Novel vanadium(iii) complexes with bidentate N,N-chelating iminopyrrolide ligands: synthesis, characterization and catalytic behaviour of ethylene polymerization and copolymerization with 10-undecen-1-ol

Abstract

A series of novel vanadium(III) complexes bearing iminopyrrolide chelating ligands [2-(RN=CH)C4H3N]V(THF)2Cl2 (2a: R = cyclohexyl; 2b: R = Ph; 2c: R = 2,6-iPr2C6H3; 2d: R = p-CF3C6H4; 2e: R = C6F5) have been synthesized and characterized. Single-crystal X-ray diffraction revealed that complexes 2a, 2c and 2e adopt an octahedral geometry around the vanadium center. In the presence of Et2AlCl as a co-catalyst, these complexes displayed high catalytic activities up to 48.6 kg PE mmol(V)(-1) h(-1) bar(-1) for ethylene polymerization, and produced high molecular weight polymers. 2a-e/Et2AlCl catalytic systems were tolerant to elevated temperature (70 degrees C) and yielded unimodal polyethylenes, indicating the single site behaviour of these catalysts. By pre-treating with equimolar amounts of alkylaluminums, functional alpha-olefin 10-undecen-1-ol can be efficiently incorporated into polyethylene chains. 10-Undecen-1-ol incorporation can easily reach 15.8 mol% under the mild conditions. When compared with VCl3(THF)3 or rac-Et[Ind]2ZrCl2, these vanadium(III) complexes exhibited higher activities towards the copolymerization, and can incorporate more 10-undecen-1-ol into polymer chains under the similar conditions.

Olefin Polymerization with Non-metallocene Catalysts (Early Transition Metals)

“…A series of vanadium(III) complexes containing b-enaminoketonato [99, 100], phenoxy-imine [101][102][103][104], imino-pyrrolide [105] ligands (exemplified in Scheme 3.11) were tested as olefin polymerization catalyst in the presence of Et 2 AlCl and Cl 3 CCO 2 Et. The selected results are summarized in Table 3.5 [99,100,103,105]. The observed activities by certain complexes were slightly/apparently higher than those by VCl 3 (THF) 3 , and the activities decreased at 70 8C probably due to the rapid deactivation even for short period (5 min) and in the presence of excess amount of re-oxidant (300 equivalent to V).…”

Copolymerization of 4-methyl-1-pentene with α,ω-alkenols

“…Besides the similar peaks to that of sample 1, other some resonances appeared in the spectrum. The peak at 63.0 ppm is the typical resonance of the carbon atom adjacent to the hydroxyl group of 9D1O [9,13]. Other resonances, δ = 42.1, 35.5, 33.4, 30.7, 30.0, 29.8, 26.9, 26.3 ppm, are assigned to the other carbon atoms of 9D1O.…”

“…Polyethylene and polypropylene are the polyolefin resins with the largest commercial scale. It follows then that most researches on the synthesis of the functional polyolefin concern ethylene [4][5][6][7][8][9][10][11][12][13] and propylene [14][15][16][17][18] copolymerization. The investigation on the copolymerization of higher α-olefin with functional monomer was rather rare.…”

Oxovanadium(IV) complexes with [ONNO]-chelating ligands as catalysts for ethylene homo- and copolymerization

“…A good thermal stability can also be expected from single-site catalysts which are based on bis(imino)pyrrolyl v a n a d i u m ( I I I ) c o m p l e x e s [ 1 2 ] . M o n o (β-enaminoketonato)vanadium(III) complexes show high catalytic activities in ethylene polymerization and an excellent capacity to copolymerize ethylene and 1-olefins or cycloolefins [13], while vanadium(III) complexes with iminopyrrolide ligands [14] or tridentate phenoxy-phosphine ligands [15] exhibit high activity in ethylene polymerization even at 70°C, and they can also efficiently catalyze the copolymerization process of ethylene with 10-undecen-1-ol to produce copolymers with around 15 mol % of comonomer. (Arylimido)(aryloxo)vanadium(V) complexes show high activity in ethylene polymerization and a good potential to incorporate the norbornene monomer [16].…”

“…The information is also vital that the majority of vanadium complexes shows a better activity in combination with simple alkylaluminium compounds, especially EtAlCl 2 and Et 2 AlCl [10,[12][13][14][15][16][17][18]21], which makes them good alternatives for MAO activated zirconium and titanium-based catalysts.…”