Bas G. G. Lohmeijer

The Reaction Mechanism for the Organocatalytic Ring-Opening Polymerization of l-Lactide Using a Guanidine-Based Catalyst: Hydrogen-Bonded or Covalently Bound?

We have investigated two alternative mechanisms for the ring-opening polymerization of l-lactide using a guanidine-based catalyst, the first involving acetyl transfer to the catalyst, and the second involving only hydrogen bonding to the catalyst. Using computational chemistry methods, we show that the hydrogen bonding pathway is considerably preferred over the acetyl transfer pathway and that this is consistent with experimental information.

Stereoselective polymerization of rac- and meso-lactide catalyzed by sterically encumbered N-heterocyclic carbenes

New sterically encumbered N-heterocyclic carbene catalysts were synthesized and used to polymerize rac-lactide to give highly isotactic polylactide or meso-lactide to give heterotactic polylactide.

Block copolymer libraries: modular versatility of the macromolecular Lego® system

The synthesis and characterization of a new 4 x 4 library of block copolymers based on polystyrene and poly(ethylene oxide) connected by an asymmetrical octahedral bis(terpyridine) ruthenium complex at the block junction are described, while initial studies on the thin film morphology of the components of the library are presented by the use of Atomic Force Microscopy, demonstrating the impact of a library approach to derive structure-property relationships.

Chirality amplification in dynamic helical columns in water

Extended core discotic molecules self-assemble in water by different secondary interactions to give well-defined, helical columns in which the chirality of one chiral molecule is transferred to on average 12 achiral molecules.