The amine elimination of lanthanide tris(amide) complexes with the phenylene-bridged bis(β-diketiminate) ligands PARAMe-H2, METAMe-H2 and PARAPr-H2 (PARAMe-H2 = 2[2,6-Me2C6H3NHC(Me)C(H)C(Me)N]-(para-phenylene), METAMe-H2 = 2[2,6-Me2C6H3NHC(Me)C(H)C(Me)N]-(meta-phenylene), PARAPr-H2 = 2[2,6-iPr2C6H3NHC(Me)C(H)C(Me)N]-(para-phenylene)), and the mono-β-diketiminate ligand L2,6-iPr2Ph-H (2,6-iPr2C6H3)NHC(Me)CHC(Me)N(C6H5)) afforded the bimetallic lanthanide amide complexes PARAMe-Ln[N(SiMe3)2]2}2 (Ln = Y (1), Sm (2)), METAMe-Y[N(SiMe3)2]2}2 (3), PARAPr-Ln[N(HSiMe2)2]2}2 (Ln = Y (4), Sm (5)), and the monomeric complexes L2,6-iPr2Ph-Y[N(SiMe3)2]2 (6) and L2,6-iPr2Ph-Y[N(HSiMe2)2]2 (7). In the presence of AlR3 and on activation with 1 equiv. of [Ph3C][B(C6F5)4], complexes 1â7 showed a high activity toward the 1,4-selective polymerization of isoprene. The heterometallic Y/Al methyl complex [L2,6-iPr2Ph]Y[(μ-Me)2AlMe2]2 (8) was prepared to elucidate the real active precursor in the polymerization.
具有芳基桥接双(
β-二酮亚胺)
配体P
ARAMe-H2、METAMe-H2和P
ARAPr-H2的
镧系
金属三(酰胺)配合物的胺消除反应(P
ARAMe-H2 = 2[2,6-Me2C6H3NHC(Me)C(H)C(Me)N]-(对位苯),METAMe-H2 = 2[2,6-Me2C6H3NHC(Me)C(H)C(Me)N]-(间位苯),P
ARAPr-H2 = 2[2,6-iPr2C6H3NHC(Me)C(H)C(Me)N]-(对位苯)以及单
β-二酮亚胺配体L2,6-iPr2Ph-H (2,6-iPr2C6H3)NHC(Me)CHC(Me)N(
C6H5)),得到双
金属
镧系
金属酰胺配合物P
ARAMe-Ln[N(SiMe3)2]2}2 (Ln = Y (1), Sm (2))、METAMe-Y[N(SiMe3)2]2}2 (3)、P
ARAPr-Ln[N(HSiMe2)2]2}2 (Ln = Y (4), Sm (5)),以及单体配合物
L2,6-iPr2Ph-Y[N(SiMe3)2]2 (6)和
L2,6-iPr2Ph-Y[N(HSiMe2)2]2 (7)。在AlR3存在的条件下,使用1当量[Ph3C][B(
C6F5)4]激活后,复合物1–7表现出对
异戊二烯1,4-选择性聚合的高活性。为阐明聚合中的真实活性前驱体,合成了异
金属Y/Al甲基复合物[
L2,6-iPr2Ph]Y[(μ-Me)2AlMe2]2 (8)。