Copolymerization of Ethylene and Long-Chain Functional α-Olefins by Dinuclear Zirconium Catalysts

Abstract

Bimetallic catalysts have shown promise for improving polar comonomer incorporation by late transition metals, but such effects are underexplored using early transition metal catalysts. Herein, the copolymerization of ethylene and α-olefins bearing alcohol groups was performed using mono- and dizirconium bisamine bisphenolate catalysts in the presence of MAO and Al i Bu3. Under these conditions, catalyst activity was retained with comonomer incorporation trends mirroring those observed with unfunctionalized α-olefins, i.e., lower incorporation by bimetallic catalysts. Although incorporation levels are low, these data provide mechanistic insight for polar comonomer incorporation. These results are consistent with our earlier proposal that larger comonomers sterically clash with the distal metal center of the bimetallic catalysts, leading to lower incorporation. Additionally, a bimetallic mechanism for polar comonomer coordination and incorporation is not supported by the current data.

Zirconium Complexes with Bulkier Amine Bis(phenolate) Ligands and Their Catalytic Properties for Ethylene (Co)polymerization

“…The T m values (124.7–137.1 °C) for the copolymers decrease with the increase in comonomer content. In general, the above observed catalytic properties of these new catalytic systems are in agreement with those reported for similar catalytic systems …”

“…Titanium complexes bearing similar tetradentate ligands have been used for olefin polymerization, in which the bulky substituents play an important role. In addition, mono- and dizirconium complexes supported by bis­[amine bis­(phenolate)] ligands have been investigated for the copolymerization of ethylene with 10-undecen-1-ol or 5-hexene-1-ol and higher copolymer incorporations were observed with the mononuclear catalysts rather than the binuclear ones …”

Syntheses of Silylene-Bridged Thiophene-Fused Cyclopentadienyl ansa-Metallocene Complexes for Preparing High-Performance Supported Catalyst

“…1 H NMR (C 6 D 6 ): δ 8.02 (s, 1H), 7.83 (d, J = 8.3 Hz, 1H), 7.80 (d, J = 8.3 Hz, 1H), 7.54 (s, 1H), 7.43 (dd, 3 J = 8.3 Hz, 4 J = 1.4 Hz, 1H), 7.34 (dd, 3 J = 8.3 Hz, 4 J = 1.4 Hz, 1H), 6.64 (q, J = 1.2 Hz, 1H), 4.47 (s, 1H), 3.74 (s, 1H), 2.35 (s, 3H, CH 3 ), 2.02 (s, 3H, CH 3 ), 1.86 (s, 3H, CH 3 ), 1.39 (s, 9H, tBu), 1.32 (s, 9H, tBu), −0.15 (s, 3H, SiCH 3 ), and −0.40 (s, 3H, SiCH 3 ) ppm. 13 34.9, 31.9, 31.9, 16.1, 15.1, 11.9, −6.3, and −6.9 ppm. HRMS(EI): m/z calcd.…”

Copolymerization of Ethylene with Selected Vinyl Monomers Catalyzed by Group 4 Metal and Vanadium Complexes with Multidentate Ligands: A Short Review

“…Mono-and dinuclear zirconium complexes Zr-14-Zr-17 were tested in ethylene/ 10-undecen-1-ol and ethylene/5-hexen-1-ol copolymerization over comonomer concentrations ranging from 0.02 to 0.16 mol/L in the presence of MAO as activator and Al(iBu) 3 as masking agent [98]. Modest polar comonomer incorporations, from 0.04 mol% to 1.7 mol%, were observed.…”