Synthesis and characterization of bimetallic lanthanide–alkali metal complexes stabilized by aminophenoxy ligands and their catalytic activity for the polymerization of 2,2-dimethyltrimethylene carbonate
aminophenoxy ligands to form a distorted octahedron. It was found that complexes 1–10 are highly efficient initiators for the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC), affording the polymers with high molecular weights, and the homoleptic heterobimetallic lanthanidecomplexes showed apparently high activity.
氨基酚盐基团的电子性质对氨基酚盐镧系元素-锂配合物的合成有明显影响。Ln [N(SiMe 3)2 ] 3(μ-Cl)Li(THF)3与氨基酚锂[ArNHCH 2(3,5- t Bu 2 C 6 H 2 -2-O)Li(THF)的胺消除反应)] 2(Ar = p -ClC 6 H 4,[ONH] Cl- p ; p -BrC 6 H 4,[ONH] Br- p)在四氢呋喃(THF)摩尔比为1:2,得到双金属镧系元素-锂酰胺基络合物[NO] Cl- p 2 Ln [N(SiMe 3)2 ] [Li(THF)] 2(Ln = Y(1),Yb (2)),和[NO] Br- p 2 Ln [N(SiMe 3)2 ] [Li(THF)] 2(Ln = Y(3),Yb(4))。当Ar基团为p -MeOC 6 H 4([ONH] MeO- p)和o -MeOC 6 H 4([ONH] MeO-o),类似的
Synthesis and Characterization of Lanthanide Amides Bearing Aminophenoxy Ligands and Their Catalytic Activity for the Polymerization of Lactides
A series of neutral lanthanide complexes supported by aminophenoxy ligands were synthesized, and their catalytic behavior in the polymerization of L-lactide and roc-lactide was explored. The amine elimination reactions of equimolar amounts of Ln[N(TMS)(2)](3)(mu-Cl)Li(THF)(3) and aminophenol [HONH](1) [HONH](1) = 2,6-Me-2-C6H4NHCH2(3,5-Bn-t(2)-C6H2-2-OH)} in toluene gave the dimeric lanthanide complexes [ON](1)Ln[ONH](1)}(2) (Ln = La (1), Nd (2)), whereas the similar reactions of La[N(TMS)(2)](3)(THF)(2) or Ln[N(TMS)(2)](3)(mu-Cl)Li(THF)(3) (Ln = Nd, Sm) with the aminophenols [HONH](2) [HONH](2) = (o-OCH3-C6H4)NHCH2(3,5-Bu-t(2)-C6H2-2-OH} and [HONH](3) ([HONH](3) = (NC5H4)NHCH2(3,5-Bu-t(2)-C6H2-2-OH)} generated the neutral aminophenoxy lanthanide amides [ON](2)Ln[N(TMS)(2)]}(2) [Ln = La (3), Nd (4), Sm (5)) and [ON](3)Ln[N(TMS)(2)](THF)}(2) [Ln = La (6), Nd (7), Sm (8)), respectively, in high isolated yields. These complexes have been fully characterized. X-ray structural determination revealed that complexes 1 and 2 have unsolvated centrosymmetric dimeric structures, in which one hydrogen atom belonging to the amino group of the ligand is reserved. Complexes 3-5 are isostructural and have an unsolvated dimeric structure. The coordination geometry around each of the lanthanide metal atoms can be described as a distorted trigonal bipyramid. Complexes 6 and 7 have a solvated dimeric structure, and the lanthanide metal centers have distorted capped trigonal-prismatic geometries. It was found that complexes 3-8 are highly efficient initiators for the ring-opening polymerization of L-lactide and rac-lactide, affording polymers with high molecular weights.
Tridentate Aryloxy‐Based Titanium Catalysts towards Ethylene Oligomerization and Polymerization
ligand parameters and influence the ligand coordination mode and the formation of stable titanium complexes. This series of titanium complexes were evaluated in ethyleneoligomerization and polymerization after activation with methylaluminoxane (MAO) and showed the preferential formation of polyethylene. In some cases, the formation of a small amount of 1-hexene suggests the existence of several catalytic
Rare‐earth metal derivatives supported by aminophenoxy ligand: Synthesis, characterization and catalytic performance in lactide polymerization
作者:Min Li、Jie Zhang、Jue Chen、Yingming Yao、Yunjie Luo
DOI:10.1002/aoc.5296
日期:2020.1
corresponding aminophenoxy rare‐earth metal derivatives [ON](μ‐OAr)Ln(μ‐OAr)Na(THF)2}2 (Ln = Yb (7), Y (8)) and [ON]Ln[(iPrN)2CN(SiMe3)2]}2 (Ln = Yb (9), Y (10)), respectively. These complexes were fully characterized, and their molecular structures were determined using single‐crystal X‐ray diffraction. Polymerization experiments showed that complexes 1, 2, 5, 6, 9 and 10 were highly active for the ring‐opening