Pyridylamido Hafnium Complexes with the Silylene Bridge: Synthesis and Olefin Polymerizationстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 7 июля 2020 г.
Аннотация:The synthesis and characterisation of six novel Cs-symmetric pyridylamido hafnium complexes with silylene bridge of the type [ArPy(R2Si)NAr’]HfAlk2 is reported. Four complexes have been structurally characterised using single crystal X-ray diffraction. Appreciable diffirences between solid state structures of these complexes and the pyridylamido hafnium complexes with CRR’ bridge were noted. Reactions with [Ph3C][B(C6F5)4] and [HMe2NPh][ B(C6F5)4] yielded catalysts active for the homopolymerisations of propene and 1-hexene and ethene/1-octene copolymerization. In spite of Cs-symmetry of the precatalysts, isotactically enriched polypropylene and poly(1-hexene) were obtained. The fact that mechanism of the catalyst activation includes insertion of alkene into the Hf-CAr bond was demonstrated. It was found that the structure of Ar and R2Si bridge influence, activity, molecular weight capability and 1-hexene affinity of the catalyst.