Ehm C, Cipullo R, Budzelaar P H M, Busico V
Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy.
Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
Dalton Trans. 2016 Apr 28;45(16):6847-55. doi: 10.1039/c5dt04895h.
Quenched-flow data for propene polymerization with rac-Me2Si(2-Me-4-Ph-1-indenyl)2ZrCl2/MAO support a picture where removal of MAO qualitatively changes the kinetic profile from a mainly enthalpic to a mainly entropic barrier. DFT studies suggest that a not previously recognized singly-bridged end-on coordination mode of Me6Al2 to catalytically active centers may be kinetically relevant as a resting state. In contrast, the more traditional doubly-bridged complex of Me3Al is proposed to be more relevant to chain transfer to cocatalyst.
用rac-Me2Si(2-Me-4-Ph-1-茚基)2ZrCl2/MAO进行丙烯聚合的猝灭流动数据支持这样一种情况，即去除MAO会使动力学曲线从主要由焓垒定性地转变为主要由熵垒。密度泛函理论研究表明，Me6Al2与催化活性中心的一种以前未被认识的单桥端基配位模式可能作为静止状态在动力学上具有相关性。相比之下，Me3Al更传统的双桥络合物被认为与向助催化剂的链转移更相关。
