Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Dalton Trans. 2013 Jul 7;42(25):9069-78. doi: 10.1039/c3dt00032j. Epub 2013 Apr 10.
The synthesis of two pyridylamidinate bis(N,N'-bis(trimethylsilyl)-2-pyridylamidinate)An(μ-Cl)2Li(TMEDA) (An = U (1), Th (2)) complexes is presented. For complex 1 the solid state X-ray structures were studied and compared to that of complex 2. The organoactinide complexes were studied as pre-catalysts in the polymerization of ethylene when activated by methylalumoxane (MAO). The catalytic activity was improved using a mixture of trityl tetrakispentafluorophenylborate (TTPB) and a small amount of methylalumoxane (MAO) as cocatalysts, and was amazingly improved, providing the greatest activity, using only triisobutyl aluminum (TIBA). We present a combination of ESR, C60 radical trapping, and MALDI-TOF studies describing the formation of the single-site active species, capturing some unique features of the complexes and shedding light on the polymerization mechanism.
本文介绍了两种吡啶酰胺二（N，N'-双（三甲基甲硅烷基）-2-吡啶酰胺）An（μ-Cl）2Li（TMEDA）（An = U（1），Th（2））配合物的合成。对配合物 1 进行了固态 X 射线结构研究，并与配合物 2 进行了比较。将有机锕配合物用作前催化剂，在甲基铝氧烷（MAO）的活化下聚合乙烯。使用三苯甲基四（五氟苯基）硼酸盐（TTPB）和少量甲基铝氧烷（MAO）的混合物作为助催化剂，可提高催化活性，仅使用三异丁基铝（TIBA），可惊人地提高活性。我们提出了一种结合电子顺磁共振（ESR）、C60 自由基捕获和 MALDI-TOF 研究的方法，描述了单活性位物种的形成，捕捉到了配合物的一些独特特征，并阐明了聚合机理。
