Chromium‐Based Ethylene Tetramerization Catalysts Supported by Silicon‐Bridged Diphosphine Ligands: Further Combination of High Activity and Selectivity

Abstract A series of silicon‐bridged diphosphine (SBDP) ligands were synthesized and characterized. The Cr precatalyst supported by bis(diphenylphosphinomethyl)dimethylsilane achieved a high activity of 4.2×10 6 g (mol Cr h) −1 and a high selectivity of 78.44 % towards valuable 1‐octene by using methylcyclohexane as the solvent at an ethylene pressure of 4.0 MPa and 45 °C. An intramolecular β‐H transfer mechanism was proposed to explain the unequal molar proportions of cyclic C 6 byproducts. The crystal structure data of two complexes proved that the SBDP system with a wide P−Cr−P bite angle could also exhibit superior performance in the tetramerization of ethylene.