Indenyl nickel complexes: synthesis, characterization and styrene polymerization catalysis

Indenylnickel(II) Halides for the Polymerization of Styrene in the Presence of NaBPh4/PPh3

“…22b It is observed that the obtained polystyrene is a syndio-rich atactic polymer in the present case. 17 As expected, the halogen atom bonded to nickel atom exhibits great influence on the catalytic behavior of the complex. In the present polymerization, the nickel(II) chloride showed a some higher activity than the nickel(II) bromide, and the nickel(II) bromide exhibited a much higher activity than the nickel(II) iodide: (1-Et-Ind)Ni(PPh 3 )Cl＞(1-Et-Ind)Ni(PPh 3 )Br>> (1-Et-Ind)Ni(PPh 3 )I (Table 2, Entries 4-6).…”

“…Indene (Fluka) dried over 4 Å molecular sieves and styrene dried over CaH 2 were distilled before use, and 2,2,6,6-tetramethyl-1-piperidinyloxy (TMPO) (Aldrich) was used as re-ceived. Ni(PPh 3 ) 2 Cl 2 , 17 (1-R-Ind)Ni(PPh 3 )Cl (R ＝ Et, (1), 18 cyclopentyl, (2), 17 and benzyl, (3)…”

“…13 Very recently, we have reported the synthesis and X-ray characterization of a series of indenylnickel(II) complexes (1-R-Ind)Ni(PPh 3 )X (R＝ethyl, cyclopentyl and benzyl, while X＝Cl, Br and I). 17,18 Preliminary studies have shown that these indenylnickel(II) complexes could initiate the polymerization of styrene in the presence of NaBPh 4 . 17 In the present paper, the effect of structural variation on the catalytic activity of the indenylnickel(II) complexes towards the polymerization of styrene, together with the mechanism of the styrene polymerization initiated by (1-Et-Ind)Ni(PPh 3 )Cl/NaBPh 4 / PPh 3 system was studied in details for the first time.…”

Cationic R‐Substituted‐Indenyl Nickel(II) Complexes of Arsine and Stibine Ligands: Synthesis, Characterization, and Catalytic Behavior in the Oligomerization of Styrene

“…The process is designated by the indenyl effect , being this η 5 ‐η 3 haptotropic shift facilitated by the presence of the fused benzene fragment in the η‐Ind ring . As a result, neutral and cationic indenyl nickel(II) complexes, [Ni(η‐Ind)(L)X] (L = phosphines; X = halides, triflate, amidates) and [Ni(η‐Ind)(L)L′] + (L = phosphines; L′ = phosphines, nitriles, amines, alkenes), are catalytically active in reactions such as the dimerization of ethylene, oligo‐/polymerization of styrene[4f], , and polymerization of norbornene,[9a] the former in the presence of halide abstractors (e.g. AgBF 4 or NaBPh 4 ), and the latter in the absence of any activator, though displaying relatively low activities.…”

Styrene polymerization catalyzed by nickel complexes bearing hydroxyindanone-iminate ligands

“…Cationic η 3 -allylnickel complexes alone or modified by phosphine and phsophite ligands afford low molecular weight polystyrene without any addition of Lewis acids as cocatalysts [11][12][13][14] . Cationic nickel complexes containing indenyl and phosphine ligands can also catalyze styrene polymerization, and the molecular weight of polymer ranged from low to high with variation on the structure of catalyst [15][16][17] . Neutral σ-acetylide nickel complexes can initiate the styrene polymerization by a radical mechanism in chloroform solution [18] .…”