Polymerisation with Homogeneous Nickel-complex

2 Polymerisation with Homogeneous Nickel-complex Catalysts 

Styrene undergoes polymerisation with the cationic organonickel(II) complex / 3-methallyl ( /4-cycloocta-l,5-diene)nickel hexafluorophosphate [(MeAll) (Co 7)/W]+[PF]6 combined in situ with tricyclohexylphosphine. The product of such polymerisation is a styrene oligomer with Mn = 1900, characterised by a 

Styrene polymerisation in both isospecific and non-stereospecific homogeneous catalyst systems is highly regioselective and involves a secondary (2,1) insertion of the monomer  

The initiation step in polymerisation with a catalyst derived from the [(MeAll)(Cod)Ni]+[PF6] complex and P(Chx)3 involves the secondary insertion of styrene into a Ni H bond in the cationic nickel hydride species formed in situ  

As already mentioned, the propagation proceeds via a secondary insertion of the monomer into a nickel-carbon bond  

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Homogeneous alkylaluminium-free olefin polymerisation catalysts also comprise non-metallocene cationic group 4 metal complexes such as those with benzyl ligands [162]. A distinct group of alkylaluminium-free homogeneous olefin polymerisation catalysts consists of nickel complexes [181-183],... 

Complexes of nickel constitute a distinct group of homogeneous alkylalumi-nium-free catalysts for olefin polymerisation. An efficient catalyst for ethylene polymerisation is formed in the reaction of bis(cycloocta-l,5-diene)nickel(0) [Ni(Cod)2] with phosphorus-ylid and triphenylphosphine in toluene solvent [181] ... 

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