Ethanol-Mediated Living Radical Homo- and Copolymerizations with Cp*-Ruthenium Catalysts: Active, Robust, and Universal for Functionalized Methacrylates

Abstract

With judiciously selected ligands (phosphines) and cocatalysts (amines), a series of highly active and functionality-tolerant pentamethylcyclopentadienyl (Cp*) ruthenium catalysts [Cp*Ru(Cl)L1L2; L1 and L2: ligands] have been developed for living radical homo- and copolymerizations universally accessible to a variety of functional methacrylates in ethanol and related alcoholic and polar media. In particular, the ligand/cocatalyst combination of tri-m-tolylphosphine [P(mTol)3; mTol = m-MeC6H5] and a hydrophilic amine, 2-dimethylamino-1-ethanol [Me2N(CH2)2OH; 2-DMAE], led to a very active and robust catalyst that induced fast polymerizations and fine molecular-weight control (Mw/Mn < 1.2) in ethanol for not only homopolymerizations but also random or block copolymerizations with pendent-functional methacrylates carrying poly(ethylene glycol) (−PEG), dimethylamino [−N(CH3)2], and hydroxyl (−OH) groups. The accessible solvents included a wide variety of alcohols (methanol, ethanol, etc.), environmentally beni...