Silane-bridged diphosphine ligands for nickel-catalyzed ethylene oligomerization
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In this study, bis(diphenyl phosphine) dimethyl silane (L1), bis(diphenyl phosphine) methyl dimethyl silane (L2), bis(diphenyl phosphine methyl) dimethyl silane (L3) and their nickel (II) halide complexes, L1/NiBr2 (C1), L2/NiBr2 (C2), L3/NiBr2 (C3), were synthesized and characterized. The X-ray single-crystal analysis of C3 complex showed bidentate coordination on the Ni center. In combination with methylaluminoxane as co-catalyst, these complexes produced catalytic systems for ethylene dimerization to butylene with catalytic activities of up to 3.12 × 106 g mol−1 (cat.) h−1 and selectivities up to 97.6 %. With the fine-tuned ligand backbone, such a PSiP-based catalyst system provides a model for precise understanding of the impact of ligand variations on catalytic performance.
KeywordsEthylene dimerization 1-Butylene Nickel complexes Methylaluminoxane (MAO)
This study was supported by the National Natural Science Foundation of China (U1162114), Program for New Century Excellent Talents in University (NCET-07-0142) and the Provincial Key Laboratory of Oil & Gas Chemical Technology (HXHG2012-04).