Zhang Guangchao, Wei Yun, Guo Liping, Zhu Xiancui, Wang Shaowu, Zhou Shuangliu, Mu Xiaolong
Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-Based Materials, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241000 (P. R. China), Fax: (+86) 553-3883517.
Chemistry. 2015 Feb 2;21(6):2519-26. doi: 10.1002/chem.201405179. Epub 2014 Dec 9.
Two series of new dinuclear rare-earth metal alkyl complexes supported by indolyl ligands in novel μ-η(2) :η(1) :η(1) hapticities are synthesized and characterized. Treatment of [RE(CH2 SiMe3 )3 (thf)2 ] with 1 equivalent of 3-(tBuN=CH)C8 H5 NH (L1 ) in THF gives the dinuclear rare-earth metal alkyl complexes trans-[(μ-η(2) :η(1) :η(1) -3-{tBuNCH(CH2 SiMe3 )}Ind)RE(thf)(CH2 SiMe3 )]2 (Ind=indolyl, RE=Y, Dy, or Yb) in good yields. In the process, the indole unit of L1 is deprotonated by the metal alkyl species and the imino C=N group is transferred to the amido group by alkyl CH2 SiMe3 insertion, affording a new dianionic ligand that bridges two metal alkyl units in μ-η(2) :η(1) :η(1) bonding modes, forming the dinuclear rare-earth metal alkyl complexes. When L1 is reduced to 3-(tBuNHCH2 )C8 H5 NH (L2 ), the reaction of [Yb(CH2 SiMe3 )3 (thf)2 ] with 1 equivalent of L2 in THF, interestingly, generated the trans-[(μ-η(2) :η(1) :η(1) -3-{tBuNCH2 }Ind)Yb(thf)(CH2 SiMe3 )]2 (major) and cis-[(μ-η(2) :η(1) :η(1) -3-{tBuNCH2 }Ind)Yb(thf)(CH2 SiMe3 )]2 (minor) complexes. The catalytic activities of these dinuclear rare-earth metal alkyl complexes for isoprene polymerization were investigated; the yttrium and dysprosium complexes exhibited high catalytic activities and high regio- and stereoselectivities for isoprene 1,4-cis-polymerization.
合成并表征了由吲哚基配体以新颖的μ-η(2) :η(1) :η(1) 配位模式支撑的两个系列的新型双核稀土金属烷基配合物。在四氢呋喃中，用1当量的3-(叔丁基氮=亚甲基)茚满基胺（L1）处理[RE(CH2 SiMe3 )3 (thf)2 ]，以良好的产率得到双核稀土金属烷基配合物反式-[(μ-η(2) :η(1) :η(1) -3-{叔丁基氮亚甲基(CH2 SiMe3 )}吲哚基)RE(thf)(CH2 SiMe3 )]2（Ind = 吲哚基，RE = Y、Dy或Yb）。在此过程中，L1的吲哚单元被金属烷基物种去质子化，并且亚氨基C=N基团通过烷基CH2 SiMe3插入转移到酰胺基团，得到一种新的双阴离子配体，该配体以μ-η(2) :η(1) :η(1) 键合模式桥连两个金属烷基单元，形成双核稀土金属烷基配合物。当L1还原为3-(叔丁基氨基甲基)茚满基胺（L2）时，有趣的是，[Yb(CH2 SiMe3 )3 (thf)2 ]与1当量的L2在四氢呋喃中的反应生成了反式-[(μ-η(2) :η(1) :η(1) -3-{叔丁基氮甲基}吲哚基)Yb(thf)(CH2 SiMe3 )]2（主要产物）和顺式-[(μ-η(2) :η(1) :η(1) -3-{叔丁基氮甲基}吲哚基)Yb(thf)(CH2 SiMe3 )]2（次要产物）配合物。研究了这些双核稀土金属烷基配合物对异戊二烯聚合的催化活性；钇和镝配合物对异戊二烯1,4-顺式聚合表现出高催化活性和高区域及立体选择性。
