Le Roux Erwan, Nief François, Jaroschik Florian, Törnroos Karl W, Anwander Reiner
Department of Chemistry, University of Bergen, Allégaten 41, N-5007, Bergen, Norway.
Dalton Trans. 2007 Nov 14(42):4866-70. doi: 10.1039/b709633j. Epub 2007 Aug 29.
Homoleptic complexes Ln(AlMe(4))(3) (Ln = La, Nd) can be straightforwardly utilized in salt metathetic exchange reactions with potassium 2,3,4,5-tetramethylphospholide (KTmp) or 3,4-dimethyl-2,5-bis(trimethylsilyl)phospholide (KDsp) affording monophosphacyclopentadienyl hydrocarbyl complexes (eta(5)-PC(4)Me(4))Ln(AlMe(4))(2) and [eta(5)-PC(4)Me(2)(SiMe(3))(2)]Ln(AlMe(4))(2) (Ln = La, Nd). The solid-state structures reveal distinct metal size effects as evidenced by X-ray diffraction analyses of monomeric neodymium Tmp and Dsp derivatives as well as the dimeric lanthanum Tmp complex. Dimerization is accomplished by intermolecular P --> La donor contacts. Upon activation with [PhMe(2)NH][B(C(6)F(5))(4)] the monophosphacyclopentadienyl complexes initiate the polymerization of isoprene producing 1,4-trans-polyisoprene (tPIP > 87%) with moderate activity (approximately 30 kg(PIP) mol(Ln)(-1) h(-1)).
均配型配合物Ln(AlMe(4))(3)（Ln = La，Nd）可直接用于与2,3,4,5-四甲基磷负离子钾（KTmp）或3,4-二甲基-2,5-双（三甲基硅基）磷负离子（KDsp）的盐复分解交换反应，得到单磷环戊二烯基烃基配合物（η(5)-PC(4)Me(4))Ln(AlMe(4))(2)和[η(5)-PC(4)Me(2)(SiMe(3))(2)]Ln(AlMe(4))(2)（Ln = La，Nd）。固态结构显示出明显的金属尺寸效应，这通过钕的Tmp和Dsp衍生物单体以及镧的Tmp配合物二聚体的X射线衍射分析得到证明。二聚作用通过分子间P→La给体接触实现。用[PhMe(2)NH][B(C(6)F(5))(4)]活化后，单磷环戊二烯基配合物引发异戊二烯聚合，以中等活性（约30 kg(PIP) mol(Ln)(-1) h(-1)）生成1,4-反式聚异戊二烯（tPIP > 87%）。
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