Trimethylsilyl-substituted triazole-based ligand for copper-mediated single-electron transfer living radical polymerization of methyl methacrylate

Abstract

© 2014 Society of Chemical Industry. The tripodal 'click' ligand tris(4-trimethylsilyl-1,2,3-triazolylmethyl)amine (TTTA) is effective at promoting copper-catalysed single-electron transfer living radical polymerization of methyl methacrylate in bulk. The corresponding copper species allow well-controlled polymerizations under aerobic conditions. The tripodal 'click' compound tris(4-trimethylsilylmethyl-1,2,3-triazolylmethyl)amine (TTTA) was prepared and investigated as a ligand for copper-catalysed single-electron transfer living radical polymerization of methyl methacrylate (MMA). Bulk polymerizations catalysed by Cu0/CuBr2/TTTA with a molar ratio of [MMA]0/[ethyl-2-bromoisobutyrate]0/[CuBr2]0/[TTTA]0=200:2:1:1 and a 1.0×1.0cm2 Cu0 sheet were fast and well controlled (76% conversion with Mw/Mn=1.19 after 3.5h). Greater amounts of added air generally gave slower polymerizations although Mw/Mn remained low (<1.3) even when the polymerization was carried out under aerobic conditions. Decreasing initial concentrations of the Cu0/CuBr2/TTTA catalyst system or polymerization temperatures also resulted in slower polymerizations and yielded polymers with broader dispersity. Kinetic studies in the temperature range 40-90°C revealed an apparent activation energy of 22.6 kJmol-1.