structure found in macromolecular auxetic materials.