Copolymerization of Ethene with Norbornene Derivatives Using Neutral Nickel Catalysts

Abstract

The copolymerization of ethene with norbornene derivatives, as well as their terpolymerization with 1-alkenes, using a series of neutral, square-planar nickel complexes containing anionic P∼O chelates is described. In copolymerizations, up to 50 mol % incorporation of norbornene, leading to an essentially alternating copolymer, is obtained. With norbornene derivatives bearing oxygen functionalities, the level of incorporation is lower, as are the reaction rates and polymer molecular weights. In the case of terpolymerization of ethene and norbornene with 1-alkenes, the polymer molecular weights tend to be low because of slower monomer insertion and additional chain-transfer pathways that are available following 1-alkene insertion. For the ethene/norbornene polymers synthesized, the glass transition temperature (T g) increases smoothly with increasing norbornene content. Solution-cast films of the polymers show good optical clarity.

Stable Nickel Catalysts for Fast Norbornene Polymerization: Tuning Reactivity

“…[8] Even in these conditions the yield and M w values are low, and the authors attribute the low reactivity of O-functionalyzed norbornenes in part to the coordinating ability of the oxygen. Examples of the poisoning effect of palladium catalysts due to the coordination of the O-donor groups of functionalyzed norbornenes have been recently reported.…”

“…[1,[3][4][5][6][7][8][9] Usually the polymerization requires a nickel() catalyst and an organometallic co-catalyst [typically methylaluminoxane or B(C 6 F 5 ) 3 ], [1,3,7,8,10] but a few nickel organometallics (cationic allyl complexes such as [Ni(η 3 -crotyl)(1,4-COD)]PF 6 , some phenyl derivatives, and [Ni(C 6 F 5 ) 2 (η 6 -toluene)]), are very efficient without co-catalyst. [1,8,9] Noteworthy, although the use of monodentate ligands, particularly phos-phanes, has been reported in the patent literature, [11] most of the catalysts used are stabilized by multidentate chelating ligands.…”

Molecular Dynamics in Cyclic Olefin Copolymer

“…• C) can be altered linearly with increasing the norbornene (NB) comonomer content [3,4]. The structure of these copolymers has been extensively studied using 13 C high resolution in solution [5][6][7].…”

Nickel(II) complexes bearing the bis(β‐ketoamino) ligand for the copolymerization of norbornene with a higher 1‐alkene

“…The weak peak at 5.3 ppm corresponded to internal vinylene groups and meant that the 1-alkene insertion followed a 2, 1 insertion pathway. 27 In addition, the absence of a significant resonance at 5.0-6.0 ppm indicated no large amounts of double bonds, which are typical for metathesis-type PNBs. 28 As shown in Figure 4(B), four groups of resonance peaks appeared between 14 and 56 ppm in the 13 C-NMR spectrum of poly(norbornene-co-1-decene).…”