Closer to the "ideal recoverable catalyst" for atom transfer radical polymerization using a molecular non-fluorous thermomorphic system

The tetramine ligand 1 hexasubstituted by very long alkyl chains (C18H37) exhibits an exceptionally large temperature-dependent solubility in 1,4-dioxane, its solubility increasing ca. ∼104-fold between 23 and 50 °C. The preformed copper(I) complex CuBr/1 was shown to catalyze the atom transfer radical polymerization of methyl methacrylate with good control of the molar masses and polydispersities. Due to the thermoresponsive character of CuBr/1 polymerizations were carried out in homogeneous conditions while lowering the temperature to 10 °C led to the precipitation of the catalyst. Catalyst recovery was achieved with high yield (∼95%) by a simple filtration under noninert atmosphere. Very low residual copper contamination (∼200 ppm) was measured in the final polymer. The catalyst was recycled two times without significant loss of activity. Copyright © 2004 American Chemical Society.