Nickel(II) alpha-diimine catalysts for the atom transfer radical polymerization of styrene

摘要

The synthesis and evaluation of (Cy)[N,N]NiX2 Complexes (where Cy[N,N] = C6H11-N=CH-CH=N-C6H11; X = Cl, Br) as catalysts for atom transfer radical polymerization are reported. (Cy)[N,N]NiCl2 offers poor control over the polymerization of MMA and styrene due to catalyst insolubility. The more soluble bromo catalyst (Cy)[N,N]NiBr2, promotes rapid styrene polymerization, but with inefficient initiation, affording higher than expected molecular weights based on [M](o)/[I](o) ratios. Utilizing 1-PEBr results in efficient initiation to give low polydispersities (M-w/M-n similar to 1.2) and polystyrene molecular weights that correlate with monomer: initiator ratios. (c) 2006 Elsevier B.V. All rights reserved.