Half-sandwich samarium (III) diketiminate bromide as a catalyst for methyl methacrylate polymerization

Half-sandwich samarium(III) diketiminate bromide was successfully synthesized and was shown to be active in methyl methacrylate (MMA) polymerization. The effects of temperature, polymerization time and catalyst concentration were studied. Activities of ca. 18 kg of polymethacrylate (PMMA) per mol of samarium per hour were obtained under optimum conditions (0 °C and a MMA/catalyst molar ratio of 100/1), giving a polymer with a molar mass Mn>24,000 g mol−1 and a molar mass distribution (Mw/Mn)<1.4. After 1 h of polymerization, conversions of MMA as high as 96% were observed.