Synthesis of high molecular weight poly(methyl methacrylate) with extremely low polydispersity by the unique function of organolanthanide(III) complexes

Polymerizations of methyl methacrylates by bis(pentamethylcyclopentadienyl)samarium hydride, [Sm(C 5 Me 5 ) 2 H] 2 , in toluene were found to afford the polymers of M n > 100×10 3 with extremely low polydispersity, M w /M n = 1.02. The polymerization is estimated to proceed in a living fashion. Highly syndiotactic polymerization (95.3%) proceeded by lowering the reaction temperature to -95°C.