New strategies in metal-catalyzed living radical polymerization

The renaissance of radical polymerization in recent years was driven by new synthetic strategies, mechanistic studies, and the growing demand for functionalized, well-defined materials for applications ranging from coatings to biomaterials. For precision polymer synthesis, the most used method is “living” polymerization that provides control over the molecular weight, molecular weight distributions, chain end functionality and architecture. Based on application of the metal-catalyzed living radical polymerization (LRP) technique we have identified new classes of universal initiators and developed new synthetic strategies. Investigations of universal initiators indicate that arylsulfonyl bromides, arylsulfonyl iodides, N-Chloro amides, N-Chloro lactams, N-Chloro carbamates, N-Chloro imides and N-Chloro sulfonamides are successfully initiating the metal-catalyzed LRP of commercial monomers including methacrylates, styrenes and acrylates. By combining polymer synthesis with organic transformations, we demonstrated a novel concept, TERMINI, derived from a TERminator Multifunctional INItiator. Combination of highly selective and quantitative organic transformations with metal-catalyzed LRP of commercial monomer methyl methacrylate (MMA) has allowed us to generate dendritic macromolecules. Several modifications of the TERMINI method accelerated the synthesis. New techniques were developed for the construction of dendritic macromolecules with different degrees of compactness and derived from a single monomer. The TERMINI concept gives unprecedented architectural control and access to a panoply of functional materials. Further exploitation of the arylsulfonyl chlorides to initiate LRP of MMA has been investigated in the presence of room temperature ionic liquids (RTIL). Polymerizations catalyzed by self-regulated Cu2O/bpy catalyst has provided a process that combines all the elements of a perfect metal-catalyzed LRP: fast process, moderate temperatures, low catalyst concentrations (5–10%), controlled polymerization (low molecular weight distribution polymer, control of molecular weight and functionality), facile catalyst removal from the polymer, and use of environmentally sound solvent