Shuttling Catalyst for Living Radical Miniemulsion Polymerization: Thermoresponsive Ligand for Efficient Catalysis and Removal

In this report, we demonstrate the use of a thermoresponsive ligand for the ruthenium-catalyzed living radical polymerization of butyl methacrylate (BMA) in miniemulsion. A phosphine-ligand-functionalized polyethylene glycol chain (PPEG) in conjunction with a Cp*-based ruthenium complex (Cp*: pentamethylcyclopentadienyl) provided thermoresponsive character as well as catalysis for living polymerization: the complex migrated from the water phase to the oil phase for polymerization upon heating and then migrated from the oil to water phase when the temperature was decreased to quench polymerization. Consequently, simple treatment (i.e., water washing or methanol reprecipitation) yielded metal-free polymeric particles containing less than 10 μg/g (by ICP-AES) of ruthenium residue

A Boron Subphthalocyanine Polymer: Poly(4-methylstyrene)-<i>co</i>-poly(phenoxy boron subphthalocyanine)

Boron subphthalocyanines have been explored as functional materials in a wide range of organic electronic applications including organic light-emitting diodes and organic solar cells. They have only, however, been studied as small molecules; there have been no reports of boron subphthalocyanine polymer(s) in the literature. Herein, the synthesis of the first boron subphthalocyanine-containing polymer, poly­(4-methylstyrene)-<i>co</i>-poly­(phenoxy boron subphthalocyanine), is reported along with its basic physical characterization/properties. The synthesis of the boron subphthalocyanine polymer was only possible via a postpolymerization functionalization approach, where the boron subphthalocyanine moiety is appended to the side chain of a styrene-based prepolymer. The three-step transformation begins with the nitroxide-mediated copolymerization of 4-methylstyrene and 4-acetoxystyrene to form poly­(4-methylstyrene)-<i>co</i>-poly­(4-acetoxystyrene). The acetoxy groups are subsequently deacetylated to afford hydroxyl groups prior to phenoxylation with bromo boron subphthalocyanine to afford the title polymer(s)