A Dinuclear Mechanism Implicated in Controlled Carbene Polymerization

Highly controlled immortal polymerization of β-butyrolactone by a dinuclear indium catalyst.

An ethoxy-bridged dinuclear indium catalyst was used for the ring opening polymerization of the cyclic ester β-butyrolactone to form the biodegradable polyester poly(hydroxybutyrate) (PHB). The catalyst shows remarkable activity and control during polymerization, allowing for formation of diblock polymers. Addition of high ratios of alcohols to the catalyst leads to fast chain transfer and immo...

Methacrylate polymerization using a dinuclear zirconocene initiator: a new approach for the controlled synthesis of methacrylate polymers.

Mechanism of immunoglobulin A polymerization.

Employing mercaptoethylamine as a reducing agent, it was demonstrated by analytical ultracentrifugation and polyacrylamide gel electrophoresis that polymeric immunoglobulin A (IgA) was reduced to a 10 S dimer and 7 S monomer, and that dimer IgA was more resistant to reductive cleavage than the higher polymers. When dimer and monomer IgA were subjected to electrophoresis in polyacrylamide gels i...

Stereospecific carbene polymerization with oxygenated Rh(diene) species.

Polymers bearing polar functionalities are important materials, since they exhibit beneficial properties with respect to adhesion, paint/printability and surface properties. Commercial synthesis of these materials is mainly based on radical processes, which (so far) only allow poor control over the stereochemistry of the resulting polymers. 2 ] Stereo-controlled polymerisation generally require...

Probing intermetallic coupling in dinuclear N-heterocyclic carbene ruthenium(II) complexes.

A series of bimetallic N-heterocyclic carbene (NHC) ruthenium(II) complexes were synthesized, which comprise two [RuCl(2)(cymene)(NHC)] units that are interlinked via the NHC nitrogens by alkyl chains of different length. Electrochemical characterization revealed two mutually dependent oxidation processes for the complex with a methylene linker, indicating moderate intramolecular electronic cou...