Ligand-Unsymmetrical Phenoxyiminato Dinickel Catalyst for High Molecular Weight Long-Chain Branched Polyethylenes

Dongxu Shu; Aidan R Mouat; Casey J Stephenson; Anna M Invergo; Massimiliano Delferro; Tobin J Marks

doi:10.1021/acsmacrolett.5b00781

Ligand-Unsymmetrical Phenoxyiminato Dinickel Catalyst for High Molecular Weight Long-Chain Branched Polyethylenes

ACS Macro Lett. 2015 Nov 17;4(11):1297-1301. doi: 10.1021/acsmacrolett.5b00781. Epub 2015 Nov 6.

Authors

Dongxu Shu¹, Aidan R Mouat¹, Casey J Stephenson¹, Anna M Invergo¹, Massimiliano Delferro¹, Tobin J Marks¹

Affiliation

¹ Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States.

PMID: 35614832
DOI: 10.1021/acsmacrolett.5b00781

Abstract

An unsymmetrical bimetallic catalyst, (CF₃/SO₂)FI²-Ni₂, having a CF₃-functionalized phenoxyiminato Ni(II) center, which produces linear high-M_w polyolefin (CF₃/Ni) joined to an adjacent SO₂-functionalized phenoxyiminato Ni(II) center, which produces highly branched low-M_w polyolefin (SO₂/Ni), was synthesized and fully characterized. In ethylene homopolymerizations, (CF₃/SO₂)FI²-Ni₂ affords monomodal (Đ = 1.7), highly, long-chain branched (69 branches/1000 C) polyethylenes with M_w = 24 kg/mol. In contrast, bimetallic (CF₃)FI²-Ni₂ and (SO₂)FI²-Ni₂ produce high-M_w (25 kg/mol) exclusively methyl-branched (40 branches/1000 C) and low-M_w (4.5 kg/mol) highly branched (105 branches/1000 C) polyethylenes, respectively, while tandem monometallic (CF₃)FI-Ni + (SO₂)FI-Ni catalyst mixtures yield a bimodal polyolefin mixture (Đ = 6.4).