Ruthenium(IV) Complexes for Ethylene Insertion Polymerization

The synthesis, characterization, and ethylene polymerization behavior of novel Ru^IV(η³:η³-C₁₀H₁₆)­(OPO) (OPO = bis­(arenesulfonato)­phosphine) complexes is reported here. Upon activation with AlMe₃-depleted methylaluminoxane (dMAO), the Ru­(IV) precursors were able to produce polyethylene with activities up to 1182 h^–1 turnover frequency (TOF). The polymers were highly linear with a low degree of branching (<12 methyl branches per 1000 C) and had high molecular weights (up to <i>M</i>_p = 289 kg mol^–1) with a bimodal molecular weight distribution. The polymerization activity increased with decreasing donor strength of the OPO ligand