Ru(Cp*)Cl(PPh3)(2): A versatile catalyst for living radical polymerizationof methacrylates, acrylates, and styrene

Ru(Cp*)Cl(PPh3)(2) (Cp* = pentamethylcyclopentadienyl; PPh3 = triphenylphos phine) has been found to be a versatile catalyst that is applicable to livi ng radical polylnerization of methyl methacrylate (MMA), methyl acrylate (M A), and styrene (St) with Al(Oi-Pr)(3) as an additive. The number-average m olecular weights (M-n) of the obtained polymers increased in proportion to monomer conversion, and the molecular weight distributions were very narrow (M-w/M-n < 1.1). Effective initiators were all alkyl halides (R-X), where X = Cl for MMA; Cl and Br for St; and Cl, Br, and I for MA. Ru(Cp*)Cl(PCy3) (Cy = cyclohexyl) also proved an effective catalyst for living radical pol ymerization of MMA, faster than that with Ru(Cp*)Cl(PPh3)(2), to produce po lymers with narrow molecular weight distributions (M-w/M-n < 1.2).