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

An unsymmetrical bimetallic catalyst, (<b>CF</b>_<b>3</b>/<b>SO</b>_<b>2</b>)<b>FI</b>^<b>2</b><b>-Ni</b>_<b>2</b>, having a CF₃-functionalized phenoxyiminato Ni­(II) center, which produces linear high-<i>M</i>_w polyolefin (<b>CF</b>_<b>3</b><b>/Ni</b>) joined to an adjacent SO₂-functionalized phenoxyiminato Ni­(II) center, which produces highly branched low-<i>M</i>_w polyolefin (<b>SO</b>_<b>2</b><b>/Ni</b>), was synthesized and fully characterized. In ethylene homopolymerizations, (<b>CF</b>_<b>3</b>/<b>SO</b>_<b>2</b>)<b>FI</b>^<b>2</b><b>-Ni</b>_<b>2</b> affords monomodal (<i>Đ</i> = 1.7), highly, long-chain branched (69 branches/1000 C) polyethylenes with <i>M</i>_w = 24 kg/mol. In contrast, bimetallic (<b>CF</b>_<b>3</b>)<b>FI</b>^<b>2</b><b>-Ni</b>_<b>2</b> and (<b>SO</b>_<b>2</b>)<b>FI</b>^<b>2</b><b>-Ni</b>_<b>2</b> produce high-<i>M</i>_w (25 kg/mol) exclusively methyl-branched (40 branches/1000 C) and low-<i>M</i>_w (4.5 kg/mol) highly branched (105 branches/1000 C) polyethylenes, respectively, while tandem monometallic (<b>CF</b>_<b>3</b>)<b>FI-Ni</b> + (<b>SO</b>_<b>2</b>)<b>FI-Ni</b> catalyst mixtures yield a bimodal polyolefin mixture (<i>Đ</i> = 6.4)