Polymerization of methyl methacrylate with Ni(acac)2–methylaluminoxane catalyst

Polymerization of Methyl Methacrylate with Nickel(II) and Palladium(II) Iminopyridyl Mononuclear Bimetallic Complexes

“…It is interesting to note that the bimetallic Pd and Ni complexes exhibit higher activities than the corresponding monometallic complexes 5 and 6 (run no. 1 vs. 13 and 7 vs. 14), Ni(acac) 2 /MAO [31], Ni a-diimine/MAO and Fe/Co pyridyl bis(imine)/ MAO systems [11,12]. The similar results have been reported for MMA polymerization with a binuclear Ni and Cu acetylacetonato complexes/MAO systems [20].…”

“…Under standard conditions and adding five equivalent (per metal) of TEMPO as a free radical inhibitor, polymer yield, and catalyst productivity remained substantially the same, thus indicating that the polymerization of MMA may not occur via a radical mechanism. It was reported that the polymerization of MMA by Ni(acac) 2 [31] and salicylaldiminate nickel complexes [8][9][10] with MAO proceeds by a coordinationinsertion mechanism. Triad testes may be a good clue to differentiate between enantiomorphic site control and chain end control.…”

Polymerization of methyl methacrylate with nickel α-diimine catalysts: Effect of the methyl position in the ligand

“…6 The data in Table I show that all catalysts produce PMMAs with narrow polydispersity index (PDI). The PDI values are narrow compared to other late transition metal catalysts such as Ni(acac) 2 /MAO, 12,13 and neutral Pd(II) and Ni(II) acetylide. 14 In order to check the degree of control attainable using (α-diimine)nickel(II)/MAO systems, we chose cat (2,4-Me) precatalyst that gives PMMA of narrow PDI and performed independent polymerizations by changing the time from 20 min to 3 hrs (see Table I).…”

N-tripodal ligands to generate copper catalysts for the syndiotactic polymerization of methyl-methacrylate: Crystal structures of copper complexes

“…A kinetic study was also carried out with these catalytic systems based on CuCl 2 . For such systems the rate of polymerization could be expressed as R p = Àd[MMA]/dt = kp[MMA] a Á [active center] b , where k p is the propagation rate constant, and a and b are the kinetic orders of the monomer and the active centers, respectively [6]. Fig.…”

“…Collins et al achieved the controlled polymerization of MMA with a two-component system consisting of a cationic zirconocenium complex Cp 2 ZrMe(THF) + BPh 4 À and a neutral zirconocene Cp 2 ZrMe 2 with a lower amount of syndiotactic dyads ([rr] = 80%) [4]. Since then, important research has been conducted with late transition metal-mediated polymerization, especially nickel-based catalysts: Ni(acac) 2 -MAO was first found to be an effective catalyst for the atactic polymerization of MMA [5,6]. Syndiotactic PMMA ([rr] = 72%) produced via late transition metal catalysts was first described with Cp 2 Ni-MAO [7].…”