Controlled radical polymerization catalyzed by copper(I)–sparteine complexes

Enantiomer-Selective Radical Polymerization of Bis(4-vinylbenzoate)s with Chiral Atom Transfer Radical Polymerization Initiating Systems

“…However, the recovered monomers showed an equimolar mixture of RR - 9 and SS - 9 enantiomers, and the resulting noncyclized polymer 10 showed no optical activity at all, demonstrating that the enantiomer-selective polymerization requires cyclization during the ATRP. The result for this control experiment for cyclization is quite consistent with the report by Yu and Ruckenstein, in which the metal catalyst consisting of CuBr/(−)-sparteine lacked any stereochemical control of the resulting poly(methylmethacrylates) and polystyrenes …”

Stereospecific Living Radical Polymerization: Dual Control of Chain Length and Tacticity for Precision Polymer Synthesis

“…No 1 H NMR spectral changes were observed for the polystyrene obtained with CuBr/sparteine (Cu-2) although the tacticity was not measured. 100 Another paper on copper ATRP of MMA with chiral ligands was reported using quadridentate ligands (Cu-3) coupled with CuBr, in which the tacticity (mm/mr/rr ) 2.7/33.9/63.5) was almost the same as that obtained with a similar but achiral quadridentate ligand (mm/mr/rr ) 2.6/34.0/63.5) and was consistent with the Bernoullian statistics. 101 For possible tacticity control by coordination of the metal catalyst to monomer, a halfsandwich molybdenum catalyst (Mo-1) with a chiral ligand was thus synthesized and used for ATRP of MMA.…”

“…A commercially available chiral ligand, sparteine, was also used for the MMA and styrene polymerizations with CuBr. No 1 H NMR spectral changes were observed for the polystyrene obtained with CuBr/sparteine ( Cu-2 ) although the tacticity was not measured . Another paper on copper ATRP of MMA with chiral ligands was reported using quadridentate ligands ( Cu-3 ) coupled with CuBr, in which the tacticity ( mm / mr / rr = 2.7/33.9/63.5) was almost the same as that obtained with a similar but achiral quadridentate ligand ( mm / mr / rr = 2.6/34.0/63.5) and was consistent with the Bernoullian statistics .…”

Dynamic Formation of Graft Polymers via Radical Crossover Reaction of Alkoxyamines

“…In the case of the radical polymerization of monomer-containing alkoxyamine moiety, initiation and termination caused by generated radicals result in poor polymerization control. To control the molecular weight as well as macromolecular architecture with a facile procedure, we have examined the use of atom transfer radical polymerization (ATRP) , for the preparation of polymer that has alkoxyamine units in the side chain. In comparison with other living polymerization techniques, the unique features of living free radical polymerizations are their compatibility with a wide range of functional groups, coupled with their ability to prepare well-defined random copolymers. , As reported in our previous report, the TEMPO-based alkoxyamine unit does not dissociate below 60 °C .…”