Synthesis of β-diketiminate-ligated bimetallic and monometallic lanthanide amide complexes and their reactivity with isoprene and AlMe3.
The amine elimination of lanthanide tris(amide) complexes with the phenylene-bridged bis(β-diketiminate) ligands PARA(Me)-H2, META(Me)-H2 and PARA(Pr)-H2 (PARA(Me)-H2 = 2[2,6-Me2C6H3NHC(Me)C(H)C(Me)N]-(para-phenylene), META(Me)-H2 = 2[2,6-Me2C6H3NHC(Me)C(H)C(Me)N]-(meta-phenylene), PARA(Pr)-H2 = 2[2,6-(i)Pr2C6H3NHC(Me)C(H)C(Me)N]-(para-phenylene)), and the mono-β-diketiminate ligand L(2,6-iPr2)Ph-H (2,6-(i)Pr2C6H3)NHC(Me)CHC(Me)N(C6H5)) afforded the bimetallic lanthanide amide complexes PARA(Me)-{Ln[N(SiMe3)2]2}2 (Ln = Y (1), Sm (2)), META(Me)-{Y[N(SiMe3)2]2}2 (3), PARA(Pr)-{Ln[N(HSiMe2)2]2}2 (Ln = Y (4), Sm (5)), and the monomeric complexes L(2,6-iPr2)Ph-Y[N(SiMe3)2]2 (6) and L(2,6-iPr2)Ph-Y[N(HSiMe2)2]2 (7). In the presence of AlR3 and on activation with 1 equiv. of [Ph3C][B(C6F5)4], complexes 1-7 showed a high activity toward the 1,4-selective polymerization of isoprene. The heterometallic Y/Al methyl complex [L(2,6-iPr2)Ph]Y[(μ-Me)2AlMe2]2 (8) was prepared to elucidate the real active precursor in the polymerization.
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Dushu Lake Campus, Soochow University, Suzhou 215123, People's Republic of China. yaoym@suda.edu.cn.
Song
S
Sun
Hao
H
Ouyang
Yunjie
Y
Luo
Yong
Y
Zhang
Qi
Q
Shen
Yingming
Y
Yao