Alkyl initiated ring opening polymerization of lactide by indium complexes supported by NCN pincer ligands.

Indium-alkyl NCN pincer complexes supported by amine and imine donors are active catalysts for the ring opening polymerization of lactide. The amine indium complexes are significantly more active for polymerization due to the decoordination of the amine donors at higher temperatures. Solid state structures of the imine and amine indium complexes indicate that the imine-indium bonds are stronger than the analogous amine-indium bonds.

Synthesis of High-Molecular-Weight Poly(ether--ester) by Selective Double Ring-Opening Polymerization of Spiroorthoesters.

We report the selective double ring-opening polymerization of presequenced spiroorthoester monomers to form high-molecular-weight (≈90 kDa) poly(ether--ester)s with a simple cationic alkyl gallium catalyst. The selective formation of double ring-opened polymer units was confirmed by NMR and IR spectroscopies. Thermal and rheological properties of homo- and copolymers were further characterized by differential scanning calorimetry, thermogravimetric analysis, and stress-controlled rotational rheometry.

Cooperative Initiation in a Dinuclear Indium Complex for CO Epoxide Copolymerization.

Dinuclear indium complexes have been synthesized and characterized. These include neutral and cationic indium complexes supported by a Schiff base ligand bearing a binaphthol linker. The new compounds were investigated for alternating copolymerization of CO and cyclohexene oxide.

Impact of counterion valency on the rheology of sulfonated cellulose nanocrystal hydrogels.

A systematic rheological study on the influence of valency of different counterions on the properties of CNC hydrogels was carried out. Rheo-polarized microscopy was used to prove that preshear of 500 s for 1 min is adequate to completely breakdown agglomerates in the suspension. Furthermore, a rest period of 30 min is sufficient to recover the equilibrium structure of hydrogels.

Thermally stable zinc hydride catalyst for hydrosilylation of CO to silyl formate at atmospheric pressure.

Neutral zinc complexes supported by H[PNNO], a diaminophenolate ligand bearing a pendant phosphine group, were synthesized and characterized. The phosphine arm adopts two different configurations in solution and prevents aggregation. The monomeric zinc hydride complex is stable at elevated temperatures up to 125 °C and reacts readily with CO to afford a zinc formate complex.