Germanium- and Tin-Catalyzed Living Radical Polymerizations of Styrene and Methacrylates |
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Authors: | Atsushi Goto Hirokazu Zushi Norihiro Hirai Tsutomu Wakada Yungwan Kwak Takeshi Fukuda |
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Affiliation: | Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan |
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Abstract: | Summary : Ge and Sn (non-transition-metal) catalyzed living radical polymerizations were developed. Low-polydispersity (Mw/Mn ∼ 1.1–1.3) polystyrenes, poly(methyl methacrylate)s, poly(glycidyl methacrylate)s, and poly(2-hydroxyethyl methacrylate) with predicted molecular weights were obtained with a fairly high conversion in a fairly short time. The pseudo-first-order activation rate constant kact for the styrene/GeI4 (catalyst) system was large enough, even with a small amount of GeI4, to explain why the system provides low-polydispersity polymers from an early stage of polymerization. The retardation in the polymerization rate observed for the styrene/GeI4 system was kinetically proved to be mainly due to the cross-termination between the propagating radical with GeI. Attractive features of the Ge and Sn catalysts include their high reactivity hence small amounts (1–5 mM) being required under a mild condition (at 60–80 °C), high solubility in organic media without ligands, insensitivity to air hence sample preparation being allowed in the air, and minor color and smell. The Ge catalysts may also be attractive for their low toxicity. |
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Keywords: | germanium iodide living radical polymerization non-transition metal tin |
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