Zirconium and Hafnium Complexes Bearing Tridentate ONN-Ligands: Extremely High Activity toward Ethylene (Co)Polymerization.

The pursuit of high-performance catalysts in the realm of polyolefins is a constant goal. In this study, a range of zirconium (, , , ) and hafnium (, ) complexes featuring phenoxy-imine-amine ONN-ligands (2,6-R-CH-NH-CH-N═CH-CH-3,5-Bu-OH; : R = H; : R = F; : R = Pr) were synthesized and characterized using NMR spectroscopy, as well as single-crystal X-ray diffraction for , , and . These Zr and Hf complexes exhibited remarkable efficiency for ethylene homopolymerization and copolymerization with 1-octene when paired with MAO as the cocatalyst.

Dual-responsive pegylated polypeptoids with tunable cloud point temperatures.

A series of pegylated polypeptoids have been readily synthesized by a strategy combining ring-opening polymerization (ROP) and thiol-yne photoaddition. The polypeptoids simultaneously incorporated branched oligo(ethylene glycol) (OEG) units and thioether bonds in the side-chains. All the polypeptoids are readily soluble in aqueous solution and show reversible thermo-responsive properties.

Charge-Determined LCST/UCST Behavior in Ionic Polypeptoids.

Stimuli-responsive polymers have received increasing interest for a variety of applications. Here, we report a series of unique charge-determined thermoresponsive polypeptoids synthesized by a combination of ring-opening polymerization and click chemistry. The LCST-type and UCST-type behavior is mainly dominated by the charge state on the side chain.