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

An unsymmetrical bimetallic catalyst, (CF3/SO2)FI2-Ni-2, 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-Ni-2 affords monomodal ((D) over bar = 1.7), highly, long-chain branched (69 branches/1000 C) polyethylenes with M-w = 24 kg/mol. In contrast, bimetallic (CF3)FI2-Ni-2 and (SO2)FI2-Ni-2 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 ((D) over bar = 6.4).