Gamer Michael T, Rastätter Marcus, Roesky Peter W, Steffens Alexandra, Glanz Mario
Institut für Chemie, Freie Universität Berlin, Fabeckstrasse 34-36, 14195 Berlin, Germany.
Chemistry. 2005 May 6;11(10):3165-72. doi: 10.1002/chem.200401062.
Yttrium and lanthanide complexes with different P,N ligands in the coordination sphere have been synthesized. First the chloride complexes [{CH(PPh2NSiMe3)2}Ln{(Ph2P)2N}Cl] (Ln = Y (1 a), La (1 b), Nd (1 c), Yb (1 d)) having the bulky [CH(PPh2NSiMe3)2]- and the flexible [(Ph2P)2N]- ligands in the same molecule were prepared by three different synthetic pathways. Compounds 1 a-d can be obtained by reaction of [{[CH(PPh2NSiMe3)2]LnCl2}2] with [K(thf)nN(PPh2)2] (n = 1.25, 1.5) or by treatment of [{(Ph2P)2N}LnCl2(thf)3] with K[CH(PPh2NSiMe3)2]. Furthermore, a one-pot reaction of K[CH(PPh2NSiMe3)2] with LnCl3 and [K(thf)nN(PPh2)2] leads to the same products. Single-crystal X-ray structures of 1 a-d show that the conformation of the six-membered metallacycle (N1-P1-C1-P2-N2-Ln) which is formed by chelation of the [CH(PPh2NSiMe3)2]- ligand to the lanthanide atom is influenced by the ionic radius of the central metal atom. In solution dynamic behavior of the [(Ph2P)2N]- ligand is observed, which is caused by rapid exchange of the two different phosphorus atoms. Further reaction of 1 b with KNPh2 resulted in [{(Me3SiNPPh2)2CH}La{N(PPh2)2}(NPh2)] (2). Compounds 1 a-d and 2 are active in the ring-opening polymerization of epsilon-caprolactone and the polymerization of methyl methacrylate. In some cases high molecular weight polymers with good conversions and narrow polydispersities were obtained. In both polymerizations the catalytic activity depends on the ionic radius of the metal center.
已合成了配位球中含有不同P、N配体的钇和镧系配合物。首先，通过三种不同的合成途径制备了在同一分子中具有庞大的[CH(PPh2NSiMe3)2]-和柔性[(Ph2P)2N]-配体的氯化物配合物[{CH(PPh2NSiMe3)2}Ln{(Ph2P)2N}Cl]（Ln = Y (1 a)、La (1 b)、Nd (1 c)、Yb (1 d)）。化合物1 a - d可通过[{[CH(PPh2NSiMe3)2]LnCl2}2]与[K(thf)nN(PPh2)2]（n = 1.25、1.5）反应或通过用K[CH(PPh2NSiMe3)2]处理[{(Ph2P)2N}LnCl2(thf)3]得到。此外，K[CH(PPh2NSiMe3)2]与LnCl3和[K(thf)nN(PPh2)2]的一锅法反应也得到相同的产物。1 a - d的单晶X射线结构表明，由[CH(PPh2NSiMe3)2]-配体与镧系原子螯合形成的六元金属环（N1 - P1 - C1 - P2 - N2 - Ln）的构象受中心金属原子离子半径的影响。在溶液中观察到[(Ph2P)2N]-配体的动态行为，这是由两个不同磷原子的快速交换引起的。1 b与KNPh2的进一步反应生成了[{(Me3SiNPPh2)2CH}La{N(PPh2)2}(NPh2)]（2）。化合物1 a - d和2在ε-己内酯的开环聚合和甲基丙烯酸甲酯的聚合中具有活性。在某些情况下，得到了具有良好转化率和窄多分散性的高分子量聚合物。在这两种聚合反应中，催化活性都取决于金属中心的离子半径。
