Transition metal-catalyzed living radical polymerization (Mt-LRP) is now a very convenient tool for precise syntheses of �well-defined� polymers. Among them, we have targeted very active catalytic systems in water, and highly robust systems with Fe (iron), abundant and safe (ref 1). Crucial is decoration of ligand under steric and electronic viewpoints.  For iron, we designed an hydrophilic phosphine ligand, P(PhOPEG)3, with PEG chains in all three para positions. This ligand led to robust iron-catalyzed systems. For example, in contrast to most of the conventional iron catalysts that are poorly tolerant to the hydroxy group, the iron complex from FeBr2 and P(PhOPEG)3 enabled a random living copolymerization of 2-hydroxyethyl methacrylate and three other methacrylates, where all the monomers randomly copolymerized into statistical copolymers of controlled molecular weights. For ruthenium, P(PhOPEG)3 also allowed aqueous controlled radical polymerizations, when combined with a precursor of Cp*Ru catalyst ([Cp*Ru(�3-Cl)]4) to in-situ give an active catalyst for aqueous polymerization of PEGMA at 40 �C. The polymerization was remarkably fast and well controlled (completion in 1 h; Mw/Mn< 1.2).References:  1) Macromolecules 2013 , 46, 3342.

"Green" metal-catalyzed living radical polymerization via ligand design: Robust, functionality-torelant iron catalysts and highly active ruthenium catalysts in water

248th National Meeting (2014)

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